// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#nullable disable

using System.Collections;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms.Layout;
using System.Windows.Forms.VisualStyles;
using Microsoft.Win32;
using static Interop;

namespace System.Windows.Forms
{
    public partial class DataGridView
    {
        protected virtual void AccessibilityNotifyCurrentCellChanged(Point cellAddress)
        {
            if (cellAddress.X < 0 || cellAddress.X >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(cellAddress));
            }

            if (cellAddress.Y < 0 || cellAddress.Y >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(cellAddress));
            }

            int visibleRowIndex = Rows.GetRowCount(DataGridViewElementStates.Visible, 0, cellAddress.Y);
            int visibleColumnIndex = Columns.ColumnIndexToActualDisplayIndex(cellAddress.X, DataGridViewElementStates.Visible);

            int topHeaderRowIncrement = ColumnHeadersVisible ? 1 : 0;
            int rowHeaderIncrement = RowHeadersVisible ? 1 : 0;

            int objectID = visibleRowIndex + topHeaderRowIncrement  // + 1 because the top header row acc obj is at index 0
                                           + 1;                     // + 1 because objectID's need to be positive and non-zero

            int childID = visibleColumnIndex + rowHeaderIncrement;  // + 1 because the column header cell is at index 0 in top header row acc obj
                                                                    //     same thing for the row header cell in the data grid view row acc obj

            if (ContainsFocus)
            {
                AccessibilityNotifyClients(AccessibleEvents.Focus, objectID, childID);

                CurrentCell?.AccessibilityObject.SetFocus();
            }
            AccessibilityNotifyClients(AccessibleEvents.Selection, objectID, childID);
        }

        internal void ActivateToolTip(bool activate, string toolTipText, int columnIndex, int rowIndex)
        {
            ToolTipPrivate = toolTipText;
            _ptToolTipCell = new Point(columnIndex, rowIndex);
            _toolTipControl.Activate(activate);
        }

        internal void AddNewRow(bool createdByEditing)
        {
            Debug.Assert(NewRowIndex == -1);

            Rows.AddInternal(true /*newRow*/, null /*values*/);
            NewRowIndex = Rows.Count - 1;
            _dataGridViewState1[State1_NewRowCreatedByEditing] = createdByEditing;

            if (createdByEditing)
            {
                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs(Rows[NewRowIndex]);
                OnUserAddedRow(dgvre);
            }
        }

        [EditorBrowsable(EditorBrowsableState.Advanced)]
        public virtual DataGridViewAdvancedBorderStyle AdjustColumnHeaderBorderStyle(DataGridViewAdvancedBorderStyle dataGridViewAdvancedBorderStyleInput,
                                                                         DataGridViewAdvancedBorderStyle dataGridViewAdvancedBorderStylePlaceholder,
                                                                         bool isFirstDisplayedColumn,
                                                                         bool isLastVisibleColumn)
        {
            if (ApplyVisualStylesToHeaderCells)
            {
                switch (dataGridViewAdvancedBorderStyleInput.All)
                {
                    case DataGridViewAdvancedCellBorderStyle.OutsetPartial:
                    case DataGridViewAdvancedCellBorderStyle.OutsetDouble:
                        if (RightToLeftInternal)
                        {
                            dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.None;
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.None : DataGridViewAdvancedCellBorderStyle.Outset;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.None;
                            }
                        }
                        else
                        {
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.None : DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.None;
                            }
                            dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.None;
                        }
                        dataGridViewAdvancedBorderStylePlaceholder.TopInternal = DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                        dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = DataGridViewAdvancedCellBorderStyle.Outset;
                        return dataGridViewAdvancedBorderStylePlaceholder;

                    case DataGridViewAdvancedCellBorderStyle.InsetDouble:
                        if (RightToLeftInternal)
                        {
                            dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.None;
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.None : DataGridViewAdvancedCellBorderStyle.Inset;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.None;
                            }
                        }
                        else
                        {
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.None : DataGridViewAdvancedCellBorderStyle.InsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.None;
                            }
                            dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.None;
                        }
                        dataGridViewAdvancedBorderStylePlaceholder.TopInternal = DataGridViewAdvancedCellBorderStyle.InsetDouble;
                        dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = DataGridViewAdvancedCellBorderStyle.Inset;
                        return dataGridViewAdvancedBorderStylePlaceholder;

                    case DataGridViewAdvancedCellBorderStyle.Single:
                    case DataGridViewAdvancedCellBorderStyle.Outset:
                    case DataGridViewAdvancedCellBorderStyle.Inset:
                        if (!isFirstDisplayedColumn || RowHeadersVisible)
                        {
                            dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.None;
                            dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.None;
                            dataGridViewAdvancedBorderStylePlaceholder.TopInternal = dataGridViewAdvancedBorderStyleInput.All;
                            dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = dataGridViewAdvancedBorderStyleInput.All;
                            return dataGridViewAdvancedBorderStylePlaceholder;
                        }
                        else
                        {
                            // isFirstDisplayedColumn == true && this.RowHeadersVisible == false
                            if (RightToLeftInternal)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.None;
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = dataGridViewAdvancedBorderStyleInput.All;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = dataGridViewAdvancedBorderStyleInput.All;
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.None;
                            }
                            dataGridViewAdvancedBorderStylePlaceholder.TopInternal = dataGridViewAdvancedBorderStyleInput.All;
                            dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = dataGridViewAdvancedBorderStyleInput.All;
                            return dataGridViewAdvancedBorderStylePlaceholder;
                        }
                }
            }
            else
            {
                switch (dataGridViewAdvancedBorderStyleInput.All)
                {
                    case DataGridViewAdvancedCellBorderStyle.OutsetPartial:
                        if (RightToLeftInternal)
                        {
                            dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = isLastVisibleColumn ? DataGridViewAdvancedCellBorderStyle.Outset : DataGridViewAdvancedCellBorderStyle.OutsetPartial;
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.Outset : DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.OutsetPartial;
                            }
                        }
                        else
                        {
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.Outset : DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.OutsetPartial;
                            }
                            dataGridViewAdvancedBorderStylePlaceholder.RightInternal = isLastVisibleColumn ? DataGridViewAdvancedCellBorderStyle.Outset : DataGridViewAdvancedCellBorderStyle.OutsetPartial;
                        }
                        dataGridViewAdvancedBorderStylePlaceholder.TopInternal = DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                        dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = DataGridViewAdvancedCellBorderStyle.Outset;
                        return dataGridViewAdvancedBorderStylePlaceholder;

                    case DataGridViewAdvancedCellBorderStyle.OutsetDouble:
                        if (RightToLeftInternal)
                        {
                            dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.Outset;
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.Outset : DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.Outset;
                            }
                        }
                        else
                        {
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.Outset : DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.Outset;
                            }
                            dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.Outset;
                        }
                        dataGridViewAdvancedBorderStylePlaceholder.TopInternal = DataGridViewAdvancedCellBorderStyle.OutsetDouble;
                        dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = DataGridViewAdvancedCellBorderStyle.Outset;
                        return dataGridViewAdvancedBorderStylePlaceholder;

                    case DataGridViewAdvancedCellBorderStyle.InsetDouble:
                        if (RightToLeftInternal)
                        {
                            dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.Inset;
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.Inset : DataGridViewAdvancedCellBorderStyle.InsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.Inset;
                            }
                        }
                        else
                        {
                            if (isFirstDisplayedColumn)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = RowHeadersVisible ? DataGridViewAdvancedCellBorderStyle.Inset : DataGridViewAdvancedCellBorderStyle.InsetDouble;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.Inset;
                            }
                            dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.Inset;
                        }
                        dataGridViewAdvancedBorderStylePlaceholder.TopInternal = DataGridViewAdvancedCellBorderStyle.InsetDouble;
                        dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = DataGridViewAdvancedCellBorderStyle.Inset;
                        return dataGridViewAdvancedBorderStylePlaceholder;

                    case DataGridViewAdvancedCellBorderStyle.Single:
                        if (!isFirstDisplayedColumn || RowHeadersVisible)
                        {
                            if (RightToLeftInternal)
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.Single;
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.None;
                            }
                            else
                            {
                                dataGridViewAdvancedBorderStylePlaceholder.LeftInternal = DataGridViewAdvancedCellBorderStyle.None;
                                dataGridViewAdvancedBorderStylePlaceholder.RightInternal = DataGridViewAdvancedCellBorderStyle.Single;
                            }
                            dataGridViewAdvancedBorderStylePlaceholder.TopInternal = DataGridViewAdvancedCellBorderStyle.Single;
                            dataGridViewAdvancedBorderStylePlaceholder.BottomInternal = DataGridViewAdvancedCellBorderStyle.Single;
                            return dataGridViewAdvancedBorderStylePlaceholder;
                        }
                        break;
                }
            }

            return dataGridViewAdvancedBorderStyleInput;
        }

        private bool AdjustExpandingColumn(DataGridViewColumn dataGridViewColumn, int rowIndex)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(rowIndex > -1);
            Debug.Assert(rowIndex < Rows.Count);

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return false;
            }

            bool ret = false; // No autosizing occurs by default.
            try
            {
                _noAutoSizeCount++;
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                int preferredThickness = dataGridViewRow.Cells[dataGridViewColumn.Index].GetPreferredWidth(rowIndex, dataGridViewRow.GetHeight(rowIndex));
                if (preferredThickness > DataGridViewBand.MaxBandThickness)
                {
                    preferredThickness = DataGridViewBand.MaxBandThickness;
                }
                if (dataGridViewColumn.Width < preferredThickness)
                {
                    // Column needs to be expanded
                    dataGridViewColumn.ThicknessInternal = preferredThickness;
                    ret = true;
                }
            }
            finally
            {
                Debug.Assert(_noAutoSizeCount > 0);
                _noAutoSizeCount--;
            }

            return ret;
        }

        private bool AdjustExpandingColumns(DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter, int rowIndex)
        {
            Debug.Assert(autoSizeColumnCriteriaFilter != DataGridViewAutoSizeColumnCriteriaInternal.None);
            Debug.Assert((autoSizeColumnCriteriaFilter & DataGridViewAutoSizeColumnCriteriaInternal.Fill) == 0);

            bool ret = false; // No column autosizes by default
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            while (dataGridViewColumn != null)
            {
                DataGridViewAutoSizeColumnCriteriaInternal inheritedAutoSizeColumnCriteria = (DataGridViewAutoSizeColumnCriteriaInternal)dataGridViewColumn.InheritedAutoSizeMode;
                DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFiltered = (inheritedAutoSizeColumnCriteria & autoSizeColumnCriteriaFilter);
                if (autoSizeColumnCriteriaFiltered != 0)
                {
                    ret |= AdjustExpandingColumn(dataGridViewColumn, rowIndex);
                }
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
            }
            return ret;
        }

        private int AdjustExpandingRow(int rowIndex, int columnIndex, bool fixedWidth)
        {
            Debug.Assert(columnIndex >= -1 && columnIndex < Columns.Count);
            Debug.Assert(rowIndex >= 0 && rowIndex < Rows.Count);
            Debug.Assert(_autoSizeRowsMode == DataGridViewAutoSizeRowsMode.DisplayedHeaders ||
                         _autoSizeRowsMode == DataGridViewAutoSizeRowsMode.DisplayedCellsExceptHeaders ||
                         _autoSizeRowsMode == DataGridViewAutoSizeRowsMode.DisplayedCells);

            // Use of WindowsFormsUtils.CreateMeasurementGraphics() avoid use of this.Handle
            // IntPtr handle = this.Handle; // Force creation of control's handle because for databound grids, handle creation wipes out and recreates the columns/rows.
            int width = 0;
            DataGridViewCell dataGridViewCell;
            if (columnIndex > -1 && (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
            {
                dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                if (fixedWidth)
                {
                    width = Columns[columnIndex].Thickness;
                }
            }
            else
            {
                Debug.Assert(columnIndex == -1);
                Debug.Assert((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.Header) != 0);
                dataGridViewCell = Rows.SharedRow(rowIndex).HeaderCell;
                if (fixedWidth)
                {
                    Debug.Assert(RowHeadersWidth > 0);
                    Debug.Assert(RowHeadersVisible);
                    width = RowHeadersWidth;
                }
            }
            int preferredThickness;
            if (fixedWidth)
            {
                preferredThickness = dataGridViewCell.GetPreferredHeight(rowIndex, width);
            }
            else
            {
                preferredThickness = dataGridViewCell.GetPreferredSize(rowIndex).Height;
            }
            Rows.SharedRow(rowIndex).GetHeightInfo(rowIndex, out int height, out int minimumHeight);
            if (preferredThickness < height)
            {
                preferredThickness = height;
            }
            Debug.Assert(preferredThickness >= minimumHeight);
            if (preferredThickness > DataGridViewBand.MaxBandThickness)
            {
                preferredThickness = DataGridViewBand.MaxBandThickness;
            }
            if (height != preferredThickness)
            {
                Debug.Assert(_autoSizeRowsMode != DataGridViewAutoSizeRowsMode.None);
                Rows[rowIndex].Thickness = preferredThickness;   // unsharing the resized row
            }
            return preferredThickness;
        }

        private void AdjustExpandingRows(int columnIndex, bool fixedWidth)
        {
            if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0 ||
                ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.Header) != 0 && RowHeadersVisible))
            {
                if (!IsHandleCreated)
                {
                    // auto sizing causes handle creation.
                    // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                    _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                    return;
                }

                // Very expensive processing - the developer should avoid this scenario.
                // Switch to batch operation
                _inBulkPaintCount++;
                try
                {
                    if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllRows) != 0)
                    {
                        _inBulkLayoutCount++;
                        try
                        {
                            for (int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                rowIndex != -1;
                                rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                            {
                                int width = 0;
                                DataGridViewCell dataGridViewCell;
                                if (columnIndex > -1 && (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
                                {
                                    dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                                    if (fixedWidth)
                                    {
                                        width = Columns[columnIndex].Thickness;
                                    }
                                }
                                else
                                {
                                    Debug.Assert((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.Header) != 0);
                                    dataGridViewCell = Rows.SharedRow(rowIndex).HeaderCell;
                                    if (fixedWidth)
                                    {
                                        Debug.Assert(RowHeadersWidth > 0);
                                        Debug.Assert(RowHeadersVisible);
                                        width = RowHeadersWidth;
                                    }
                                }
                                int preferredHeight;
                                if (fixedWidth)
                                {
                                    preferredHeight = dataGridViewCell.GetPreferredHeight(rowIndex, width);
                                }
                                else
                                {
                                    preferredHeight = dataGridViewCell.GetPreferredSize(rowIndex).Height;
                                }
                                if (Rows.SharedRow(rowIndex).Height < preferredHeight)
                                {
                                    Rows[rowIndex].Height = preferredHeight;  // unsharing the row to be resized
                                }
                            }
                        }
                        finally
                        {
                            ExitBulkLayout(false /*invalidInAdjustFillingColumns*/);
                        }
                    }
                    else
                    {
                        Debug.Assert((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.DisplayedRows) != 0);
                        int displayHeight = _layout.Data.Height;
                        int cy = 0;

                        int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                        while (rowIndex != -1 && cy < displayHeight)
                        {
                            cy += AdjustExpandingRow(rowIndex, columnIndex, fixedWidth);
                            rowIndex = Rows.GetNextRow(rowIndex,
                                DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                        }

                        if (cy < displayHeight)
                        {
                            rowIndex = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                            while (rowIndex != -1 && cy < displayHeight)
                            {
                                cy += AdjustExpandingRow(rowIndex, columnIndex, fixedWidth);
                                rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                            }
                        }
                    }
                }
                finally
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        internal void AdjustFillingColumn(DataGridViewColumn dataGridViewColumn, int width)
        {
            if (InAdjustFillingColumns)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAlterAutoFillColumnParameter);
            }

            _dataGridViewOper[OperationInAdjustFillingColumn] = true;

            try
            {
                Debug.Assert(dataGridViewColumn != null);
                Debug.Assert(dataGridViewColumn.Visible);
                Debug.Assert(!dataGridViewColumn.Frozen);
                Debug.Assert(dataGridViewColumn.MinimumWidth <= width);
                Debug.Assert(dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill);
                Debug.Assert(!_layout._dirty);

                if (Columns.GetColumnsWidth(DataGridViewElementStates.Visible) > _layout.Data.Width)
                {
                    // Columns are scrolling - this means that all columns have reached their minimum width.
                    // Do not affect their width or fill weight
                    Debug.Assert(dataGridViewColumn.MinimumWidth == dataGridViewColumn.Width);
                    return;
                }

                int availableWidth = _layout.Data.Width;  // Width available for auto-filled columns

                // Check if the column is the first or last visible scrolling column
                if (DesignMode ||
                    dataGridViewColumn == Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen) ||
                    dataGridViewColumn == Columns.GetLastColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen))
                {
                    // Changing the width is equivalent to adjusting the FillWeight when:
                    //  - the column is not scrolling and is the first non-frozen visible column
                    //  - the column is not scrolling and is the last non-frozen visible column

                    float weightSum = 0;        // Weights of all auto filled visible columns.
                    int widthSum = 0;           // Sum of widths of visible auto filled columns.
                    int imposedWidthSum = 0;    // Minimum width required for all other columns.
                    bool otherFillingColumnExists = false;
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Visible)
                        {
                            if (dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                            {
                                Debug.Assert(!dataGridViewColumnTmp.Frozen);
                                widthSum += dataGridViewColumnTmp.Width;
                                if (dataGridViewColumnTmp.Index != dataGridViewColumn.Index)
                                {
                                    imposedWidthSum += dataGridViewColumnTmp.MinimumWidth;
                                    otherFillingColumnExists = true;
                                }
                                weightSum += dataGridViewColumnTmp.FillWeight;
                            }
                            else
                            {
                                imposedWidthSum += dataGridViewColumnTmp.Width;
                                availableWidth -= dataGridViewColumnTmp.Width;
                            }
                        }
                    }

                    if (!otherFillingColumnExists)
                    {
                        // The resized column is the only one that is filling. This is a no-op operation.
                        // Neither the width nor the fill weight can change
                        return;
                    }

                    int maximumPossibleWidth = _layout.Data.Width - imposedWidthSum;
                    if (width > maximumPossibleWidth)
                    {
                        width = maximumPossibleWidth;
                    }

                    // Determine fill weight equivalent to 'width'
                    float oldWeight = dataGridViewColumn.FillWeight;
                    float newWeight = (float)(width * weightSum) / (float)widthSum;
                    bool desiredWidthTooSmall = false;
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Index != dataGridViewColumn.Index &&
                            dataGridViewColumnTmp.Visible &&
                            dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                        {
                            dataGridViewColumnTmp.FillWeightInternal = (weightSum - newWeight) * dataGridViewColumnTmp.FillWeight / (weightSum - oldWeight);

                            if (dataGridViewColumnTmp.FillWeight < (dataGridViewColumnTmp.MinimumWidth * weightSum) / (float)widthSum)
                            {
                                desiredWidthTooSmall = true;
                                dataGridViewColumnTmp.DesiredFillWidth = -1;
                            }
                            else
                            {
                                dataGridViewColumnTmp.DesiredFillWidth = 0;
                            }
                        }
                    }

                    dataGridViewColumn.FillWeightInternal = newWeight;

                    if (desiredWidthTooSmall)
                    {
                        // At least one column hits its minimum width
                        // Adjust UsedFillWeight values are adjusted FillWeight values
                        float usedWeightSumNoneMinimal = weightSum;
                        float weightSumNoneMinimal = weightSum;
                        float usedFillWeights = 0F;
                        foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                        {
                            if (dataGridViewColumnTmp.Visible &&
                                dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                            {
                                if (dataGridViewColumnTmp.Index == dataGridViewColumn.Index)
                                {
                                    dataGridViewColumnTmp.UsedFillWeight = dataGridViewColumnTmp.FillWeight;
                                    usedWeightSumNoneMinimal -= dataGridViewColumnTmp.UsedFillWeight;
                                    weightSumNoneMinimal -= dataGridViewColumnTmp.FillWeight;
                                    usedFillWeights += dataGridViewColumnTmp.UsedFillWeight;
                                }
                                else if (dataGridViewColumnTmp.DesiredFillWidth == -1)
                                {
                                    dataGridViewColumnTmp.UsedFillWeight = weightSum * dataGridViewColumnTmp.MinimumWidth / widthSum;
                                    usedWeightSumNoneMinimal -= dataGridViewColumnTmp.UsedFillWeight;
                                    weightSumNoneMinimal -= dataGridViewColumnTmp.FillWeight;
                                    usedFillWeights += dataGridViewColumnTmp.UsedFillWeight;
                                }
                            }
                        }
                        foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                        {
                            if (dataGridViewColumnTmp.Index != dataGridViewColumn.Index &&
                                dataGridViewColumnTmp.Visible &&
                                dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill &&
                                dataGridViewColumnTmp.DesiredFillWidth != -1)
                            {
                                dataGridViewColumnTmp.UsedFillWeight = Math.Max(dataGridViewColumnTmp.FillWeight * usedWeightSumNoneMinimal / weightSumNoneMinimal,
                                                                                weightSum * dataGridViewColumnTmp.MinimumWidth / widthSum);
                                usedFillWeights += dataGridViewColumnTmp.UsedFillWeight;
                            }
                        }
                        dataGridViewColumn.UsedFillWeight += weightSum - usedFillWeights;
                    }
                    else
                    {
                        // No column hits its minimum width
                        // Each UsedFillWeight simply equals the FillWeight
                        foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                        {
                            if (dataGridViewColumnTmp.Visible &&
                                dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                            {
                                dataGridViewColumnTmp.UsedFillWeight = dataGridViewColumnTmp.FillWeight;
                            }
                        }
                    }
#if DEBUG
                    float weightSumDbg = 0F;
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Visible &&
                            dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                        {
                            weightSumDbg += dataGridViewColumnTmp.UsedFillWeight;
                        }
                    }
                    Debug.Assert(Math.Abs(weightSum - weightSumDbg) < 1.0F);
#endif
                }
                else
                {
                    // This column is not the first nor the last visible non-frozen column
                    // Changing its width only affects the width and weight of the columns displayed after it

                    // First figure out the maximum possible width
                    int imposedWidthSum = 0;    // Minimum width required for all other columns
                    float weightSum = 0;        // Weights of all auto filled visible columns.
                    float oldWeightSum = 0F;    // Fill weights of the columns displayed after this resized column
                    bool otherFillingColumnExists = false;
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Visible)
                        {
                            if (dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                            {
                                Debug.Assert(!dataGridViewColumnTmp.Frozen);
                                if (dataGridViewColumnTmp.Index != dataGridViewColumn.Index)
                                {
                                    if (Columns.DisplayInOrder(dataGridViewColumn.Index, dataGridViewColumnTmp.Index))
                                    {
                                        imposedWidthSum += dataGridViewColumnTmp.MinimumWidth;   // Column is allowed to shrink down to its minimum
                                        oldWeightSum += dataGridViewColumnTmp.FillWeight;
                                    }
                                    else
                                    {
                                        // Column is displayed before 'dataGridViewColumn', it is not allowed to shrink at all
                                        imposedWidthSum += dataGridViewColumnTmp.Width;
                                    }
                                    otherFillingColumnExists = true;
                                }
                                weightSum += dataGridViewColumnTmp.FillWeight;
                            }
                            else
                            {
                                imposedWidthSum += dataGridViewColumnTmp.Width;
                                availableWidth -= dataGridViewColumnTmp.Width;
                            }
                        }
                    }

                    if (!otherFillingColumnExists)
                    {
                        // The resized column is the only one that is filling. This is a no-op operation.
                        // Neither the width nor the fill weight can change
                        return;
                    }

                    int maximumPossibleWidth = _layout.Data.Width - imposedWidthSum;
                    if (width > maximumPossibleWidth)
                    {
                        width = maximumPossibleWidth;
                    }

                    // Then figure out the target fill weights
                    float oldWeight = dataGridViewColumn.FillWeight;
                    float newWeight = weightSum * width / availableWidth;
                    float newWeightSum = oldWeightSum + oldWeight - newWeight;
                    Debug.Assert(newWeightSum > 0);
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Index != dataGridViewColumn.Index &&
                            dataGridViewColumnTmp.Visible &&
                            dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill &&
                            Columns.DisplayInOrder(dataGridViewColumn.Index, dataGridViewColumnTmp.Index))
                        {
                            dataGridViewColumnTmp.FillWeightInternal = dataGridViewColumnTmp.FillWeight * newWeightSum / oldWeightSum;
                        }
                    }

                    dataGridViewColumn.FillWeightInternal = newWeight;

                    bool desiredWidthTooSmall = false;
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Visible &&
                            dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                        {
                            if (dataGridViewColumnTmp.FillWeight < (dataGridViewColumnTmp.MinimumWidth * weightSum) / (float)availableWidth)
                            {
                                desiredWidthTooSmall = true;
                                dataGridViewColumnTmp.DesiredFillWidth = -1;
                            }
                            else
                            {
                                dataGridViewColumnTmp.DesiredFillWidth = 0;
                            }
                        }
                    }

                    if (desiredWidthTooSmall)
                    {
                        // At least one column hits its minimum width
                        // Adjust UsedFillWeight values are adjusted FillWeight values
                        float usedWeightSumNoneMinimal = weightSum;
                        float weightSumNoneMinimal = weightSum;
                        float usedFillWeights = 0F;
                        foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                        {
                            if (dataGridViewColumnTmp.Visible &&
                                dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                            {
                                if (dataGridViewColumnTmp.Index == dataGridViewColumn.Index ||
                                    Columns.DisplayInOrder(dataGridViewColumnTmp.Index, dataGridViewColumn.Index))
                                {
                                    if (dataGridViewColumnTmp.Index == dataGridViewColumn.Index)
                                    {
                                        dataGridViewColumnTmp.UsedFillWeight = dataGridViewColumnTmp.FillWeight;
                                    }
                                    else
                                    {
                                        dataGridViewColumnTmp.UsedFillWeight = weightSum * dataGridViewColumnTmp.Width / availableWidth;
                                    }
                                    usedWeightSumNoneMinimal -= dataGridViewColumnTmp.UsedFillWeight;
                                    weightSumNoneMinimal -= dataGridViewColumnTmp.FillWeight;
                                    usedFillWeights += dataGridViewColumnTmp.UsedFillWeight;
                                }
                                else if (dataGridViewColumnTmp.DesiredFillWidth == -1)
                                {
                                    dataGridViewColumnTmp.UsedFillWeight = weightSum * dataGridViewColumnTmp.MinimumWidth / availableWidth;
                                    usedWeightSumNoneMinimal -= dataGridViewColumnTmp.UsedFillWeight;
                                    weightSumNoneMinimal -= dataGridViewColumnTmp.FillWeight;
                                    usedFillWeights += dataGridViewColumnTmp.UsedFillWeight;
                                }
                            }
                        }
                        foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                        {
                            if (Columns.DisplayInOrder(dataGridViewColumn.Index, dataGridViewColumnTmp.Index) &&
                                dataGridViewColumnTmp.Visible &&
                                dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill &&
                                dataGridViewColumnTmp.DesiredFillWidth != -1)
                            {
                                dataGridViewColumnTmp.UsedFillWeight = Math.Max(dataGridViewColumnTmp.FillWeight * usedWeightSumNoneMinimal / weightSumNoneMinimal,
                                                                                weightSum * dataGridViewColumnTmp.MinimumWidth / availableWidth);
                                usedFillWeights += dataGridViewColumnTmp.UsedFillWeight;
                            }
                        }
                        dataGridViewColumn.UsedFillWeight += weightSum - usedFillWeights;
                    }
                    else
                    {
                        // No column hits its minimum width
                        // Each UsedFillWeight simply equals the FillWeight
                        foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                        {
                            if (dataGridViewColumnTmp.Visible &&
                                dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                            {
                                dataGridViewColumnTmp.UsedFillWeight = dataGridViewColumnTmp.FillWeight;
                            }
                        }
                    }
#if DEBUG
                    float weightSumDbg = 0F;
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Visible &&
                            dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                        {
                            weightSumDbg += dataGridViewColumnTmp.UsedFillWeight;
                        }
                    }
                    Debug.Assert(Math.Abs(weightSum - weightSumDbg) < 1.0F);
#endif
                }

                // UsedFillWeight properties are up-to-date
                _dataGridViewState2[State2_UsedFillWeightsDirty] = false;
                _availableWidthForFillColumns = availableWidth;
                // AdjustFillingColumns() will resize columns based on the UsedFillWeight values
                PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            }
            finally
            {
                _dataGridViewOper[OperationInAdjustFillingColumn] = false;
            }
        }

        private bool AdjustFillingColumns()
        {
            if (_dataGridViewOper[OperationInAdjustFillingColumns])
            {
                // No need to auto fill columns while we're already doing it.
                return false;
            }

            _dataGridViewOper[OperationInAdjustFillingColumns] = true;

            bool columnsAdjusted = false;
            try
            {
                // Determine free space for filling columns.
                int numVisibleFillColumns = 0;  // number of visible columns that are auto filled.
                int imposedWidthSum = 0;        // total width of columns that don't have a flexible width.
                int requiredWidthSum = 0;       // total of the minimum widths of the visible auto filled columns.
                float weightSum = 0F;           // total of the weights of the visible auto filled columns.
                ArrayList autoFillColumns = null;
                foreach (DataGridViewColumn dataGridViewColumn in Columns)
                {
                    if (dataGridViewColumn.Visible)
                    {
                        if (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                        {
                            Debug.Assert(!dataGridViewColumn.Frozen);
                            numVisibleFillColumns++;
                            requiredWidthSum += dataGridViewColumn.DesiredMinimumWidth > 0 ? dataGridViewColumn.DesiredMinimumWidth : dataGridViewColumn.MinimumWidth;
                            weightSum += dataGridViewColumn.FillWeight;
                            if (autoFillColumns is null)
                            {
                                autoFillColumns = new ArrayList(Columns.Count);
                            }
                            autoFillColumns.Add(dataGridViewColumn);
                        }
                        else
                        {
                            imposedWidthSum += dataGridViewColumn.Width;
                        }
                    }
                }

                if (numVisibleFillColumns > 0)
                {
                    // Assuming no vertical scrollbar has been accounted for yet
                    Debug.Assert(_layout.Data.Width == _layout.Inside.Width - _layout.RowHeaders.Width - (SingleVerticalBorderAdded ? 1 : 0));
                    int availableWidth = _layout.Data.Width - imposedWidthSum;
                    if ((_scrollBars == ScrollBars.Both || _scrollBars == ScrollBars.Vertical))
                    {
                        int totalVisibleRowCount = Rows.GetRowCount(DataGridViewElementStates.Visible);
                        int totalVisibleHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible);
                        int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);

                        // Assuming there is no horizontal scrollbar, is a vertical scrollbar required?
                        ComputeVisibleRows(); // Make sure this.DisplayedBandsInfo.FirstDisplayedScrollingRow and other row count info variables have been set

                        if (DisplayedBandsInfo.NumTotallyDisplayedFrozenRows == Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) &&
                            DisplayedBandsInfo.NumTotallyDisplayedScrollingRows != totalVisibleRowCount - Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) &&
                            (totalVisibleHeight - totalVisibleFrozenHeight != ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight)) &&
                            _layout.Data.Height > totalVisibleFrozenHeight &&
                            SystemInformation.VerticalScrollBarWidth <= _layout.Data.Width)
                        {
                            // Vertical scrollbar is required, even when there is not horizontal one.
                            availableWidth -= SystemInformation.VerticalScrollBarWidth;
                        }
                    }

                    int columnEntry;

                    if (availableWidth <= requiredWidthSum)
                    {
                        // All auto filled columns need to take their minimum width. If (availableWidth < requiredWidthSum) a horizontal scrollbar appears.
                        availableWidth = 0;
                        for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                        {
                            DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                            int minimumWidth = dataGridViewColumn.DesiredMinimumWidth > 0 ? dataGridViewColumn.DesiredMinimumWidth : dataGridViewColumn.MinimumWidth;
                            if (dataGridViewColumn.Thickness != minimumWidth)
                            {
                                columnsAdjusted = true;
                                dataGridViewColumn.ThicknessInternal = minimumWidth;
                            }
                            availableWidth += dataGridViewColumn.Thickness;
                        }
                        //if (this.dataGridViewState2[State2_UsedFillWeightsDirty])
                        {
                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                            {
                                // Make sure the UsedFillWeight correspond to the actual column width
                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                dataGridViewColumn.UsedFillWeight = dataGridViewColumn.Width * weightSum / availableWidth;
                            }
                            _dataGridViewState2[State2_UsedFillWeightsDirty] = false;
                            _availableWidthForFillColumns = availableWidth;
                        }
                        return columnsAdjusted;
                    }

                    // Auto filling columns can share some real estate.

                    int usedWidth = 0;

                    // Update the UsedFillWeight value if dirty
                    if (_dataGridViewState2[State2_UsedFillWeightsDirty])
                    {
                        // Assign desired widths
                        Debug.Assert(weightSum > 0);
                        bool desiredWidthTooSmall = false;
                        for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                        {
                            DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                            if (columnEntry == autoFillColumns.Count - 1)
                            {
                                dataGridViewColumn.DesiredFillWidth = availableWidth - usedWidth;
                            }
                            else
                            {
                                float desiredFillWidth = (dataGridViewColumn.FillWeight / weightSum) * availableWidth;
                                dataGridViewColumn.DesiredFillWidth = (int)Math.Round(desiredFillWidth, MidpointRounding.AwayFromZero);
                                usedWidth += dataGridViewColumn.DesiredFillWidth;
                            }
                            int minimumWidth = dataGridViewColumn.DesiredMinimumWidth > 0 ? dataGridViewColumn.DesiredMinimumWidth : dataGridViewColumn.MinimumWidth;
                            if (dataGridViewColumn.DesiredFillWidth < minimumWidth)
                            {
                                desiredWidthTooSmall = true;
                                dataGridViewColumn.DesiredFillWidth = -1;
                            }
                        }

                        if (desiredWidthTooSmall)
                        {
                            // At least one column hits its minimum width
                            // Adjust UsedFillWeight values are adjusted FillWeight values
                            float usedWeightSumNoneMinimal = weightSum;
                            float weightSumNoneMinimal = weightSum;
                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                            {
                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                if (dataGridViewColumn.DesiredFillWidth == -1)
                                {
                                    int minimumWidth = dataGridViewColumn.DesiredMinimumWidth > 0 ? dataGridViewColumn.DesiredMinimumWidth : dataGridViewColumn.MinimumWidth;
                                    dataGridViewColumn.UsedFillWeight = weightSum * minimumWidth / availableWidth;
                                    usedWeightSumNoneMinimal -= dataGridViewColumn.UsedFillWeight;
                                    weightSumNoneMinimal -= dataGridViewColumn.FillWeight;
                                }
                            }
                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                            {
                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                if (dataGridViewColumn.DesiredFillWidth != -1)
                                {
                                    dataGridViewColumn.UsedFillWeight = dataGridViewColumn.FillWeight * usedWeightSumNoneMinimal / weightSumNoneMinimal;
                                }
                            }
                        }
                        else
                        {
                            // No column hits its minimum width
                            // Each UsedFillWeight simply equals the FillWeight
                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                            {
                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                dataGridViewColumn.UsedFillWeight = dataGridViewColumn.FillWeight;
                            }
                        }

                        _dataGridViewState2[State2_UsedFillWeightsDirty] = false;
                        _availableWidthForFillColumns = availableWidth;
                    }
                    else if (availableWidth != _availableWidthForFillColumns)
                    {
                        // The available width for auto-filled columns has changed - UsedFillWeight values need to be adjusted.
                        if (availableWidth > _availableWidthForFillColumns)
                        {
                            // Available width increased
                            int widthGain = availableWidth - _availableWidthForFillColumns;
                            // Allocate additional width according to UsedFillWeight and FillWeight values
                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                            {
                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                dataGridViewColumn.DesiredFillWidth = dataGridViewColumn.Width;
                            }
                            float[] floatDesiredWidths = new float[autoFillColumns.Count];
                            for (int gain = 0; gain < widthGain; gain++)
                            {
                                float fillWeightRatioSum = 0F;
                                bool minimumColumnExists = false;
                                for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                                {
                                    DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                    fillWeightRatioSum += dataGridViewColumn.FillWeight / dataGridViewColumn.UsedFillWeight;
                                    if (dataGridViewColumn.DesiredFillWidth <= dataGridViewColumn.MinimumWidth)
                                    {
                                        minimumColumnExists = true;
                                    }
                                }
                                for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                                {
                                    DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                    if (gain == 0)
                                    {
                                        floatDesiredWidths[columnEntry] = _availableWidthForFillColumns * dataGridViewColumn.UsedFillWeight / weightSum;
                                    }
                                    if (minimumColumnExists)
                                    {
                                        floatDesiredWidths[columnEntry] += dataGridViewColumn.FillWeight / dataGridViewColumn.UsedFillWeight / fillWeightRatioSum;
                                    }
                                    else
                                    {
                                        floatDesiredWidths[columnEntry] += dataGridViewColumn.FillWeight / weightSum;
                                    }
                                }
                            }
                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                            {
                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                dataGridViewColumn.UsedFillWeight = weightSum / availableWidth * floatDesiredWidths[columnEntry];
                            }
                        }
                        else
                        {
                            // availableWidth < this.availableWidthForFillColumns - Available width decreased
                            int totalWidthLoss = _availableWidthForFillColumns - availableWidth;
                            int cumulatedWidthLoss = 0;
                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                            {
                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                dataGridViewColumn.DesiredFillWidth = dataGridViewColumn.Width;
                            }
                            // the width loss is accounted for in steps of 10%
                            do
                            {
                                int stepDownAvailableWidthForFillColumns = _availableWidthForFillColumns - cumulatedWidthLoss;
                                int widthLoss = Math.Min(stepDownAvailableWidthForFillColumns - availableWidth, Math.Max(1, (int)(stepDownAvailableWidthForFillColumns * 0.1F)));
                                cumulatedWidthLoss += widthLoss;
                                bool changeDone;
                                do
                                {
                                    changeDone = false;
                                    // Determine which column deserves to shrink the most
                                    float biggestWeightDeficiency = 0F, fillWeightRatioSum = 0F, fillWeightRatio;
                                    DataGridViewColumn mostDeservingDataGridViewColumn = null;
                                    for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                                    {
                                        DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                        if (dataGridViewColumn.DesiredFillWidth > dataGridViewColumn.MinimumWidth)
                                        {
                                            fillWeightRatio = dataGridViewColumn.UsedFillWeight / dataGridViewColumn.FillWeight;
                                            fillWeightRatioSum += fillWeightRatio;
                                            if (fillWeightRatio > biggestWeightDeficiency)
                                            {
                                                mostDeservingDataGridViewColumn = dataGridViewColumn;
                                                biggestWeightDeficiency = fillWeightRatio;
                                            }
                                        }
                                    }
                                    if (mostDeservingDataGridViewColumn != null)
                                    {
                                        float floatDesiredWidth = (stepDownAvailableWidthForFillColumns * mostDeservingDataGridViewColumn.UsedFillWeight / weightSum) - widthLoss * mostDeservingDataGridViewColumn.UsedFillWeight / mostDeservingDataGridViewColumn.FillWeight / fillWeightRatioSum;
                                        if (floatDesiredWidth < (float)mostDeservingDataGridViewColumn.MinimumWidth)
                                        {
                                            floatDesiredWidth = (int)mostDeservingDataGridViewColumn.MinimumWidth;
                                        }
                                        int oldDesiredWidth = mostDeservingDataGridViewColumn.DesiredFillWidth;
                                        mostDeservingDataGridViewColumn.DesiredFillWidth = Math.Min(oldDesiredWidth, (int)Math.Round(floatDesiredWidth, MidpointRounding.AwayFromZero));
                                        changeDone = (oldDesiredWidth != mostDeservingDataGridViewColumn.DesiredFillWidth);
                                        if (!changeDone && widthLoss == 1 && oldDesiredWidth > mostDeservingDataGridViewColumn.MinimumWidth)
                                        {
                                            mostDeservingDataGridViewColumn.DesiredFillWidth--;
                                            changeDone = true;
                                        }
                                        Debug.Assert(oldDesiredWidth >= mostDeservingDataGridViewColumn.DesiredFillWidth);
                                        widthLoss -= oldDesiredWidth - mostDeservingDataGridViewColumn.DesiredFillWidth;
                                        if (changeDone)
                                        {
                                            stepDownAvailableWidthForFillColumns -= oldDesiredWidth - mostDeservingDataGridViewColumn.DesiredFillWidth;
                                            for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                                            {
                                                DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                                dataGridViewColumn.UsedFillWeight = weightSum / stepDownAvailableWidthForFillColumns * dataGridViewColumn.DesiredFillWidth;
                                            }
                                        }
                                        Debug.Assert(widthLoss >= 0);
                                    }
                                }
                                while (changeDone && widthLoss > 0);
                            }
                            while (cumulatedWidthLoss < totalWidthLoss);
                        }
                        _availableWidthForFillColumns = availableWidth;
                    }

#if DEBUG
                    float weightSumDbg = 0F;
                    for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                    {
                        DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                        weightSumDbg += dataGridViewColumn.UsedFillWeight;
                    }
                    Debug.Assert(Math.Abs(weightSum - weightSumDbg) < 1.0F);
#endif

                    // Finally update the columns' width according the UsedFillWeight values.
                    try
                    {
                        _dataGridViewState2[State2_AllowHorizontalScrollbar] = false;
                        usedWidth = 0;
                        float carryover = 0F;
                        while (autoFillColumns.Count > 0)
                        {
                            DataGridViewColumn mostDeservingDataGridViewColumn = null;
                            if (autoFillColumns.Count == 1)
                            {
                                mostDeservingDataGridViewColumn = (DataGridViewColumn)autoFillColumns[0];
                                mostDeservingDataGridViewColumn.DesiredFillWidth = Math.Max(availableWidth - usedWidth, mostDeservingDataGridViewColumn.MinimumWidth);
                                autoFillColumns.Clear();
                            }
                            else
                            {
                                float biggestWeightDiscrepancy = 0F, weightDiscrepancy;
                                for (columnEntry = 0; columnEntry < autoFillColumns.Count; columnEntry++)
                                {
                                    DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)autoFillColumns[columnEntry];
                                    weightDiscrepancy = Math.Abs(dataGridViewColumn.UsedFillWeight - dataGridViewColumn.FillWeight) / dataGridViewColumn.FillWeight;
                                    if (weightDiscrepancy > biggestWeightDiscrepancy || mostDeservingDataGridViewColumn is null)
                                    {
                                        mostDeservingDataGridViewColumn = dataGridViewColumn;
                                        biggestWeightDiscrepancy = weightDiscrepancy;
                                    }
                                }
                                float floatDesiredWidth = (mostDeservingDataGridViewColumn.UsedFillWeight * availableWidth / weightSum) + carryover;
                                mostDeservingDataGridViewColumn.DesiredFillWidth = Math.Max(mostDeservingDataGridViewColumn.MinimumWidth, (int)Math.Round(floatDesiredWidth, MidpointRounding.AwayFromZero));
                                carryover = floatDesiredWidth - mostDeservingDataGridViewColumn.DesiredFillWidth;
                                usedWidth += mostDeservingDataGridViewColumn.DesiredFillWidth;
                                autoFillColumns.Remove(mostDeservingDataGridViewColumn);
                            }
                            if (mostDeservingDataGridViewColumn.DesiredFillWidth != mostDeservingDataGridViewColumn.Thickness)
                            {
                                columnsAdjusted = true;
                                mostDeservingDataGridViewColumn.ThicknessInternal = mostDeservingDataGridViewColumn.DesiredFillWidth;
                            }
                        }
                    }
                    finally
                    {
                        _dataGridViewState2[State2_AllowHorizontalScrollbar] = true;
                    }
                }
#if DEBUG
                if (!_dataGridViewState2[State2_UsedFillWeightsDirty])
                {
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumnTmp.Visible &&
                            dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                        {
                            Debug.Assert(Math.Abs(dataGridViewColumnTmp.UsedFillWeight * _availableWidthForFillColumns - weightSum * dataGridViewColumnTmp.Width) / weightSum / dataGridViewColumnTmp.Width <= 1.25F / dataGridViewColumnTmp.Width);
                        }
                    }
                }

                bool nonMinColumnExists = false;
                int widthSum = 0;
                foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                {
                    if (dataGridViewColumnTmp.Visible &&
                        dataGridViewColumnTmp.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                    {
                        widthSum += dataGridViewColumnTmp.Width;
                        if (dataGridViewColumnTmp.Width > dataGridViewColumnTmp.MinimumWidth)
                        {
                            nonMinColumnExists = true;
                        }
                    }
                }
                if (nonMinColumnExists)
                {
                    Debug.Assert(widthSum == _availableWidthForFillColumns);
                }
#endif
            }
            finally
            {
                _dataGridViewOper[OperationInAdjustFillingColumns] = false;
            }

            return columnsAdjusted;
        }

        private void AdjustShrinkingRows(DataGridViewAutoSizeRowsMode autoSizeRowsMode, bool fixedWidth, bool internalAutosizing)
        {
            if ((((DataGridViewAutoSizeRowsModeInternal)autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0 ||
                ((((DataGridViewAutoSizeRowsModeInternal)autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.Header) != 0 && RowHeadersVisible))
            {
                // Switch to batch operation
                _inBulkPaintCount++;
                try
                {
                    if ((((DataGridViewAutoSizeRowsModeInternal)autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllRows) != 0)
                    {
                        // Very expensive processing - the developer should avoid this scenario.
                        _inBulkLayoutCount++;
                        try
                        {
                            for (int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                rowIndex != -1;
                                rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                            {
                                AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(autoSizeRowsMode), fixedWidth, internalAutosizing);
                            }
                        }
                        finally
                        {
                            ExitBulkLayout(false /*invalidInAdjustFillingColumns*/);
                        }
                    }
                    else
                    {
                        Debug.Assert((((DataGridViewAutoSizeRowsModeInternal)autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.DisplayedRows) != 0);
                        int displayHeight = _layout.Data.Height;
                        int cy = 0;

                        int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                        while (rowIndex != -1 && cy < displayHeight)
                        {
                            AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(autoSizeRowsMode), fixedWidth, internalAutosizing);
                            cy += Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                            rowIndex = Rows.GetNextRow(rowIndex,
                                DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                        }

                        if (cy < displayHeight)
                        {
                            int cyFrozen = cy;
                            int oldFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                            rowIndex = oldFirstVisibleScrollingRow;
                            while (rowIndex != -1 &&
                                cy < displayHeight &&
                                oldFirstVisibleScrollingRow == DisplayedBandsInfo.FirstDisplayedScrollingRow)
                            {
                                AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(autoSizeRowsMode), fixedWidth, internalAutosizing);
                                cy += Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                                rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                            }

                            do
                            {
                                oldFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                                if (cy < displayHeight)
                                {
                                    int rowAboveFirstVisibleScrollingRow = Rows.GetPreviousRow(DisplayedBandsInfo.FirstDisplayedScrollingRow, DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                                    if (rowAboveFirstVisibleScrollingRow != -1)
                                    {
                                        AutoResizeRowInternal(rowAboveFirstVisibleScrollingRow, MapAutoSizeRowsModeToRowMode(autoSizeRowsMode), fixedWidth, internalAutosizing);
                                    }
                                }
                                cy = cyFrozen;
                                rowIndex = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                                while (rowIndex != -1 && cy < displayHeight)
                                {
                                    AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(autoSizeRowsMode), fixedWidth, internalAutosizing);
                                    cy += Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                                    rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                                }
                            }
                            while (oldFirstVisibleScrollingRow != DisplayedBandsInfo.FirstDisplayedScrollingRow);
                        }
                    }
                }
                finally
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        public bool AreAllCellsSelected(bool includeInvisibleCells)
        {
            if (Columns.Count == 0 && Rows.Count == 0)
            {
                return true;
            }
            if (!includeInvisibleCells &&
                (Rows.GetFirstRow(DataGridViewElementStates.Visible) == -1 ||
                 Columns.GetFirstColumn(DataGridViewElementStates.Visible) is null))
            {
                return true;
            }

            DataGridViewRow dataGridViewRow = null;
            bool allCellsSelected;
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.CellSelect:
                    {
                        allCellsSelected = _individualSelectedCells.Count == Columns.Count * Rows.Count;
                        if (allCellsSelected || includeInvisibleCells)
                        {
                            return allCellsSelected;
                        }
                        else
                        {
                            for (int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                 rowIndex != -1;
                                 rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                            {
                                dataGridViewRow = Rows[rowIndex]; // unshares this row

                                DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                                while (dataGridViewColumn != null)
                                {
                                    if (!dataGridViewRow.Cells[dataGridViewColumn.Index].Selected)
                                    {
                                        return false;
                                    }
                                    dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                                        DataGridViewElementStates.Visible,
                                        DataGridViewElementStates.None);
                                }
                            }
                            return true;
                        }
                    }
                case DataGridViewSelectionMode.FullColumnSelect:
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    {
                        allCellsSelected = _selectedBandIndexes.Count * Rows.Count + _individualSelectedCells.Count == Columns.Count * Rows.Count;
                        if (allCellsSelected || includeInvisibleCells)
                        {
                            return allCellsSelected;
                        }
                        else
                        {
                            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                            while (dataGridViewColumn != null)
                            {
                                if (!_selectedBandIndexes.Contains(dataGridViewColumn.Index))
                                {
                                    for (int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                        rowIndex != -1;
                                        rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                                    {
                                        dataGridViewRow = Rows[rowIndex]; // unshares this row
                                        if (!dataGridViewRow.Cells[dataGridViewColumn.Index].Selected)
                                        {
                                            return false;
                                        }
                                    }
                                }
                                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                                    DataGridViewElementStates.Visible,
                                    DataGridViewElementStates.None);
                            }
                            return true;
                        }
                    }
                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    {
                        allCellsSelected = _selectedBandIndexes.Count * Columns.Count + _individualSelectedCells.Count == Columns.Count * Rows.Count;
                        if (allCellsSelected || includeInvisibleCells)
                        {
                            return allCellsSelected;
                        }
                        else
                        {
                            for (int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                rowIndex != -1;
                                rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                            {
                                Debug.Assert(_selectedBandIndexes.Contains(rowIndex) ==
                                             ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Selected) != 0));
                                if ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Selected) == 0)
                                {
                                    dataGridViewRow = Rows[rowIndex]; // unshares this row
                                    DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                                    while (dataGridViewColumn != null)
                                    {
                                        if (!dataGridViewRow.Cells[dataGridViewColumn.Index].Selected)
                                        {
                                            return false;
                                        }
                                        dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                                            DataGridViewElementStates.Visible,
                                            DataGridViewElementStates.None);
                                    }
                                }
                            }
                            return true;
                        }
                    }
            }
            Debug.Fail("DataGridView.AreAllCellsSelected - Shouldn't reach this code");
            return false;
        }

        /// <summary>
        ///  Assigns a new parent control to the DataGridView.
        /// </summary>
        internal override void AssignParent(Control value)
        {
            if (_toolTipControl.Activated)
            {
                _toolTipControl.Activate(false /*activate*/);
            }
            base.AssignParent(value);
        }

        private void AutoGenerateDataBoundColumns(DataGridViewColumn[] boundColumns)
        {
            DataGridViewColumnCollection dataGridViewCols = Columns;
            DataGridViewColumn[] clonedColumns = new DataGridViewColumn[dataGridViewCols.Count];
            int clonedColumnsCount = 0;
            int i;

            // 1. Clone all the columns which are currently bound and will also be bound under the new DataSource/DataMember combination.
            // 2. Delete all the currently bound columns.
            // 3. Sort the cloned columns in order of their DisplayIndex.
            // 4. Add the new data bound columns. Here are the rules:
            //      a. if the cloned collection contains (possible multiple) columns with DataProperyHame == current data field,
            //          add the first cloned column that maps to the data field.
            //      b. other wise add the new bound column.
            // 5. Add the remaining cloned columns in the order of their DisplayIndex.

            // 1. Clone all the currently bound columns.
            //
            // We can't do 1. and 2. in the same loop because we need to save the DisplayIndex.
            for (i = 0; i < dataGridViewCols.Count; i++)
            {
                if (DataSource != null &&
                    !string.IsNullOrEmpty(dataGridViewCols[i].DataPropertyName) &&
                    !dataGridViewCols[i].IsDataBound)
                {
                    MapDataGridViewColumnToDataBoundField(dataGridViewCols[i]);
                }

                if (dataGridViewCols[i].IsDataBound)
                {
                    // We only clone columns which are data bound w/ the new DataSource/DataMember combination.
                    if (DataConnection != null && DataConnection.BoundColumnIndex(dataGridViewCols[i].DataPropertyName) != -1)
                    {
                        clonedColumns[clonedColumnsCount] = (DataGridViewColumn)dataGridViewCols[i].Clone();
                        clonedColumns[clonedColumnsCount].DisplayIndex = dataGridViewCols[i].DisplayIndex;
                        clonedColumnsCount++;
                    }
                }
            }

            i = 0;
            // 2. Delete all the currently bound columns.
            while (i < dataGridViewCols.Count)
            {
                if (dataGridViewCols[i].IsDataBound)
                {
                    dataGridViewCols.RemoveAtInternal(i, true /*force*/);
                }
                else
                {
                    i++;
                }
            }

            // 3. Sort the cloned columns in the order of their DisplayIndex.

            // Sort the cloned columns array by the display index.
            // We need to copy the cloned columns into a possibly smaller array.
            DataGridViewColumn[] finalClonedColumns;
            if (clonedColumns.Length == clonedColumnsCount)
            {
                finalClonedColumns = clonedColumns;
            }
            else
            {
                finalClonedColumns = new DataGridViewColumn[clonedColumnsCount];
                Array.Copy(clonedColumns, finalClonedColumns, clonedColumnsCount);
            }

            // Sort the array.
            Array.Sort(finalClonedColumns, System.Windows.Forms.DataGridViewColumnCollection.ColumnCollectionOrderComparer);

            // 4. Add new columns for the Fields which were not data bound previously ( ie, for fields which do not have a clone ).
            if (boundColumns != null)
            {
                for (int j = 0; j < boundColumns.Length; j++)
                {
                    if (boundColumns[j] != null && boundColumns[j].IsBrowsableInternal)
                    {
                        bool addNewColumn = true;
                        // Go thru the list of cloned columns and see if there is another column w/ the same data property name.
                        int clonedColIndex = 0;
                        for (; clonedColIndex < clonedColumnsCount; clonedColIndex++)
                        {
                            if (finalClonedColumns[clonedColIndex] != null &&
                                string.Compare(finalClonedColumns[clonedColIndex].DataPropertyName,
                                    boundColumns[j].DataPropertyName,
                                    true /*ignoreCase*/,
                                    CultureInfo.InvariantCulture) == 0)
                            {
                                addNewColumn = false;
                                break;
                            }
                        }

                        if (addNewColumn)
                        {
                            dataGridViewCols.Add(boundColumns[j]);
                        }
                        else
                        {
                            // add the cloned column.
                            dataGridViewCols.Add(finalClonedColumns[clonedColIndex]);
                            MapDataGridViewColumnToDataBoundField(finalClonedColumns[clonedColIndex]);
                            Debug.Assert(finalClonedColumns[clonedColIndex].IsDataBound);
                            finalClonedColumns[clonedColIndex] = null;
                        }
                    }
                }
            }
#if DEBUG
            else
            {
                // If there are no data bound columns then there are no cloned columns either.
                Debug.Assert(finalClonedColumns.Length == 0);
                Debug.Assert(clonedColumnsCount == 0);
            }
#endif // DEBUG

            // 5. Add remaining cloned columns.
            if (clonedColumnsCount > 0)
            {
                for (int k = 0; k < finalClonedColumns.Length; k++)
                {
                    if (finalClonedColumns[k] != null)
                    {
                        dataGridViewCols.Add(finalClonedColumns[k]);
                        MapDataGridViewColumnToDataBoundField(finalClonedColumns[k]);
                        Debug.Assert(finalClonedColumns[k].IsDataBound);
                    }
                }
            }
        }

        private bool AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter, bool fixedHeight)
        {
            Debug.Assert(autoSizeColumnCriteriaFilter != DataGridViewAutoSizeColumnCriteriaInternal.None);
            Debug.Assert((autoSizeColumnCriteriaFilter & DataGridViewAutoSizeColumnCriteriaInternal.Fill) == 0);

            bool ret = false; // No column autosizes by default
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            while (dataGridViewColumn != null)
            {
                DataGridViewAutoSizeColumnCriteriaInternal inheritedAutoSizeColumnCriteria = (DataGridViewAutoSizeColumnCriteriaInternal)dataGridViewColumn.InheritedAutoSizeMode;
                DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFiltered = (inheritedAutoSizeColumnCriteria & autoSizeColumnCriteriaFilter);
                if (autoSizeColumnCriteriaFiltered != 0)
                {
                    ret |= AutoResizeColumnInternal(dataGridViewColumn.Index, inheritedAutoSizeColumnCriteria, fixedHeight);
                }
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
            }
            return ret;
        }

        public void AutoResizeColumn(int columnIndex)
        {
            AutoResizeColumn(columnIndex, DataGridViewAutoSizeColumnMode.AllCells);
        }

        public void AutoResizeColumn(int columnIndex, DataGridViewAutoSizeColumnMode autoSizeColumnMode)
        {
            AutoResizeColumn(columnIndex, autoSizeColumnMode, true);
        }

        protected void AutoResizeColumn(int columnIndex, DataGridViewAutoSizeColumnMode autoSizeColumnMode, bool fixedHeight)
        {
            if (autoSizeColumnMode == DataGridViewAutoSizeColumnMode.NotSet ||
                autoSizeColumnMode == DataGridViewAutoSizeColumnMode.None ||
                autoSizeColumnMode == DataGridViewAutoSizeColumnMode.Fill)
            {
                throw new ArgumentException(string.Format(SR.DataGridView_NeedColumnAutoSizingCriteria, "autoSizeColumnMode"));
            }

            switch (autoSizeColumnMode)
            {
                case DataGridViewAutoSizeColumnMode.NotSet:
                case DataGridViewAutoSizeColumnMode.None:
                case DataGridViewAutoSizeColumnMode.ColumnHeader:
                case DataGridViewAutoSizeColumnMode.AllCellsExceptHeader:
                case DataGridViewAutoSizeColumnMode.AllCells:
                case DataGridViewAutoSizeColumnMode.DisplayedCellsExceptHeader:
                case DataGridViewAutoSizeColumnMode.DisplayedCells:
                case DataGridViewAutoSizeColumnMode.Fill:
                    break;
                default:
                    throw new InvalidEnumArgumentException(nameof(autoSizeColumnMode), (int)autoSizeColumnMode, typeof(DataGridViewAutoSizeColumnMode));
            }

            if (columnIndex < 0 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }

            if (autoSizeColumnMode == DataGridViewAutoSizeColumnMode.ColumnHeader && !ColumnHeadersVisible)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAutoSizeInvisibleColumnHeader);
            }

            AutoResizeColumnInternal(columnIndex, (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode, fixedHeight);
        }

        public void AutoResizeColumnHeadersHeight()
        {
            AutoResizeColumnHeadersHeight(true, true);
        }

        public void AutoResizeColumnHeadersHeight(int columnIndex)
        {
            AutoResizeColumnHeadersHeight(columnIndex, true, true);
        }

        protected void AutoResizeColumnHeadersHeight(bool fixedRowHeadersWidth, bool fixedColumnsWidth)
        {
            if (!ColumnHeadersVisible)
            {
                return;
            }

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return;
            }

            try
            {
                _noAutoSizeCount++;
                // Use of WindowsFormsUtils.CreateMeasurementGraphics() avoid use of this.Handle
                // IntPtr handle = this.Handle; // Force creation of control's handle because for databound grids, handle creation wipes out and recreates the columns/rows.
                int preferredHeight = 0;
                if (_layout.TopLeftHeader.Width > 0)
                {
                    if (fixedRowHeadersWidth)
                    {
                        preferredHeight = TopLeftHeaderCell.GetPreferredHeight(-1, _layout.TopLeftHeader.Width);
                    }
                    else
                    {
                        preferredHeight = TopLeftHeaderCell.GetPreferredSize(-1).Height;
                    }
                }
                int columnsCount = Columns.Count;
                for (int columnIndex = 0; columnIndex < columnsCount; columnIndex++)
                {
                    if (Columns[columnIndex].Visible)
                    {
                        if (fixedColumnsWidth)
                        {
                            preferredHeight = Math.Max(preferredHeight, Columns[columnIndex].HeaderCell.GetPreferredHeight(-1, Columns[columnIndex].Thickness));
                        }
                        else
                        {
                            preferredHeight = Math.Max(preferredHeight, Columns[columnIndex].HeaderCell.GetPreferredSize(-1).Height);
                        }
                    }
                }
                if (preferredHeight < MinimumColumnHeadersHeight)
                {
                    preferredHeight = MinimumColumnHeadersHeight;
                }
                if (preferredHeight > MaxHeadersThickness)
                {
                    preferredHeight = MaxHeadersThickness;
                }
                if (preferredHeight != ColumnHeadersHeight)
                {
                    SetColumnHeadersHeightInternal(preferredHeight, !fixedColumnsWidth /*invalidInAdjustFillingColumns*/);
                }
            }
            finally
            {
                Debug.Assert(_noAutoSizeCount > 0);
                _noAutoSizeCount--;
            }
        }

        protected void AutoResizeColumnHeadersHeight(int columnIndex, bool fixedRowHeadersWidth, bool fixedColumnWidth)
        {
            if (columnIndex < -1 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }

            if (!ColumnHeadersVisible)
            {
                return;
            }

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return;
            }

            try
            {
                _noAutoSizeCount++;
                // Use of WindowsFormsUtils.CreateMeasurementGraphics() avoid use of this.Handle
                // IntPtr handle = this.Handle; // Force creation of control's handle because for databound grids, handle creation wipes out and recreates the columns/rows.
                int preferredHeight = 0;
                if (_layout.TopLeftHeader.Width > 0)
                {
                    if (columnIndex != -1 || fixedRowHeadersWidth)
                    {
                        preferredHeight = TopLeftHeaderCell.GetPreferredHeight(-1, _layout.TopLeftHeader.Width);
                    }
                    else
                    {
                        preferredHeight = TopLeftHeaderCell.GetPreferredSize(-1).Height;
                    }
                }
                int columnsCount = Columns.Count;
                for (int columnIndexTmp = 0; columnIndexTmp < columnsCount; columnIndexTmp++)
                {
                    if (Columns[columnIndexTmp].Visible)
                    {
                        if (columnIndex != columnIndexTmp || fixedColumnWidth)
                        {
                            preferredHeight = Math.Max(preferredHeight, Columns[columnIndexTmp].HeaderCell.GetPreferredHeight(-1, Columns[columnIndexTmp].Thickness));
                        }
                        else
                        {
                            preferredHeight = Math.Max(preferredHeight, Columns[columnIndexTmp].HeaderCell.GetPreferredSize(-1).Height);
                        }
                    }
                }
                if (preferredHeight < MinimumColumnHeadersHeight)
                {
                    preferredHeight = MinimumColumnHeadersHeight;
                }
                if (preferredHeight > MaxHeadersThickness)
                {
                    preferredHeight = MaxHeadersThickness;
                }
                if (preferredHeight != ColumnHeadersHeight)
                {
                    SetColumnHeadersHeightInternal(preferredHeight, !fixedColumnWidth /*invalidInAdjustFillingColumns*/);
                }
            }
            finally
            {
                Debug.Assert(_noAutoSizeCount > 0);
                _noAutoSizeCount--;
            }
        }

        private bool AutoResizeColumnInternal(int columnIndex, DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal, bool fixedHeight)
        {
            Debug.Assert(autoSizeColumnCriteriaInternal == DataGridViewAutoSizeColumnCriteriaInternal.Header ||
                autoSizeColumnCriteriaInternal == DataGridViewAutoSizeColumnCriteriaInternal.AllRows ||
                autoSizeColumnCriteriaInternal == DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows ||
                autoSizeColumnCriteriaInternal == (DataGridViewAutoSizeColumnCriteriaInternal.Header | DataGridViewAutoSizeColumnCriteriaInternal.AllRows) ||
                autoSizeColumnCriteriaInternal == (DataGridViewAutoSizeColumnCriteriaInternal.Header | DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows));
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count);

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return false;
            }

            bool ret = false; // No autosizing occurs by default.
            try
            {
                _noAutoSizeCount++;
                // Use of WindowsFormsUtils.CreateMeasurementGraphics() avoid use of this.Handle
                // IntPtr handle = this.Handle; // Force creation of control's handle because for databound grids, handle creation wipes out and recreates the columns.
                // Note: Even none-resizable column can programmatically be resized.
                DataGridViewColumn dataGridViewColumn = Columns[columnIndex];
                int preferredColumnWidth = dataGridViewColumn.GetPreferredWidth((DataGridViewAutoSizeColumnMode)autoSizeColumnCriteriaInternal, fixedHeight);
                if (preferredColumnWidth < dataGridViewColumn.MinimumThickness)
                {
                    preferredColumnWidth = dataGridViewColumn.MinimumThickness;
                }
                if (preferredColumnWidth > DataGridViewBand.MaxBandThickness)
                {
                    preferredColumnWidth = DataGridViewBand.MaxBandThickness;
                }
                if (preferredColumnWidth != dataGridViewColumn.Thickness)
                {
                    if (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                    {
                        AdjustFillingColumn(dataGridViewColumn, preferredColumnWidth);
                    }
                    else
                    {
                        Columns[columnIndex].ThicknessInternal = preferredColumnWidth;
                    }
                    ret = true;
                }
            }
            finally
            {
                Debug.Assert(_noAutoSizeCount > 0);
                _noAutoSizeCount--;
            }
            return ret;
        }

        public void AutoResizeColumns()
        {
            AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
        }

        public void AutoResizeColumns(DataGridViewAutoSizeColumnsMode autoSizeColumnsMode)
        {
            AutoResizeColumns(autoSizeColumnsMode, true);
        }

        protected void AutoResizeColumns(DataGridViewAutoSizeColumnsMode autoSizeColumnsMode, bool fixedHeight)
        {
            for (int columnIndex = 0; columnIndex < Columns.Count; columnIndex++)
            {
                AutoResizeColumn(columnIndex, (DataGridViewAutoSizeColumnMode)autoSizeColumnsMode, fixedHeight);
            }
        }

        public void AutoResizeRow(int rowIndex)
        {
            AutoResizeRow(rowIndex, DataGridViewAutoSizeRowMode.AllCells);
        }

        public void AutoResizeRow(int rowIndex, DataGridViewAutoSizeRowMode autoSizeRowMode)
        {
            AutoResizeRow(rowIndex, autoSizeRowMode, true /*fixedWidth*/);
        }

        protected void AutoResizeRow(int rowIndex, DataGridViewAutoSizeRowMode autoSizeRowMode, bool fixedWidth)
        {
            if (rowIndex < 0 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            // not using ClientUtils here because it's a flags enum, masking instead.
            if (((DataGridViewAutoSizeRowCriteriaInternal)autoSizeRowMode & InvalidDataGridViewAutoSizeRowCriteriaInternalMask) != 0)
            {
                throw new InvalidEnumArgumentException(nameof(autoSizeRowMode), (int)autoSizeRowMode, typeof(DataGridViewAutoSizeRowMode));
            }
            if (autoSizeRowMode == DataGridViewAutoSizeRowMode.RowHeader && !RowHeadersVisible)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAutoSizeRowInvisibleRowHeader);
            }
            AutoResizeRowInternal(rowIndex, autoSizeRowMode, fixedWidth, false /*internalAutosizing*/);
        }

        // User can override this if there is a quicker way to determine preferred row headers width
        public void AutoResizeRowHeadersWidth(DataGridViewRowHeadersWidthSizeMode rowHeadersWidthSizeMode)
        {
            AutoResizeRowHeadersWidth(rowHeadersWidthSizeMode,
                                      true /*fixedColumnHeadersHeight*/,
                                      true /*fixedRowsHeight*/);
        }

        // User can override this if there is a quicker way to determine preferred row headers width
        protected void AutoResizeRowHeadersWidth(DataGridViewRowHeadersWidthSizeMode rowHeadersWidthSizeMode,
                                                 bool fixedColumnHeadersHeight,
                                                 bool fixedRowsHeight)
        {
            if (rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing ||
                rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.DisableResizing)
            {
                throw new ArgumentException(string.Format(SR.DataGridView_NeedAutoSizingCriteria, "rowHeadersWidthSizeMode"));
            }
            // custom range checking, not using ClientUtils.
            if (rowHeadersWidthSizeMode < DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders || rowHeadersWidthSizeMode > DataGridViewRowHeadersWidthSizeMode.AutoSizeToFirstHeader)
            {
                throw new InvalidEnumArgumentException(nameof(rowHeadersWidthSizeMode), (int)rowHeadersWidthSizeMode, typeof(DataGridViewRowHeadersWidthSizeMode));
            }

            if (!RowHeadersVisible)
            {
                return;
            }

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return;
            }

            try
            {
                _noAutoSizeCount++;
                // Use of WindowsFormsUtils.CreateMeasurementGraphics() avoid use of this.Handle
                // IntPtr handle = this.Handle; // Force creation of control's handle because for databound grids, handle creation wipes out and recreates the columns/rows.
                int preferredWidth = 0, rowIndex;
                if (_layout.TopLeftHeader.Width > 0)
                {
                    if (fixedColumnHeadersHeight)
                    {
                        preferredWidth = TopLeftHeaderCell.GetPreferredWidth(-1, _layout.TopLeftHeader.Height);
                    }
                    else
                    {
                        preferredWidth = TopLeftHeaderCell.GetPreferredSize(-1).Width;
                    }
                }
                switch (rowHeadersWidthSizeMode)
                {
                    case DataGridViewRowHeadersWidthSizeMode.AutoSizeToFirstHeader:
                        {
                            rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                            if (rowIndex != -1)
                            {
                                if (fixedRowsHeight)
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndex).HeaderCell.GetPreferredWidth(rowIndex, Rows.SharedRow(rowIndex).GetHeight(rowIndex)));
                                }
                                else
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndex).HeaderCell.GetPreferredSize(rowIndex).Width);
                                }
                            }
                            break;
                        }
                    case DataGridViewRowHeadersWidthSizeMode.AutoSizeToDisplayedHeaders:
                        {
                            int displayHeight = _layout.Data.Height, cy = 0;
                            rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                            while (rowIndex != -1 && cy < displayHeight)
                            {
                                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                                int dataGridViewRowHeight = dataGridViewRow.GetHeight(rowIndex);
                                cy += dataGridViewRowHeight;
                                if (fixedRowsHeight)
                                {
                                    preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredWidth(rowIndex, dataGridViewRowHeight));
                                }
                                else
                                {
                                    preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredSize(rowIndex).Width);
                                }
                                rowIndex = Rows.GetNextRow(rowIndex,
                                                                DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                            }
                            if (cy < displayHeight)
                            {
                                rowIndex = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                                while (rowIndex != -1 && cy < displayHeight)
                                {
                                    DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                                    int dataGridViewRowHeight = dataGridViewRow.GetHeight(rowIndex);
                                    cy += dataGridViewRowHeight;
                                    if (fixedRowsHeight)
                                    {
                                        preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredWidth(rowIndex, dataGridViewRowHeight));
                                    }
                                    else
                                    {
                                        preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredSize(rowIndex).Width);
                                    }
                                    rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                                }
                            }
                            break;
                        }
                    case DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders:
                        {
                            for (rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                rowIndex != -1;
                                rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                            {
                                if (fixedRowsHeight)
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndex).HeaderCell.GetPreferredWidth(rowIndex, Rows.SharedRow(rowIndex).GetHeight(rowIndex)));
                                }
                                else
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndex).HeaderCell.GetPreferredSize(rowIndex).Width);
                                }
                            }
                            break;
                        }
                    default:
                        {
                            Debug.Fail("Unexpected rowHeadersWidthSizeMode value in AutoResizeRowHeadersWidth");
                            break;
                        }
                }
                if (preferredWidth < MinimumRowHeadersWidth)
                {
                    preferredWidth = MinimumRowHeadersWidth;
                }
                if (preferredWidth != RowHeadersWidth)
                {
                    RowHeadersWidthInternal = preferredWidth;
                }
            }
            finally
            {
                Debug.Assert(_noAutoSizeCount > 0);
                _noAutoSizeCount--;
            }
        }

        public void AutoResizeRowHeadersWidth(int rowIndex, DataGridViewRowHeadersWidthSizeMode rowHeadersWidthSizeMode)
        {
            AutoResizeRowHeadersWidth(rowIndex,
                                      rowHeadersWidthSizeMode,
                                      true /*fixedColumnHeadersHeight*/,
                                      true /*fixedRowHeight*/);
        }

        protected void AutoResizeRowHeadersWidth(int rowIndex,
                                                 DataGridViewRowHeadersWidthSizeMode rowHeadersWidthSizeMode,
                                                 bool fixedColumnHeadersHeight,
                                                 bool fixedRowHeight)
        {
            if (rowIndex < -1 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            if (rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing ||
                rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.DisableResizing)
            {
                throw new ArgumentException(string.Format(SR.DataGridView_NeedAutoSizingCriteria, "rowHeadersWidthSizeMode"));
            }
            if (rowHeadersWidthSizeMode < DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders || rowHeadersWidthSizeMode > DataGridViewRowHeadersWidthSizeMode.AutoSizeToFirstHeader)
            {
                throw new InvalidEnumArgumentException(nameof(rowHeadersWidthSizeMode), (int)rowHeadersWidthSizeMode, typeof(DataGridViewRowHeadersWidthSizeMode));
            }

            if (!RowHeadersVisible)
            {
                return;
            }
            if (rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.AutoSizeToFirstHeader &&
                rowIndex != -1 &&
                rowIndex != Rows.GetFirstRow(DataGridViewElementStates.Visible))
            {
                return;
            }
            if (rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.AutoSizeToDisplayedHeaders &&
                rowIndex != -1)
            {
                DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
                bool rowDisplayed = (rowState & DataGridViewElementStates.Displayed) != 0;
                if (!rowDisplayed)
                {
                    return;
                }
            }

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return;
            }

            try
            {
                _noAutoSizeCount++;
                // Use of WindowsFormsUtils.CreateMeasurementGraphics() avoid use of this.Handle
                // IntPtr handle = this.Handle; // Force creation of control's handle because for databound grids, handle creation wipes out and recreates the columns/rows.
                int preferredWidth = 0, rowIndexTmp;
                if (_layout.TopLeftHeader.Width > 0)
                {
                    if (rowIndex != -1 || fixedColumnHeadersHeight)
                    {
                        preferredWidth = TopLeftHeaderCell.GetPreferredWidth(-1, _layout.TopLeftHeader.Height);
                    }
                    else
                    {
                        preferredWidth = TopLeftHeaderCell.GetPreferredSize(-1).Width;
                    }
                }
                switch (rowHeadersWidthSizeMode)
                {
                    case DataGridViewRowHeadersWidthSizeMode.AutoSizeToFirstHeader:
                        {
                            rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                            if (rowIndexTmp != -1)
                            {
                                if (rowIndex != rowIndexTmp || fixedRowHeight)
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndexTmp).HeaderCell.GetPreferredWidth(rowIndexTmp, Rows.SharedRow(rowIndexTmp).GetHeight(rowIndexTmp)));
                                }
                                else
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndexTmp).HeaderCell.GetPreferredSize(rowIndexTmp).Width);
                                }
                            }
                            break;
                        }
                    case DataGridViewRowHeadersWidthSizeMode.AutoSizeToDisplayedHeaders:
                        {
                            int displayHeight = _layout.Data.Height, cy = 0;
                            rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                            while (rowIndexTmp != -1 && cy < displayHeight)
                            {
                                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndexTmp);
                                int dataGridViewRowHeight = dataGridViewRow.GetHeight(rowIndexTmp);
                                cy += dataGridViewRowHeight;
                                if (rowIndex != rowIndexTmp || fixedRowHeight)
                                {
                                    preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredWidth(rowIndexTmp, dataGridViewRowHeight));
                                }
                                else
                                {
                                    preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredSize(rowIndexTmp).Width);
                                }
                                rowIndexTmp = Rows.GetNextRow(rowIndexTmp,
                                                                DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                            }
                            if (cy < displayHeight)
                            {
                                rowIndexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                                while (rowIndexTmp != -1 && cy < displayHeight)
                                {
                                    DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndexTmp);
                                    int dataGridViewRowHeight = dataGridViewRow.GetHeight(rowIndexTmp);
                                    cy += dataGridViewRowHeight;
                                    if (rowIndex != rowIndexTmp || fixedRowHeight)
                                    {
                                        preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredWidth(rowIndexTmp, dataGridViewRowHeight));
                                    }
                                    else
                                    {
                                        preferredWidth = Math.Max(preferredWidth, dataGridViewRow.HeaderCell.GetPreferredSize(rowIndexTmp).Width);
                                    }
                                    rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                                }
                            }
                            break;
                        }
                    case DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders:
                        {
                            for (rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                rowIndexTmp != -1;
                                rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible))
                            {
                                if (rowIndex != rowIndexTmp || fixedRowHeight)
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndexTmp).HeaderCell.GetPreferredWidth(rowIndexTmp, Rows.SharedRow(rowIndexTmp).GetHeight(rowIndexTmp)));
                                }
                                else
                                {
                                    preferredWidth = Math.Max(preferredWidth, Rows.SharedRow(rowIndexTmp).HeaderCell.GetPreferredSize(rowIndexTmp).Width);
                                }
                            }
                            break;
                        }
                    default:
                        {
                            Debug.Fail("Unexpected rowHeadersWidthSizeMode value in AutoResizeRowHeadersWidth");
                            break;
                        }
                }
                if (preferredWidth < MinimumRowHeadersWidth)
                {
                    preferredWidth = MinimumRowHeadersWidth;
                }
                if (preferredWidth != RowHeadersWidth)
                {
                    RowHeadersWidthInternal = preferredWidth;
                }
            }
            finally
            {
                Debug.Assert(_noAutoSizeCount > 0);
                _noAutoSizeCount--;
            }
        }

        private void AutoResizeRowInternal(int rowIndex, DataGridViewAutoSizeRowMode autoSizeRowMode, bool fixedWidth, bool internalAutosizing)
        {
            Debug.Assert(rowIndex >= 0 && rowIndex < Rows.Count);
            Debug.Assert(((DataGridViewAutoSizeRowCriteriaInternal)autoSizeRowMode & InvalidDataGridViewAutoSizeRowCriteriaInternalMask) == 0);

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return;
            }

            try
            {
                _noAutoSizeCount++;
                // Use of WindowsFormsUtils.CreateMeasurementGraphics() avoid use of this.Handle
                // IntPtr handle = this.Handle; // Force creation of control's handle because for databound grids, handle creation wipes out and recreates the columns/rows.
                // Note: Even none-resizable row can programmatically be resized.
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                dataGridViewRow.GetHeightInfo(rowIndex, out int height, out int minimumHeight);
                int preferredThickness = dataGridViewRow.GetPreferredHeight(rowIndex, autoSizeRowMode, fixedWidth);
                if (preferredThickness < minimumHeight)
                {
                    preferredThickness = minimumHeight;
                }
                if (preferredThickness > DataGridViewBand.MaxBandThickness)
                {
                    preferredThickness = DataGridViewBand.MaxBandThickness;
                }
                if (height != preferredThickness)
                {
                    if (_autoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
                    {
                        if (!OnRowHeightInfoPushed(rowIndex, preferredThickness, minimumHeight))
                        {
                            Rows[rowIndex].ThicknessInternal = preferredThickness;   // unsharing the resized row
                        }
                    }
                    else
                    {
                        if (internalAutosizing)
                        {
                            Rows[rowIndex].ThicknessInternal = preferredThickness;   // unsharing the resized row
                        }
                        else
                        {
                            Rows[rowIndex].Thickness = preferredThickness;   // unsharing the resized row
                        }
                    }
                }
            }
            finally
            {
                Debug.Assert(_noAutoSizeCount > 0);
                _noAutoSizeCount--;
            }
        }

        public void AutoResizeRows()
        {
            AutoResizeRows(DataGridViewAutoSizeRowsMode.AllCells);
        }

        public void AutoResizeRows(DataGridViewAutoSizeRowsMode autoSizeRowsMode)
        {
            AutoResizeRows(autoSizeRowsMode, true /*fixedWidth*/);
        }

        protected void AutoResizeRows(DataGridViewAutoSizeRowsMode autoSizeRowsMode, bool fixedWidth)
        {
            switch (autoSizeRowsMode)
            {
                case DataGridViewAutoSizeRowsMode.None:
                case DataGridViewAutoSizeRowsMode.AllHeaders:
                case DataGridViewAutoSizeRowsMode.AllCellsExceptHeaders:
                case DataGridViewAutoSizeRowsMode.AllCells:
                case DataGridViewAutoSizeRowsMode.DisplayedHeaders:
                case DataGridViewAutoSizeRowsMode.DisplayedCellsExceptHeaders:
                case DataGridViewAutoSizeRowsMode.DisplayedCells:
                    break;
                default:
                    throw new InvalidEnumArgumentException(nameof(autoSizeRowsMode), (int)autoSizeRowsMode, typeof(DataGridViewAutoSizeRowsMode));
            }

            if (autoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
            {
                throw new ArgumentException(string.Format(SR.DataGridView_NeedAutoSizingCriteria, "autoSizeRowsMode"));
            }

            if ((autoSizeRowsMode == DataGridViewAutoSizeRowsMode.AllHeaders || autoSizeRowsMode == DataGridViewAutoSizeRowsMode.DisplayedHeaders) &&
                !RowHeadersVisible)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAutoSizeRowsInvisibleRowHeader);
            }

            AdjustShrinkingRows(autoSizeRowsMode, fixedWidth, false /*internalAutosizing*/);
        }

        protected void AutoResizeRows(int rowIndexStart, int rowsCount, DataGridViewAutoSizeRowMode autoSizeRowMode, bool fixedWidth)
        {
            // not using ClientUtils.IsEnumValid here because DataGridViewAutoSizeRowCriteriaInternal is a flags enum.
            if (((DataGridViewAutoSizeRowCriteriaInternal)autoSizeRowMode & InvalidDataGridViewAutoSizeRowCriteriaInternalMask) != 0)
            {
                throw new InvalidEnumArgumentException(nameof(autoSizeRowMode), (int)autoSizeRowMode, typeof(DataGridViewAutoSizeRowMode));
            }

            if (autoSizeRowMode == DataGridViewAutoSizeRowMode.RowHeader && !RowHeadersVisible)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAutoSizeRowsInvisibleRowHeader);
            }

            if (rowsCount < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(rowsCount));
            }

            if (rowIndexStart < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndexStart));
            }

            if (!IsHandleCreated)
            {
                // auto sizing causes handle creation.
                // don't create the handle inside InitializeComponent because that causes problems w/ data binding
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = true;
                return;
            }

            _inBulkPaintCount++;
            _inBulkLayoutCount++;
            try
            {
                int rowIndex = Rows.GetNextRow(rowIndexStart - 1, DataGridViewElementStates.Visible);
                int autoSizedCount = 0;
                while (rowIndex != -1 && autoSizedCount < rowsCount)
                {
                    AutoResizeRowInternal(rowIndex, autoSizeRowMode, fixedWidth, false /*internalAutosizing*/);
                    autoSizedCount++;
                    if (autoSizedCount < rowsCount)
                    {
                        rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                    }
                }
            }
            finally
            {
                ExitBulkLayout(true /*invalidInAdjustFillingColumns*/);
                ExitBulkPaint(-1, -1);
            }
        }

        private void BeginColumnHeadersResize(int mouseY, int mouseBarOffset)
        {
            if (IsKeyboardOperationActive())
            {
                return;
            }

            Rectangle clip = Rectangle.Union(_layout.ColumnHeaders, _layout.Data);
            if (_layout.TopLeftHeader.Width > 0)
            {
                clip = Rectangle.Union(_layout.TopLeftHeader, clip);
            }
            clip.Y += MinimumColumnHeadersHeight - mouseBarOffset - 1;
            // No need to limit the bottom edge of the cursor clip since maxHeadersThickness is very large.
            CaptureMouse(clip);
            _dataGridViewOper[OperationTrackColHeadersResize] = true;
            _trackRowAnchor = mouseY;
            this._mouseBarOffset = mouseBarOffset;
            Debug.Assert(_lastRowSplitBar == -1);
            _currentRowSplitBar = mouseY;
            Invalidate(CalcRowResizeFeedbackRect(_currentRowSplitBar));
        }

        private void BeginColumnRelocation(int mouseX, int index)
        {
            if (IsKeyboardOperationActive())
            {
                return;
            }

            Rectangle cursorClip = _layout.ColumnHeaders;
            int frozenWidth = Columns.GetColumnsWidth(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            int scrollingWidth = Columns.GetColumnsWidth(DataGridViewElementStates.Visible) - frozenWidth;
            if (Columns[index].Frozen)
            {
                // A frozen column cannot be relocated into an unfrozen area
                if (RightToLeftInternal)
                {
                    cursorClip.X += cursorClip.Width - frozenWidth;
                }
                cursorClip.Width = Math.Min(frozenWidth, _layout.Data.Width);
            }
            else
            {
                // An unfrozen column cannot be relocated into a frozen area
                if (!RightToLeftInternal)
                {
                    cursorClip.X += frozenWidth;
                }
                else if (_layout.Data.Width > frozenWidth + scrollingWidth)
                {
                    cursorClip.X += _layout.Data.Width - frozenWidth - scrollingWidth;
                }
                cursorClip.Width = Math.Min(scrollingWidth, _layout.Data.Width);
            }
            CaptureMouse(cursorClip);
            _dataGridViewOper[OperationTrackColRelocation] = true;
            _dataGridViewState2[State2_ShowColumnRelocationInsertion] = false;
            _trackColumn = index;
            _trackColumnEdge = -1;

            _mouseBarOffset = GetColumnXFromIndex(index) - mouseX;
            _lastHeaderShadow = mouseX;
            Invalidate(_layout.ColumnHeaders);
        }

        private void BeginColumnResize(int x, int columnIndex)
        {
            _trackColAnchor = x;
            _trackColumn = columnIndex;

            _currentColSplitBar = x;
            Invalidate(CalcColResizeFeedbackRect(_currentColSplitBar));
        }

        private void BeginMouseColumnResize(int mouseX, int mouseBarOffset, int index)
        {
            if (IsKeyboardOperationActive())
            {
                return;
            }

            _dataGridViewOper[OperationTrackColResize] = true;
            this._mouseBarOffset = mouseBarOffset;
            _resizeClipRectangle = GetResizeClipRectangle(index);
            CaptureMouse(_resizeClipRectangle);

            BeginColumnResize(mouseX, index);
        }

        private void BeginKeyboardColumnResize(int columnIndex)
        {
            if (IsMouseOperationActive())
            {
                return;
            }

            _dataGridViewOper[OperationTrackKeyboardColResize] = true;
            _mouseBarOffset = 0;
            _resizeClipRectangle = GetResizeClipRectangle(columnIndex);
            _keyboardResizeStep = ScaleToCurrentDpi(RightToLeftInternal ? -1 : 1);
            int x = GetColumnXFromIndex(columnIndex);
            x += RightToLeftInternal ? -Columns[columnIndex].Width : Columns[columnIndex].Width;

            BeginColumnResize(x, columnIndex);
        }

        private Rectangle GetResizeClipRectangle(int columnIndex)
        {
            Rectangle clip = Rectangle.Union(_layout.ColumnHeaders, _layout.Data);
            int leftEdge = GetColumnXFromIndex(columnIndex);
            if (RightToLeftInternal)
            {
                clip.X = _layout.Data.X - _mouseBarOffset - 1;
                clip.Width = leftEdge - Columns[columnIndex].MinimumThickness - _layout.Data.X + 3;
                int overflowWidth = leftEdge - _mouseBarOffset - clip.Left - DataGridViewBand.MaxBandThickness + 1;
                if (overflowWidth > 0)
                {
                    clip.X += overflowWidth;
                    clip.Width -= overflowWidth;
                }
            }
            else
            {
                clip.X = leftEdge + Columns[columnIndex].MinimumThickness - _mouseBarOffset - 1;
                clip.Width = _layout.Data.Right - leftEdge - 1;
                int overflowWidth = clip.Right + _mouseBarOffset - leftEdge - DataGridViewBand.MaxBandThickness;
                if (overflowWidth > 0)
                {
                    clip.Width -= overflowWidth;
                }
            }

            return clip;
        }

        public virtual bool BeginEdit(bool selectAll)
        {
            if (_ptCurrentCell.X == -1)
            {
                throw new InvalidOperationException(SR.DataGridView_NoCurrentCell);
            }

            if (IsCurrentCellInEditMode)
            {
                return true;
            }

            return BeginEditInternal(selectAll);
        }

        private bool BeginEditInternal(bool selectAll)
        {
            if (_dataGridViewOper[OperationInBeginEdit])
            {
                throw new InvalidOperationException(SR.DataGridView_BeginEditNotReentrant);
            }
            try
            {
                _dataGridViewOper[OperationInBeginEdit] = true;
                Debug.Assert(_ptCurrentCell.X >= 0 && _ptCurrentCell.X < Columns.Count);
                Debug.Assert(_ptCurrentCell.Y >= 0 && _ptCurrentCell.Y < Rows.Count);
                Debug.Assert(!IsCurrentCellInEditMode);

                DataGridViewCell dataGridViewCell = CurrentCellInternal;
                Debug.Assert(dataGridViewCell != null);

                if (IsSharedCellReadOnly(dataGridViewCell, _ptCurrentCell.Y) ||
                    !ColumnEditable(_ptCurrentCell.X))
                {
                    return false;
                }

                Type editControlType = dataGridViewCell.EditType;
                if (editControlType is null)
                {
                    // Current cell does not have an editing control. Does it implement IDataGridViewEditingCell?
                    Type editingCellInterface = dataGridViewCell.GetType().GetInterface("System.Windows.Forms.IDataGridViewEditingCell");
                    if (editingCellInterface is null)
                    {
                        return false;
                    }
                }

                DataGridViewCellCancelEventArgs dgvcce = new DataGridViewCellCancelEventArgs(_ptCurrentCell.X, _ptCurrentCell.Y);
                OnCellBeginEdit(dgvcce);
                if (dgvcce.Cancel)
                {
                    return false;
                }
                Debug.Assert(!IsCurrentCellInEditMode);

                if (_ptCurrentCell.X > -1)
                {
                    DataGridViewCell previousCurrentCell = dataGridViewCell;
                    dataGridViewCell = CurrentCellInternal;
                    if (previousCurrentCell != dataGridViewCell)
                    {
                        // The new current cell can be a whole different cell.
                        // In that case, all tests previously done are no longer valid.
                        if (IsSharedCellReadOnly(dataGridViewCell, _ptCurrentCell.Y) ||
                            !ColumnEditable(_ptCurrentCell.X))
                        {
                            return false;
                        }

                        editControlType = dataGridViewCell.EditType;
                        if (editControlType is null)
                        {
                            // Current cell does not have an editing control. Does it implement IDataGridViewEditingCell?
                            Type editingCellInterface = dataGridViewCell.GetType().GetInterface("System.Windows.Forms.IDataGridViewEditingCell");
                            if (editingCellInterface is null)
                            {
                                return false;
                            }
                        }
                    }
                }
                else
                {
                    return false;
                }

                DataGridViewCellStyle dataGridViewCellStyle = dataGridViewCell.GetInheritedStyle(null, _ptCurrentCell.Y, true);

                if (editControlType is null)
                {
                    _dataGridViewState1[State1_CurrentCellInEditMode] = true;
                    InitializeEditingCellValue(ref dataGridViewCellStyle, ref dataGridViewCell);
                    ((IDataGridViewEditingCell)dataGridViewCell).PrepareEditingCellForEdit(selectAll);
                    return true;
                }

                Type editingCtrlInterface = editControlType.GetInterface("System.Windows.Forms.IDataGridViewEditingControl");
                if (!editControlType.IsSubclassOf(Type.GetType("System.Windows.Forms.Control")) ||
                    editingCtrlInterface is null)
                {
                    throw new InvalidCastException(SR.DataGridView_InvalidEditingControl);
                }
                if (_latestEditingControl != null &&
                    editControlType.IsInstanceOfType(_latestEditingControl) &&
                    !_latestEditingControl.GetType().IsSubclassOf(editControlType))
                {
                    EditingControl = _latestEditingControl;
                    Debug.Assert(((IDataGridViewEditingControl)EditingControl).EditingControlDataGridView == this);
                }
                else
                {
                    Debug.Assert(EditingControl is null);
                    EditingControl = (Control)Activator.CreateInstance(editControlType);
                    Debug.Assert(EditingControl != null);

                    ((IDataGridViewEditingControl)EditingControl).EditingControlDataGridView = this;
                    if (_latestEditingControl != null)
                    {
                        _latestEditingControl.Dispose();
                        _latestEditingControl = null;
                    }
                }

                Debug.Assert(EditingControl != null);
                if (string.IsNullOrEmpty(EditingControl.AccessibleName))
                {
                    EditingControl.AccessibleName = SR.DataGridView_AccEditingControlAccName;
                }
                EditingControl.ImeMode = ImeMode;

                ((IDataGridViewEditingControl)EditingControl).EditingControlRowIndex = _ptCurrentCell.Y;

                InitializeEditingControlValue(ref dataGridViewCellStyle, dataGridViewCell);

                WireEditingControlEvents();

                Debug.Assert(EditingControl != null);
                Debug.Assert(_editingPanel != null);
                DataGridViewEditingControlShowingEventArgs dgvese = new DataGridViewEditingControlShowingEventArgs(EditingControl, dataGridViewCellStyle);
                OnEditingControlShowing(dgvese);
                Debug.Assert(dgvese.CellStyle != null);
                if (_editingPanel is null || EditingControl is null)
                {
                    return false;
                }
                _editingPanel.BackColor = dgvese.CellStyle.BackColor;
                ((IDataGridViewEditingControl)EditingControl).ApplyCellStyleToEditingControl(dgvese.CellStyle);

                // Get rid of the tooltip if it's showing for the current cell
                if (_toolTipControl.Activated && _ptToolTipCell == _ptCurrentCell)
                {
                    _toolTipControl.Activate(false /*activate*/);
                }

                PositionEditingControl(true, true, true);

                // Guarding against bugs in customer code.
                // For example setting the CurrentCell to null in DataGridView_OnLostFocus(...) causes this.editingControl
                // to become null.
                if (_editingPanel is null || EditingControl is null)
                {
                    return false;
                }
                else
                {
                    ((IDataGridViewEditingControl)EditingControl).PrepareEditingControlForEdit(selectAll);
                    InvalidateCellPrivate(_ptCurrentCell.X, _ptCurrentCell.Y);
                    return true;
                }
            }
            finally
            {
                _dataGridViewOper[OperationInBeginEdit] = false;
            }
        }

        private void BeginRowHeadersResize(int mouseX, int mouseBarOffset)
        {
            if (IsKeyboardOperationActive())
            {
                return;
            }

            Rectangle clip = Rectangle.Union(_layout.RowHeaders, _layout.Data);
            if (_layout.TopLeftHeader.Width > 0)
            {
                clip = Rectangle.Union(_layout.TopLeftHeader, clip);
            }
            if (RightToLeftInternal)
            {
                clip.X -= mouseBarOffset + 1;
                clip.Width -= MinimumRowHeadersWidth - 1;
                // No need to limit the left edge of the cursor clip since maxHeadersThickness is very large.
            }
            else
            {
                clip.X += MinimumRowHeadersWidth - mouseBarOffset - 1;
                // No need to limit the right edge of the cursor clip since maxHeadersThickness is very large.
            }
            CaptureMouse(clip);

            _dataGridViewOper[OperationTrackRowHeadersResize] = true;
            _trackColAnchor = mouseX;
            this._mouseBarOffset = mouseBarOffset;
            Debug.Assert(_lastColSplitBar == -1);
            _currentColSplitBar = mouseX;
            Invalidate(CalcColResizeFeedbackRect(_currentColSplitBar));
        }

        private void BeginRowResize(int mouseY, int mouseBarOffset, int index)
        {
            if (IsKeyboardOperationActive())
            {
                return;
            }

            Rectangle clip = Rectangle.Union(_layout.RowHeaders, _layout.Data);
            int topEdge = GetRowYFromIndex(index);
            clip.Y = topEdge + Rows.SharedRow(index).GetMinimumHeight(index) - mouseBarOffset - 1;
            clip.Height = _layout.Data.Y + _layout.Data.Height - topEdge - 1;
            CaptureMouse(clip);

            _dataGridViewOper[OperationTrackRowResize] = true;
            _trackRowAnchor = mouseY;
            _trackRow = index;

            this._mouseBarOffset = mouseBarOffset;
            Debug.Assert(_lastRowSplitBar == -1);
            _currentRowSplitBar = mouseY;
            Invalidate(CalcRowResizeFeedbackRect(_currentRowSplitBar));
        }

        private void BuildInheritedColumnHeaderCellStyle(DataGridViewCellStyle inheritedCellStyle, DataGridViewCell cell)
        {
            Debug.Assert(inheritedCellStyle != null);

            DataGridViewCellStyle cellStyle = null;
            if (cell.HasStyle)
            {
                cellStyle = cell.Style;
                Debug.Assert(cellStyle != null);
            }

            DataGridViewCellStyle columnHeadersStyle = ColumnHeadersDefaultCellStyle;
            Debug.Assert(columnHeadersStyle != null);

            DataGridViewCellStyle dataGridViewStyle = DefaultCellStyle;
            Debug.Assert(dataGridViewStyle != null);

            if (cellStyle != null && !cellStyle.BackColor.IsEmpty)
            {
                inheritedCellStyle.BackColor = cellStyle.BackColor;
            }
            else if (!columnHeadersStyle.BackColor.IsEmpty)
            {
                inheritedCellStyle.BackColor = columnHeadersStyle.BackColor;
            }
            else
            {
                inheritedCellStyle.BackColor = dataGridViewStyle.BackColor;
            }

            if (cellStyle != null && !cellStyle.ForeColor.IsEmpty)
            {
                inheritedCellStyle.ForeColor = cellStyle.ForeColor;
            }
            else if (!columnHeadersStyle.ForeColor.IsEmpty)
            {
                inheritedCellStyle.ForeColor = columnHeadersStyle.ForeColor;
            }
            else
            {
                inheritedCellStyle.ForeColor = dataGridViewStyle.ForeColor;
            }

            if (cellStyle != null && !cellStyle.SelectionBackColor.IsEmpty)
            {
                inheritedCellStyle.SelectionBackColor = cellStyle.SelectionBackColor;
            }
            else if (!columnHeadersStyle.SelectionBackColor.IsEmpty)
            {
                inheritedCellStyle.SelectionBackColor = columnHeadersStyle.SelectionBackColor;
            }
            else
            {
                inheritedCellStyle.SelectionBackColor = dataGridViewStyle.SelectionBackColor;
            }

            if (cellStyle != null && !cellStyle.SelectionForeColor.IsEmpty)
            {
                inheritedCellStyle.SelectionForeColor = cellStyle.SelectionForeColor;
            }
            else if (!columnHeadersStyle.SelectionForeColor.IsEmpty)
            {
                inheritedCellStyle.SelectionForeColor = columnHeadersStyle.SelectionForeColor;
            }
            else
            {
                inheritedCellStyle.SelectionForeColor = dataGridViewStyle.SelectionForeColor;
            }

            if (cellStyle != null && cellStyle.Font != null)
            {
                inheritedCellStyle.Font = cellStyle.Font;
            }
            else if (columnHeadersStyle.Font != null)
            {
                inheritedCellStyle.Font = columnHeadersStyle.Font;
            }
            else
            {
                inheritedCellStyle.Font = dataGridViewStyle.Font;
            }

            if (cellStyle != null && !cellStyle.IsNullValueDefault)
            {
                inheritedCellStyle.NullValue = cellStyle.NullValue;
            }
            else if (!columnHeadersStyle.IsNullValueDefault)
            {
                inheritedCellStyle.NullValue = columnHeadersStyle.NullValue;
            }
            else
            {
                inheritedCellStyle.NullValue = dataGridViewStyle.NullValue;
            }

            if (cellStyle != null && !cellStyle.IsDataSourceNullValueDefault)
            {
                inheritedCellStyle.DataSourceNullValue = cellStyle.DataSourceNullValue;
            }
            else if (!columnHeadersStyle.IsDataSourceNullValueDefault)
            {
                inheritedCellStyle.DataSourceNullValue = columnHeadersStyle.DataSourceNullValue;
            }
            else
            {
                inheritedCellStyle.DataSourceNullValue = dataGridViewStyle.DataSourceNullValue;
            }

            if (cellStyle != null && cellStyle.Format.Length != 0)
            {
                inheritedCellStyle.Format = cellStyle.Format;
            }
            else if (columnHeadersStyle.Format.Length != 0)
            {
                inheritedCellStyle.Format = columnHeadersStyle.Format;
            }
            else
            {
                inheritedCellStyle.Format = dataGridViewStyle.Format;
            }

            if (cellStyle != null && !cellStyle.IsFormatProviderDefault)
            {
                inheritedCellStyle.FormatProvider = cellStyle.FormatProvider;
            }
            else if (!columnHeadersStyle.IsFormatProviderDefault)
            {
                inheritedCellStyle.FormatProvider = columnHeadersStyle.FormatProvider;
            }
            else
            {
                inheritedCellStyle.FormatProvider = dataGridViewStyle.FormatProvider;
            }

            if (cellStyle != null && cellStyle.Alignment != DataGridViewContentAlignment.NotSet)
            {
                inheritedCellStyle.AlignmentInternal = cellStyle.Alignment;
            }
            else if (columnHeadersStyle != null && columnHeadersStyle.Alignment != DataGridViewContentAlignment.NotSet)
            {
                inheritedCellStyle.AlignmentInternal = columnHeadersStyle.Alignment;
            }
            else
            {
                Debug.Assert(dataGridViewStyle.Alignment != DataGridViewContentAlignment.NotSet);
                inheritedCellStyle.AlignmentInternal = dataGridViewStyle.Alignment;
            }

            if (cellStyle != null && cellStyle.WrapMode != DataGridViewTriState.NotSet)
            {
                inheritedCellStyle.WrapModeInternal = cellStyle.WrapMode;
            }
            else if (columnHeadersStyle != null && columnHeadersStyle.WrapMode != DataGridViewTriState.NotSet)
            {
                inheritedCellStyle.WrapModeInternal = columnHeadersStyle.WrapMode;
            }
            else
            {
                Debug.Assert(dataGridViewStyle.WrapMode != DataGridViewTriState.NotSet);
                inheritedCellStyle.WrapModeInternal = dataGridViewStyle.WrapMode;
            }

            if (cellStyle != null && cellStyle.Tag != null)
            {
                inheritedCellStyle.Tag = cellStyle.Tag;
            }
            else if (columnHeadersStyle.Tag != null)
            {
                inheritedCellStyle.Tag = columnHeadersStyle.Tag;
            }
            else
            {
                inheritedCellStyle.Tag = dataGridViewStyle.Tag;
            }

            if (cellStyle != null && cellStyle.Padding != Padding.Empty)
            {
                inheritedCellStyle.PaddingInternal = cellStyle.Padding;
            }
            else if (columnHeadersStyle.Padding != Padding.Empty)
            {
                inheritedCellStyle.PaddingInternal = columnHeadersStyle.Padding;
            }
            else
            {
                inheritedCellStyle.PaddingInternal = dataGridViewStyle.Padding;
            }
        }

        private Rectangle CalcColRelocationFeedbackRect(int mouseX)
        {
            Rectangle r, inside = _layout.ColumnHeaders;
            if (_layout.TopLeftHeader.Width > 0)
            {
                inside = Rectangle.Union(_layout.TopLeftHeader, inside);
            }
            if (RightToLeftInternal)
            {
                r = new Rectangle(mouseX + _mouseBarOffset - Columns[_trackColumn].Thickness + 1,
                                  inside.Y,
                                  Columns[_trackColumn].Thickness,
                                  inside.Height);
                r.X = Math.Max(inside.Left, r.X);
                r.X = Math.Min(r.X, inside.Right - r.Width);
            }
            else
            {
                r = new Rectangle(mouseX + _mouseBarOffset - 1, inside.Y, Columns[_trackColumn].Thickness, inside.Height);
                r.X = Math.Min(inside.Right - r.Width, r.X);
                r.X = Math.Max(r.X, inside.Left);
            }
            return r;
        }

        private Rectangle CalcColResizeFeedbackRect(int mouseX)
        {
            Rectangle inside = _layout.Data;
            Rectangle r = new Rectangle(mouseX + _mouseBarOffset - 1, inside.Y, 3, inside.Height);
            if (RightToLeftInternal)
            {
                r.X = Math.Max(inside.Left, r.X);
            }
            else
            {
                r.X = Math.Min(inside.Right - 3, r.X);
                r.X = Math.Max(r.X, 0);
            }
            return r;
        }

        private Rectangle CalcRowResizeFeedbackRect(int mouseY)
        {
            Rectangle inside = _layout.Data;
            Rectangle r = new Rectangle(inside.X, mouseY + _mouseBarOffset - 1, inside.Width, 3);
            r.Y = Math.Min(inside.Bottom - 3, r.Y);
            r.Y = Math.Max(r.Y, 0);
            return r;
        }

        public bool CancelEdit()
        {
            return CancelEdit(false /*endEdit, DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.InitialValueRestoration*/);
        }

        private bool CancelEdit(bool endEdit /*, DataGridViewDataErrorContexts context*/)
        {
            if (_ptCurrentCell.X != -1)
            {
                Debug.Assert(_ptCurrentCell.Y != -1);

                int oldCurrentCellX = _ptCurrentCell.X;
                DataGridViewDataErrorEventArgs dgvdee = CancelEditPrivate(/*ref dataGridViewCurrentCell, context*/);

                if (null != dgvdee)
                {
                    if (dgvdee.ThrowException)
                    {
                        throw dgvdee.Exception;
                    }

                    if (dgvdee.Cancel)
                    {
                        return false;
                    }
                }

                if (IsCurrentCellInEditMode)
                {
                    if (endEdit && EditMode != DataGridViewEditMode.EditOnEnter && EditingControl != null)
                    {
                        bool success = EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.InitialValueRestoration,
                                               DataGridViewValidateCellInternal.Never /*validateCell*/,
                                               false /*fireCellLeave*/,
                                               false /*fireCellEnter*/,
                                               false /*fireRowLeave*/,
                                               false /*fireRowEnter*/,
                                               false /*fireLeave*/,
                                               true /*keepFocus*/,
                                               true /*resetCurrentCell unused here*/,
                                               true /*resetAnchorCell unused here*/);
                        Debug.Assert(success);
                    }
                    else
                    {
                        DataGridViewDataErrorEventArgs dgvdee2 = null;
                        IDataGridViewEditingCell dataGridViewEditingCell = null;
                        try
                        {
                            _dataGridViewState1[State1_IgnoringEditingChanges] = true;
                            if (EditingControl != null)
                            {
                                ((IDataGridViewEditingControl)EditingControl).EditingControlFormattedValue = _uneditedFormattedValue;
                                ((IDataGridViewEditingControl)EditingControl).EditingControlValueChanged = false;
                            }
                            else
                            {
                                Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                                dataGridViewEditingCell = CurrentCellInternal as IDataGridViewEditingCell;
                                Debug.Assert(dataGridViewEditingCell != null);
                                dataGridViewEditingCell.EditingCellFormattedValue = _uneditedFormattedValue;
                                dataGridViewEditingCell.EditingCellValueChanged = false;
                            }
                        }
                        catch (Exception exception)
                        {
                            if (ClientUtils.IsCriticalException(exception))
                            {
                                throw;
                            }
                            dgvdee2 = new DataGridViewDataErrorEventArgs(exception, _ptCurrentCell.X,
                                _ptCurrentCell.Y,
                                DataGridViewDataErrorContexts.InitialValueRestoration);
                        }
                        finally
                        {
                            _dataGridViewState1[State1_IgnoringEditingChanges] = false;
                        }
                        if (dgvdee2 != null)
                        {
                            OnDataErrorInternal(dgvdee2);
                            if (dgvdee2.ThrowException)
                            {
                                throw dgvdee2.Exception;
                            }
                        }

                        if (EditingControl != null)
                        {
                            ((IDataGridViewEditingControl)EditingControl).PrepareEditingControlForEdit(true /*selectAll*/);
                        }
                        else
                        {
                            Debug.Assert(dataGridViewEditingCell != null);
                            dataGridViewEditingCell.PrepareEditingCellForEdit(true /*selectAll*/);
                            InvalidateCellPrivate(_ptCurrentCell.X, _ptCurrentCell.Y);
                        }
                    }
                }
                else if (_ptCurrentCell.X == -1 && Focused)
                {
                    Debug.Assert((AllowUserToAddRowsInternal && Rows.Count == 1) ||
                                 (!AllowUserToAddRowsInternal && Rows.Count == 0));
                    if (Rows.Count > 0)
                    {
                        if (Columns.Count > oldCurrentCellX && Columns[oldCurrentCellX].Visible)
                        {
                            int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                            if (rowIndex != -1)
                            {
                                bool success = SetAndSelectCurrentCellAddress(oldCurrentCellX,
                                                                              rowIndex,
                                                                              true /*setAnchorCellAddress*/,
                                                                              false /*validateCurrentCell*/,
                                                                              false /*throughMouseClick*/,
                                                                              false /*clearSelection*/,
                                                                              false /*forceCurrentCellSelection*/);
                                Debug.Assert(success);
                            }
                        }
                        else
                        {
                            MakeFirstDisplayedCellCurrentCell(true /*includeNewRow*/);
                        }
                    }
                }
            }
            return true;
        }

        private DataGridViewDataErrorEventArgs CancelEditPrivate()
        {
            bool currentCellDirty = IsCurrentCellDirty;
            bool currentRowDirty = IsCurrentRowDirty;

            if (IsCurrentCellInEditMode)
            {
                /* Do not push original value back into the cell

*/
                if (EditingControl != null)
                {
                    ((IDataGridViewEditingControl)EditingControl).EditingControlValueChanged = false;
                }
                else
                {
                    Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                    ((IDataGridViewEditingCell)CurrentCellInternal).EditingCellValueChanged = false;
                }
                IsCurrentCellDirtyInternal = false;
            }

            if (DataSource != null || VirtualMode)
            {
                if ((currentRowDirty && !currentCellDirty) ||
                    (_dataGridViewState1[State1_NewRowEdited] &&
                    !_dataGridViewState1[State1_EditedRowChanged]))
                {
                    bool discardNewRow = _dataGridViewState1[State1_NewRowEdited];
                    IsCurrentRowDirtyInternal = false;
                    if (VirtualMode)
                    {
                        QuestionEventArgs qe = new QuestionEventArgs(discardNewRow);
                        OnCancelRowEdit(qe);
                        discardNewRow &= qe.Response;
                    }
                    if (DataSource != null)
                    {
                        int oldCurrentCellX = _ptCurrentCell.X;
                        DataConnection.CancelRowEdit(true /*restoreRow*/, _dataGridViewState1[State1_NewRowEdited]/*addNewFinished*/);
                        if (DataConnection.List.Count == 0)
                        {
                            // There are no rows left in the back end.
                            if (currentCellDirty || _ptCurrentCell.Y == -1 || _ptCurrentCell.X == -1)
                            {
                                if (!IsColumnOutOfBounds(oldCurrentCellX) && Columns[oldCurrentCellX].Visible)
                                {
                                    Debug.Assert(0 == Rows.GetFirstRow(DataGridViewElementStates.Visible));
                                    // Setting the current cell to the current column in the first row
                                    // will create the new row if the user was editing the cell.
                                    SetAndSelectCurrentCellAddress(oldCurrentCellX,
                                                                   0,
                                                                   true,  /*setAnchorCellAddress*/
                                                                   false, /*validateCurrentCell*/
                                                                   false,  /*throughMouseClick*/
                                                                   true /*clearSelecttion*/,
                                                                   false /*forceCurrentCellSelection (unused)*/);
                                }
                            }
                            else
                            {
                                // Else, simply add a new row.
                                DataConnection.OnNewRowNeeded();
                            }
                        }

                        // CancelRowEdit discarded the new row if we were editing the new row.
                        discardNewRow = false;
                    }
                    if (_ptCurrentCell.Y > -1)
                    {
                        InvalidateRowPrivate(_ptCurrentCell.Y);
                        DataGridViewCell dataGridViewCell = CurrentCellInternal;
                        if (IsCurrentCellInEditMode)
                        {
                            DataGridViewCellStyle dataGridViewCellStyle = dataGridViewCell.GetInheritedStyle(null, _ptCurrentCell.Y, true);
                            if (EditingControl != null)
                            {
                                InitializeEditingControlValue(ref dataGridViewCellStyle, dataGridViewCell);
                                if (((IDataGridViewEditingControl)EditingControl).RepositionEditingControlOnValueChange)
                                {
                                    PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                                }
                            }
                            else
                            {
                                Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                                InitializeEditingCellValue(ref dataGridViewCellStyle, ref dataGridViewCell);
                            }
                        }
                    }
                    if (discardNewRow && _ptCurrentCell.Y == NewRowIndex - 1)
                    {
                        DiscardNewRow();
                    }
                }
            }
            else
            {
                if (!IsCurrentRowDirty &&
                    _ptCurrentCell.Y == NewRowIndex - 1 &&
                    _dataGridViewState1[State1_NewRowCreatedByEditing])
                {
                    DiscardNewRow();
                }
            }
            return null;
        }

        internal bool CancelToolTipPopup(ToolTip toolTip)
        {
            if (_toolTipControl.ToolTip == toolTip || KeyboardToolTip == toolTip)
            {
                // Our own tool tip wants to show its text.
                return false;
            }
            else
            {
                // This is an external tool tip control which wants to show a tool tip over the DataGridView.
                // ToolTips from the data Grid view ( the error text, or the formatted text that does not fit in, or the tool tip text from the cell)
                // and the ShowCellToolTips take precedence over the external tool tip.
                return string.IsNullOrEmpty(ToolTipPrivate) && ShowCellToolTips;
            }
        }

        private bool CanSort(DataGridViewColumn dataGridViewColumn)
        {
            return dataGridViewColumn.SortMode == DataGridViewColumnSortMode.Automatic && (!VirtualMode || dataGridViewColumn.IsDataBound);
        }

        private bool IsSortable(DataGridViewColumn dataGridViewColumn)
        {
            return dataGridViewColumn.SortMode != DataGridViewColumnSortMode.NotSortable && (!VirtualMode || dataGridViewColumn.IsDataBound);
        }

        // determines if a data bound cell can be validated or not
        private bool CanValidateDataBoundDataGridViewCell(DataGridViewCell dataGridViewCurrentCell)
        {
            if (dataGridViewCurrentCell is null)
            {
                if (_ptCurrentCell.X > -1)
                {
                    dataGridViewCurrentCell = CurrentCellInternal;
                }
            }

            if (dataGridViewCurrentCell is null)
            {
                return true;
            }

            Debug.Assert(dataGridViewCurrentCell.OwningColumn != null);

            if (!dataGridViewCurrentCell.OwningColumn.IsDataBoundInternal)
            {
                // we are not data bound so it's not up to us to decide to stop validation
                return true;
            }

            if (_dataGridViewOper[OperationInDispose])
            {
                // Dispose is not the place to validate data. Also, chances are that the data source is also disposing itself.
                return false;
            }

            if (DataConnection is null)
            {
                // if there is no dataConnection then it is not up to this function to stop validation.
                return true;
            }

            /////////////////////////////////////////////////////////////////////////////////////////////////
            //                                                                                             //
            // FROM HERE DOWN THE DATA CONNECTION DETERMINES IF THE DATAGRIDVIEW SHOULD VALIDATE THE CELL. //
            //                                                                                             //
            /////////////////////////////////////////////////////////////////////////////////////////////////
            if (DataConnection.ProcessingMetaDataChanges)
            {
                // don't validate a cell in a data bound column while the property descriptors change under us
                return false;
            }

            if (DataConnection.CancellingRowEdit && !DataConnection.RestoreRow)
            {
                // don't validate a cell in a data bound column while we are cancelling a row edit and the old row is not restored
                return false;
            }

            if (DataConnection.CurrencyManager.Count <= _ptCurrentCell.Y)
            {
                // don't validate a row beyond the last row in the back end list
                return false;
            }

            if (DataConnection.PositionChangingOutsideDataGridView)
            {
                // the position changed outside the data grid view and we haven't validated the data grid view cell already
                // we can't validate it now because if the user cancels validation then we end up
                // with a position different than the position in the currency manager
                return false;
            }

            if (DataConnection.ListWasReset)
            {
                // The list was reset outside data grid view.
                // We can't validate it now because we would be pushing a value into a different object ( possibly located in a different list ).
                return false;
            }

            return true;
        }

        private void CaptureMouse(Rectangle cursorClip)
        {
            Capture = true;
            Cursor.Clip = RectangleToScreen(cursorClip);
        }

        private void ClearRegionCache()
        {
            _cachedScrollableRegion = null;
        }

        public void ClearSelection()
        {
            _noDimensionChangeCount++;
            _noSelectionChangeCount++;

            bool switchedToBulkPaint = false;

            if (_selectedBandIndexes.Count > BulkPaintThreshold ||
                _individualSelectedCells.Count > BulkPaintThreshold)
            {
                _inBulkPaintCount++;
                switchedToBulkPaint = true;
            }
            try
            {
                RemoveIndividuallySelectedCells();
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        {
                            // If we change the design and start using this.selectedBandIndexes in this SelectionMode,
                            // we'll have to clear those selections too.
                            break;
                        }

                    case DataGridViewSelectionMode.FullRowSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        {
                            while (_selectedBandIndexes.Count > 0)
                            {
                                SetSelectedRowCore(_selectedBandIndexes.HeadInt, false);
                            }

                            // Force repainting of the current collumn's header cell to remove highlighting
                            if (_ptCurrentCell.X != -1 &&
                                SelectionMode == DataGridViewSelectionMode.FullRowSelect)
                            {
                                InvalidateCellPrivate(_ptCurrentCell.X, -1);
                            }
                            break;
                        }

                    case DataGridViewSelectionMode.FullColumnSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        {
                            while (_selectedBandIndexes.Count > 0)
                            {
                                SetSelectedColumnCore(_selectedBandIndexes.HeadInt, false);
                            }
                            break;
                        }
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
                NoSelectionChangeCount--;
                if (switchedToBulkPaint)
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        protected void ClearSelection(int columnIndexException, int rowIndexException, bool selectExceptionElement)
        {
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.CellSelect:
                case DataGridViewSelectionMode.FullColumnSelect:
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    {
                        if (columnIndexException < 0 || columnIndexException >= Columns.Count)
                        {
                            throw new ArgumentOutOfRangeException(nameof(columnIndexException));
                        }
                        break;
                    }

                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    {
                        if (columnIndexException < -1 || columnIndexException >= Columns.Count)
                        {
                            throw new ArgumentOutOfRangeException(nameof(columnIndexException));
                        }
                        break;
                    }
            }

            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.CellSelect:
                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    {
                        if (rowIndexException < 0 || rowIndexException >= Rows.Count)
                        {
                            throw new ArgumentOutOfRangeException(nameof(rowIndexException));
                        }
                        break;
                    }

                case DataGridViewSelectionMode.FullColumnSelect:
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    {
                        if (rowIndexException < -1 || rowIndexException >= Rows.Count)
                        {
                            throw new ArgumentOutOfRangeException(nameof(rowIndexException));
                        }
                        break;
                    }
            }

            // Clears all selection except the row/column/cell specified as parameter
            _noDimensionChangeCount++;
            _noSelectionChangeCount++;

            bool switchedToBulkPaint = false;

            if (_selectedBandIndexes.Count > BulkPaintThreshold ||
                _individualSelectedCells.Count > BulkPaintThreshold)
            {
                _inBulkPaintCount++;
                switchedToBulkPaint = true;
            }
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        {
                            // If we change the design and start using this.selectedBandIndexes in this SelectionMode,
                            // we'll have to clear those selections too.
                            RemoveIndividuallySelectedCells(columnIndexException, rowIndexException);
                            break;
                        }

                    case DataGridViewSelectionMode.FullRowSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        {
                            int bandIndex = 0;
                            while (bandIndex < _selectedBandIndexes.Count)
                            {
                                if (_selectedBandIndexes[bandIndex] != rowIndexException)
                                {
                                    // deselect currently selected row
                                    SetSelectedRowCore(_selectedBandIndexes[bandIndex], false);
                                }
                                else
                                {
                                    bandIndex++;
                                }
                            }
                            if (SelectionMode == DataGridViewSelectionMode.RowHeaderSelect)
                            {
                                RemoveIndividuallySelectedCells(columnIndexException, rowIndexException);
                            }
                            break;
                        }

                    case DataGridViewSelectionMode.FullColumnSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        {
                            int bandIndex = 0;
                            while (bandIndex < _selectedBandIndexes.Count)
                            {
                                if (_selectedBandIndexes[bandIndex] != columnIndexException)
                                {
                                    // deselect currently selected column
                                    SetSelectedColumnCore(_selectedBandIndexes[bandIndex], false);
                                }
                                else
                                {
                                    bandIndex++;
                                }
                            }
                            if (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect)
                            {
                                RemoveIndividuallySelectedCells(columnIndexException, rowIndexException);
                            }
                            break;
                        }
                }
                if (selectExceptionElement)
                {
                    SetSelectedElementCore(columnIndexException, rowIndexException, true);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
                NoSelectionChangeCount--;
                if (switchedToBulkPaint)
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        private bool ColumnEditable(int columnIndex)
        {
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count, "Invalid columnIndex: " + columnIndex);
            if (Columns[columnIndex].IsDataBound &&
                DataConnection != null &&
                !DataConnection.AllowEdit)
            {
                return false;
            }
            return true;
        }

        private bool ColumnNeedsDisplayedState(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);

            if (!dataGridViewColumn.Visible)
            {
                return false;
            }

            if (dataGridViewColumn.Frozen)
            {
                DataGridViewColumn firstVisibleFrozenColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                Debug.Assert(firstVisibleFrozenColumn != null);
                if (firstVisibleFrozenColumn.Index == dataGridViewColumn.Index)
                {
                    return DisplayedBandsInfo.NumDisplayedFrozenCols > 0;
                }
                Debug.Assert(Columns.DisplayInOrder(firstVisibleFrozenColumn.Index, dataGridViewColumn.Index));
                return Columns.GetColumnCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen, firstVisibleFrozenColumn.Index, dataGridViewColumn.Index) < DisplayedBandsInfo.NumDisplayedFrozenCols;
            }
            else
            {
                int firstDisplayedScrollingColumnIndex = DisplayedBandsInfo.FirstDisplayedScrollingCol;
                if (firstDisplayedScrollingColumnIndex != -1)
                {
                    if (firstDisplayedScrollingColumnIndex == dataGridViewColumn.Index)
                    {
                        return DisplayedBandsInfo.NumDisplayedScrollingCols > 0;
                    }
                    if (Columns.DisplayInOrder(firstDisplayedScrollingColumnIndex, dataGridViewColumn.Index))
                    {
                        return Columns.GetColumnCount(DataGridViewElementStates.Visible, firstDisplayedScrollingColumnIndex, dataGridViewColumn.Index) < DisplayedBandsInfo.NumDisplayedScrollingCols;
                    }
                }
            }
            return false;
        }

        private bool ColumnRelocationTarget(MouseEventArgs e, HitTestInfo hti, out int previousColumnIndex)
        {
            previousColumnIndex = -1;
            if (hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeadersResizeBottom ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeader ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnResizeLeft ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnResizeRight ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeaderLeft ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeaderRight)
            {
                Debug.Assert(hti._col != -1);
                if (hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeadersResizeBottom ||
                    hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeader)
                {
                    int xColumnLeftEdge = GetColumnXFromIndex(hti._col);
                    int wColumn = Columns[hti._col].Width;
                    if ((RightToLeftInternal && e.X < xColumnLeftEdge - wColumn / 2) ||
                        (!RightToLeftInternal && e.X > xColumnLeftEdge + wColumn / 2))
                    {
                        // Insert column on the right of hti.col
                        previousColumnIndex = hti._col;
                    }
                    else
                    {
                        // Insert column on the left of hti.col
                        DataGridViewColumn dataGridViewColumnPrev = Columns.GetPreviousColumn(Columns[hti._col],
                                                                                                            DataGridViewElementStates.Visible,
                                                                                                            DataGridViewElementStates.None);
                        if (dataGridViewColumnPrev != null)
                        {
                            previousColumnIndex = dataGridViewColumnPrev.Index;
                        }
                    }
                }
                else
                {
                    previousColumnIndex = (hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnResizeRight || hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeaderRight) ?
                                          hti._col : hti._adjacentCol;
                }
                DataGridViewColumn dataGridViewColumnNext = null;
                if (previousColumnIndex != -1)
                {
                    dataGridViewColumnNext = Columns.GetNextColumn(Columns[previousColumnIndex],
                                                                                 DataGridViewElementStates.Visible,
                                                                                 DataGridViewElementStates.None);
                }
                if (_trackColumn != previousColumnIndex &&
                    !(previousColumnIndex == -1 && hti._col == _trackColumn) &&
                    (dataGridViewColumnNext is null || _trackColumn != dataGridViewColumnNext.Index))
                {
                    return true;
                }
            }
            else if (hti._typeInternal == DataGridViewHitTestTypeInternal.FirstColumnHeaderLeft ||
                     hti._typeInternal == DataGridViewHitTestTypeInternal.TopLeftHeaderResizeRight)
            {
                Debug.Assert(hti._col != -1);
                if (hti._col != _trackColumn)
                {
                    return true;
                }
            }
            return false;
        }

        private static bool ColumnsDisplayInOrder(int columnIndex1,
            int columnDisplayIndex1,
            int columnIndex2,
            int columnDisplayIndex2)
        {
            return columnDisplayIndex1 < columnDisplayIndex2 ||
                (columnDisplayIndex1 == columnDisplayIndex2 && columnIndex1 < columnIndex2);
        }

        public bool CommitEdit(DataGridViewDataErrorContexts context)
        {
            if (IsCurrentCellInEditMode)
            {
                DataGridViewCell dataGridViewCurrentCell = CurrentCellInternal;
                DataGridViewDataErrorEventArgs dgvdee = CommitEdit(ref dataGridViewCurrentCell,
                    context,
                    DataGridViewValidateCellInternal.Never,
                    false /*fireCellLeave*/,
                    false /*fireCellEnter*/,
                    false /*fireRowLeave*/,
                    false /*fireRowEnter*/,
                    false /*fireLeave*/);
                if (null != dgvdee)
                {
                    if (dgvdee.ThrowException)
                    {
                        throw dgvdee.Exception;
                    }
                    if (dgvdee.Cancel)
                    {
                        return false;
                    }
                }
            }
            return true;
        }

        private DataGridViewDataErrorEventArgs CommitEdit(ref DataGridViewCell dataGridViewCurrentCell,
            DataGridViewDataErrorContexts context,
            DataGridViewValidateCellInternal validateCell,
            bool fireCellLeave,
            bool fireCellEnter,
            bool fireRowLeave,
            bool fireRowEnter,
            bool fireLeave)
        {
            if (validateCell == DataGridViewValidateCellInternal.Always)
            {
                Debug.Assert(_ptCurrentCell.X > -1);
                if (fireCellLeave)
                {
                    if (_ptCurrentCell.X == -1)
                    {
                        return null;
                    }
                    OnCellLeave(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y);
                }
                if (fireRowLeave)
                {
                    if (_ptCurrentCell.X == -1)
                    {
                        return null;
                    }
                    OnRowLeave(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y);
                }
                if (fireLeave)
                {
                    base.OnLeave(EventArgs.Empty);

                    // Microsoft: can we be smarter about this? What if validating the current cell below forces a repaint on the cell?
                    // we would end up repainting the current cell twice.
                    //
                    // invalidate the current cell so the data grid view does not paint the focus rectangle any longer
                    if (_ptCurrentCell.X > -1 && _ptCurrentCell.Y > -1)
                    {
                        InvalidateCellPrivate(_ptCurrentCell.X /*columnIndex*/, _ptCurrentCell.Y /*rowIndex*/);
                    }
                }
                // OnCellValidating returns true if the dev cancelled the validation.
                bool validateFormattedValue = CanValidateDataBoundDataGridViewCell(dataGridViewCurrentCell);
                if (validateFormattedValue)
                {
                    if (_ptCurrentCell.X == -1)
                    {
                        return null;
                    }
                    if (OnCellValidating(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y, context))
                    {
                        if (fireRowEnter)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                return null;
                            }
                            OnRowEnter(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y, true /*canCreateNewRow*/, true /*validationFailureOccurred*/);
                        }
                        if (fireCellEnter)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                return null;
                            }
                            OnCellEnter(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y);
                        }
                        if (_ptCurrentCell.X == -1)
                        {
                            return null;
                        }
                        DataGridViewDataErrorEventArgs dgvdee = new DataGridViewDataErrorEventArgs(null,
                                                                                    _ptCurrentCell.X,
                                                                                    _ptCurrentCell.Y,
                                                                                    // null,
                                                                                    // null,
                                                                                    context)
                        {
                            Cancel = true
                        };
                        return dgvdee;
                    }

                    if (!IsCurrentCellInEditMode || !IsCurrentCellDirty)
                    {
                        if (_ptCurrentCell.X == -1)
                        {
                            return null;
                        }
                        OnCellValidated(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y);
                    }
                }
            }

            if (_ptCurrentCell.X == -1 || !IsCurrentCellInEditMode)
            {
                return null;
            }

            Debug.Assert(
                 (
                  (EditingControl != null && ((IDataGridViewEditingControl)EditingControl).EditingControlValueChanged) ||
                  (_dataGridViewState1[State1_CurrentCellInEditMode] && ((IDataGridViewEditingCell)CurrentCellInternal).EditingCellValueChanged)
                 ) == IsCurrentCellDirty ||
                 _dataGridViewState1[State1_IgnoringEditingChanges]);

            if (IsCurrentCellDirty)
            {
                bool validateAndPushFormattedValue = CanValidateDataBoundDataGridViewCell(dataGridViewCurrentCell);
                if (validateAndPushFormattedValue)
                {
                    if (validateCell == DataGridViewValidateCellInternal.WhenChanged)
                    {
                        Debug.Assert(_ptCurrentCell.X > -1);
                        if (_ptCurrentCell.X == -1)
                        {
                            return null;
                        }
                        if (OnCellValidating(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y, context))
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                return null;
                            }
                            DataGridViewDataErrorEventArgs dgvdee = new DataGridViewDataErrorEventArgs(null,
                                                                                                       _ptCurrentCell.X,
                                                                                                       _ptCurrentCell.Y,
                                                                                                       context)
                            {
                                Cancel = true
                            };
                            return dgvdee;
                        }
                    }

                    object formattedValue;

                    if (EditingControl != null)
                    {
                        formattedValue = ((IDataGridViewEditingControl)EditingControl).GetEditingControlFormattedValue(context);
                    }
                    else
                    {
                        Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                        formattedValue = ((IDataGridViewEditingCell)CurrentCellInternal).GetEditingCellFormattedValue(context);
                    }

                    if (!PushFormattedValue(ref dataGridViewCurrentCell, formattedValue, out Exception exception))
                    {
                        if (_ptCurrentCell.X == -1)
                        {
                            return null;
                        }
                        DataGridViewDataErrorEventArgs dgvdee = new DataGridViewDataErrorEventArgs(exception,
                                                                                    _ptCurrentCell.X,
                                                                                    _ptCurrentCell.Y,
                                                                                    // dataGridViewCurrentCell.Value,
                                                                                    // formattedValue,
                                                                                    context)
                        {
                            Cancel = true
                        };
                        OnDataErrorInternal(dgvdee);
                        return dgvdee;
                    }
                    if (!IsCurrentCellInEditMode)
                    {
                        return null;
                    }
                    _uneditedFormattedValue = formattedValue;
                }

                if (EditingControl != null)
                {
                    ((IDataGridViewEditingControl)EditingControl).EditingControlValueChanged = false;
                }
                else
                {
                    Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                    ((IDataGridViewEditingCell)CurrentCellInternal).EditingCellValueChanged = false;
                }
                IsCurrentCellDirtyInternal = false;
                IsCurrentRowDirtyInternal = true;

                if (validateAndPushFormattedValue)
                {
                    if (validateCell == DataGridViewValidateCellInternal.Always ||
                        validateCell == DataGridViewValidateCellInternal.WhenChanged)
                    {
                        if (_ptCurrentCell.X == -1)
                        {
                            return null;
                        }
                        OnCellValidated(ref dataGridViewCurrentCell, _ptCurrentCell.X, _ptCurrentCell.Y);
                    }
                }
            }
            return null;
        }

        private bool CommitEdit(DataGridViewDataErrorContexts context,
                                bool forCurrentCellChange,
                                bool forCurrentRowChange)
        {
            // If we're already within a CellValidating event handler, don't try to commit the cell again.
            if (_dataGridViewOper[OperationInCellValidating])
            {
                return false;
            }

            DataGridViewCell dataGridViewCurrentCell = CurrentCellInternal;
            DataGridViewDataErrorEventArgs dgvdee = CommitEdit(ref dataGridViewCurrentCell,
                context,
                forCurrentCellChange ? DataGridViewValidateCellInternal.Always : DataGridViewValidateCellInternal.WhenChanged /*validateCell*/,
                forCurrentCellChange /*fireCellLeave*/,
                forCurrentCellChange /*fireCellEnter*/,
                forCurrentRowChange /*fireRowLeave*/,
                forCurrentRowChange /*fireRowEnter*/,
                false /*fireLeave*/);
            if (null != dgvdee)
            {
                if (dgvdee.ThrowException)
                {
                    throw dgvdee.Exception;
                }
                if (dgvdee.Cancel)
                {
                    return false;
                }

                // Restore old value
                dgvdee = CancelEditPrivate();
                if (null != dgvdee)
                {
                    if (dgvdee.ThrowException)
                    {
                        throw dgvdee.Exception;
                    }
                    if (dgvdee.Cancel)
                    {
                        return false;
                    }
                }
            }

            // See if we can leave the row
            if (forCurrentRowChange && forCurrentCellChange)
            {
                Debug.Assert(_ptCurrentCell.X > -1);
                if (_ptCurrentCell.X == -1)
                {
                    return false;
                }
                int columnIndex = _ptCurrentCell.X;
                int rowIndex = _ptCurrentCell.Y;
                // OnRowValidating returns true when the row validation was cancelled.
                if (OnRowValidating(ref dataGridViewCurrentCell, columnIndex, rowIndex))
                {
                    if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                    {
                        return false;
                    }
                    OnRowEnter(ref dataGridViewCurrentCell, columnIndex, rowIndex, true /*canCreateNewRow*/, true /*validationFailureOccurred*/);
                    if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                    {
                        return false;
                    }
                    OnCellEnter(ref dataGridViewCurrentCell, columnIndex, rowIndex);
                    return false;
                }
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    return false;
                }
                OnRowValidated(ref dataGridViewCurrentCell, columnIndex, rowIndex);
            }
            return true;
        }

        private bool CommitEditForOperation(int columnIndex, int rowIndex, bool forCurrentCellChange)
        {
            if (forCurrentCellChange)
            {
                if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.CurrentCellChange,
                                DataGridViewValidateCellInternal.Always /*validateCell*/,
                                true /*fireCellLeave*/,
                                true /*fireCellEnter*/,
                                _ptCurrentCell.Y != rowIndex /*fireRowLeave*/,
                                _ptCurrentCell.Y != rowIndex /*fireRowEnter*/,
                                false /*fireLeave*/,
                                EditMode != DataGridViewEditMode.EditOnEnter /*keepFocus*/,
                                false /*resetCurrentCell*/,
                                false /*resetAnchorCell unused here*/))
                {
                    return false;
                }
                if (_ptCurrentCell.Y != rowIndex && _ptCurrentCell.Y != -1)
                {
                    DataGridViewCell dataGridViewCellTmp = null;
                    int columnIndexTmp = _ptCurrentCell.X;
                    int rowIndexTmp = _ptCurrentCell.Y;
                    if (OnRowValidating(ref dataGridViewCellTmp, columnIndexTmp, rowIndexTmp))
                    {
                        // Row validation was cancelled
                        if (IsInnerCellOutOfBounds(columnIndexTmp, rowIndexTmp))
                        {
                            return false;
                        }
                        OnRowEnter(ref dataGridViewCellTmp, columnIndexTmp, rowIndexTmp, true /*canCreateNewRow*/, true /*validationFailureOccurred*/);
                        if (IsInnerCellOutOfBounds(columnIndexTmp, rowIndexTmp))
                        {
                            return false;
                        }
                        OnCellEnter(ref dataGridViewCellTmp, columnIndexTmp, rowIndexTmp);
                        if (IsInnerCellOutOfBounds(columnIndexTmp, rowIndexTmp))
                        {
                            return false;
                        }

                        // Re-enter editing mode if needed
                        if (Focused &&
                            (!IsCurrentCellInEditMode && (EditMode == DataGridViewEditMode.EditOnEnter ||
                            (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null))))
                        {
                            BeginEditInternal(true /*selectAll*/);
                        }

                        return false;
                    }
                    if (IsInnerCellOutOfBounds(columnIndexTmp, rowIndexTmp))
                    {
                        return false;
                    }
                    OnRowValidated(ref dataGridViewCellTmp, columnIndexTmp, rowIndexTmp);
                }
            }
            else
            {
                if (!CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                false /*forCurrentCellChange*/,
                                _ptCurrentCell.Y != rowIndex /*forCurrentRowChange*/))
                {
                    return false;
                }
            }

            // Row validation was not cancelled, but operation needs to be re-evaluated.
            Debug.Assert(columnIndex < Columns.Count);
            if (IsColumnOutOfBounds(columnIndex))
            {
                return false;
            }
            if (rowIndex >= Rows.Count)
            {
                // CurrentCell was reset because the commit deleted row(s).
                // Since the user wants to change the current cell, we don't
                // want to end up with no CurrentCell. We pick the last visible
                // row in the grid which may be the 'new row'.
                int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
                if (forCurrentCellChange &&
                    _ptCurrentCell.X == -1 &&
                    lastVisibleRowIndex != -1)
                {
                    bool success = SetAndSelectCurrentCellAddress(columnIndex, lastVisibleRowIndex, true, false, false, false /*clearSelection*/, false /*forceCurrentCellSelection*/);
                    Debug.Assert(success);
                }
                // Interrupt operation because it has become invalid.
                return false;
            }
            if (rowIndex > -1 && (Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) == 0)
            {
                // Interrupt operation because target row has become invisible.
                return false;
            }
            return true;
        }

        internal void CompleteCellsCollection(DataGridViewRow dataGridViewRow)
        {
            Debug.Assert(dataGridViewRow != null);
            int cellsInCollection = dataGridViewRow.Cells.Count;
            if (Columns.Count > cellsInCollection)
            {
                int cellCount = 0;
                DataGridViewCell[] cells = new DataGridViewCell[Columns.Count - cellsInCollection];
                for (int columnIndex = cellsInCollection; columnIndex < Columns.Count; columnIndex++)
                {
                    if (Columns[columnIndex].CellTemplate is null)
                    {
                        throw new InvalidOperationException(SR.DataGridView_AColumnHasNoCellTemplate);
                    }
                    DataGridViewCell dgvcNew = (DataGridViewCell)Columns[columnIndex].CellTemplate.Clone();
                    cells[cellCount] = dgvcNew;
                    cellCount++;
                }
                dataGridViewRow.Cells.AddRange(cells);
            }
        }

        /// <summary>
        ///  Determines which column is the first visible scrolling
        ///  column given the object's horizontalOffset.
        /// </summary>
        private int ComputeFirstVisibleScrollingColumn()
        {
            if (Columns.GetColumnsWidth(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) >= _layout.Data.Width)
            {
                // Not enough room for scrolling columns.
                FirstDisplayedScrollingColumnHiddenWidth = 0;
                return -1;
            }

            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);

            if (_horizontalOffset == 0)
            {
                FirstDisplayedScrollingColumnHiddenWidth = 0;
                return (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            }

            int cx = 0;
            while (dataGridViewColumn != null)
            {
                cx += dataGridViewColumn.Thickness;
                if (cx > _horizontalOffset)
                {
                    break;
                }
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
            }

            if (dataGridViewColumn is null)
            {
                Debug.Assert(cx <= _horizontalOffset);
                dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                if (dataGridViewColumn is null)
                {
                    FirstDisplayedScrollingColumnHiddenWidth = 0;
                    return -1;
                }
                else
                {
                    if (FirstDisplayedScrollingColumnHiddenWidth != _horizontalOffset)
                    {
                        FirstDisplayedScrollingColumnHiddenWidth = 0;
                    }
                    return dataGridViewColumn.Index;
                }
            }
            else
            {
                FirstDisplayedScrollingColumnHiddenWidth = dataGridViewColumn.Thickness - (cx - _horizontalOffset);
                return dataGridViewColumn.Index;
            }
        }

        private int ComputeHeightOfFittingTrailingScrollingRows(int totalVisibleFrozenHeight)
        {
            //
            int displayHeight = _layout.Data.Height - totalVisibleFrozenHeight;
            int rowHeight = 0, rowHeights = 0;
            int indexTmp = Rows.Count;

            if (indexTmp == 0 || displayHeight <= 0)
            {
                return 0;
            }
            else
            {
                indexTmp--;
            }

            DataGridViewElementStates rowState = Rows.GetRowState(indexTmp);
            if ((rowState & DataGridViewElementStates.Frozen) != 0)
            {
                return 0;
            }
            if ((rowState & DataGridViewElementStates.Visible) == 0)
            {
                indexTmp = Rows.GetPreviousRow(indexTmp,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.Frozen);
            }

            if (indexTmp != -1)
            {
                rowHeight = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                if (rowHeight > displayHeight)
                {
                    return rowHeight;
                }
            }

            while (indexTmp != -1 && rowHeights + rowHeight <= displayHeight)
            {
                rowHeights += rowHeight;
                indexTmp = Rows.GetPreviousRow(indexTmp,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.Frozen);
                if (indexTmp != -1)
                {
                    rowHeight = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                }
            }

            return rowHeights;
        }

        private int ComputeHeightOfScrolledOffRows()
        {
            //
            int height = 0;
            if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0)
            {
                int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                if (rowIndex != -1)
                {
                    while (rowIndex != DisplayedBandsInfo.FirstDisplayedScrollingRow)
                    {
                        Debug.Assert(rowIndex < DisplayedBandsInfo.FirstDisplayedScrollingRow);
                        height += Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                        rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                    }
                }
            }
            return height;
        }

        private int ComputeHeightOfTrailingScrollingRows()
        {
            if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0)
            {
                int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
                return Rows.GetRowsHeight(DataGridViewElementStates.Visible, DisplayedBandsInfo.FirstDisplayedScrollingRow, lastVisibleRowIndex) +
                       Rows.SharedRow(lastVisibleRowIndex).GetHeight(lastVisibleRowIndex);
            }
            return 0;
        }

        private bool ComputeLayout()
        {
            ClearRegionCache();

            LayoutData newLayout = new LayoutData(_layout);
            Rectangle oldResizeRect = _layout.ResizeBoxRect;

            // Inside region
            if (_normalClientRectangle.Width > 0 || _normalClientRectangle.Height > 0)
            {
                newLayout.Inside = _normalClientRectangle;
            }
            else
            {
                newLayout.Inside = ClientRectangle;
            }
            Rectangle inside = newLayout.Inside;
            int borderWidth = BorderWidth;
            inside.Inflate(-borderWidth, -borderWidth);
            if (inside.Height < 0)
            {
                inside.Height = 0;
            }
            if (inside.Width < 0)
            {
                inside.Width = 0;
            }

            Rectangle insideLeft = inside;

            // Headers
            if (_layout.ColumnHeadersVisible)
            {
                Rectangle colHeaders = insideLeft;
                colHeaders.Height = Math.Min(_columnHeadersHeight, colHeaders.Height);
                insideLeft.Y += colHeaders.Height;
                insideLeft.Height -= colHeaders.Height;
                Debug.Assert(insideLeft.Height >= 0);
                newLayout.ColumnHeaders = colHeaders;
            }
            else
            {
                newLayout.ColumnHeaders = Rectangle.Empty;
            }

            if (_layout.RowHeadersVisible)
            {
                Rectangle rowHeaders = insideLeft;
                rowHeaders.Width = Math.Min(RowHeadersWidth, rowHeaders.Width);
                if (RightToLeftInternal)
                {
                    rowHeaders.X += insideLeft.Width - rowHeaders.Width;
                }
                else
                {
                    insideLeft.X += rowHeaders.Width;
                }
                insideLeft.Width -= rowHeaders.Width;
                Debug.Assert(insideLeft.Width >= 0);
                newLayout.RowHeaders = rowHeaders;

                if (_layout.ColumnHeadersVisible)
                {
                    Rectangle topLeft;
                    Rectangle colHeaders = newLayout.ColumnHeaders;
                    topLeft = colHeaders;
                    topLeft.Width = Math.Min(RowHeadersWidth, topLeft.Width);
                    colHeaders.Width -= topLeft.Width;
                    if (RightToLeftInternal)
                    {
                        topLeft.X += insideLeft.Width;
                    }
                    else
                    {
                        colHeaders.X += topLeft.Width;
                    }
                    Debug.Assert(colHeaders.Width >= 0);
                    newLayout.TopLeftHeader = topLeft;
                    newLayout.ColumnHeaders = colHeaders;
                }
                else
                {
                    newLayout.TopLeftHeader = Rectangle.Empty;
                }
            }
            else
            {
                newLayout.RowHeaders = Rectangle.Empty;
                newLayout.TopLeftHeader = Rectangle.Empty;
            }

            // Adjust insideLeft in case static top / left edge needs to be painted
            if (SingleVerticalBorderAdded)
            {
                if (!RightToLeftInternal)
                {
                    insideLeft.X++;
                }
                if (insideLeft.Width > 0)
                {
                    insideLeft.Width--;
                }
            }
            if (SingleHorizontalBorderAdded)
            {
                insideLeft.Y++;
                if (insideLeft.Height > 0)
                {
                    insideLeft.Height--;
                }
            }

            // Data region
            newLayout.Data = insideLeft;
            newLayout.Inside = inside;

            Debug.Assert(newLayout.Data.X >= 0);
            Debug.Assert(newLayout.Data.Y >= 0);
            Debug.Assert(newLayout.Data.Width >= 0);
            Debug.Assert(newLayout.Data.Height >= 0);

            _layout = newLayout;
            _layout._dirty = false;

            bool columnsAdjusted = AdjustFillingColumns();

            _layout = newLayout;
            Debug.Assert(!_layout._dirty);
            LayoutScrollBars();

            // if the user shrank the grid client area, then OnResize invalidated the old
            // resize area. however, we need to invalidate the left upper corner in the new ResizeArea
            // note that we can't take the Invalidate call from the OnResize method, because if the
            // user enlarges the form then the old area will not be invalidated.
            //
            if (!oldResizeRect.Equals(_layout.ResizeBoxRect) && !_layout.ResizeBoxRect.IsEmpty)
            {
                Invalidate(_layout.ResizeBoxRect);
            }

            return columnsAdjusted;
        }

        private void ComputeLayoutShortcut(bool computeVisibleRows)
        {
            // Called instead of ComputeLayout when a row is added, inserted or deleted beyond the limits of
            // the layout.Data area.
            // this.layout is unchanged - only the potential vertical scrollbar is affected.

            if (computeVisibleRows)
            {
                ComputeVisibleRows();
            }
#if DEBUG
            else
            {
                int oldNumTotallyVisibleFrozenRows = DisplayedBandsInfo.NumTotallyDisplayedFrozenRows;
                int oldNumVisibleScrollingRows = DisplayedBandsInfo.NumDisplayedScrollingRows;
                int oldNumTotallyVisibleScrollingRows = DisplayedBandsInfo.NumTotallyDisplayedScrollingRows;
                int oldFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                ComputeVisibleRows();
                Debug.Assert(oldNumTotallyVisibleFrozenRows == DisplayedBandsInfo.NumTotallyDisplayedFrozenRows);
                Debug.Assert(oldNumVisibleScrollingRows == DisplayedBandsInfo.NumDisplayedScrollingRows);
                Debug.Assert(oldNumTotallyVisibleScrollingRows == DisplayedBandsInfo.NumTotallyDisplayedScrollingRows);
                Debug.Assert(oldFirstVisibleScrollingRow == DisplayedBandsInfo.FirstDisplayedScrollingRow);
            }
#endif

#if DEBUG
            int newFirstVisibleScrollingCol = ComputeFirstVisibleScrollingColumn();
            Debug.Assert(newFirstVisibleScrollingCol == DisplayedBandsInfo.FirstDisplayedScrollingCol);

            int oldLastTotallyVisibleScrollingCol = DisplayedBandsInfo.LastTotallyDisplayedScrollingCol;
            int oldFirstVisibleScrollingCol = DisplayedBandsInfo.FirstDisplayedScrollingCol;
            ComputeVisibleColumns();
            Debug.Assert(oldLastTotallyVisibleScrollingCol == DisplayedBandsInfo.LastTotallyDisplayedScrollingCol);
            Debug.Assert(oldFirstVisibleScrollingCol == DisplayedBandsInfo.FirstDisplayedScrollingCol);
#endif

            if (_vertScrollBar.Enabled)
            {
                int totalVisibleHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible);
                int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                int oldVertScrollBarValue = _vertScrollBar.Value;
                int oldThumbHeight = Math.Max(((_vertScrollBar.Height - 2 * SystemInformation.VerticalScrollBarArrowHeight) * _vertScrollBar.LargeChange) / _vertScrollBar.Maximum, 8);

                _vertScrollBar.Maximum = totalVisibleHeight - totalVisibleFrozenHeight;
                Debug.Assert(_vertScrollBar.Maximum > 0);
                _vertScrollBar.Value = ComputeHeightOfScrolledOffRows();
                _vertScrollBar.LargeChange = _layout.Data.Height - totalVisibleFrozenHeight;
                VerticalScrollingOffset = _vertScrollBar.Value;

                if (_vertScrollBar.Visible &&
                    (oldVertScrollBarValue != VerticalScrollingOffset ||
                     oldThumbHeight != Math.Max(((_vertScrollBar.Height - 2 * SystemInformation.VerticalScrollBarArrowHeight) * _vertScrollBar.LargeChange) / _vertScrollBar.Maximum, 8)))
                {
                    // Only update the vertical scroll bar is the thumb moved or resized.
                    _vertScrollBar.Invalidate();
                }
                Debug.Assert(VerticalScrollingOffset == _vertScrollBar.Value);
            }
        }

        private void ComputeVisibleColumns()
        {
            DataGridViewColumn dataGridViewColumn = null;
            int numVisibleScrollingCols = 0, visibleScrollingColumnsTmp = 0;
            int displayWidth = _layout.Data.Width, cx = 0;
            int numDisplayedFrozenCols = 0, firstDisplayedFrozenCol = -1, lastDisplayedFrozenCol = -1;
            int firstDisplayedScrollingCol = DisplayedBandsInfo.FirstDisplayedScrollingCol;

            // the same problem with negative numbers:
            // if the width passed in is negative, then return 0
            if (displayWidth <= 0 || Columns.GetColumnCount(DataGridViewElementStates.Visible) == 0)
            {
                DisplayedBandsInfo.FirstDisplayedFrozenCol = -1;
                DisplayedBandsInfo.NumDisplayedFrozenCols = 0;
                DisplayedBandsInfo.FirstDisplayedScrollingCol = -1;
                DisplayedBandsInfo.NumDisplayedScrollingCols = 0;
                DisplayedBandsInfo.LastDisplayedFrozenCol = -1;
                DisplayedBandsInfo.LastTotallyDisplayedScrollingCol = -1;
                return;
            }

            dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.None);
            while (dataGridViewColumn != null)
            {
                if (!dataGridViewColumn.Frozen && dataGridViewColumn.Visible)
                {
                    break;
                }
                if (dataGridViewColumn.Visible)
                {
                    if (firstDisplayedFrozenCol == -1)
                    {
                        firstDisplayedFrozenCol = dataGridViewColumn.Index;
                    }
                    cx += dataGridViewColumn.Width;
                    numDisplayedFrozenCols++;
                    lastDisplayedFrozenCol = dataGridViewColumn.Index;
                    if (cx >= displayWidth)
                    {
                        break;
                    }
                }
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.None, DataGridViewElementStates.None);
            }

            Debug.Assert(cx <= Columns.GetColumnsWidth(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen));

            if (cx < displayWidth && firstDisplayedScrollingCol >= 0)
            {
                dataGridViewColumn = Columns[firstDisplayedScrollingCol];
                if (dataGridViewColumn.Frozen)
                {
                    dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible,
                        DataGridViewElementStates.Frozen);
                    FirstDisplayedScrollingColumnHiddenWidth = 0;
                    if (dataGridViewColumn is null)
                    {
                        DisplayedBandsInfo.FirstDisplayedFrozenCol = firstDisplayedFrozenCol;
                        DisplayedBandsInfo.LastDisplayedFrozenCol = lastDisplayedFrozenCol;
                        DisplayedBandsInfo.NumDisplayedFrozenCols = numDisplayedFrozenCols;
                        DisplayedBandsInfo.FirstDisplayedScrollingCol = DisplayedBandsInfo.LastTotallyDisplayedScrollingCol = -1;
                        DisplayedBandsInfo.NumDisplayedScrollingCols = 0;
                        return;
                    }
                    else
                    {
                        firstDisplayedScrollingCol = dataGridViewColumn.Index;
                    }
                }

                cx -= FirstDisplayedScrollingColumnHiddenWidth;
                while (cx < displayWidth && dataGridViewColumn != null)
                {
                    cx += dataGridViewColumn.Thickness;
                    visibleScrollingColumnsTmp++;
                    dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.None);
                }
                numVisibleScrollingCols = visibleScrollingColumnsTmp;

                // if we inflate the data area then we paint columns to the left of firstDisplayedScrollingCol
                if (cx < displayWidth)
                {
                    bool invalidate = false;
                    Debug.Assert(firstDisplayedScrollingCol >= 0);
                    //first minimize value of this.negOffset
                    if (FirstDisplayedScrollingColumnHiddenWidth > 0)
                    {
                        invalidate = true;
                        if (displayWidth - cx > FirstDisplayedScrollingColumnHiddenWidth)
                        {
                            cx += FirstDisplayedScrollingColumnHiddenWidth;
                            _horizontalOffset -= FirstDisplayedScrollingColumnHiddenWidth;
                            FirstDisplayedScrollingColumnHiddenWidth = 0;
                        }
                        else
                        {
                            _horizontalOffset -= displayWidth - cx;
                            FirstDisplayedScrollingColumnHiddenWidth -= displayWidth - cx;
                            cx = displayWidth;
                        }
                    }
                    // second try to scroll entire columns
                    if (cx < displayWidth && _horizontalOffset > 0)
                    {
                        Debug.Assert(FirstDisplayedScrollingColumnHiddenWidth == 0);
                        dataGridViewColumn = Columns.GetPreviousColumn((Columns[firstDisplayedScrollingCol]),
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.Frozen);
                        while (dataGridViewColumn != null && cx + dataGridViewColumn.Thickness <= displayWidth)
                        {
                            cx += dataGridViewColumn.Thickness;
                            visibleScrollingColumnsTmp++;
                            invalidate = true;
                            firstDisplayedScrollingCol = dataGridViewColumn.Index;
                            _horizontalOffset -= dataGridViewColumn.Thickness;
                            dataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn,
                                DataGridViewElementStates.Visible,
                                DataGridViewElementStates.Frozen);
                        }
                    }
                    // third try to partially scroll in first scrolled off column
                    if (cx < displayWidth && _horizontalOffset > 0 && firstDisplayedScrollingCol != 0)
                    {
                        Debug.Assert(FirstDisplayedScrollingColumnHiddenWidth == 0);
                        dataGridViewColumn = Columns.GetPreviousColumn((Columns[firstDisplayedScrollingCol]),
                                                                            DataGridViewElementStates.Visible,
                                                                            DataGridViewElementStates.Frozen);
                        Debug.Assert(dataGridViewColumn != null);
                        Debug.Assert(dataGridViewColumn.Thickness > displayWidth - cx);
                        firstDisplayedScrollingCol = dataGridViewColumn.Index;
                        FirstDisplayedScrollingColumnHiddenWidth = dataGridViewColumn.Thickness - displayWidth + cx;
                        _horizontalOffset -= displayWidth - cx;
                        visibleScrollingColumnsTmp++;
                        invalidate = true;
                        cx = displayWidth;
                        Debug.Assert(FirstDisplayedScrollingColumnHiddenWidth == GetNegOffsetFromHorizontalOffset(_horizontalOffset));
                    }

                    // update the number of visible columns to the new reality
                    Debug.Assert(numVisibleScrollingCols <= visibleScrollingColumnsTmp, "the number of displayed columns can only grow");
                    numVisibleScrollingCols = visibleScrollingColumnsTmp;

                    if (invalidate)
                    {
                        InvalidateData();
                        Invalidate(_layout.ColumnHeaders);
                    }
                }

                int jumpFromFirstVisibleScrollingCol = numVisibleScrollingCols - 1;
                if (cx > displayWidth)
                {
                    jumpFromFirstVisibleScrollingCol--;
                }

                Debug.Assert(jumpFromFirstVisibleScrollingCol >= -1);

                if (jumpFromFirstVisibleScrollingCol < 0)
                {
                    DisplayedBandsInfo.LastTotallyDisplayedScrollingCol = -1; // no totally visible scrolling column at all
                }
                else
                {
                    Debug.Assert(firstDisplayedScrollingCol >= 0);
                    dataGridViewColumn = Columns[firstDisplayedScrollingCol];
                    for (int jump = 0; jump < jumpFromFirstVisibleScrollingCol; jump++)
                    {
                        dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None);
                        Debug.Assert(dataGridViewColumn != null);
                    }
                    DisplayedBandsInfo.LastTotallyDisplayedScrollingCol = dataGridViewColumn.Index;
                }
            }
            else
            {
                DisplayedBandsInfo.LastTotallyDisplayedScrollingCol = -1;
            }
            DisplayedBandsInfo.FirstDisplayedFrozenCol = firstDisplayedFrozenCol;
            DisplayedBandsInfo.LastDisplayedFrozenCol = lastDisplayedFrozenCol;
            DisplayedBandsInfo.NumDisplayedFrozenCols = numDisplayedFrozenCols;
            DisplayedBandsInfo.FirstDisplayedScrollingCol = firstDisplayedScrollingCol;
            DisplayedBandsInfo.NumDisplayedScrollingCols = numVisibleScrollingCols;
            Debug.Assert((DisplayedBandsInfo.NumDisplayedScrollingCols > 0 && DisplayedBandsInfo.FirstDisplayedScrollingCol != -1) ||
                         (DisplayedBandsInfo.NumDisplayedScrollingCols == 0 && DisplayedBandsInfo.FirstDisplayedScrollingCol == -1));
        }

        private void ComputeVisibleRows()
        {
            int firstDisplayedFrozenRow = -1;
            int firstDisplayedScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
            int lastDisplayedFrozenRow = -1, lastDisplayedScrollingRow = -1;
            int numTotallyDisplayedFrozenRows = 0;
            int displayHeight = _layout.Data.Height;
            int cy = 0;
            int visibleScrollingRows = 0;
            int nRows = Rows.Count;
            int rowIndex;

            // when minimizing the dataGridView window, we will get negative values for the
            // layout.Data.Width and layout.Data.Height

            if (displayHeight <= 0 || nRows == 0)
            {
                DisplayedBandsInfo.NumDisplayedFrozenRows = DisplayedBandsInfo.NumTotallyDisplayedFrozenRows =
                    DisplayedBandsInfo.NumDisplayedScrollingRows = DisplayedBandsInfo.NumTotallyDisplayedScrollingRows = 0;
                DisplayedBandsInfo.FirstDisplayedFrozenRow = DisplayedBandsInfo.FirstDisplayedScrollingRow =
                    DisplayedBandsInfo.LastDisplayedFrozenRow = DisplayedBandsInfo.LastDisplayedScrollingRow = -1;
                return;
            }

            for (rowIndex = 0; rowIndex < nRows; rowIndex++)
            {
                Debug.Assert(cy < displayHeight);
                DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
                if ((rowState & DataGridViewElementStates.Frozen) == 0 &&
                    (rowState & DataGridViewElementStates.Visible) != 0)
                {
                    break;
                }
                if ((rowState & DataGridViewElementStates.Visible) != 0)
                {
                    cy += Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                    if (firstDisplayedFrozenRow == -1)
                    {
                        firstDisplayedFrozenRow = rowIndex;
                    }
                    lastDisplayedFrozenRow = rowIndex;
                    if (cy <= displayHeight)
                    {
                        numTotallyDisplayedFrozenRows++;
                    }
                    if (cy >= displayHeight)
                    {
                        break;
                    }
                }
            }

            if (cy > displayHeight)
            {
                DisplayedBandsInfo.NumDisplayedFrozenRows = numTotallyDisplayedFrozenRows + 1;
            }
            else
            {
                DisplayedBandsInfo.NumDisplayedFrozenRows = numTotallyDisplayedFrozenRows;
            }

            // loop exited when:
            // - all rows are frozen and fit in displayHeight: rowIndex == nRows, cy <= displayHeight
            // - rowIndex is not frozen: rowIndex < nRows, cy <= displayHeight
            // - there are more frozen rows than can fit in displayHeight: rowIndex <= nRows, cy > displayHeight

            if (cy < displayHeight && rowIndex < nRows)
            {
                if (firstDisplayedScrollingRow == -1)
                {
                    firstDisplayedScrollingRow = rowIndex;
                }

                while (firstDisplayedScrollingRow < nRows &&
                    (
                    (Rows.GetRowState(firstDisplayedScrollingRow) & DataGridViewElementStates.Frozen) != 0 ||
                    (Rows.GetRowState(firstDisplayedScrollingRow) & DataGridViewElementStates.Visible) == 0
                    )
                    )
                {
                    firstDisplayedScrollingRow++;
                }

                for (int i = firstDisplayedScrollingRow; i < nRows; i++)
                {
                    if ((Rows.GetRowState(i) & DataGridViewElementStates.Visible) != 0)
                    {
                        cy += Rows.SharedRow(i).GetHeight(i);
                        visibleScrollingRows++;
                        lastDisplayedScrollingRow = i;
                    }
                    if (cy >= displayHeight)
                    {
                        break;
                    }
                }

                if (cy < displayHeight)
                {
                    for (int i = firstDisplayedScrollingRow - 1; i >= numTotallyDisplayedFrozenRows; i--)
                    {
                        if ((Rows.GetRowState(i) & (DataGridViewElementStates.Frozen | DataGridViewElementStates.Visible)) == DataGridViewElementStates.Visible)
                        {
                            int height = Rows.SharedRow(i).GetHeight(i);
                            if (cy + height > displayHeight)
                            {
                                break;
                            }
                            cy += height;
                            firstDisplayedScrollingRow = i;
                            visibleScrollingRows++;
                            lastDisplayedScrollingRow = i;
                        }
                    }
                }

                DisplayedBandsInfo.NumDisplayedScrollingRows = visibleScrollingRows;
                if (cy > displayHeight)
                {
                    DisplayedBandsInfo.NumTotallyDisplayedScrollingRows = visibleScrollingRows - 1;
                }
                else
                {
                    DisplayedBandsInfo.NumTotallyDisplayedScrollingRows = visibleScrollingRows;
                }
                if (visibleScrollingRows == 0)
                {
                    firstDisplayedScrollingRow = -1;
                    Debug.Assert(lastDisplayedScrollingRow == -1);
                }
            }
            else
            {
                DisplayedBandsInfo.NumDisplayedScrollingRows = DisplayedBandsInfo.NumTotallyDisplayedScrollingRows = 0;
                firstDisplayedScrollingRow = -1;
            }

            Debug.Assert(firstDisplayedFrozenRow < nRows, "firstDisplayedFrozenRow larger than number of rows");
            Debug.Assert(lastDisplayedFrozenRow < nRows, "lastDisplayedFrozenRow larger than number of rows");
            Debug.Assert(lastDisplayedScrollingRow < nRows, "lastDisplayedScrollingRow larger than number of rows");

            DisplayedBandsInfo.FirstDisplayedFrozenRow = firstDisplayedFrozenRow;
            DisplayedBandsInfo.FirstDisplayedScrollingRow = firstDisplayedScrollingRow;
            DisplayedBandsInfo.NumTotallyDisplayedFrozenRows = numTotallyDisplayedFrozenRows;
            DisplayedBandsInfo.LastDisplayedFrozenRow = lastDisplayedFrozenRow;
            DisplayedBandsInfo.LastDisplayedScrollingRow = lastDisplayedScrollingRow;

            Debug.Assert(DisplayedBandsInfo.NumTotallyDisplayedFrozenRows >= 0, "the number of visible frozen rows can't be negative");
            Debug.Assert(DisplayedBandsInfo.NumDisplayedScrollingRows >= 0, "the number of visible scrolling rows can't be negative");
            Debug.Assert(DisplayedBandsInfo.NumTotallyDisplayedScrollingRows >= 0, "the number of totally visible scrolling rows can't be negative");
            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow < nRows, "firstDisplayedScrollingRow larger than number of rows");
        }

        private Point ConvertCellToGridCoord(int columnIndex, int rowIndex, int x, int y)
        {
            int columnX, rowY;
            if (columnIndex > -1)
            {
                columnX = GetColumnXFromIndex(columnIndex);
                if (RightToLeftInternal)
                {
                    columnX -= Columns[columnIndex].Width;
                }
            }
            else
            {
                if (RightToLeftInternal)
                {
                    columnX = _layout.RowHeaders.Left - 1;
                }
                else
                {
                    columnX = _layout.RowHeaders.Left;
                }
            }

            if (rowIndex > -1)
            {
                rowY = GetRowYFromIndex(rowIndex);
            }
            else
            {
                rowY = _layout.ColumnHeaders.Top;
            }

            return new Point(columnX + x, rowY + y);
        }

        private void CorrectColumnDisplayIndexesAfterDeletion(DataGridViewColumn dataGridViewColumn)
        {
            // Column indexes have already been adjusted.
            // This column has already been detached and has retained its old Index and DisplayIndex

            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(dataGridViewColumn.DataGridView is null);
            Debug.Assert(dataGridViewColumn.Index >= 0);
            Debug.Assert(dataGridViewColumn.DisplayIndex >= 0);

            try
            {
                _dataGridViewOper[OperationInDisplayIndexAdjustments] = true;

                // All remaining columns with a DisplayIndex greater than dataGridViewColumn.DisplayIndex need to be decremented
                foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                {
                    if (dataGridViewColumnTmp.DisplayIndex > dataGridViewColumn.DisplayIndex)
                    {
                        dataGridViewColumnTmp.DisplayIndexInternal = dataGridViewColumnTmp.DisplayIndex - 1;
                        dataGridViewColumnTmp.DisplayIndexHasChanged = true; // OnColumnDisplayIndexChanged needs to be raised later on
                    }
                }

#if DEBUG
                Debug.Assert(Columns.VerifyColumnDisplayIndexes());
#endif
                // Now raise all the OnColumnDisplayIndexChanged events
                FlushDisplayIndexChanged(true /*raiseEvent*/);
            }
            finally
            {
                _dataGridViewOper[OperationInDisplayIndexAdjustments] = false;
                FlushDisplayIndexChanged(false /*raiseEvent*/);
            }
        }

        private void CorrectColumnDisplayIndexesAfterInsertion(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(dataGridViewColumn.DataGridView == this);
            // dataGridViewColumn.DisplayIndex has been set already.
            Debug.Assert(dataGridViewColumn.DisplayIndex >= 0);

            try
            {
                _dataGridViewOper[OperationInDisplayIndexAdjustments] = true;

                // All other columns with a DisplayIndex equal or greater than dataGridViewColumn.DisplayIndex need to be incremented
                foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                {
                    if (dataGridViewColumnTmp != dataGridViewColumn && dataGridViewColumnTmp.DisplayIndex >= dataGridViewColumn.DisplayIndex)
                    {
                        dataGridViewColumnTmp.DisplayIndexInternal = dataGridViewColumnTmp.DisplayIndex + 1;
                        dataGridViewColumnTmp.DisplayIndexHasChanged = true; // OnColumnDisplayIndexChanged needs to be raised later on
                    }
                }

#if DEBUG
                Debug.Assert(Columns.VerifyColumnDisplayIndexes());
#endif
                // Now raise all the OnColumnDisplayIndexChanged events
                FlushDisplayIndexChanged(true /*raiseEvent*/);
            }
            finally
            {
                _dataGridViewOper[OperationInDisplayIndexAdjustments] = false;
                FlushDisplayIndexChanged(false /*raiseEvent*/);
            }
        }

        private void CorrectColumnFrozenState(DataGridViewColumn dataGridViewColumn, int anticipatedColumnIndex)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(anticipatedColumnIndex >= 0 && anticipatedColumnIndex <= Columns.Count);

            int anticipatedColumnDisplayIndex;
            if (dataGridViewColumn.DisplayIndex == -1 || dataGridViewColumn.DisplayIndex > Columns.Count)
            {
                anticipatedColumnDisplayIndex = anticipatedColumnIndex; // By default, we pick the Index as the DisplayIndex.
            }
            else
            {
                Debug.Assert(dataGridViewColumn.DisplayIndex >= 0 && dataGridViewColumn.DisplayIndex <= Columns.Count);
                anticipatedColumnDisplayIndex = dataGridViewColumn.DisplayIndex; // The specified DisplayIndex is just fine.
            }

            DataGridViewColumn dataGridViewColumnPrev;
            int displayIndex = anticipatedColumnDisplayIndex - 1;
            do
            {
                dataGridViewColumnPrev = Columns.GetColumnAtDisplayIndex(displayIndex);
                displayIndex--;
            }
            while (displayIndex >= 0 && (dataGridViewColumnPrev is null || !dataGridViewColumnPrev.Visible));
            if (dataGridViewColumnPrev != null && !dataGridViewColumnPrev.Frozen && dataGridViewColumn.Frozen)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAddFrozenColumn);
            }
            else
            {
                DataGridViewColumn dataGridViewColumnNext;
                displayIndex = anticipatedColumnDisplayIndex;
                do
                {
                    dataGridViewColumnNext = Columns.GetColumnAtDisplayIndex(displayIndex);
                    displayIndex++;
                }
                while (displayIndex < Columns.Count && (dataGridViewColumnNext is null || !dataGridViewColumnNext.Visible));
                if (dataGridViewColumnNext != null && dataGridViewColumnNext.Frozen && !dataGridViewColumn.Frozen)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddNonFrozenColumn);
                }
            }
        }

        private void CorrectColumnFrozenStates(DataGridViewColumn[] dataGridViewColumns)
        {
            DataGridView dataGridViewTmp = new DataGridView();
            DataGridViewColumn dataGridViewColumnClone;
            foreach (DataGridViewColumn dataGridViewColumn in Columns)
            {
                dataGridViewColumnClone = (DataGridViewColumn)dataGridViewColumn.Clone();
                // DataGridViewColumn.Clone does not replicate the DisplayIndex value.
                dataGridViewColumnClone.DisplayIndex = dataGridViewColumn.DisplayIndex;
                dataGridViewTmp.Columns.Add(dataGridViewColumnClone);
            }
            foreach (DataGridViewColumn dataGridViewColumn in dataGridViewColumns)
            {
                dataGridViewColumnClone = (DataGridViewColumn)dataGridViewColumn.Clone();
                dataGridViewColumnClone.DisplayIndex = dataGridViewColumn.DisplayIndex;
                dataGridViewTmp.Columns.Add(dataGridViewColumnClone);
            }
        }

        private void CorrectColumnFrozenStates(DataGridViewColumn dataGridViewColumn, bool frozenStateChanging)
        {
            Debug.Assert(dataGridViewColumn != null);
            DataGridViewColumn dataGridViewColumnTmp;
            if ((dataGridViewColumn.Frozen && !frozenStateChanging) ||
                (!dataGridViewColumn.Frozen && frozenStateChanging))
            {
                // make sure the previous visible columns are frozen as well
                dataGridViewColumnTmp = Columns.GetPreviousColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen,
                    DataGridViewElementStates.None);
                if (dataGridViewColumnTmp is null)
                {
                    DataGridViewColumn dataGridViewColumnFirst = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                    if (dataGridViewColumnFirst != dataGridViewColumn)
                    {
                        dataGridViewColumnTmp = dataGridViewColumnFirst;
                    }
                }
                while (dataGridViewColumnTmp != null && Columns.DisplayInOrder(dataGridViewColumnTmp.Index, dataGridViewColumn.Index))
                {
                    dataGridViewColumnTmp.Frozen = true;
                    dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.Frozen);
                }
            }
            else
            {
                // make sure the next visible columns are not frozen
                dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.Frozen);
                if (dataGridViewColumnTmp is null)
                {
                    DataGridViewColumn dataGridViewColumnLast = dataGridViewColumn;
                    do
                    {
                        dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnLast,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None);
                        if (dataGridViewColumnTmp != null)
                        {
                            dataGridViewColumnLast = dataGridViewColumnTmp;
                        }
                    }
                    while (dataGridViewColumnTmp != null);
                    if (dataGridViewColumnLast != dataGridViewColumn)
                    {
                        dataGridViewColumnTmp = dataGridViewColumnLast;
                    }
                }
                while (dataGridViewColumnTmp != null && Columns.DisplayInOrder(dataGridViewColumn.Index, dataGridViewColumnTmp.Index))
                {
                    dataGridViewColumnTmp.Frozen = false;
                    dataGridViewColumnTmp = Columns.GetPreviousColumn(dataGridViewColumnTmp,
                        DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen,
                        DataGridViewElementStates.None);
                }
            }
        }

        private void CorrectColumnFrozenStatesForMove(DataGridViewColumn dataGridViewColumn, int newDisplayIndex)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(newDisplayIndex != dataGridViewColumn.DisplayIndex);
            Debug.Assert(!_dataGridViewOper[OperationInDisplayIndexAdjustments]);

            // No check necessary when:
            // - column is invisible.
            // - DisplayIndex decreases and column is frozen.
            // - DisplayIndex increases and column is unfrozen.

            if (!dataGridViewColumn.Visible ||
                (newDisplayIndex < dataGridViewColumn.DisplayIndex && dataGridViewColumn.Frozen) ||
                (newDisplayIndex > dataGridViewColumn.DisplayIndex && !dataGridViewColumn.Frozen))
            {
                return;
            }

            int colCount = Columns.Count, displayIndex;

            if (newDisplayIndex < dataGridViewColumn.DisplayIndex)
            {
                // DisplayIndex decreases.
                // Throw an exception if the visible unfrozen column is placed before a frozen column
                // Get the closest visible column placed after the displaced column
                DataGridViewColumn dataGridViewColumnNext;
                displayIndex = newDisplayIndex;
                do
                {
                    dataGridViewColumnNext = Columns.GetColumnAtDisplayIndex(displayIndex);
                    displayIndex++;
                }
                while (displayIndex < colCount && (dataGridViewColumnNext is null || dataGridViewColumnNext == dataGridViewColumn || !dataGridViewColumnNext.Visible));

                if (dataGridViewColumnNext != null && dataGridViewColumnNext.Frozen)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotMoveNonFrozenColumn);
                }
            }
            else
            {
                // DisplayIndex increases.
                // Throw an exception if the visible frozen column is placed after a non-frozen column
                // Get the closest visible column placed before the displaced column
                DataGridViewColumn dataGridViewColumnPrev;
                displayIndex = newDisplayIndex;
                do
                {
                    dataGridViewColumnPrev = Columns.GetColumnAtDisplayIndex(displayIndex);
                    displayIndex--;
                }
                while (displayIndex >= 0 && (dataGridViewColumnPrev is null || !dataGridViewColumnPrev.Visible));

                if (dataGridViewColumnPrev != null && !dataGridViewColumnPrev.Frozen)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotMoveFrozenColumn);
                }
            }
        }

        private void CorrectColumnIndexesAfterDeletion(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);
            for (int columnIndex = dataGridViewColumn.Index; columnIndex < Columns.Count; columnIndex++)
            {
                Columns[columnIndex].Index = Columns[columnIndex].Index - 1;
                Debug.Assert(Columns[columnIndex].Index == columnIndex);
            }
        }

        private void CorrectColumnIndexesAfterInsertion(DataGridViewColumn dataGridViewColumn, int insertionCount)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(insertionCount > 0);
            for (int columnIndex = dataGridViewColumn.Index + insertionCount; columnIndex < Columns.Count; columnIndex++)
            {
                Columns[columnIndex].Index = columnIndex;
            }
        }

        private void CorrectFocus(bool onlyIfGridHasFocus)
        {
            if ((!onlyIfGridHasFocus || Focused) && EditingControl != null)
            {
                Debug.Assert(CurrentCellInternal != null);
                EditingControl.Focus();
            }
        }

        private void CorrectRowFrozenState(DataGridViewRow dataGridViewRow, DataGridViewElementStates rowState, int anticipatedRowIndex)
        {
            Debug.Assert(dataGridViewRow != null);
            Debug.Assert(anticipatedRowIndex >= 0 && anticipatedRowIndex <= Rows.Count);

            int previousRowIndex = Rows.GetPreviousRow(anticipatedRowIndex,
                                                            DataGridViewElementStates.Visible,
                                                            DataGridViewElementStates.None);
            if (previousRowIndex != -1 &&
                (Rows.GetRowState(previousRowIndex) & DataGridViewElementStates.Frozen) == 0 &&
                (rowState & DataGridViewElementStates.Frozen) != 0)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAddFrozenRow);
            }
            else
            {
                int nextRowIndex = Rows.GetNextRow((previousRowIndex == -1) ? anticipatedRowIndex - 1 : previousRowIndex,
                                                        DataGridViewElementStates.Visible,
                                                        DataGridViewElementStates.None);
                if (nextRowIndex != -1 &&
                    (Rows.GetRowState(nextRowIndex) & DataGridViewElementStates.Frozen) != 0 &&
                    (rowState & DataGridViewElementStates.Frozen) == 0)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddNonFrozenRow);
                }
            }
        }

        private void CorrectRowFrozenStates(DataGridViewRow[] dataGridViewRows, int rowIndexInserted)
        {
            bool nextVisibleRowPresent = false, previousRowFrozen = true, nextRowFrozen = false, currentRowFrozen;

            // Check if there is a visible row before the insertion point, and if it's frozen
            int rowIndexTmp = Rows.GetPreviousRow(rowIndexInserted, DataGridViewElementStates.Visible);
            if (rowIndexTmp != -1)
            {
                previousRowFrozen = (Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Frozen) == DataGridViewElementStates.Frozen;
            }

            // Check if there is a visible row at or after the insertion point, and if it's frozen
            rowIndexTmp = Rows.GetNextRow(rowIndexInserted - 1, DataGridViewElementStates.Visible);
            if (rowIndexTmp != -1)
            {
                nextVisibleRowPresent = true;
                nextRowFrozen = (Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Frozen) == DataGridViewElementStates.Frozen;
            }

            for (int arrayIndex = 0; arrayIndex < dataGridViewRows.Length; arrayIndex++)
            {
                currentRowFrozen = ((DataGridViewRow)dataGridViewRows[arrayIndex]).Frozen;
                if (!previousRowFrozen && currentRowFrozen)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddFrozenRow);
                }
                previousRowFrozen = currentRowFrozen;
                if (arrayIndex == dataGridViewRows.Length - 1 &&
                    !currentRowFrozen &&
                    nextVisibleRowPresent &&
                    nextRowFrozen)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddNonFrozenRow);
                }
            }
        }

        private void CorrectRowFrozenStates(DataGridViewRow dataGridViewRow, int rowIndex, bool frozenStateChanging)
        {
            Debug.Assert(dataGridViewRow != null);
            int rowIndexTmp;
            if (((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Frozen) != 0 && !frozenStateChanging) ||
                ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Frozen) == 0 && frozenStateChanging))
            {
                // make sure the previous visible rows are frozen as well
                rowIndexTmp = Rows.GetPreviousRow(rowIndex,
                    DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                if (rowIndexTmp == -1)
                {
                    int dataGridViewRowFirst = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                    if (dataGridViewRowFirst != rowIndex)
                    {
                        rowIndexTmp = dataGridViewRowFirst;
                    }
                }
                while (rowIndexTmp != -1 && rowIndexTmp < rowIndex)
                {
                    Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Frozen, true);
                    rowIndexTmp = Rows.GetNextRow(rowIndexTmp,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.Frozen);
                }
            }
            else
            {
                // make sure the next visible rows are not frozen
                rowIndexTmp = Rows.GetNextRow(rowIndex,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.Frozen);
                if (rowIndexTmp == -1)
                {
                    int dataGridViewRowLast = rowIndex;
                    do
                    {
                        rowIndexTmp = Rows.GetNextRow(dataGridViewRowLast,
                            DataGridViewElementStates.Visible);
                        if (rowIndexTmp != -1)
                        {
                            dataGridViewRowLast = rowIndexTmp;
                        }
                    }
                    while (rowIndexTmp != -1);
                    if (dataGridViewRowLast != rowIndex)
                    {
                        rowIndexTmp = dataGridViewRowLast;
                    }
                }
                while (rowIndexTmp != -1 && rowIndexTmp > rowIndex)
                {
                    Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Frozen, false);
                    rowIndexTmp = Rows.GetPreviousRow(rowIndexTmp,
                        DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                }
            }
        }

        private void CorrectRowIndexesAfterDeletion(int rowIndexDeleted)
        {
            Debug.Assert(rowIndexDeleted >= 0);
            int rowsCount = Rows.Count;
            for (int rowIndex = rowIndexDeleted; rowIndex < rowsCount; rowIndex++)
            {
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                if (dataGridViewRow.Index >= 0)
                {
                    dataGridViewRow.Index = dataGridViewRow.Index - 1;
                    Debug.Assert(dataGridViewRow.Index == rowIndex);
                }
            }

            // Fix 'new' row index if existant
            if (NewRowIndex == rowIndexDeleted)
            {
                NewRowIndex = -1; // No more 'new' row.
            }
            else if (NewRowIndex != -1)
            {
                NewRowIndex--;
            }
        }

        private void CorrectRowIndexesAfterInsertion(int rowIndexInserted, int insertionCount)
        {
            Debug.Assert(rowIndexInserted >= 0);
            Debug.Assert(insertionCount > 0);
            int rowsCount = Rows.Count;
            for (int rowIndex = rowIndexInserted + insertionCount; rowIndex < rowsCount; rowIndex++)
            {
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                if (dataGridViewRow.Index >= 0)
                {
                    dataGridViewRow.Index = dataGridViewRow.Index + insertionCount;
                    Debug.Assert(dataGridViewRow.Index == rowIndex);
                }
            }

            // Lastly update the 'new' row index if needed.
            if (NewRowIndex != -1)
            {
                NewRowIndex += insertionCount;
            }
        }

        protected override AccessibleObject CreateAccessibilityInstance()
        {
            return new DataGridViewAccessibleObject(this);
        }

        protected override ControlCollection CreateControlsInstance()
        {
            return new DataGridViewControlCollection(this);
        }

        /// <summary>
        ///  Constructs the new instance of the Columns collection objects. Subclasses
        ///  should not call base.CreateColumnsInstance.
        /// </summary>
        [EditorBrowsable(EditorBrowsableState.Advanced)]
        protected virtual DataGridViewColumnCollection CreateColumnsInstance()
        {
            return new DataGridViewColumnCollection(this);
        }

        /// <summary>
        ///  Constructs the new instance of the Rows collection objects. Subclasses
        ///  should not call base.CreateRowsInstance.
        /// </summary>
        [EditorBrowsable(EditorBrowsableState.Advanced)]
        protected virtual DataGridViewRowCollection CreateRowsInstance()
        {
            return new DataGridViewRowCollection(this);
        }

        private RECT[] CreateScrollableRegion(Rectangle scroll)
        {
            if (_cachedScrollableRegion != null)
            {
                return _cachedScrollableRegion;
            }

            using (Region region = new Region(scroll))
            {
                IntPtr handle = IntPtr.Zero;
                using (Graphics graphics = CreateGraphicsInternal())
                {
                    handle = region.GetHrgn(graphics);
                }
                if (handle != IntPtr.Zero)
                {
                    _cachedScrollableRegion = GetRectsFromRegion(handle);

                    region.ReleaseHrgn(handle);
                }
            }
            return _cachedScrollableRegion;
        }

        private unsafe static RECT[] GetRectsFromRegion(IntPtr hRgn)
        {
            // see how much memory we need to allocate
            uint regionDataSize = Gdi32.GetRegionData(hRgn, 0, IntPtr.Zero);
            if (regionDataSize == 0)
            {
                return null;
            }

            IntPtr pBytes = IntPtr.Zero;
            try
            {
                pBytes = Marshal.AllocCoTaskMem((int)regionDataSize);
                // get the data
                uint ret = Gdi32.GetRegionData(hRgn, regionDataSize, pBytes);
                if (ret != regionDataSize)
                {
                    return null;
                }

                // cast to the structure
                Gdi32.RGNDATAHEADER* pRgnDataHeader = (Gdi32.RGNDATAHEADER*)pBytes;
                if (pRgnDataHeader->iType != 1)
                {
                    return null;
                }

                // expecting RDH_RECTANGLES
                var regionRects = new RECT[pRgnDataHeader->nCount];

                Debug.Assert(regionDataSize == pRgnDataHeader->dwSize + pRgnDataHeader->nCount * pRgnDataHeader->nRgnSize);
                Debug.Assert(sizeof(RECT) == pRgnDataHeader->nRgnSize || pRgnDataHeader->nRgnSize == 0);

                // use the header size as the offset, and cast each rect in.
                uint rectStart = pRgnDataHeader->dwSize;
                for (int i = 0; i < pRgnDataHeader->nCount; i++)
                {
                    regionRects[i] = *((RECT*)((byte*)pBytes + rectStart + (sizeof(RECT) * i)));
                }

                return regionRects;
            }
            finally
            {
                if (pBytes != IntPtr.Zero)
                {
                    Marshal.FreeCoTaskMem(pBytes);
                }
            }
        }

        private void DiscardNewRow()
        {
            Debug.Assert(Rows.Count > 1);
            Debug.Assert(NewRowIndex != -1);

            DataGridViewRowCancelEventArgs dgvrce = new DataGridViewRowCancelEventArgs(Rows[NewRowIndex]);
            OnUserDeletingRow(dgvrce);
            if (dgvrce.Cancel)
            {
                return;
            }

            // Delete the 'new' row
            Debug.Assert(NewRowIndex == Rows.Count - 1);
            DataGridViewRow dataGridViewRow = Rows[NewRowIndex];
            Rows.RemoveAtInternal(NewRowIndex, false /*force*/);
            Debug.Assert(dataGridViewRow.Index == -1);
            DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs(dataGridViewRow);
            OnUserDeletedRow(dgvre);
            // CorrectRowIndexesAfterDeletion resets this.newRowIndex to -1.
            Debug.Assert(NewRowIndex == -1);

            if (AllowUserToAddRowsInternal)
            {
                NewRowIndex = Rows.Count - 1;
                Debug.Assert((Rows.GetRowState(NewRowIndex) & DataGridViewElementStates.Visible) != 0);
                Debug.Assert(_ptCurrentCell.Y == NewRowIndex);

                OnDefaultValuesNeeded(new DataGridViewRowEventArgs(Rows[NewRowIndex]));
                InvalidateRowPrivate(NewRowIndex);
            }
        }

        private void DiscardZonesInScrollingArea(ref Rectangle rectScrollingArea,
                                                 int emptyBackgroundWidth,
                                                 int emptyBackgroundHeight,
                                                 int frozenVisibleRowsHeight,
                                                 bool discardFrozenColumns,
                                                 bool discardFrozenRows)
        {
            // Discard empty background
            rectScrollingArea.Width -= emptyBackgroundWidth;
            rectScrollingArea.Height -= emptyBackgroundHeight;
            if (RightToLeftInternal)
            {
                rectScrollingArea.X += emptyBackgroundWidth;
            }

            if (discardFrozenColumns)
            {
                // Discard frozen columns
                int frozenVisibleColumnsWidth = Columns.GetColumnsWidth(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                if (!RightToLeftInternal)
                {
                    rectScrollingArea.X += frozenVisibleColumnsWidth;
                }
                rectScrollingArea.Width -= frozenVisibleColumnsWidth;
            }
            if (discardFrozenRows)
            {
                // Discard frozen rows
                rectScrollingArea.Y += frozenVisibleRowsHeight;
                rectScrollingArea.Height -= frozenVisibleRowsHeight;
            }
        }

        public int DisplayedColumnCount(bool includePartialColumns)
        {
            int cxMax = _layout.Data.Width, cx = 0;
            int completeColumns = 0, partialColumns = 0;
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            while (dataGridViewColumn != null && cx < cxMax)
            {
                partialColumns++;
                cx += dataGridViewColumn.Thickness;
                if (cx <= cxMax)
                {
                    completeColumns++;
                    dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                        DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen,
                        DataGridViewElementStates.None);
                }
            }

            if (cx < cxMax && DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0)
            {
                if (FirstDisplayedScrollingColumnHiddenWidth > 0)
                {
                    cx -= FirstDisplayedScrollingColumnHiddenWidth;
                    completeColumns--;
                }
                dataGridViewColumn = (DataGridViewColumn)Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
                Debug.Assert(dataGridViewColumn.Visible && !dataGridViewColumn.Frozen);

                while (dataGridViewColumn != null && cx < cxMax)
                {
                    partialColumns++;
                    cx += dataGridViewColumn.Thickness;
                    if (cx <= cxMax)
                    {
                        completeColumns++;
                        dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None);
                    }
                }
            }

            return includePartialColumns ? partialColumns : completeColumns;
        }

        public int DisplayedRowCount(bool includePartialRow)
        {
            return includePartialRow ? (DisplayedBandsInfo.NumDisplayedFrozenRows + DisplayedBandsInfo.NumDisplayedScrollingRows) :
                (DisplayedBandsInfo.NumTotallyDisplayedFrozenRows + DisplayedBandsInfo.NumTotallyDisplayedScrollingRows);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                _dataGridViewOper[OperationInDispose] = true;
                try
                {
                    // Remove any Columns contained in this control
                    for (int i = 0; i < Columns.Count; i++)
                    {
                        Columns[i].Dispose();
                    }

                    Columns.Clear();

                    UnwireScrollBarsEvents();

                    _vertScrollBar?.Dispose();
                    _vertScrollBar = null;

                    _horizScrollBar?.Dispose();
                    _horizScrollBar = null;

                    _placeholderStringFormat?.Dispose();
                    _placeholderStringFormat = null;

                    _latestEditingControl?.Dispose();
                    _latestEditingControl = null;

                    EditingControl?.Dispose();
                    EditingControl = null;

                    _editingPanel?.Dispose();
                    _editingPanel = null;

                    Debug.Assert(NoSelectionChangeCount == 0);

                    DataConnection?.Dispose();

                    // DGV should dispose the tool tip control before disposing itself.
                    _toolTipControl.Dispose();
                }
                finally
                {
                    _dataGridViewOper[OperationInDispose] = false;
                }
            }

            // Dispose unmanaged resources.
            _toolTipBuffer.Dispose();

            base.Dispose(disposing);
        }

        private void DrawColHeaderShadow(Graphics g, int mouseX)
        {
            Rectangle r = CalcColRelocationFeedbackRect(mouseX);
            DrawShadowRect(r);
            if (_dataGridViewState2[State2_ShowColumnRelocationInsertion])
            {
                Rectangle rectInsertionBar = new Rectangle(0, _layout.ColumnHeaders.Top, InsertionBarWidth, _layout.ColumnHeaders.Height);
                // this.trackColumnEdge is the column preceeding the insertion point
                if (_trackColumnEdge == -1)
                {
                    // Insert as first column
                    rectInsertionBar.X = GetColumnXFromIndex(Columns.GetFirstColumn(DataGridViewElementStates.Visible).Index);
                    if (RightToLeftInternal)
                    {
                        rectInsertionBar.X -= InsertionBarWidth;
                    }
                }
                else
                {
                    int offsetFromCenter = 0;
                    if (Columns.GetNextColumn(Columns[_trackColumnEdge], DataGridViewElementStates.Visible, DataGridViewElementStates.None) is null)
                    {
                        if (!RightToLeftInternal)
                        {
                            offsetFromCenter = InsertionBarWidth;
                        }
                    }
                    else
                    {
                        if (RightToLeftInternal)
                        {
                            offsetFromCenter = InsertionBarWidth / 2 - 1;
                        }
                        else
                        {
                            offsetFromCenter = InsertionBarWidth / 2 + 1;
                        }
                    }
                    if (RightToLeftInternal)
                    {
                        rectInsertionBar.X = Math.Max(_layout.ColumnHeaders.X,
                                                      GetColumnXFromIndex(_trackColumnEdge) - Columns[_trackColumnEdge].Width - offsetFromCenter);
                    }
                    else
                    {
                        rectInsertionBar.X = Math.Min(GetColumnXFromIndex(_trackColumnEdge) + Columns[_trackColumnEdge].Width - offsetFromCenter,
                                                      _layout.ColumnHeaders.Right - InsertionBarWidth);
                    }
                }

                if (ApplyVisualStylesToHeaderCells)
                {
                    using var brush = SystemColors.HotTrack.GetCachedSolidBrushScope();
                    g.FillRectangle(brush, rectInsertionBar);
                }
                else
                {
                    ControlPaint.FillReversibleRectangle(RectangleToScreen(rectInsertionBar), Color.White);
                }
            }
        }

        /// <summary>
        ///  Draws an XOR region to give UI feedback for Column Resizing.
        ///  This looks just like the Splitter control's UI when resizing.
        /// </summary>
        private void DrawColSplitBar(int mouseX)
        {
            Rectangle r = CalcColResizeFeedbackRect(mouseX);
            DrawSplitBar(r);
        }

        /// <summary>
        ///  Draws an XOR region to give UI feedback for Row Resizing.
        ///  This looks just like the Splitter control's UI when resizing.
        /// </summary>
        private void DrawRowSplitBar(int mouseY)
        {
            Rectangle r = CalcRowResizeFeedbackRect(mouseY);
            DrawSplitBar(r);
        }

        private void DrawShadowRect(Rectangle r)
        {
            const byte DATAGRIDVIEW_shadowEdgeThickness = 3;

            using var dc = new User32.GetDcScope(Handle, IntPtr.Zero, User32.DCX.CACHE | User32.DCX.LOCKWINDOWUPDATE);
            Gdi32.HBRUSH halftone = ControlPaint.CreateHalftoneHBRUSH();
            Gdi32.HGDIOBJ saveBrush = Gdi32.SelectObject(dc, halftone);

            Gdi32.PatBlt(dc, r.X, r.Y, r.Width, DATAGRIDVIEW_shadowEdgeThickness, Gdi32.ROP.PATINVERT);
            Gdi32.PatBlt(dc, r.X, r.Y + r.Height - DATAGRIDVIEW_shadowEdgeThickness, r.Width, DATAGRIDVIEW_shadowEdgeThickness, Gdi32.ROP.PATINVERT);
            Gdi32.PatBlt(dc, r.X, r.Y + DATAGRIDVIEW_shadowEdgeThickness, DATAGRIDVIEW_shadowEdgeThickness, r.Height - 2 * DATAGRIDVIEW_shadowEdgeThickness, Gdi32.ROP.PATINVERT);
            Gdi32.PatBlt(dc, r.X + r.Width - DATAGRIDVIEW_shadowEdgeThickness, r.Y + DATAGRIDVIEW_shadowEdgeThickness, DATAGRIDVIEW_shadowEdgeThickness, r.Height - 2 * DATAGRIDVIEW_shadowEdgeThickness, Gdi32.ROP.PATINVERT);

            Gdi32.SelectObject(dc, saveBrush);
            Gdi32.DeleteObject(halftone);
        }

        /// <summary>
        ///  Draws an XOR region to give UI feedback for Column/Row Resizing.
        ///  This looks just like the Splitter control's UI when resizing.
        /// </summary>
        private void DrawSplitBar(Rectangle r)
        {
            Gdi32.HDC dc = User32.GetDCEx(this, IntPtr.Zero, User32.DCX.CACHE | User32.DCX.LOCKWINDOWUPDATE);
            Gdi32.HBRUSH halftone = ControlPaint.CreateHalftoneHBRUSH();
            Gdi32.HGDIOBJ saveBrush = Gdi32.SelectObject(dc, halftone);
            Gdi32.PatBlt(dc, r.X, r.Y, r.Width, r.Height, Gdi32.ROP.PATINVERT);
            Gdi32.SelectObject(dc, saveBrush);
            Gdi32.DeleteObject(halftone);
            User32.ReleaseDC(new HandleRef(this, Handle), dc);
        }

        private void EditingControls_CommonMouseEventHandler(object sender, MouseEventArgs e, DataGridViewMouseEvent dgvme)
        {
            Debug.Assert(_ptCurrentCell.X != -1);
            int adjustedX = _editingPanel.Location.X + e.X;
            int adjustedY = _editingPanel.Location.Y + e.Y;
            if (sender == EditingControl)
            {
                adjustedX += EditingControl.Location.X;
                adjustedY += EditingControl.Location.Y;
            }

            if (dgvme == DataGridViewMouseEvent.MouseDown && e.Clicks == 1)
            {
                // Reset the flag that records single-click exposed as double-click.
                _dataGridViewOper[OperationLastEditCtrlClickDoubled] = false;
            }

            MouseEventArgs me = new MouseEventArgs(e.Button,
                                                   e.Clicks,
                                                   adjustedX,
                                                   adjustedY,
                                                   e.Delta);

            HitTestInfo hti = HitTest(me.X, me.Y);
            int mouseX = me.X - hti.ColumnX;
            if (RightToLeftInternal)
            {
                mouseX += ((hti._col == -1) ? RowHeadersWidth : Columns[hti._col].Thickness);
            }
            DataGridViewCellMouseEventArgs dgvcme = new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, me.Y - hti.RowY, me);

            try
            {
                _dataGridViewState2[State2_MessageFromEditingCtrls] = true;
                // Check to see if this is a CellMouseDoubleClick situation
                if ((dgvme == DataGridViewMouseEvent.MouseDown ||
                     dgvme == DataGridViewMouseEvent.Click ||
                     dgvme == DataGridViewMouseEvent.MouseClick) &&
                    (DateTime.Now.Ticks - _lastMouseClickInfo.TimeStamp) / 10000 <= SystemInformation.DoubleClickTime &&
                    e.Button == _lastMouseClickInfo.Button &&
                    e.Clicks == 1 &&
                    dgvcme.ColumnIndex == _lastMouseClickInfo.Col &&
                    dgvcme.RowIndex == _lastMouseClickInfo.Row)
                {
                    Size hotDoubleClickZone = SystemInformation.DoubleClickSize;
                    if (Math.Abs(dgvcme.X - _lastMouseClickInfo.X) <= hotDoubleClickZone.Width / 2 &&
                        Math.Abs(dgvcme.Y - _lastMouseClickInfo.Y) <= hotDoubleClickZone.Height / 2)
                    {
                        me = new MouseEventArgs(e.Button,
                                                2,
                                                adjustedX,
                                                adjustedY,
                                                e.Delta);
                        dgvcme = new DataGridViewCellMouseEventArgs(dgvcme.ColumnIndex, dgvcme.RowIndex, dgvcme.X, dgvcme.Y, me);
                        switch (dgvme)
                        {
                            case DataGridViewMouseEvent.MouseDown:
                                {
                                    OnMouseDown(me);
                                    if (dgvcme.ColumnIndex < Columns.Count &&
                                        dgvcme.RowIndex < Rows.Count)
                                    {
                                        OnCellMouseDown(dgvcme);
                                    }
                                    break;
                                }
                            case DataGridViewMouseEvent.Click:
                                {
                                    OnDoubleClick(me);
                                    if (e.Button == MouseButtons.Left &&
                                        dgvcme.ColumnIndex < Columns.Count &&
                                        dgvcme.RowIndex < Rows.Count)
                                    {
                                        OnCellDoubleClick(new DataGridViewCellEventArgs(dgvcme.ColumnIndex, dgvcme.RowIndex));
                                    }
                                    break;
                                }
                            case DataGridViewMouseEvent.MouseClick:
                                {
                                    // Set the flag that prevents the triple-click to be exposed as a double-click
                                    _dataGridViewOper[OperationLastEditCtrlClickDoubled] = true;

                                    OnMouseDoubleClick(me);
                                    if (dgvcme.ColumnIndex < Columns.Count && dgvcme.RowIndex < Rows.Count)
                                    {
                                        OnCellMouseDoubleClick(dgvcme);
                                    }
                                    break;
                                }
                        }
                        return;
                    }
                }

                if (_dataGridViewOper[OperationLastEditCtrlClickDoubled])
                {
                    // Make sure that the triple-click is exposed as a single-click and not a double-click.
                    if (e.Clicks == 2)
                    {
                        me = new MouseEventArgs(e.Button,
                                                1,
                                                adjustedX,
                                                adjustedY,
                                                e.Delta);
                        dgvcme = new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, me.Y - hti.RowY, me);
                    }
                    switch (dgvme)
                    {
                        case DataGridViewMouseEvent.DoubleClick:
                            dgvme = DataGridViewMouseEvent.Click;
                            break;
                        case DataGridViewMouseEvent.MouseDoubleClick:
                            dgvme = DataGridViewMouseEvent.MouseClick;
                            break;
                    }
                }

                switch (dgvme)
                {
                    case DataGridViewMouseEvent.Click:
                        OnClick(me);
                        if (e.Button == MouseButtons.Left &&
                            dgvcme.ColumnIndex < Columns.Count &&
                            dgvcme.RowIndex < Rows.Count)
                        {
                            OnCellClick(new DataGridViewCellEventArgs(dgvcme.ColumnIndex, dgvcme.RowIndex));
                        }
                        break;
                    case DataGridViewMouseEvent.DoubleClick:
                        OnDoubleClick(me);
                        if (e.Button == MouseButtons.Left &&
                            dgvcme.ColumnIndex < Columns.Count &&
                            dgvcme.RowIndex < Rows.Count)
                        {
                            OnCellDoubleClick(new DataGridViewCellEventArgs(dgvcme.ColumnIndex, dgvcme.RowIndex));
                        }
                        break;
                    case DataGridViewMouseEvent.MouseClick:
                        OnMouseClick(me);
                        if (dgvcme.ColumnIndex < Columns.Count &&
                            dgvcme.RowIndex < Rows.Count)
                        {
                            OnCellMouseClick(dgvcme);
                        }
                        break;
                    case DataGridViewMouseEvent.MouseDoubleClick:
                        OnMouseDoubleClick(me);
                        if (dgvcme.ColumnIndex < Columns.Count &&
                            dgvcme.RowIndex < Rows.Count)
                        {
                            OnCellMouseDoubleClick(dgvcme);
                        }
                        break;
                    case DataGridViewMouseEvent.MouseDown:
                        OnMouseDown(me);
                        if (dgvcme.ColumnIndex < Columns.Count &&
                            dgvcme.RowIndex < Rows.Count)
                        {
                            OnCellMouseDown(dgvcme);
                        }
                        break;
                    case DataGridViewMouseEvent.MouseUp:
                        if (_dataGridViewState2[State2_NextMouseUpIsDouble])
                        {
                            MouseEventArgs meTmp = new MouseEventArgs(e.Button,
                                                                      2,
                                                                      adjustedX,
                                                                      adjustedY,
                                                                      e.Delta);
                            dgvcme = new DataGridViewCellMouseEventArgs(dgvcme.ColumnIndex, dgvcme.RowIndex, dgvcme.X, dgvcme.Y, meTmp);
                        }
                        OnCellMouseUp(dgvcme);
                        OnMouseUp(me);
                        break;
                    case DataGridViewMouseEvent.MouseMove:
                        OnCellMouseMove(dgvcme);
                        break;
                }
            }
            finally
            {
                _dataGridViewState2[State2_MessageFromEditingCtrls] = false;
            }
        }

        private void EditingControls_Click(object sender, EventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            Debug.Assert(_ptCurrentCell.X != -1);
            if (e is MouseEventArgs me)
            {
                EditingControls_CommonMouseEventHandler(sender, me, DataGridViewMouseEvent.Click);
            }
        }

        private void EditingControls_DoubleClick(object sender, EventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            Debug.Assert(_ptCurrentCell.X != -1);
            if (e is MouseEventArgs me)
            {
                EditingControls_CommonMouseEventHandler(sender, me, DataGridViewMouseEvent.DoubleClick);
            }
        }

        private void EditingControls_MouseClick(object sender, MouseEventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            EditingControls_CommonMouseEventHandler(sender, e, DataGridViewMouseEvent.MouseClick);
        }

        private void EditingControls_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            EditingControls_CommonMouseEventHandler(sender, e, DataGridViewMouseEvent.MouseDoubleClick);
        }

        private void EditingControls_MouseDown(object sender, MouseEventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            EditingControls_CommonMouseEventHandler(sender, e, DataGridViewMouseEvent.MouseDown);
        }

        private void EditingControls_MouseEnter(object sender, EventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            if (sender == _editingPanel)
            {
                Debug.Assert(EditingControl != null);
                Debug.Assert(!_dataGridViewState1[State1_CustomCursorSet]);
                _dataGridViewState1[State1_CustomCursorSet] = true;
                _oldCursor = Cursor;
                CursorInternal = ((IDataGridViewEditingControl)EditingControl).EditingPanelCursor;
            }

            if (_dataGridViewState2[State2_MouseEnterExpected])
            {
                OnMouseEnter(EventArgs.Empty);
            }

            UpdateMouseEnteredCell(hti: null, e: null);
        }

        private void EditingControls_MouseLeave(object sender, EventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            if (sender == _editingPanel)
            {
                Debug.Assert(EditingControl != null);
                if (_dataGridViewState1[State1_CustomCursorSet])
                {
                    _dataGridViewState1[State1_CustomCursorSet] = false;
                    CursorInternal = _oldCursor;
                }
            }

            UpdateMouseEnteredCell(hti: null, e: null);

            Point ptMouse = PointToClient(Control.MousePosition);
            if (!ClientRectangle.Contains(ptMouse))
            {
                OnMouseLeave(EventArgs.Empty);
            }
        }

        private void EditingControls_MouseMove(object sender, MouseEventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            EditingControls_CommonMouseEventHandler(sender, e, DataGridViewMouseEvent.MouseMove);
        }

        private void EditingControls_MouseUp(object sender, MouseEventArgs e)
        {
            Debug.Assert(sender == EditingControl || sender == _editingPanel);
            EditingControls_CommonMouseEventHandler(sender, e, DataGridViewMouseEvent.MouseUp);
        }

        private void EndColumnHeadersResize(MouseEventArgs e)
        {
            try
            {
                if (_currentRowSplitBar != -1)
                {
                    Invalidate(CalcRowResizeFeedbackRect(_currentRowSplitBar), true);
                    _lastRowSplitBar = _currentRowSplitBar = -1;
                }

                int y = Math.Min(e.Y + _mouseBarOffset, _layout.Data.Bottom - 1);
                int delta = y - _layout.ColumnHeaders.Y - ColumnHeadersHeight + 1;
                if (_trackRowAnchor != y && delta != 0)
                {
                    ColumnHeadersHeight += delta;
                }
            }
            finally
            {
                RealeaseMouse();
            }
        }

        private void EndColumnRelocation(MouseEventArgs e, HitTestInfo hti)
        {
            try
            {
                if (_lastHeaderShadow != -1)
                {
                    _dataGridViewState2[State2_ShowColumnRelocationInsertion] = false;
                    _trackColumnEdge = -1;
                    _lastHeaderShadow = -1;
                    Invalidate(Rectangle.Union(_layout.TopLeftHeader, _layout.ColumnHeaders));
                }

                if (ColumnRelocationTarget(e, hti, out int previousColumnIndex))
                {
                    if (previousColumnIndex == -1)
                    {
                        Columns[_trackColumn].DisplayIndex = 0;
                    }
                    else if (Columns[_trackColumn].DisplayIndex > Columns[previousColumnIndex].DisplayIndex)
                    {
                        Columns[_trackColumn].DisplayIndex = Columns[previousColumnIndex].DisplayIndex + 1;
                    }
                    else
                    {
                        Columns[_trackColumn].DisplayIndex = Columns[previousColumnIndex].DisplayIndex;
                    }
                }
            }
            finally
            {
                RealeaseMouse();
            }
        }

        private void EndColumnResize(MouseEventArgs e)
        {
            try
            {
                EndColumnResize(e.X);
            }
            finally
            {
                RealeaseMouse();
            }
        }

        private void EndColumnResize(int x)
        {
            int newX, delta;
            if (RightToLeftInternal)
            {
                newX = Math.Max(x + _mouseBarOffset, _layout.Data.X);
                delta = GetColumnXFromIndex(_trackColumn) - Columns[_trackColumn].Thickness - newX + 1;
            }
            else
            {
                newX = Math.Min(x + _mouseBarOffset, _layout.Data.Right - 1);
                delta = newX - (GetColumnXFromIndex(_trackColumn) + Columns[_trackColumn].Thickness) + 1;
            }

            if (_trackColAnchor != newX && delta != 0)
            {
                int proposed = Columns[_trackColumn].Thickness + delta;
                Debug.Assert(proposed >= Columns[_trackColumn].MinimumThickness);
                Debug.Assert(proposed <= DataGridViewBand.MaxBandThickness);
                Columns[_trackColumn].Thickness = proposed;
            }
        }

        public bool EndEdit()
        {
            return EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit);
        }

        public bool EndEdit(DataGridViewDataErrorContexts context)
        {
            if (EditMode == DataGridViewEditMode.EditOnEnter)
            {
                return CommitEdit(context);
            }
            else
            {
                return EndEdit(context,
                    DataGridViewValidateCellInternal.Never /*validateCell*/,
                    false /*fireCellLeave*/,
                    false /*fireCellEnter*/,
                    false /*fireRowLeave*/,
                    false /*fireRowEnter*/,
                    false /*fireLeave*/,
                    true /*keepFocus*/,
                    true /*resetCurrentCell*/,
                    true /*resetAnchorCell*/);
            }
        }

        private bool EndEdit(DataGridViewDataErrorContexts context,
            DataGridViewValidateCellInternal validateCell,
            bool fireCellLeave,
            bool fireCellEnter,
            bool fireRowLeave,
            bool fireRowEnter,
            bool fireLeave,
            bool keepFocus,
            bool resetCurrentCell,
            bool resetAnchorCell)
        {
            if (_ptCurrentCell.X == -1)
            {
                return true;
            }

            _dataGridViewOper[OperationInEndEdit] = true;
            try
            {
                int curRowIndex = _ptCurrentCell.Y;
                int curColIndex = _ptCurrentCell.X;
                DataGridViewCell dataGridViewCurrentCell = CurrentCellInternal;
                DataGridViewDataErrorEventArgs dgvdee = CommitEdit(ref dataGridViewCurrentCell, context, validateCell,
                    fireCellLeave, fireCellEnter, fireRowLeave, fireRowEnter, fireLeave);
                if (dgvdee != null)
                {
                    if (dgvdee.ThrowException)
                    {
                        throw dgvdee.Exception;
                    }
                    if (dgvdee.Cancel)
                    {
                        return false;
                    }

                    // Restore old value
                    dgvdee = CancelEditPrivate();
                    if (null != dgvdee)
                    {
                        if (dgvdee.ThrowException)
                        {
                            throw dgvdee.Exception;
                        }
                        if (dgvdee.Cancel)
                        {
                            return false;
                        }
                    }
                }

                if (!IsCurrentCellInEditMode)
                {
                    return true;
                }

                if (curRowIndex != _ptCurrentCell.Y || curColIndex != _ptCurrentCell.X)
                {
                    return true;
                }

                if (EditingControl != null)
                {
                    UnwireEditingControlEvents();
                    _dataGridViewState2[State2_MouseOverRemovedEditingCtrl] = MouseOverEditingControl;
                    _dataGridViewState2[State2_MouseOverRemovedEditingPanel] = MouseOverEditingPanel;
                    _dataGridViewState1[State1_EditingControlChanging] = true;
                    try
                    {
                        dataGridViewCurrentCell.DetachEditingControl();
                    }
                    finally
                    {
                        _dataGridViewState1[State1_EditingControlChanging] = false;
                    }

                    ImeMode editingControlImeMode = EditingControl.CachedImeMode; // If in restricted mode, ImeMode will be Disable.
                    _latestEditingControl = EditingControl;
                    Debug.Assert(_editingPanel is null || _editingPanel.Controls.Count == 0);
                    EditingControl = null;
                    InvalidateCellPrivate(_ptCurrentCell.X, _ptCurrentCell.Y);

                    if (EditMode == DataGridViewEditMode.EditOnEnter)
                    {
                        if (resetCurrentCell)
                        {
                            bool success = SetCurrentCellAddressCore(-1, -1, resetAnchorCell, false, false);
                            Debug.Assert(success);
                        }
                    }
                    if (keepFocus)
                    {
                        Focus();
                    }
                    ImeMode = editingControlImeMode;
                }
                else
                {
                    Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                    _dataGridViewState1[State1_CurrentCellInEditMode] = false;
                    InvalidateCellPrivate(_ptCurrentCell.X, _ptCurrentCell.Y);
                }

                if (!IsInnerCellOutOfBounds(curColIndex, curRowIndex))
                {
                    DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(curColIndex, curRowIndex);
                    OnCellEndEdit(dgvce);
                }

                return true;
            }
            finally
            {
                _dataGridViewOper[OperationInEndEdit] = false;
            }
        }

        private void EndRowHeadersResize(MouseEventArgs e)
        {
            try
            {
                if (_currentColSplitBar != -1)
                {
                    Invalidate(CalcColResizeFeedbackRect(_currentColSplitBar), true);
                    _lastColSplitBar = _currentColSplitBar = -1;
                }

                int x, delta;
                if (RightToLeftInternal)
                {
                    x = Math.Max(e.X + _mouseBarOffset, _layout.Data.Left - 1);
                    delta = _layout.RowHeaders.Right - RowHeadersWidth - x - 1;
                }
                else
                {
                    x = Math.Min(e.X + _mouseBarOffset, _layout.Data.Right - 1);
                    delta = x - _layout.RowHeaders.X - RowHeadersWidth + 1;
                }
                if (_trackColAnchor != x && delta != 0)
                {
                    RowHeadersWidth += delta;
                }
            }
            finally
            {
                RealeaseMouse();
            }
        }

        private void EndRowResize(MouseEventArgs e)
        {
            try
            {
                if (_currentRowSplitBar != -1)
                {
                    Invalidate(CalcRowResizeFeedbackRect(_currentRowSplitBar), true);
                    _lastRowSplitBar = _currentRowSplitBar = -1;
                }

                DataGridViewRow dataGridViewRow = Rows.SharedRow(_trackRow);
                dataGridViewRow.GetHeightInfo(_trackRow, out int height, out int minimumHeight);
                int y = Math.Min(e.Y + _mouseBarOffset, _layout.Data.Bottom - 1);
                int delta = y - (GetRowYFromIndex(_trackRow) + height) + 1;
                if (_trackRowAnchor != y && delta != 0)
                {
                    int proposedHeight = height + delta;
                    proposedHeight = Math.Max(proposedHeight, minimumHeight);
                    if (!OnRowHeightInfoPushed(_trackRow, proposedHeight, minimumHeight))
                    {
                        if (dataGridViewRow.Index == -1)
                        {
                            dataGridViewRow = Rows[_trackRow];  // Unsharing row
                        }
                        Debug.Assert(_autoSizeRowsMode == DataGridViewAutoSizeRowsMode.None);
                        dataGridViewRow.ThicknessInternal = proposedHeight;
                    }
                }
            }
            finally
            {
                RealeaseMouse();
            }
        }

        private void ExitBulkLayout(bool invalidInAdjustFillingColumns)
        {
            if (_inBulkLayoutCount > 0)
            {
                _inBulkLayoutCount--;
                if (_inBulkLayoutCount == 0)
                {
                    PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, invalidInAdjustFillingColumns, false /*repositionEditingControl*/);
                }
            }
        }

        private void ExitBulkPaint(int columnIndex, int rowIndex)
        {
            if (_inBulkPaintCount > 0)
            {
                _inBulkPaintCount--;
                if (_inBulkPaintCount == 0)
                {
                    if (columnIndex >= 0)
                    {
                        InvalidateColumnInternal(columnIndex);
                    }
                    else if (rowIndex >= 0)
                    {
                        InvalidateRowPrivate(rowIndex);
                    }
                    else
                    {
                        Invalidate();
                    }
                }
            }
        }

        private void FirstVisibleScrollingRowTempted(int rowIndex)
        {
            Debug.Assert(rowIndex >= 0);
            Debug.Assert(rowIndex < Rows.Count);
            Debug.Assert((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) != 0);
            Debug.Assert((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Frozen) == 0);

            int displayHeight = _layout.Data.Height;
            if (displayHeight <= 0)
            {
                return;
            }

            int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            if (totalVisibleFrozenHeight < displayHeight)
            {
                DisplayedBandsInfo.FirstDisplayedScrollingRow = rowIndex;
            }
        }

        private void FlushDisplayedChanged()
        {
            if (DisplayedBandsInfo.Dirty && Visible)
            {
                // Handle the rows

                if (!RowHeadersVisible && Columns.GetColumnCount(DataGridViewElementStates.Visible) == 0)
                {
                    // All rows are hidden
                    UpdateRowsDisplayedState(false /*displayed*/);
                }
                else
                {
                    Rectangle rectScreen = Screen.FromControl(this).WorkingArea;
                    int maxDisplayedRows = (int)(rectScreen.Height / DataGridViewBand.MinBandThickness);

                    // Make sure all displayed scrolling rows have the Displayed state.
                    int rowIndexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                    if (rowIndexTmp != -1)
                    {
                        int numDisplayedScrollingRows = DisplayedBandsInfo.NumDisplayedScrollingRows;
                        Debug.Assert(numDisplayedScrollingRows > 0);
                        while (numDisplayedScrollingRows > 0)
                        {
                            Debug.Assert(rowIndexTmp != -1);
                            if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) == 0)
                            {
                                Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, true);
                            }
                            rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                            numDisplayedScrollingRows--;
                        }

                        int rowIndexTmp2 = rowIndexTmp;

                        // Make sure all scrolling rows before FirstDisplayedScrollingRow have their Displayed state set to false
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow != -1);
                        rowIndexTmp = Rows.GetPreviousRow(DisplayedBandsInfo.FirstDisplayedScrollingRow, DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                        while (rowIndexTmp != -1 && (Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0)
                        {
                            Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, false);
                            rowIndexTmp = Rows.GetPreviousRow(rowIndexTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                        }

                        // Make sure all rows below last displayed scrolling row have Displayed state set to false (next loop)
                        rowIndexTmp = rowIndexTmp2;
                    }
                    else
                    {
                        // No displayed scrolling rows. Make sure all non-frozen rows have their Displayed state set to false (next loop)
                        rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                    }
                    while (rowIndexTmp != -1 && (Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0)
                    {
                        Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, false);
                        rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                    }

                    // Make sure all displayed frozen rows have their Displayed state set to true
                    int numDisplayedFrozenRows = DisplayedBandsInfo.NumDisplayedFrozenRows;
                    rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    while (numDisplayedFrozenRows > 0)
                    {
                        Debug.Assert(rowIndexTmp != -1);
                        if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) == 0)
                        {
                            Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, true);
                        }
                        rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                        numDisplayedFrozenRows--;
                    }

                    // Make sure all non-displayed frozen rows have their Displayed state set to false
                    while (rowIndexTmp != -1 && (Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0)
                    {
                        Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, false);
                        rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    }

                    // Treat the cases where the old displayed rows are completely disjoint from the new displayed rows
                    int lastDisplayedFrozenRowIndex = -1;
                    int lastDisplayedScrollingRowIndex = -1;

                    if (DisplayedBandsInfo.NumDisplayedFrozenRows > 0)
                    {
                        int firstDisplayedFrozenRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                        Debug.Assert(firstDisplayedFrozenRowIndex != -1);
                        if (DisplayedBandsInfo.NumDisplayedFrozenRows > 1)
                        {
                            lastDisplayedFrozenRowIndex = Rows.GetNextRow(firstDisplayedFrozenRowIndex, DataGridViewElementStates.Visible, DisplayedBandsInfo.NumDisplayedFrozenRows - 2 /*skipRows*/);
                        }
                        else
                        {
                            lastDisplayedFrozenRowIndex = firstDisplayedFrozenRowIndex;
                        }
                    }

                    if (DisplayedBandsInfo.FirstDisplayedScrollingRow != -1)
                    {
                        if (DisplayedBandsInfo.NumDisplayedScrollingRows > 1)
                        {
                            lastDisplayedScrollingRowIndex = Rows.GetNextRow(DisplayedBandsInfo.FirstDisplayedScrollingRow, DataGridViewElementStates.Visible, DisplayedBandsInfo.NumDisplayedScrollingRows - 2 /*skipRows*/);
                        }
                        else
                        {
                            lastDisplayedScrollingRowIndex = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                        }
                    }

                    rowIndexTmp = DisplayedBandsInfo.OldFirstDisplayedScrollingRow;
                    while (rowIndexTmp != -1 &&
                        rowIndexTmp < DisplayedBandsInfo.FirstDisplayedScrollingRow &&
                        !RowNeedsDisplayedState(rowIndexTmp, lastDisplayedFrozenRowIndex, lastDisplayedScrollingRowIndex))
                    {
                        if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) == 0)
                        {
                            break;
                        }
                        else
                        {
                            Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, false);
                            rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                        }
                    }

                    rowIndexTmp = DisplayedBandsInfo.OldFirstDisplayedScrollingRow;
                    if (rowIndexTmp != -1 &&
                        rowIndexTmp < Rows.Count &&
                        (DisplayedBandsInfo.FirstDisplayedScrollingRow == -1 || DisplayedBandsInfo.FirstDisplayedScrollingRow < rowIndexTmp) &&
                        !RowNeedsDisplayedState(rowIndexTmp, lastDisplayedFrozenRowIndex, lastDisplayedScrollingRowIndex))
                    {
                        while (rowIndexTmp != -1)
                        {
                            if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) == 0)
                            {
                                break;
                            }
                            else
                            {
                                Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, false);
                                rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                            }
                        }
                    }

                    if (DisplayedBandsInfo.RowInsertionOccurred)
                    {
                        // Adjust the scrolling rows that were pushed down by the rows insertion
                        rowIndexTmp = DisplayedBandsInfo.OldFirstDisplayedScrollingRow;
                        if (rowIndexTmp != -1)
                        {
                            rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible, DisplayedBandsInfo.OldNumDisplayedScrollingRows - 1);
                            if (rowIndexTmp == -1)
                            {
                                rowIndexTmp = Rows.GetLastRow(DataGridViewElementStates.Visible);
                            }
                            int rowCount = 0;
                            while (rowIndexTmp != -1 &&
                                   rowCount <= maxDisplayedRows &&
                                   !RowNeedsDisplayedState(rowIndexTmp, lastDisplayedFrozenRowIndex, lastDisplayedScrollingRowIndex))
                            {
                                if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0)
                                {
                                    Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, false);
                                }
                                rowIndexTmp = Rows.GetPreviousRow(rowIndexTmp, DataGridViewElementStates.Visible);
                                rowCount++;
                            }
                        }

                        // Adjust the frozen rows that were pushed down by the rows insertion
                        rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                        if (rowIndexTmp != -1)
                        {
                            rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen, DisplayedBandsInfo.OldNumDisplayedFrozenRows - 1);
                            if (rowIndexTmp == -1)
                            {
                                rowIndexTmp = Rows.GetLastRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                            }
                            int rowCount = 0;
                            while (rowIndexTmp != -1 &&
                                   rowCount <= maxDisplayedRows &&
                                   !RowNeedsDisplayedState(rowIndexTmp, lastDisplayedFrozenRowIndex, lastDisplayedScrollingRowIndex))
                            {
                                if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0)
                                {
                                    Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, false);
                                }
                                rowIndexTmp = Rows.GetPreviousRow(rowIndexTmp, DataGridViewElementStates.Visible);
                                rowCount++;
                            }
                        }
                    }

#if DEBUG
                    for (rowIndexTmp = 0; rowIndexTmp < Rows.Count; rowIndexTmp++)
                    {
                        DataGridViewElementStates rowStateDbg = Rows.GetRowState(rowIndexTmp);
                        bool rowNeedsDisplayedState = RowNeedsDisplayedState(rowIndexTmp, lastDisplayedFrozenRowIndex, lastDisplayedScrollingRowIndex);
                        if (((rowStateDbg & DataGridViewElementStates.Displayed) != 0) != rowNeedsDisplayedState)
                        {
                            Debug.Fail("Unexpected Displayed state for row");
                        }
                    }
#endif
                }

                // Handle the columns

                if (!ColumnHeadersVisible && Rows.GetRowCount(DataGridViewElementStates.Visible) == 0)
                {
                    // All columns are hidden
                    UpdateColumnsDisplayedState(false /*displayed*/);
                }
                else
                {
                    // Make sure all displayed scrolling columns have the Displayed state.
                    DataGridViewColumn dataGridViewColumnTmp;
                    int columnIndexTmp = DisplayedBandsInfo.FirstDisplayedScrollingCol;
                    if (columnIndexTmp != -1)
                    {
                        int numDisplayedScrollingCols = DisplayedBandsInfo.NumDisplayedScrollingCols;
                        Debug.Assert(numDisplayedScrollingCols > 0);
                        dataGridViewColumnTmp = Columns[columnIndexTmp];
                        while (numDisplayedScrollingCols > 0)
                        {
                            Debug.Assert(dataGridViewColumnTmp != null);
                            if (!dataGridViewColumnTmp.Displayed)
                            {
                                dataGridViewColumnTmp.Displayed = true;
                            }
                            dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                            numDisplayedScrollingCols--;
                        }

                        DataGridViewColumn dataGridViewColumnTmp2 = dataGridViewColumnTmp;

                        // Make sure all scrolling columns before FirstDisplayedScrollingCol have their Displayed state set to false
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingCol != -1);
                        dataGridViewColumnTmp = Columns.GetPreviousColumn(Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol], DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                        while (dataGridViewColumnTmp != null && dataGridViewColumnTmp.Displayed)
                        {
                            dataGridViewColumnTmp.Displayed = false;
                            dataGridViewColumnTmp = Columns.GetPreviousColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                        }

                        // Make sure all columns after last displayed scrolling column have Displayed state set to false (next loop)
                        dataGridViewColumnTmp = dataGridViewColumnTmp2;
                    }
                    else
                    {
                        // No displayed scrolling columns. Make sure all non-frozen columns have their Displayed state set to false (next loop)
                        dataGridViewColumnTmp = Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                    }
                    while (dataGridViewColumnTmp != null && dataGridViewColumnTmp.Displayed)
                    {
                        dataGridViewColumnTmp.Displayed = false;
                        dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    }

                    // Make sure all displayed frozen columns have their Displayed state set to true
                    int numDisplayedFrozenCols = DisplayedBandsInfo.NumDisplayedFrozenCols;
                    dataGridViewColumnTmp = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    while (numDisplayedFrozenCols > 0)
                    {
                        Debug.Assert(dataGridViewColumnTmp != null);
                        if (!dataGridViewColumnTmp.Displayed)
                        {
                            dataGridViewColumnTmp.Displayed = true;
                        }
                        dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen, DataGridViewElementStates.None);
                        numDisplayedFrozenCols--;
                    }

                    // Make sure all non-displayed frozen columns have their Displayed state set to false
                    while (dataGridViewColumnTmp != null && dataGridViewColumnTmp.Displayed)
                    {
                        dataGridViewColumnTmp.Displayed = false;
                        dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen, DataGridViewElementStates.None);
                    }

                    // Treat the cases where the old displayed columns are completely disjoint from the new displayed columns

                    columnIndexTmp = DisplayedBandsInfo.OldFirstDisplayedScrollingCol;
                    while (columnIndexTmp != -1 &&
                        columnIndexTmp < Columns.Count &&
                        DisplayedBandsInfo.FirstDisplayedScrollingCol != -1 &&
                        columnIndexTmp != DisplayedBandsInfo.FirstDisplayedScrollingCol &&
                        Columns.DisplayInOrder(columnIndexTmp, DisplayedBandsInfo.FirstDisplayedScrollingCol) &&
                        !ColumnNeedsDisplayedState(Columns[columnIndexTmp]))
                    {
                        dataGridViewColumnTmp = Columns[columnIndexTmp];
                        if (!dataGridViewColumnTmp.Displayed)
                        {
                            break;
                        }
                        else
                        {
                            dataGridViewColumnTmp.Displayed = false;
                            dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                            columnIndexTmp = (dataGridViewColumnTmp is null) ? -1 : dataGridViewColumnTmp.Index;
                        }
                    }

                    columnIndexTmp = DisplayedBandsInfo.OldFirstDisplayedScrollingCol;
                    if (columnIndexTmp != -1 &&
                        columnIndexTmp < Columns.Count &&
                        (DisplayedBandsInfo.FirstDisplayedScrollingCol == -1 || (DisplayedBandsInfo.FirstDisplayedScrollingCol != columnIndexTmp && Columns.DisplayInOrder(DisplayedBandsInfo.FirstDisplayedScrollingCol, columnIndexTmp))) &&
                        !ColumnNeedsDisplayedState(Columns[columnIndexTmp]))
                    {
                        dataGridViewColumnTmp = Columns[columnIndexTmp];
                        while (dataGridViewColumnTmp != null)
                        {
                            if (!dataGridViewColumnTmp.Displayed)
                            {
                                break;
                            }
                            else
                            {
                                dataGridViewColumnTmp.Displayed = false;
                                dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                            }
                        }
                    }

                    if (DisplayedBandsInfo.ColumnInsertionOccurred)
                    {
                        dataGridViewColumnTmp = Columns[Columns.Count - 1];
                        while (dataGridViewColumnTmp != null && !ColumnNeedsDisplayedState(dataGridViewColumnTmp))
                        {
                            if (dataGridViewColumnTmp.Displayed)
                            {
                                dataGridViewColumnTmp.Displayed = false;
                            }
                            dataGridViewColumnTmp = Columns.GetPreviousColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                        }
                    }

#if DEBUG
                    for (columnIndexTmp = 0; columnIndexTmp < Columns.Count; columnIndexTmp++)
                    {
                        DataGridViewElementStates colStateDbg = Columns[columnIndexTmp].State;
                        bool columnNeedsDisplayedState = ColumnNeedsDisplayedState(Columns[columnIndexTmp]);
                        if (((colStateDbg & DataGridViewElementStates.Displayed) != 0) != columnNeedsDisplayedState)
                        {
                            Debug.Fail("Unexpected Displayed state for column");
                        }
                    }
#endif
                }

                DisplayedBandsInfo.Dirty = false;
            }
        }

        private void FlushDisplayIndexChanged(bool raiseEvent)
        {
            foreach (DataGridViewColumn dataGridViewColumn in Columns)
            {
                if (dataGridViewColumn.DisplayIndexHasChanged)
                {
                    dataGridViewColumn.DisplayIndexHasChanged = false;
                    if (raiseEvent)
                    {
                        OnColumnDisplayIndexChanged(dataGridViewColumn);
                    }
                }
            }
        }

        private void FlushSelectionChanged()
        {
            if (_dataGridViewState2[State2_RaiseSelectionChanged])
            {
                OnSelectionChanged(EventArgs.Empty);
            }
        }

        protected override AccessibleObject GetAccessibilityObjectById(int objectId)
        {
            // decrement the objectId because in our implementation of AccessibilityClient notitification objectId's are 1 - based.
            // 0 == NativeMethods.CHILDID_SELF corresponds to the AccessibleObject itself
            return AccessibilityObject.GetChild(objectId - 1);
        }

        internal TypeConverter GetCachedTypeConverter(Type type)
        {
            if (_converters.ContainsKey(type))
            {
                return (TypeConverter)_converters[type];
            }

            TypeConverter converter = TypeDescriptor.GetConverter(type);
            _converters.Add(type, converter);
            return converter;
        }

        internal Rectangle GetCellAdjustedDisplayRectangle(int columnIndex, int rowIndex, bool cutOverflow)
        {
            Rectangle rect = GetCellDisplayRectangle(columnIndex, rowIndex, cutOverflow);
            if (!rect.IsEmpty)
            {
                if (SingleVerticalBorderAdded && columnIndex == FirstDisplayedColumnIndex)
                {
                    if (!RightToLeftInternal)
                    {
                        rect.X--;
                    }
                    rect.Width++;
                }
                if (SingleHorizontalBorderAdded && rowIndex == FirstDisplayedRowIndex)
                {
                    rect.Y--;
                    rect.Height++;
                }
            }
            return rect;
        }

        public int GetCellCount(DataGridViewElementStates includeFilter)
        {
            if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
                                   DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
            {
                throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
            }

            int cellCount = 0;
            bool displayedRequired, frozenRequired, resizableRequired, readOnlyRequired, visibleRequired;

            if ((includeFilter & DataGridViewElementStates.Selected) == DataGridViewElementStates.Selected)
            {
                if (includeFilter == DataGridViewElementStates.Selected)
                {
                    cellCount = _individualSelectedCells.Count;
                    switch (SelectionMode)
                    {
                        case DataGridViewSelectionMode.CellSelect:
                            {
                                // If we change the design and decide that SelectAll() should use band selection,
                                // we need to take the bands into account.
                                return cellCount;
                            }
                        case DataGridViewSelectionMode.FullColumnSelect:
                        case DataGridViewSelectionMode.ColumnHeaderSelect:
                            {
                                return cellCount + _selectedBandIndexes.Count * Rows.Count;
                            }
                        case DataGridViewSelectionMode.FullRowSelect:
                        case DataGridViewSelectionMode.RowHeaderSelect:
                            {
                                return cellCount + _selectedBandIndexes.Count * Columns.Count;
                            }
                    }
                }

                displayedRequired = (includeFilter & DataGridViewElementStates.Displayed) == DataGridViewElementStates.Displayed;
                frozenRequired = (includeFilter & DataGridViewElementStates.Frozen) == DataGridViewElementStates.Frozen;
                resizableRequired = (includeFilter & DataGridViewElementStates.Resizable) == DataGridViewElementStates.Resizable;
                readOnlyRequired = (includeFilter & DataGridViewElementStates.ReadOnly) == DataGridViewElementStates.ReadOnly;
                visibleRequired = (includeFilter & DataGridViewElementStates.Visible) == DataGridViewElementStates.Visible;

                foreach (DataGridViewCell dataGridViewCell in _individualSelectedCells)
                {
                    if (GetCellCount_CellIncluded(dataGridViewCell, dataGridViewCell.RowIndex, displayedRequired, frozenRequired, resizableRequired, readOnlyRequired, visibleRequired))
                    {
                        cellCount++;
                    }
                }
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        {
                            // If we change the design and decide that SelectAll() should use band selection,
                            // we need to take the bands into account.
                            return cellCount;
                        }
                    case DataGridViewSelectionMode.FullColumnSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        {
                            for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
                            {
                                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                                foreach (int columnIndex in _selectedBandIndexes)
                                {
                                    DataGridViewCell dataGridViewCell = dataGridViewRow.Cells[columnIndex];
                                    if (GetCellCount_CellIncluded(dataGridViewCell, rowIndex, displayedRequired, frozenRequired, resizableRequired, readOnlyRequired, visibleRequired))
                                    {
                                        cellCount++;
                                    }
                                }
                            }
                            return cellCount;
                        }
                    case DataGridViewSelectionMode.FullRowSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        {
                            foreach (int rowIndex in _selectedBandIndexes)
                            {
                                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                                foreach (DataGridViewCell dataGridViewCell in dataGridViewRow.Cells)
                                {
                                    if (GetCellCount_CellIncluded(dataGridViewCell, rowIndex, displayedRequired, frozenRequired, resizableRequired, readOnlyRequired, visibleRequired))
                                    {
                                        cellCount++;
                                    }
                                }
                            }
                            return cellCount;
                        }
                }
            }

            if ((includeFilter == DataGridViewElementStates.ReadOnly && ReadOnly) ||
                includeFilter == DataGridViewElementStates.None)
            {
                return Rows.Count * Columns.Count;
            }

            displayedRequired = (includeFilter & DataGridViewElementStates.Displayed) == DataGridViewElementStates.Displayed;
            frozenRequired = (includeFilter & DataGridViewElementStates.Frozen) == DataGridViewElementStates.Frozen;
            resizableRequired = (includeFilter & DataGridViewElementStates.Resizable) == DataGridViewElementStates.Resizable;
            readOnlyRequired = (includeFilter & DataGridViewElementStates.ReadOnly) == DataGridViewElementStates.ReadOnly;
            visibleRequired = (includeFilter & DataGridViewElementStates.Visible) == DataGridViewElementStates.Visible;

            for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
            {
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                if (!visibleRequired || (Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) != 0)
                {
                    foreach (DataGridViewCell dataGridViewCell in dataGridViewRow.Cells)
                    {
                        if (GetCellCount_CellIncluded(dataGridViewCell, rowIndex, displayedRequired, frozenRequired, resizableRequired, readOnlyRequired, visibleRequired))
                        {
                            cellCount++;
                        }
                    }
                }
            }
            return cellCount;
        }

        private bool GetCellCount_CellIncluded(DataGridViewCell dataGridViewCell,
                                               int rowIndex,
                                               bool displayedRequired,
                                               bool frozenRequired,
                                               bool resizableRequired,
                                               bool readOnlyRequired,
                                               bool visibleRequired)
        {
            Debug.Assert(dataGridViewCell != null);
            Debug.Assert(rowIndex >= 0);
            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
            if (displayedRequired)
            {
                bool cellDisplayed = (rowState & DataGridViewElementStates.Displayed) != 0 &&
                                     dataGridViewCell.OwningColumn.Displayed;
                if (!cellDisplayed)
                {
                    return false;
                }
            }
            if (frozenRequired)
            {
                bool cellFrozen = (rowState & DataGridViewElementStates.Frozen) != 0 ||
                                  dataGridViewCell.OwningColumn.Frozen ||
                                  dataGridViewCell.StateIncludes(DataGridViewElementStates.Frozen);
                if (!cellFrozen)
                {
                    return false;
                }
            }
            if (resizableRequired)
            {
                if (!RowIsResizable(rowIndex) && dataGridViewCell.OwningColumn.Resizable != DataGridViewTriState.True)
                {
                    return false;
                }
            }
            if (readOnlyRequired)
            {
                bool cellReadOnly = ReadOnly ||
                                    (rowState & DataGridViewElementStates.ReadOnly) != 0 ||
                                    dataGridViewCell.OwningColumn.ReadOnly ||
                                    dataGridViewCell.StateIncludes(DataGridViewElementStates.ReadOnly);
                if (!cellReadOnly)
                {
                    return false;
                }
            }
            if (visibleRequired)
            {
                bool cellVisible = (rowState & DataGridViewElementStates.Visible) != 0 &&
                                   dataGridViewCell.OwningColumn.Visible;
                if (!cellVisible)
                {
                    return false;
                }
            }
            return true;
        }

        public Rectangle GetCellDisplayRectangle(int columnIndex, int rowIndex, bool cutOverflow)
        {
            Rectangle rowRect;
            Rectangle columnRect;

            if (columnIndex >= 0)
            {
                if (columnIndex >= Columns.Count)
                {
                    throw new ArgumentOutOfRangeException(nameof(columnIndex));
                }
                columnRect = GetColumnDisplayRectanglePrivate(columnIndex, cutOverflow);
            }
            else
            {
                if (columnIndex != -1)
                {
                    throw new ArgumentOutOfRangeException(nameof(columnIndex));
                }
                if (rowIndex >= 0)
                {
                    columnRect = _layout.RowHeaders;
                }
                else
                {
                    columnRect = _layout.TopLeftHeader;
                }
            }

            if (rowIndex >= 0)
            {
                if (rowIndex >= Rows.Count)
                {
                    throw new ArgumentOutOfRangeException(nameof(rowIndex));
                }
                rowRect = GetRowDisplayRectanglePrivate(rowIndex, cutOverflow);
            }
            else
            {
                if (rowIndex != -1)
                {
                    throw new ArgumentOutOfRangeException(nameof(rowIndex));
                }
                if (columnIndex >= 0)
                {
                    rowRect = _layout.ColumnHeaders;
                }
                else
                {
                    rowRect = _layout.TopLeftHeader;
                }
            }

            if (!cutOverflow)
            {
                int height = rowRect.Bottom - columnRect.Bottom;
                if (height > 0)
                {
                    columnRect.Height += height;
                }
                int width;
                if (RightToLeftInternal)
                {
                    width = rowRect.X - columnRect.X;
                    if (width > 0)
                    {
                        rowRect.Width += width;
                        rowRect.X -= width;
                    }
                }
                else
                {
                    width = columnRect.Right - rowRect.Right;
                    if (width > 0)
                    {
                        rowRect.Width += width;
                    }
                }
            }

            rowRect.Intersect(columnRect);

            return rowRect;
        }

        internal DataGridViewCell GetCellInternal(int columnIndex, int rowIndex)
        {
            Debug.Assert(columnIndex >= -1 && columnIndex < Columns.Count);
            Debug.Assert(rowIndex >= -1 && rowIndex < Rows.Count);
            if (rowIndex >= 0)
            {
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                Debug.Assert(dataGridViewRow != null);
                if (columnIndex >= 0)
                {
                    return dataGridViewRow.Cells[columnIndex];
                }
                else
                {
                    return dataGridViewRow.HeaderCell;
                }
            }
            else
            {
                if (columnIndex >= 0)
                {
                    return Columns[columnIndex].HeaderCell;
                }
                else
                {
                    return TopLeftHeaderCell;
                }
            }
        }

        public virtual DataObject GetClipboardContent()
        {
            if (ClipboardCopyMode == DataGridViewClipboardCopyMode.Disable)
            {
                throw new NotSupportedException(SR.DataGridView_DisabledClipboardCopy);
            }

            if (CurrentCellIsEditedAndOnlySelectedCell)
            {
                return null;
            }

            string[] formats = new string[] { DataFormats.Html, DataFormats.Text, DataFormats.UnicodeText, DataFormats.CommaSeparatedValue };
            DataObject dataObject = new DataObject();
            bool includeColumnHeaders = false, includeRowHeaders = false;
            string cellContent = null;
            StringBuilder sbContent = null;
            DataGridViewColumn dataGridViewColumn, prevDataGridViewColumn, nextDataGridViewColumn;

            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.FullRowSelect:
                    if (Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected) == 0)
                    {
                        return null;
                    }

                    if (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableWithAutoHeaderText)
                    {
                        includeColumnHeaders = (Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Selected) == -1);
                        includeRowHeaders = true;
                    }
                    else
                    {
                        includeColumnHeaders = includeRowHeaders = (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText);
                    }

                    includeColumnHeaders &= ColumnHeadersVisible;
                    includeRowHeaders &= RowHeadersVisible;

                    foreach (string format in formats)
                    {
                        if (sbContent is null)
                        {
                            sbContent = new StringBuilder(1024);
                        }
                        else
                        {
                            sbContent.Length = 0;
                        }

                        if (includeColumnHeaders)
                        {
                            if (RightToLeftInternal)
                            {
                                // Cycle through the visible columns in their reverse display order
                                dataGridViewColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                if (dataGridViewColumn != null)
                                {
                                    prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                            true /*firstCell*/,
                                                                                                            !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                            true /*inFirstRow*/,
                                                                                                            false /*inLastRow*/,
                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (prevDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = prevDataGridViewColumn;
                                        prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                                false /*firstCell*/,
                                                                                                                !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                                true /*inFirstRow*/,
                                                                                                                false /*inLastRow*/,
                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }
                                if (includeRowHeaders)
                                {
                                    cellContent = TopLeftHeaderCell.GetClipboardContentInternal(-1,
                                                                                                     Columns.GetColumnCount(DataGridViewElementStates.Visible) == 0 /*firstCell*/,
                                                                                                     true /*lastCell*/,
                                                                                                     true /*inFirstRow*/,
                                                                                                     false /*inLastRow*/,
                                                                                                     format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                            }
                            else
                            {
                                if (includeRowHeaders)
                                {
                                    cellContent = TopLeftHeaderCell.GetClipboardContentInternal(-1,
                                                                                                     true /*firstCell*/,
                                                                                                     Columns.GetColumnCount(DataGridViewElementStates.Visible) == 0 /*lastCell*/,
                                                                                                     true /*inFirstRow*/,
                                                                                                     false /*inLastRow*/,
                                                                                                     format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                                // Cycle through the visible columns in their display order
                                dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                                if (dataGridViewColumn != null)
                                {
                                    nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                            !includeRowHeaders /*firstCell*/,
                                                                                                            nextDataGridViewColumn is null /*lastCell*/,
                                                                                                            true /*inFirstRow*/,
                                                                                                            false /*inLastRow*/,
                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (nextDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = nextDataGridViewColumn;
                                        nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                                false /*firstCell*/,
                                                                                                                nextDataGridViewColumn is null /*lastCell*/,
                                                                                                                true /*inFirstRow*/,
                                                                                                                false /*inLastRow*/,
                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }
                            }
                        }
                        // Cycle through the visible selected rows.
                        bool firstRowIndex = true;
                        int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected);
                        Debug.Assert(rowIndex != -1);
                        int nextRowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected);
                        while (rowIndex != -1)
                        {
                            if (RightToLeftInternal)
                            {
                                dataGridViewColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.None);

                                // Cycle through the visible columns in their reverse display order
                                if (dataGridViewColumn != null)
                                {
                                    prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                            true /*firstCell*/,
                                                                                                                                            !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                                                            !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                            nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (prevDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = prevDataGridViewColumn;
                                        prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                                false /*firstCell*/,
                                                                                                                                                !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                                                                !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                                nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }

                                // Get the row header clipboard content
                                if (includeRowHeaders)
                                {
                                    cellContent = Rows.SharedRow(rowIndex).HeaderCell.GetClipboardContentInternal(rowIndex,
                                                                                                                       Columns.GetColumnCount(DataGridViewElementStates.Visible) == 0 /*firstCell*/,
                                                                                                                       true /*lastCell*/,
                                                                                                                       !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                       nextRowIndex == -1 /*inLastRow*/,
                                                                                                                       format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                            }
                            else
                            {
                                dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);

                                // Get the row header clipboard content
                                if (includeRowHeaders)
                                {
                                    cellContent = Rows.SharedRow(rowIndex).HeaderCell.GetClipboardContentInternal(rowIndex,
                                                                                                                       true /*firstCell*/,
                                                                                                                       dataGridViewColumn is null /*lastCell*/,
                                                                                                                       !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                       nextRowIndex == -1 /*inLastRow*/,
                                                                                                                       format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }

                                // Cycle through the visible columns in their display order
                                if (dataGridViewColumn != null)
                                {
                                    nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                            !includeRowHeaders /*firstCell*/,
                                                                                                                                            nextDataGridViewColumn is null /*lastCell*/,
                                                                                                                                            !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                            nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (nextDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = nextDataGridViewColumn;
                                        nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                                false /*firstCell*/,
                                                                                                                                                nextDataGridViewColumn is null /*lastCell*/,
                                                                                                                                                !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                                nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }
                            }
                            rowIndex = nextRowIndex;
                            if (rowIndex != -1)
                            {
                                nextRowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected);
                            }
                            firstRowIndex = false;
                        }
                        if (string.Equals(format, DataFormats.Html, StringComparison.OrdinalIgnoreCase))
                        {
                            GetClipboardContentForHtml(sbContent, out IO.MemoryStream utf8Stream);
                            dataObject.SetData(format, false /*autoConvert*/, utf8Stream);
                        }
                        else
                        {
                            dataObject.SetData(format, false /*autoConvert*/, sbContent.ToString());
                        }
                    }
                    break;

                case DataGridViewSelectionMode.FullColumnSelect:
                    if (Columns.GetColumnCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected) == 0)
                    {
                        return null;
                    }

                    if (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableWithAutoHeaderText)
                    {
                        includeColumnHeaders = true;
                        includeRowHeaders = (Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Selected) is null);
                    }
                    else
                    {
                        includeColumnHeaders = includeRowHeaders = (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText);
                    }

                    includeColumnHeaders &= ColumnHeadersVisible;
                    includeRowHeaders &= RowHeadersVisible;

                    int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);

                    foreach (string format in formats)
                    {
                        if (sbContent is null)
                        {
                            sbContent = new StringBuilder(1024);
                        }
                        else
                        {
                            sbContent.Length = 0;
                        }

                        if (includeColumnHeaders)
                        {
                            if (RightToLeftInternal)
                            {
                                // Cycle through the visible & selected columns in their display order
                                DataGridViewColumn lastDataGridViewColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                dataGridViewColumn = lastDataGridViewColumn;
                                Debug.Assert(dataGridViewColumn != null);
                                if (dataGridViewColumn != null)
                                {
                                    prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                    cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                            true /*firstCell*/,
                                                                                                            !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                            true /*inFirstRow*/,
                                                                                                            firstVisibleRowIndex == -1 /*inLastRow*/,
                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (prevDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = prevDataGridViewColumn;
                                        prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                        cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                                false /*firstCell*/,
                                                                                                                !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                                true /*inFirstRow*/,
                                                                                                                firstVisibleRowIndex == -1 /*inLastRow*/,
                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }
                                if (includeRowHeaders)
                                {
                                    cellContent = TopLeftHeaderCell.GetClipboardContentInternal(-1,
                                                                                                     lastDataGridViewColumn is null /*firstCell*/,
                                                                                                     true /*lastCell*/,
                                                                                                     true /*inFirstRow*/,
                                                                                                     firstVisibleRowIndex == -1 /*inLastRow*/,
                                                                                                     format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                            }
                            else
                            {
                                dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected);

                                if (includeRowHeaders)
                                {
                                    cellContent = TopLeftHeaderCell.GetClipboardContentInternal(-1,
                                                                                                     true /*firstCell*/,
                                                                                                     dataGridViewColumn is null /*lastCell*/,
                                                                                                     true /*inFirstRow*/,
                                                                                                     firstVisibleRowIndex == -1 /*inLastRow*/,
                                                                                                     format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                                // Cycle through the visible & selected columns in their display order
                                Debug.Assert(dataGridViewColumn != null);
                                if (dataGridViewColumn != null)
                                {
                                    nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                    cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                            !includeRowHeaders /*firstCell*/,
                                                                                                            nextDataGridViewColumn is null /*lastCell*/,
                                                                                                            true /*inFirstRow*/,
                                                                                                            firstVisibleRowIndex == -1 /*inLastRow*/,
                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (nextDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = nextDataGridViewColumn;
                                        nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                        cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                                false /*firstCell*/,
                                                                                                                nextDataGridViewColumn is null /*lastCell*/,
                                                                                                                true /*inFirstRow*/,
                                                                                                                firstVisibleRowIndex == -1 /*inLastRow*/,
                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }
                            }
                        }
                        // Cycle through the visible rows.
                        bool firstRowIndex = true;
                        int rowIndex = firstVisibleRowIndex;
                        int nextRowIndex = -1;
                        if (rowIndex != -1)
                        {
                            nextRowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                        }
                        while (rowIndex != -1)
                        {
                            if (RightToLeftInternal)
                            {
                                DataGridViewColumn lastDataGridViewColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);

                                // Cycle through the visible & selected columns in their reverse display order
                                dataGridViewColumn = lastDataGridViewColumn;
                                if (dataGridViewColumn != null)
                                {
                                    prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                    cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                            true /*firstCell*/,
                                                                                                                                            !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                                                            !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                            nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (prevDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = prevDataGridViewColumn;
                                        prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                        cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                                false /*firstCell*/,
                                                                                                                                                !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                                                                !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                                nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }

                                // Get the row header clipboard content
                                if (includeRowHeaders)
                                {
                                    cellContent = Rows.SharedRow(rowIndex).HeaderCell.GetClipboardContentInternal(rowIndex,
                                                                                                                       lastDataGridViewColumn is null /*firstCell*/,
                                                                                                                       true /*lastCell*/,
                                                                                                                       !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                       nextRowIndex == -1 /*inLastRow*/,
                                                                                                                       format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                            }
                            else
                            {
                                dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected);

                                // Get the row header clipboard content
                                if (includeRowHeaders)
                                {
                                    cellContent = Rows.SharedRow(rowIndex).HeaderCell.GetClipboardContentInternal(rowIndex,
                                                                                                                       true /*firstCell*/,
                                                                                                                       dataGridViewColumn is null /*lastCell*/,
                                                                                                                       !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                       nextRowIndex == -1 /*inLastRow*/,
                                                                                                                       format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }

                                // Cycle through the visible & selected columns in their display order
                                if (dataGridViewColumn != null)
                                {
                                    nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                    cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                            !includeRowHeaders /*firstCell*/,
                                                                                                                                            nextDataGridViewColumn is null /*lastCell*/,
                                                                                                                                            !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                            nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    while (nextDataGridViewColumn != null)
                                    {
                                        dataGridViewColumn = nextDataGridViewColumn;
                                        nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible | DataGridViewElementStates.Selected, DataGridViewElementStates.None);
                                        cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                                false /*firstCell*/,
                                                                                                                                                nextDataGridViewColumn is null /*lastCell*/,
                                                                                                                                                !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                                nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                                format) as string;
                                        if (cellContent != null)
                                        {
                                            sbContent.Append(cellContent);
                                        }
                                    }
                                }
                            }
                            rowIndex = nextRowIndex;
                            if (rowIndex != -1)
                            {
                                nextRowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                            }
                            firstRowIndex = false;
                        }
                        if (string.Equals(format, DataFormats.Html, StringComparison.OrdinalIgnoreCase))
                        {
                            GetClipboardContentForHtml(sbContent, out IO.MemoryStream utf8Stream);
                            dataObject.SetData(format, false /*autoConvert*/, utf8Stream);
                        }
                        else
                        {
                            dataObject.SetData(format, false /*autoConvert*/, sbContent.ToString());
                        }
                    }
                    break;

                case DataGridViewSelectionMode.CellSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    bool selectedVisibleCellExists = false;
                    bool selectedVisibleColumnExists = false;
                    bool selectedVisibleRowExists = false;
                    if (SelectionMode == DataGridViewSelectionMode.RowHeaderSelect)
                    {
                        selectedVisibleRowExists = Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected) != 0;
                        selectedVisibleCellExists = selectedVisibleRowExists && Columns.GetColumnCount(DataGridViewElementStates.Visible) != 0;
                    }
                    else if (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect)
                    {
                        selectedVisibleColumnExists = Columns.GetColumnCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Selected) != 0;
                        selectedVisibleCellExists = selectedVisibleColumnExists && Rows.GetRowCount(DataGridViewElementStates.Visible) != 0;
                    }
                    if (!selectedVisibleCellExists && _individualSelectedCells.Count > 0)
                    {
                        foreach (DataGridViewCell dataGridViewCell in _individualSelectedCells)
                        {
                            if (dataGridViewCell.Visible)
                            {
                                selectedVisibleCellExists = true;
                                break;
                            }
                        }
                    }
                    if (!selectedVisibleCellExists)
                    {
                        return null;
                    }

                    // There is at least one selected visible cell.
                    if (SelectionMode == DataGridViewSelectionMode.CellSelect)
                    {
                        includeColumnHeaders = includeRowHeaders = (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText);
                        includeColumnHeaders &= ColumnHeadersVisible;
                        includeRowHeaders &= RowHeadersVisible;
                    }
                    else
                    {
                        includeColumnHeaders = includeRowHeaders = false;
                        if (ColumnHeadersVisible)
                        {
                            if (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableWithAutoHeaderText)
                            {
                                if (selectedVisibleColumnExists)
                                {
                                    includeColumnHeaders = true;
                                }
                            }
                            else
                            {
                                includeColumnHeaders = (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText);
                            }
                        }

                        if (RowHeadersVisible)
                        {
                            if (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableWithAutoHeaderText)
                            {
                                if (selectedVisibleRowExists)
                                {
                                    includeRowHeaders = true;
                                }
                            }
                            else
                            {
                                includeRowHeaders = (_clipboardCopyMode == DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText);
                            }
                        }
                    }

                    // Get the four corners of the 'selected table'
                    int lRowIndex = int.MaxValue;
                    int uRowIndex = -1;
                    DataGridViewColumn lColumn = null, uColumn = null;

                    if (SelectionMode == DataGridViewSelectionMode.RowHeaderSelect)
                    {
                        DataGridViewColumn firstVisibleColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                        DataGridViewColumn lastVisibleColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.None);

                        Debug.Assert(firstVisibleColumn != null);
                        Debug.Assert(lastVisibleColumn != null);
                        foreach (int rowIndex in _selectedBandIndexes)
                        {
                            if ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) != 0)
                            {
                                if (rowIndex < lRowIndex)
                                {
                                    lRowIndex = rowIndex;
                                }
                                if (rowIndex > uRowIndex)
                                {
                                    uRowIndex = rowIndex;
                                }
                                lColumn = firstVisibleColumn;
                                uColumn = lastVisibleColumn;
                            }
                        }
                    }
                    else if (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect)
                    {
                        firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                        int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
                        Debug.Assert(firstVisibleRowIndex != -1);
                        Debug.Assert(lastVisibleRowIndex != -1);
                        foreach (int columnIndex in _selectedBandIndexes)
                        {
                            if (Columns[columnIndex].Visible)
                            {
                                if (lColumn is null || Columns.DisplayInOrder(columnIndex, lColumn.Index))
                                {
                                    lColumn = Columns[columnIndex];
                                }
                                if (uColumn is null || Columns.DisplayInOrder(uColumn.Index, columnIndex))
                                {
                                    uColumn = Columns[columnIndex];
                                }
                                lRowIndex = firstVisibleRowIndex;
                                uRowIndex = lastVisibleRowIndex;
                            }
                        }
                    }

                    // Go through the individually selected cells to potentially stretch the current 'selected table'.
                    foreach (DataGridViewCell dataGridViewCell in _individualSelectedCells)
                    {
                        if (dataGridViewCell.Visible)
                        {
                            if (dataGridViewCell.RowIndex < lRowIndex)
                            {
                                lRowIndex = dataGridViewCell.RowIndex;
                            }
                            if (dataGridViewCell.RowIndex > uRowIndex)
                            {
                                uRowIndex = dataGridViewCell.RowIndex;
                            }
                            if (lColumn is null || Columns.DisplayInOrder(dataGridViewCell.ColumnIndex, lColumn.Index))
                            {
                                lColumn = dataGridViewCell.OwningColumn;
                            }
                            if (uColumn is null || Columns.DisplayInOrder(uColumn.Index, dataGridViewCell.ColumnIndex))
                            {
                                uColumn = dataGridViewCell.OwningColumn;
                            }
                        }
                    }

                    Debug.Assert(lRowIndex != -1);
                    Debug.Assert(uRowIndex != -1);
                    Debug.Assert(lColumn != null);
                    Debug.Assert(uColumn != null);
                    Debug.Assert(lColumn.Index == uColumn.Index || Columns.DisplayInOrder(lColumn.Index, uColumn.Index));
                    Debug.Assert(lRowIndex <= uRowIndex);

                    foreach (string format in formats)
                    {
                        if (sbContent is null)
                        {
                            sbContent = new StringBuilder(1024);
                        }
                        else
                        {
                            sbContent.Length = 0;
                        }

                        if (includeColumnHeaders)
                        {
                            if (RightToLeftInternal)
                            {
                                // Cycle through the visible columns from uColumn to lColumn
                                dataGridViewColumn = uColumn;
                                Debug.Assert(dataGridViewColumn != null);
                                while (dataGridViewColumn != null)
                                {
                                    if (dataGridViewColumn != lColumn)
                                    {
                                        prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        Debug.Assert(prevDataGridViewColumn != null);
                                    }
                                    else
                                    {
                                        prevDataGridViewColumn = null;
                                    }
                                    cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                            dataGridViewColumn == uColumn /*firstCell*/,
                                                                                                            !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                            true /*inFirstRow*/,
                                                                                                            false /*inLastRow*/,
                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    dataGridViewColumn = prevDataGridViewColumn;
                                }
                                if (includeRowHeaders)
                                {
                                    cellContent = TopLeftHeaderCell.GetClipboardContentInternal(-1,
                                                                                                     false /*firstCell*/,
                                                                                                     true /*lastCell*/,
                                                                                                     true  /*inFirstRow*/,
                                                                                                     false /*inLastRow*/,
                                                                                                     format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                            }
                            else
                            {
                                if (includeRowHeaders)
                                {
                                    cellContent = TopLeftHeaderCell.GetClipboardContentInternal(-1,
                                                                                                     true  /*firstCell*/,
                                                                                                     false /*lastCell*/,
                                                                                                     true  /*inFirstRow*/,
                                                                                                     false /*inLastRow*/,
                                                                                                     format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                                // Cycle through the visible columns from lColumn to uColumn
                                dataGridViewColumn = lColumn;
                                Debug.Assert(dataGridViewColumn != null);
                                while (dataGridViewColumn != null)
                                {
                                    if (dataGridViewColumn != uColumn)
                                    {
                                        nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        Debug.Assert(nextDataGridViewColumn != null);
                                    }
                                    else
                                    {
                                        nextDataGridViewColumn = null;
                                    }
                                    cellContent = dataGridViewColumn.HeaderCell.GetClipboardContentInternal(-1,
                                                                                                            !includeRowHeaders && dataGridViewColumn == lColumn /*firstCell*/,
                                                                                                            nextDataGridViewColumn is null /*lastCell*/,
                                                                                                            true /*inFirstRow*/,
                                                                                                            false /*inLastRow*/,
                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    dataGridViewColumn = nextDataGridViewColumn;
                                }
                            }
                        }
                        // Cycle through the visible rows from lRowIndex to uRowIndex.
                        bool firstRowIndex = true;
                        int rowIndex = lRowIndex;
                        int nextRowIndex = -1;
                        Debug.Assert(rowIndex != -1);
                        while (rowIndex != -1)
                        {
                            if (rowIndex != uRowIndex)
                            {
                                nextRowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                                Debug.Assert(nextRowIndex != -1);
                            }
                            else
                            {
                                nextRowIndex = -1;
                            }

                            if (RightToLeftInternal)
                            {
                                // Cycle through the visible columns from uColumn to lColumn
                                dataGridViewColumn = uColumn;
                                Debug.Assert(dataGridViewColumn != null);
                                while (dataGridViewColumn != null)
                                {
                                    if (dataGridViewColumn != lColumn)
                                    {
                                        prevDataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        Debug.Assert(prevDataGridViewColumn != null);
                                    }
                                    else
                                    {
                                        prevDataGridViewColumn = null;
                                    }

                                    cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                            dataGridViewColumn == uColumn /*firstCell*/,
                                                                                                                                            !includeRowHeaders && prevDataGridViewColumn is null /*lastCell*/,
                                                                                                                                            !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                            nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    dataGridViewColumn = prevDataGridViewColumn;
                                }

                                if (includeRowHeaders)
                                {
                                    // Get the row header clipboard content
                                    cellContent = Rows.SharedRow(rowIndex).HeaderCell.GetClipboardContentInternal(rowIndex,
                                                                                                                       false /*firstCell*/,
                                                                                                                       true /*lastCell*/,
                                                                                                                       !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                       nextRowIndex == -1 /*inLastRow*/,
                                                                                                                       format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }
                            }
                            else
                            {
                                if (includeRowHeaders)
                                {
                                    // Get the row header clipboard content
                                    cellContent = Rows.SharedRow(rowIndex).HeaderCell.GetClipboardContentInternal(rowIndex,
                                                                                                                       true /*firstCell*/,
                                                                                                                       false /*lastCell*/,
                                                                                                                       !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                       nextRowIndex == -1 /*inLastRow*/,
                                                                                                                       format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                }

                                // Cycle through the visible columns from lColumn to uColumn
                                dataGridViewColumn = lColumn;
                                Debug.Assert(dataGridViewColumn != null);
                                while (dataGridViewColumn != null)
                                {
                                    if (dataGridViewColumn != uColumn)
                                    {
                                        nextDataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                        Debug.Assert(nextDataGridViewColumn != null);
                                    }
                                    else
                                    {
                                        nextDataGridViewColumn = null;
                                    }

                                    cellContent = Rows.SharedRow(rowIndex).Cells[dataGridViewColumn.Index].GetClipboardContentInternal(rowIndex,
                                                                                                                                            !includeRowHeaders && dataGridViewColumn == lColumn /*firstCell*/,
                                                                                                                                            nextDataGridViewColumn is null /*lastCell*/,
                                                                                                                                            !includeColumnHeaders && firstRowIndex /*inFirstRow*/,
                                                                                                                                            nextRowIndex == -1 /*inLastRow*/,
                                                                                                                                            format) as string;
                                    if (cellContent != null)
                                    {
                                        sbContent.Append(cellContent);
                                    }
                                    dataGridViewColumn = nextDataGridViewColumn;
                                }
                            }
                            rowIndex = nextRowIndex;
                            firstRowIndex = false;
                        }
                        if (string.Equals(format, DataFormats.Html, StringComparison.OrdinalIgnoreCase))
                        {
                            GetClipboardContentForHtml(sbContent, out IO.MemoryStream utf8Stream);
                            dataObject.SetData(format, false /*autoConvert*/, utf8Stream);
                        }
                        else
                        {
                            dataObject.SetData(format, false /*autoConvert*/, sbContent.ToString());
                        }
                    }
                    break;
            }
            return dataObject;
        }

        private static void GetClipboardContentForHtml(StringBuilder sbContent, out IO.MemoryStream utf8Stream)
        {
            byte[] sourceBytes = Encoding.Unicode.GetBytes(sbContent.ToString());
            byte[] destinationBytes = Encoding.Convert(Encoding.Unicode, Encoding.UTF8, sourceBytes);

            int bytecountEndOfFragment = 135 + destinationBytes.Length;
            int bytecountEndOfHtml = bytecountEndOfFragment + 36;
            string prefix = string.Format(CultureInfo.InvariantCulture, HtmlPrefix, bytecountEndOfHtml.ToString("00000000", CultureInfo.InvariantCulture), bytecountEndOfFragment.ToString("00000000", CultureInfo.InvariantCulture)) + HtmlStartFragment;
            sbContent.Insert(0, prefix);
            sbContent.Append(HtmlEndFragment);

            sourceBytes = Encoding.Unicode.GetBytes(sbContent.ToString());
            destinationBytes = Encoding.Convert(Encoding.Unicode, Encoding.UTF8, sourceBytes);

            utf8Stream = new IO.MemoryStream(bytecountEndOfHtml + 1);
            utf8Stream.Write(destinationBytes, 0, bytecountEndOfHtml);
            utf8Stream.WriteByte((byte)0);

#if DEBUG
            Debug.Assert(destinationBytes[97] == '<');
            Debug.Assert(destinationBytes[bytecountEndOfHtml - 1] == '>');
            Debug.Assert(destinationBytes[133] == '<');
            Debug.Assert(destinationBytes[bytecountEndOfFragment] == '<');
#endif
        }

        // Rectangle returned includes the potential column header
        public Rectangle GetColumnDisplayRectangle(int columnIndex, bool cutOverflow)
        {
            if (columnIndex < 0 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }
            return GetColumnDisplayRectanglePrivate(columnIndex, cutOverflow);
        }

        private Rectangle GetColumnDisplayRectanglePrivate(int columnIndex, bool cutOverflow)
        {
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count);

            if (!Columns[columnIndex].Displayed)
            {
                return Rectangle.Empty;
            }

            Rectangle data = _layout.Data;
            int cx;
            bool columnFound = false;
            DataGridViewColumn dataGridViewColumn;
            if (RightToLeftInternal)
            {
                cx = data.Right;
            }
            else
            {
                cx = data.X;
            }
            for (dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                dataGridViewColumn != null && !columnFound;
                )
            {
                if ((RightToLeftInternal && cx < data.X) ||
                    (!RightToLeftInternal && cx > data.Right))
                {
                    break;
                }
                if (dataGridViewColumn.Index == columnIndex)
                {
                    columnFound = true;
                }
                else
                {
                    if (RightToLeftInternal)
                    {
                        cx -= dataGridViewColumn.Thickness;
                    }
                    else
                    {
                        cx += dataGridViewColumn.Thickness;
                    }
                    dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                        DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen,
                        DataGridViewElementStates.None);
                }
            }

            if (!columnFound && DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0)
            {
                for (dataGridViewColumn = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
                    dataGridViewColumn != null && !columnFound;
                    )
                {
                    if ((RightToLeftInternal && cx < data.X) ||
                        (!RightToLeftInternal && cx > data.Right))
                    {
                        break;
                    }
                    if (dataGridViewColumn.Index == columnIndex)
                    {
                        columnFound = true;
                    }
                    else
                    {
                        if (RightToLeftInternal)
                        {
                            cx -= dataGridViewColumn.Thickness;
                        }
                        else
                        {
                            cx += dataGridViewColumn.Thickness;
                        }
                        if (dataGridViewColumn.Index == DisplayedBandsInfo.FirstDisplayedScrollingCol)
                        {
                            if (RightToLeftInternal)
                            {
                                cx += FirstDisplayedScrollingColumnHiddenWidth;
                            }
                            else
                            {
                                cx -= FirstDisplayedScrollingColumnHiddenWidth;
                            }
                        }
                        dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None);
                    }
                }
            }

            if (columnFound)
            {
                Debug.Assert(dataGridViewColumn != null);
                int displayWidth, viewedColumnWidth = dataGridViewColumn.Thickness;
                if (dataGridViewColumn.Index == DisplayedBandsInfo.FirstDisplayedScrollingCol)
                {
                    viewedColumnWidth -= FirstDisplayedScrollingColumnHiddenWidth;
                }
                if (cutOverflow &&
                    ((!RightToLeftInternal && cx + viewedColumnWidth > data.Right) ||
                     (RightToLeftInternal && cx - viewedColumnWidth < data.X)))
                {
                    if (RightToLeftInternal)
                    {
                        displayWidth = cx - data.X;
                    }
                    else
                    {
                        displayWidth = data.Right - cx;
                    }
                }
                else
                {
                    displayWidth = viewedColumnWidth;
                }

                Rectangle columnRect;
                if (RightToLeftInternal)
                {
                    columnRect = new Rectangle(cx - displayWidth, data.Y, displayWidth, data.Height);
                }
                else
                {
                    columnRect = new Rectangle(cx, data.Y, displayWidth, data.Height);
                }
                if (_layout.ColumnHeadersVisible)
                {
                    columnRect.Height += _layout.ColumnHeaders.Height;
                    columnRect.Y -= _layout.ColumnHeaders.Height;
                }
                return columnRect;
            }

            return Rectangle.Empty;
        }

        // xColumnLeftEdge returns the left edge of the column when RightToLeft is false.
        // xColumnLeftEdge returns the right edge of the column when RightToLeft is true.
        private int GetColumnIndexFromX(int x, out int xColumnLeftEdge)
        {
            Rectangle data = _layout.Data;
            Debug.Assert(RightToLeftInternal || (x >= data.X - 1 && x < data.Right), "x must be inside the horizontal bounds of this.layout.Data");
            Debug.Assert(!RightToLeftInternal || (x >= data.X && x <= data.Right), "x must be inside the horizontal bounds of this.layout.Data");

            if (!RightToLeftInternal && x == data.X - 1)
            {
                x++;
            }
            else if (RightToLeftInternal && x == data.Right)
            {
                x--;
            }

            int cx;
            if (RightToLeftInternal)
            {
                cx = data.Right - 1;
            }
            else
            {
                cx = data.X;
            }

            // first try to match x against a frozen column
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            while (dataGridViewColumn != null &&
                   ((!RightToLeftInternal && cx < data.Right) || (RightToLeftInternal && cx >= data.X)))
            {
                if (RightToLeftInternal)
                {
                    cx -= dataGridViewColumn.Thickness;
                }
                else
                {
                    cx += dataGridViewColumn.Thickness;
                }
                if (!RightToLeftInternal && cx > x)
                {
                    xColumnLeftEdge = cx - dataGridViewColumn.Thickness;
                    return dataGridViewColumn.Index;
                }
                else if (RightToLeftInternal && cx < x)
                {
                    xColumnLeftEdge = cx + dataGridViewColumn.Thickness;
                    return dataGridViewColumn.Index;
                }
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen,
                    DataGridViewElementStates.None);
            }

            if (RightToLeftInternal)
            {
                cx += FirstDisplayedScrollingColumnHiddenWidth;
            }
            else
            {
                cx -= FirstDisplayedScrollingColumnHiddenWidth;
            }

            // second try to match x against a scrolling column
            if (DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0)
            {
                dataGridViewColumn = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
                while (dataGridViewColumn != null &&
                       ((!RightToLeftInternal && cx < data.Right) || (RightToLeftInternal && cx >= data.X)))
                {
                    Debug.Assert(dataGridViewColumn.Visible && !dataGridViewColumn.Frozen);
                    if (RightToLeftInternal)
                    {
                        cx -= dataGridViewColumn.Thickness;
                    }
                    else
                    {
                        cx += dataGridViewColumn.Thickness;
                    }
                    if (!RightToLeftInternal && cx > x)
                    {
                        xColumnLeftEdge = cx - dataGridViewColumn.Thickness;
                        return dataGridViewColumn.Index;
                    }
                    else if (RightToLeftInternal && cx < x)
                    {
                        xColumnLeftEdge = cx + dataGridViewColumn.Thickness;
                        return dataGridViewColumn.Index;
                    }
                    dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.None);
                }
            }

            xColumnLeftEdge = -1;
            return -1;
        }

        private static int GetColumnScrollRate(int xOffset)
        {
            Debug.Assert(xOffset > 0);
            // Counting 20ms for executing the actual column scrolling
            if (xOffset <= 10)
            {
                return 480;     // Two columns per second
            }
            if (xOffset <= 15)
            {
                return 313;     // Three columns per second
            }
            if (xOffset <= 25)
            {
                return 180;     // Five columns per second
            }
            if (xOffset <= 35)
            {
                return 123;     // Seven columns per second
            }
            return Math.Max(1, 4000 / xOffset);
        }

        /// <summary>
        ///  Returns the coordinate of the left edge of the given column. Note that
        ///  the column does not need to be completely visible on the display area.
        ///  Value returned is not necessarily within layout.Data because of the
        ///  this.negOffset value, or because the column may start to the right of
        ///  data area, or behind the frozen area, or completely on the left of the control.
        ///  The right edge is returned in RightToLeft mode.
        /// </summary>
        internal int GetColumnXFromIndex(int index)
        {
            Debug.Assert(index < Columns.Count);
            Debug.Assert(Columns[index].Visible);

            int x;
            if (RightToLeftInternal)
            {
                x = _layout.Data.Right - 1;
            }
            else
            {
                x = _layout.Data.X;
            }

            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            while (dataGridViewColumn != null)
            {
                if (index == dataGridViewColumn.Index)
                {
                    return x;
                }
                if (RightToLeftInternal)
                {
                    x -= dataGridViewColumn.Thickness;
                }
                else
                {
                    x += dataGridViewColumn.Thickness;
                }
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen,
                    DataGridViewElementStates.None);
            }

            if (RightToLeftInternal)
            {
                x += FirstDisplayedScrollingColumnHiddenWidth;
            }
            else
            {
                x -= FirstDisplayedScrollingColumnHiddenWidth;
            }

            int xFirstVisibleScrollingCol = x;

            if (DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0)
            {
                dataGridViewColumn = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
            }
            else
            {
                dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
            }
            Debug.Assert(dataGridViewColumn.Visible && !dataGridViewColumn.Frozen);

            while (dataGridViewColumn != null)
            {
                if (index == dataGridViewColumn.Index)
                {
                    return x;
                }
                if (RightToLeftInternal)
                {
                    x -= dataGridViewColumn.Thickness;
                }
                else
                {
                    x += dataGridViewColumn.Thickness;
                }
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
            }

            // The column is completely hidden on the left/right of the dataGridView
            x = xFirstVisibleScrollingCol;
            dataGridViewColumn = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
            dataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn,
                DataGridViewElementStates.Visible,
                DataGridViewElementStates.Frozen);
            while (dataGridViewColumn != null)
            {
                if (RightToLeftInternal)
                {
                    x += dataGridViewColumn.Thickness;
                }
                else
                {
                    x -= dataGridViewColumn.Thickness;
                }
                if (index == dataGridViewColumn.Index)
                {
                    return x;
                }
                dataGridViewColumn = Columns.GetPreviousColumn(dataGridViewColumn,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.Frozen);
            }

            Debug.Fail("Could not find column in GetColumnXFromIndex");
            return 0;
        }

        private int GetNegOffsetFromHorizontalOffset(int horizontalOffset)
        {
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
            while (dataGridViewColumn != null && dataGridViewColumn.Thickness <= horizontalOffset)
            {
                horizontalOffset -= dataGridViewColumn.Thickness;
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
            }
            return horizontalOffset;
        }

        private bool GetOutOfBoundCorrectedHitTestInfo(ref HitTestInfo hti, ref int mouseX, ref int mouseY, out int xOffset, out int yOffset)
        {
            xOffset = yOffset = 0;
            Rectangle rectScrollingArea = _layout.Data;
            int visibleRowsHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible);
            int frozenVisibleRowsHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            int fittingTrailingScrollingRowsHeight = ComputeHeightOfFittingTrailingScrollingRows(frozenVisibleRowsHeight);
            int trailingScrollingRowsHeight = ComputeHeightOfTrailingScrollingRows();
            int emptyBackgroundWidth = Math.Max(0, _layout.Data.Width - Columns.GetColumnsWidth(DataGridViewElementStates.Visible));
            int emptyBackgroundHeight = Math.Max(0, _layout.Data.Height - frozenVisibleRowsHeight - trailingScrollingRowsHeight);

            Debug.Assert(!_vertScrollBar.Enabled ||
                         !_vertScrollBar.Visible ||
                         _vertScrollBar.Maximum == visibleRowsHeight - frozenVisibleRowsHeight);

            if (_dataGridViewOper[OperationTrackRowSelect])
            {
                if (_layout.RowHeadersVisible)
                {
                    // Include row headers
                    rectScrollingArea = Rectangle.Union(rectScrollingArea, _layout.RowHeaders);
                }
                // Discard frozen rows
                DiscardZonesInScrollingArea(ref rectScrollingArea, emptyBackgroundWidth, emptyBackgroundHeight, frozenVisibleRowsHeight,
                                            false /*discardFrozenColumns*/, true /*discardFrozenRows*/);

                if (mouseY >= rectScrollingArea.Top && mouseY <= rectScrollingArea.Bottom)
                {
                    // Mouse's Y is in-bound -- correct X value
                    hti = HitTest(RightToLeftInternal ? rectScrollingArea.Right - 1 : rectScrollingArea.Left, mouseY);
                    if (_ptAnchorCell.Y != -1 &&
                        (Rows.GetRowState(_ptAnchorCell.Y) & DataGridViewElementStates.Frozen) != 0 &&
                        _trackRowEdge != -1 &&
                        (Rows.GetRowState(_trackRowEdge) & DataGridViewElementStates.Frozen) != 0 &&
                        hti._row >= 0 &&
                        (Rows.GetRowState(hti._row) & DataGridViewElementStates.Frozen) == 0)
                    {
                        // Anchor cell is in frozen row and target cell is in unfrozen row. Make sure no row is scrolled off.
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                        int firstUnfrozenRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                        int firstColumnIndex;
                        if (hti._col >= 0)
                        {
                            firstColumnIndex = hti._col;
                        }
                        else
                        {
                            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                            firstColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
                        }
                        if (firstColumnIndex >= 0 && firstUnfrozenRowIndex >= 0)
                        {
                            if (!ScrollIntoView(firstColumnIndex, firstUnfrozenRowIndex, false /*forCurrentCellChange*/))
                            {
                                return false;
                            }
                            hti = HitTest(RightToLeftInternal ? rectScrollingArea.Right : rectScrollingArea.Left, mouseY);
                        }
                    }
                    return true;
                }

                // Mouse's Y is outside of scrolling bands
                if (mouseY < rectScrollingArea.Top)
                {
                    if (_ptAnchorCell.Y != -1 &&
                        ((Rows.GetRowState(_ptAnchorCell.Y) & DataGridViewElementStates.Frozen) == 0 ||
                         (_trackRowEdge != -1 && (Rows.GetRowState(_trackRowEdge) & DataGridViewElementStates.Frozen) == 0)) &&
                        VerticalScrollingOffset != 0)
                    {
                        // Up scrolling is required because the anchor's row is unfrozen
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                        yOffset = mouseY - rectScrollingArea.Top;   // yOffset strictly negative
                        if (RightToLeftInternal)
                        {
                            mouseX = rectScrollingArea.Right - 1;
                        }
                        else
                        {
                            mouseX = rectScrollingArea.Left + 1;
                        }
                    }
                    else
                    {
                        hti = HitTest(RightToLeftInternal ? rectScrollingArea.Right : rectScrollingArea.Left, mouseY);
                    }
                }
                else
                {
                    Debug.Assert(mouseY > rectScrollingArea.Bottom);
                    if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0)
                    {
                        if (VerticalScrollingOffset + Rows.SharedRow(DisplayedBandsInfo.FirstDisplayedScrollingRow).GetHeight(DisplayedBandsInfo.FirstDisplayedScrollingRow) <=
                            visibleRowsHeight - frozenVisibleRowsHeight - fittingTrailingScrollingRowsHeight)
                        {
                            // Down scrolling is required
                            yOffset = mouseY - rectScrollingArea.Bottom;   // yOffset strictly positive
                            if (RightToLeftInternal)
                            {
                                mouseX = rectScrollingArea.Right - 1;
                            }
                            else
                            {
                                mouseX = rectScrollingArea.Left + 1;
                            }
                        }
                    }
                }
                return true;
            }

            if (_dataGridViewOper[OperationTrackColSelect])
            {
                if (_layout.ColumnHeadersVisible)
                {
                    // Include column headers
                    rectScrollingArea = Rectangle.Union(rectScrollingArea, _layout.ColumnHeaders);
                }

                // Discard frozen columns
                DiscardZonesInScrollingArea(ref rectScrollingArea, emptyBackgroundWidth, emptyBackgroundHeight, frozenVisibleRowsHeight,
                                            true /*discardFrozenColumns*/, false /*discardFrozenRows*/);

                if (mouseX >= rectScrollingArea.Left && mouseX <= rectScrollingArea.Right)
                {
                    // Mouse's X is in-bound -- correct Y value
                    hti = HitTest(mouseX, rectScrollingArea.Top);
                    if (_ptAnchorCell.X != -1 &&
                        Columns[_ptAnchorCell.X].Frozen &&
                        _trackColumnEdge != -1 &&
                        Columns[_trackColumnEdge].Frozen &&
                        hti._col >= 0 &&
                        !Columns[hti._col].Frozen)
                    {
                        // Anchor cell is in frozen column and target cell is in unfrozen column. Make sure no column is scrolled off.
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0);
                        int firstUnfrozenColumnIndex = Columns.GetFirstColumn(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen).Index;
                        int firstRowIndex;
                        if (hti._row >= 0)
                        {
                            firstRowIndex = hti._row;
                        }
                        else
                        {
                            firstRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                        }
                        if (firstRowIndex >= 0 && firstUnfrozenColumnIndex >= 0)
                        {
                            if (!ScrollIntoView(firstUnfrozenColumnIndex, firstRowIndex, false /*forCurrentCellChange*/))
                            {
                                return false;
                            }
                            hti = HitTest(mouseX, rectScrollingArea.Top);
                        }
                    }
                    return true;
                }

                // Mouse's X is outside of scrolling bands
                if ((!RightToLeftInternal && mouseX < rectScrollingArea.Left) ||
                    (RightToLeftInternal && mouseX > rectScrollingArea.Right))
                {
                    if (_ptAnchorCell.X != -1 &&
                        (!Columns[_ptAnchorCell.X].Frozen ||
                         (_trackColumnEdge != -1 && !Columns[_trackColumnEdge].Frozen)) &&
                        DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0 &&
                        (FirstDisplayedScrollingColumnHiddenWidth > 0 ||
                         Columns.GetPreviousColumn(Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol], DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen) != null))
                    {
                        // xOffset strictly negative
                        if (RightToLeftInternal)
                        {
                            // Right scrolling is required
                            xOffset = rectScrollingArea.Right - mouseX;
                        }
                        else
                        {
                            // Left scrolling is required
                            xOffset = mouseX - rectScrollingArea.Left;
                        }
                        mouseY = rectScrollingArea.Top + 1;
                    }
                    else
                    {
                        hti = HitTest(mouseX, rectScrollingArea.Top);
                    }
                }
                else
                {
                    Debug.Assert((!RightToLeftInternal && mouseX > rectScrollingArea.Right) || (RightToLeftInternal && mouseX < rectScrollingArea.Left));
                    if (DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0)
                    {
                        if (DisplayedBandsInfo.LastTotallyDisplayedScrollingCol != -1 &&
                            Columns.GetNextColumn(Columns[DisplayedBandsInfo.LastTotallyDisplayedScrollingCol], DataGridViewElementStates.Visible, DataGridViewElementStates.None) is null)
                        {
                            // No more columns to scroll
                            return true;
                        }

                        DataGridViewColumn newFirstVisibleScrollingCol = Columns.GetNextColumn(Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol],
                                                                                                             DataGridViewElementStates.Visible,
                                                                                                             DataGridViewElementStates.None);
                        int newColOffset = 0;
                        for (DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible,
                                                                                                          DataGridViewElementStates.Frozen);
                            dataGridViewColumn != newFirstVisibleScrollingCol;
                            dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None))
                        {
                            newColOffset += dataGridViewColumn.Thickness;
                        }

                        if (HorizontalOffset != newColOffset)
                        {
                            // xOffset strictly positive
                            if (RightToLeftInternal)
                            {
                                // Left scrolling is required
                                xOffset = rectScrollingArea.Left - mouseX;
                            }
                            else
                            {
                                // Right scrolling is required
                                xOffset = mouseX - rectScrollingArea.Right;
                            }
                            mouseY = rectScrollingArea.Top + 1;
                        }
                    }
                }
                return true;
            }

            if (_dataGridViewOper[OperationTrackCellSelect])
            {
                bool recomputeHitTestInfo = false;

                // Discard frozen columns and rows
                DiscardZonesInScrollingArea(ref rectScrollingArea, emptyBackgroundWidth, emptyBackgroundHeight, frozenVisibleRowsHeight,
                                            true /*discardFrozenColumns*/, true /*discardFrozenRows*/);

                if (mouseY < rectScrollingArea.Top)
                {
                    // Mouse's Y is above scrolling bands
                    if (
                        (
                         (_ptAnchorCell.Y != -1 && (Rows.GetRowState(_ptAnchorCell.Y) & DataGridViewElementStates.Frozen) == 0)
                         ||
                         (_ptCurrentCell.Y != -1 && (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Frozen) == 0)
                        )
                        &&
                        VerticalScrollingOffset != 0
                       )
                    {
                        // Up scrolling is required - the anchor's row is unfrozen
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                        yOffset = mouseY - rectScrollingArea.Top;   // yOffset strictly negative
                    }
                    else
                    {
                        // Correct mouse's Y - no scrolling can be performed
                        if (mouseY < _layout.Data.Top)
                        {
                            mouseY = _layout.Data.Top + 1;
                            recomputeHitTestInfo = true;
                        }
                    }
                }
                else if (mouseY > rectScrollingArea.Bottom)
                {
                    // Mouse's Y is below scrolling bands
                    if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0)
                    {
                        if (VerticalScrollingOffset + Rows.SharedRow(DisplayedBandsInfo.FirstDisplayedScrollingRow).GetHeight(DisplayedBandsInfo.FirstDisplayedScrollingRow) <=
                            visibleRowsHeight - frozenVisibleRowsHeight - fittingTrailingScrollingRowsHeight)
                        {
                            // Down scrolling is required
                            yOffset = mouseY - rectScrollingArea.Bottom;   // yOffset strictly positive
                        }
                        else
                        {
                            // Correct mouse's Y - no scrolling can be performed
                            mouseY = rectScrollingArea.Bottom - 1;
                            recomputeHitTestInfo = true;
                        }
                    }
                    else
                    {
                        // Correct mouse's Y - no scrolling can be performed
                        mouseY = rectScrollingArea.Bottom - 1;
                        recomputeHitTestInfo = true;
                    }
                }
#if DEBUG
                else
                {
                    // Mouse's Y is in-bound
                    Debug.Assert(mouseY >= rectScrollingArea.Top && mouseY <= rectScrollingArea.Bottom);
                }
#endif
                if ((!RightToLeftInternal && mouseX < rectScrollingArea.Left) ||
                    (RightToLeftInternal && mouseX > rectScrollingArea.Right))
                {
                    // Mouse's X is on the left of scrolling bands (LTR)
                    if (
                        (
                         (_ptAnchorCell.X != -1 && !Columns[_ptAnchorCell.X].Frozen)
                         ||
                         (_ptCurrentCell.X != -1 && !Columns[_ptCurrentCell.X].Frozen)
                        )
                        &&
                        DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0 &&
                        (FirstDisplayedScrollingColumnHiddenWidth > 0 ||
                         Columns.GetPreviousColumn(Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol], DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen) != null)
                       )
                    {
                        // xOffset strictly negative
                        if (RightToLeftInternal)
                        {
                            // Right scrolling is required - anchor's column is unfrozen
                            xOffset = rectScrollingArea.Right - mouseX;
                        }
                        else
                        {
                            // Left scrolling is required - anchor's column is unfrozen
                            xOffset = mouseX - rectScrollingArea.Left;
                        }
                    }
                    else
                    {
                        // Correct mouse's X - no scrolling can be performed
                        if (!RightToLeftInternal && mouseX < _layout.Data.Left)
                        {
                            mouseX = _layout.Data.Left + 1;
                            recomputeHitTestInfo = true;
                        }
                        else if (RightToLeftInternal && mouseX > _layout.Data.Right)
                        {
                            mouseX = _layout.Data.Right - 1;
                            recomputeHitTestInfo = true;
                        }
                    }
                }
                else if ((!RightToLeftInternal && mouseX > rectScrollingArea.Right) ||
                         (RightToLeftInternal && mouseX < rectScrollingArea.Left))
                {
                    // Mouse's X is on the right of scrolling bands (LTR)
                    if (DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0 &&
                        (DisplayedBandsInfo.LastTotallyDisplayedScrollingCol == -1 ||
                         Columns.GetNextColumn(Columns[DisplayedBandsInfo.LastTotallyDisplayedScrollingCol], DataGridViewElementStates.Visible, DataGridViewElementStates.None) != null))
                    {
                        DataGridViewColumn newFirstVisibleScrollingCol = Columns.GetNextColumn(Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol],
                                                                                                            DataGridViewElementStates.Visible,
                                                                                                            DataGridViewElementStates.None);
                        int newColOffset = 0;
                        for (DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible,
                                                                                                          DataGridViewElementStates.Frozen);
                            dataGridViewColumn != newFirstVisibleScrollingCol;
                            dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None))
                        {
                            newColOffset += dataGridViewColumn.Thickness;
                        }
                        if (HorizontalOffset != newColOffset)
                        {
                            // xOffset strictly positive
                            if (RightToLeftInternal)
                            {
                                // Left scrolling is required
                                xOffset = rectScrollingArea.Left - mouseX;
                            }
                            else
                            {
                                // Right scrolling is required
                                xOffset = mouseX - rectScrollingArea.Right;
                            }
                        }
                        else
                        {
                            // Correct mouse's X - no scrolling can be performed
                            if (RightToLeftInternal)
                            {
                                mouseX = rectScrollingArea.Left + 1;
                            }
                            else
                            {
                                mouseX = rectScrollingArea.Right - 1;
                            }
                            recomputeHitTestInfo = true;
                        }
                    }
                    else
                    {
                        // Correct mouse's X - no scrolling can be performed
                        if (RightToLeftInternal)
                        {
                            mouseX = rectScrollingArea.Left + 1;
                        }
                        else
                        {
                            mouseX = rectScrollingArea.Right - 1;
                        }
                        recomputeHitTestInfo = true;
                    }
                }
#if DEBUG
                else
                {
                    // Mouse's X is in-bound
                    Debug.Assert(mouseX >= rectScrollingArea.Left && mouseX <= rectScrollingArea.Right);
                }
#endif
                if (recomputeHitTestInfo)
                {
                    hti = HitTest(mouseX, mouseY);
                }
            }
            return true;
        }

        internal override Size GetPreferredSizeCore(Size proposedConstraints)
        {
            int bordersAndPaddingWidth = 2 * (BorderWidth + Padding.Size.Width);
            int bordersAndPaddingHeight = 2 * (BorderWidth + Padding.Size.Height);

            bool allowHorizScrollbar = (_scrollBars == ScrollBars.Both) || (_scrollBars == ScrollBars.Horizontal);
            bool allowVertScrollbar = (_scrollBars == ScrollBars.Both) || (_scrollBars == ScrollBars.Vertical);

            int minimumWidth = 16 + bordersAndPaddingWidth;
            if (allowVertScrollbar)
            {
                minimumWidth += _vertScrollBar.Width;
            }
            if (RowHeadersVisible)
            {
                minimumWidth += RowHeadersWidth;
            }
            int preferredWidth = Math.Min(minimumWidth + Columns.GetColumnsWidth(DataGridViewElementStates.Visible), proposedConstraints.Width);
            if (preferredWidth < minimumWidth)
            {
                preferredWidth = minimumWidth;
            }

            int minimumHeight = 16 + bordersAndPaddingHeight;
            if (allowHorizScrollbar)
            {
                minimumHeight += _horizScrollBar.Height;
            }
            if (ColumnHeadersVisible)
            {
                minimumHeight += ColumnHeadersHeight;
            }
            int preferredHeight = Math.Min(minimumHeight + Rows.GetRowsHeight(DataGridViewElementStates.Visible), proposedConstraints.Height);
            if (preferredHeight < minimumHeight)
            {
                preferredHeight = minimumHeight;
            }

            return new Size(preferredWidth, preferredHeight);
        }

        // Rectangle returned includes the potential row header
        public Rectangle GetRowDisplayRectangle(int rowIndex, bool cutOverflow)
        {
            if (rowIndex < 0 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            return GetRowDisplayRectanglePrivate(rowIndex, cutOverflow);
        }

        private Rectangle GetRowDisplayRectanglePrivate(int rowIndex, bool cutOverflow)
        {
            Debug.Assert(rowIndex >= 0 && rowIndex < Rows.Count);

            if ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Displayed) == 0)
            {
                return Rectangle.Empty;
            }

            Rectangle data = _layout.Data;
            int cy = data.Y;
            bool rowFound = false;
            int indexTmp;
            for (indexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                indexTmp != -1 && !rowFound;
                )
            {
                if (cy > data.Bottom)
                {
                    break;
                }
                if (indexTmp == rowIndex)
                {
                    rowFound = true;
                }
                else
                {
                    cy += Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                    indexTmp = Rows.GetNextRow(indexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                }
            }

            if (!rowFound && DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0)
            {
                for (indexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                    indexTmp != -1 && !rowFound;
                    )
                {
                    if (cy > data.Bottom)
                    {
                        break;
                    }
                    if (indexTmp == rowIndex)
                    {
                        rowFound = true;
                    }
                    else
                    {
                        cy += Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                        indexTmp = Rows.GetNextRow(indexTmp, DataGridViewElementStates.Visible);
                    }
                }
            }

            if (rowFound)
            {
                int displayHeight;
                if (cutOverflow && cy + Rows.SharedRow(indexTmp).GetHeight(indexTmp) > data.Bottom)
                {
                    displayHeight = data.Bottom - cy;
                }
                else
                {
                    displayHeight = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                }

                Rectangle rowRect = new Rectangle(data.X,
                    cy,
                    data.Width,
                    displayHeight);
                if (_layout.RowHeadersVisible)
                {
                    rowRect.Width += _layout.RowHeaders.Width;
                    if (!RightToLeftInternal)
                    {
                        rowRect.X -= _layout.RowHeaders.Width;
                    }
                }
                return rowRect;
            }

            return Rectangle.Empty;
        }

        private int GetRowIndexFromY(int y, out int yRowTopEdge)
        {
            Rectangle data = _layout.Data;
            Debug.Assert(y >= data.Y - 1 && y < data.Bottom, "y must be inside the vertical bounds of the data area.");

            if (y == data.Y - 1)
            {
                y++;
            }

            int rowHeight;
            int cy = data.Y;

            // first try to match y against a frozen rows
            int indexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            while (indexTmp != -1 && cy < data.Bottom)
            {
                rowHeight = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                cy += rowHeight;
                if (cy > y)
                {
                    yRowTopEdge = cy - rowHeight;
                    return indexTmp;
                }
                indexTmp = Rows.GetNextRow(indexTmp,
                    DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            }

            // second try to match y against a scrolling row
            if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0)
            {
                indexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                Debug.Assert((Rows.GetRowState(indexTmp) & DataGridViewElementStates.Visible) != 0 &&
                    (Rows.GetRowState(indexTmp) & DataGridViewElementStates.Frozen) == 0);

                while (indexTmp != -1 && cy < data.Bottom)
                {
                    rowHeight = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                    cy += rowHeight;
                    if (cy > y)
                    {
                        yRowTopEdge = cy - rowHeight;
                        return indexTmp;
                    }
                    indexTmp = Rows.GetNextRow(indexTmp,
                        DataGridViewElementStates.Visible);
                }
            }

            yRowTopEdge = -1;
            return -1;
        }

        private static int GetRowScrollRate(int yOffset)
        {
            Debug.Assert(yOffset > 0);
            // Counting 10ms for executing the actual row scrolling
            if (yOffset <= 10)
            {
                return 90;      // Ten rows per second
            }
            if (yOffset <= 15)
            {
                return 57;     // Fifteen rows per second
            }
            if (yOffset <= 25)
            {
                return 30;     // Twenty-five rows per second
            }
            if (yOffset <= 35)
            {
                return 18;     // Thirty-five rows per second
            }
            return Math.Max(1, 600 / yOffset);
        }

        /// <summary>
        ///  Returns the coordinate of the upper edge of the given row. Note that
        ///  the row does not need to be completely visible on the display area.
        ///  Value returned is not necessarily within layout.Data because the row
        ///  may start below the data area.
        /// </summary>
        internal int GetRowYFromIndex(int index)
        {
            Debug.Assert(index >= 0 && index < Rows.Count);
            Debug.Assert((Rows.GetRowState(index) & DataGridViewElementStates.Visible) != 0);

            int y = _layout.Data.Y;

            int indexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            while (indexTmp != -1)
            {
                if (index == indexTmp)
                {
                    return y;
                }
                y += Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                indexTmp = Rows.GetNextRow(indexTmp,
                    DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            }

            int yFirstVisibleScrollingRow = y;

            if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0)
            {
                if (index >= DisplayedBandsInfo.FirstDisplayedScrollingRow)
                {
                    // index is part of the scrolling rows below the frozen rows
                    indexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                }
                else
                {
                    // index is part of the rows hidden behind the frozen rows or on top of the control
                    indexTmp = -1;
                }
            }
            else
            {
                // frozen rows cover all the rows real-estate. Look for index starting at the first visible non-frozen row.
                indexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                Debug.Assert(indexTmp != -1);
            }

            if (indexTmp != -1)
            {
                Debug.Assert((Rows.GetRowState(indexTmp) & DataGridViewElementStates.Visible) != 0 &&
                    (Rows.GetRowState(indexTmp) & DataGridViewElementStates.Frozen) == 0);

                while (indexTmp != -1)
                {
                    if (index == indexTmp)
                    {
                        return y;
                    }
                    y += Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                    indexTmp = Rows.GetNextRow(indexTmp, DataGridViewElementStates.Visible);
                }
            }

            // Row is completely hidden behind frozen rows or on top of control
            y = yFirstVisibleScrollingRow;
            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow != -1);
            indexTmp = Rows.GetPreviousRow(DisplayedBandsInfo.FirstDisplayedScrollingRow,
                DataGridViewElementStates.Visible,
                DataGridViewElementStates.Frozen);
            while (indexTmp != -1)
            {
                y -= Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                if (index == indexTmp)
                {
                    return y;
                }
                indexTmp = Rows.GetPreviousRow(indexTmp,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.Frozen);
            }

            Debug.Fail("Could not find row in GetRowYFromIndex");
            return 0;
        }

        private bool GetTabKeyEffective(bool shift, bool ctrl)
        {
            if (StandardTab)
            {
                return ctrl &&
                       !((!shift && (!VisibleCellExists || CurrentCellIsLastVisibleCell)) ||
                         (shift && (!VisibleCellExists || CurrentCellIsFirstVisibleCell)));
            }
            else
            {
                return !ctrl &&
                       !((!shift && (!VisibleCellExists || CurrentCellIsLastVisibleCell)) ||
                         (shift && (!VisibleCellExists || CurrentCellIsFirstVisibleCell)));
            }
        }

        public HitTestInfo HitTest(int x, int y)
        {
            HitTestInfo hti = new HitTestInfo();

            if (!_layout.Inside.Contains(x, y))
            {
                return hti;
            }

            if (_horizScrollBar != null && _horizScrollBar.Visible && _horizScrollBar.Bounds.Contains(x, y))
            {
                hti._type = DataGridViewHitTestType.HorizontalScrollBar;
                return hti;
            }

            if (_vertScrollBar != null && _vertScrollBar.Visible && _vertScrollBar.Bounds.Contains(x, y))
            {
                hti._type = DataGridViewHitTestType.VerticalScrollBar;
                return hti;
            }

            if (_layout.TopLeftHeader.Contains(x, y))
            {
                hti._type = DataGridViewHitTestType.TopLeftHeader;
                hti._typeInternal = DataGridViewHitTestTypeInternal.TopLeftHeader;
                if (RightToLeftInternal)
                {
                    hti._colStart = _layout.TopLeftHeader.Right - 1;
                }
                else
                {
                    hti._colStart = _layout.TopLeftHeader.Left;
                }
                hti._rowStart = _layout.TopLeftHeader.Top;
                if ((!RightToLeftInternal && _layout.TopLeftHeader.Right - x < ColumnSizingHotZone) ||
                    (RightToLeftInternal && x - _layout.TopLeftHeader.Left < ColumnSizingHotZone))
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Right;
                    if (RowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing)
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.TopLeftHeaderResizeLeft;
                        if (RightToLeftInternal)
                        {
                            hti._mouseBarOffset = _layout.TopLeftHeader.Left - x - 1;
                        }
                        else
                        {
                            hti._mouseBarOffset = _layout.TopLeftHeader.Right - x - 1;
                        }
                    }
                }
                else if (_layout.TopLeftHeader.Top + _layout.TopLeftHeader.Height - y < RowSizingHotZone)
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Bottom;
                    if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.EnableResizing)
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.TopLeftHeaderResizeTop;
                        hti._mouseBarOffset = _layout.TopLeftHeader.Top + _layout.TopLeftHeader.Height - y - 1;
                    }
                }
                return hti;
            }

            // check for column resize / insertion
            if (_layout.ColumnHeaders.Contains(x, y))
            {
                // this is actually the right edge in RTL mode
                hti._col = GetColumnIndexFromX(x, out int xColumnLeftEdge);
                if (hti._col < 0)
                {
                    return HitTestInfo.Nowhere;
                }
                Debug.Assert(xColumnLeftEdge == GetColumnXFromIndex(hti._col));
                hti._type = DataGridViewHitTestType.ColumnHeader;
                hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnHeader;
                hti._rowStart = _layout.ColumnHeaders.Top;
                hti._colStart = xColumnLeftEdge;
                int columnWidth = Columns[hti._col].Thickness;
                if ((!RightToLeftInternal && xColumnLeftEdge + columnWidth - x < ColumnSizingHotZone) ||
                    (RightToLeftInternal && x - xColumnLeftEdge + columnWidth < ColumnSizingHotZone))
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Right;
                    if (RightToLeftInternal)
                    {
                        hti._mouseBarOffset = xColumnLeftEdge - columnWidth - x + 1;
                    }
                    else
                    {
                        hti._mouseBarOffset = xColumnLeftEdge + columnWidth - x - 1;
                    }
                    DataGridViewColumn dataGridViewColumn = Columns[hti._col];
                    if (dataGridViewColumn.Resizable == DataGridViewTriState.True &&
                        (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.None || dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill))
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnResizeRight;
                    }
                    else
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnHeaderRight;
                    }
                }
                else if ((!RightToLeftInternal && x - xColumnLeftEdge < ColumnSizingHotZone) ||
                         (RightToLeftInternal && xColumnLeftEdge - x < ColumnSizingHotZone))
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Left;
                    DataGridViewColumn dataGridViewColumn = null;

                    dataGridViewColumn = Columns.GetPreviousColumn(Columns[hti._col],
                                                                                 DataGridViewElementStates.Visible,
                                                                                 DataGridViewElementStates.None);
                    //}
                    if (dataGridViewColumn != null)
                    {
                        hti._adjacentCol = dataGridViewColumn.Index;
                        if (RightToLeftInternal)
                        {
                            hti._mouseBarOffset = xColumnLeftEdge - x + 1;
                        }
                        else
                        {
                            hti._mouseBarOffset = xColumnLeftEdge - x - 1;
                        }
                        if (dataGridViewColumn.Resizable == DataGridViewTriState.True &&
                            (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.None || dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill))
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnResizeLeft;
                        }
                        else
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnHeaderLeft;
                        }
                    }
                    else
                    {
                        if (RowHeadersVisible && RowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing)
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.TopLeftHeaderResizeRight;
                            if (RightToLeftInternal)
                            {
                                hti._mouseBarOffset = xColumnLeftEdge - x;
                            }
                            else
                            {
                                hti._mouseBarOffset = xColumnLeftEdge - x - 1;
                            }
                        }
                        else
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.FirstColumnHeaderLeft;
                        }
                    }
                }
                else if (_layout.ColumnHeaders.Bottom - y < RowSizingHotZone)
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Bottom;
                    if (/*!this.RowHeadersVisible &&*/ ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.EnableResizing)
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnHeadersResizeBottom;
                        hti._mouseBarOffset = _layout.ColumnHeaders.Bottom - y - 1;
                    }
                }
            }

            // check for row resize
            if (_layout.RowHeaders.Contains(x, y))
            {
                hti._row = GetRowIndexFromY(y, out int yRowTopEdge);
                if (hti._row < 0)
                {
                    return HitTestInfo.Nowhere;
                }
                Debug.Assert(yRowTopEdge == GetRowYFromIndex(hti._row));
                hti._type = DataGridViewHitTestType.RowHeader;
                hti._typeInternal = DataGridViewHitTestTypeInternal.RowHeader;
                hti._rowStart = yRowTopEdge;
                if (RightToLeftInternal)
                {
                    hti._colStart = _layout.RowHeaders.Right - 1;
                }
                else
                {
                    hti._colStart = _layout.RowHeaders.Left;
                }
                int rowHeight = Rows.SharedRow(hti._row).GetHeight(hti._row);
                if (yRowTopEdge + rowHeight - y < RowSizingHotZone)
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Bottom;

                    if (RowIsResizable(hti._row) && AutoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.RowResizeBottom;
                        hti._mouseBarOffset = yRowTopEdge + rowHeight - y - 1;
                    }
                }
                else if (y - yRowTopEdge < RowSizingHotZone)
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Top;
                    int indexTmp = -1;
                    if (hti._row != DisplayedBandsInfo.FirstDisplayedScrollingRow || DisplayedBandsInfo.NumDisplayedFrozenRows > 0)
                    {
                        indexTmp = Rows.GetPreviousRow(hti._row, DataGridViewElementStates.Visible);
                    }
                    if (indexTmp != -1)
                    {
                        if (RowIsResizable(indexTmp) && AutoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.RowResizeTop;
                            hti._adjacentRow = indexTmp;
                            hti._mouseBarOffset = yRowTopEdge - y - 1;
                        }
                    }
                    else
                    {
                        if (ColumnHeadersVisible && ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.EnableResizing)
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.TopLeftHeaderResizeBottom;
                            hti._mouseBarOffset = yRowTopEdge - y - 1;
                        }
                    }
                }
                else if ((!RightToLeftInternal && _layout.RowHeaders.Right - x < ColumnSizingHotZone) ||
                         (RightToLeftInternal && x - _layout.RowHeaders.Left < ColumnSizingHotZone))
                {
                    //hti.edge = DataGridViewHitTestTypeCloseEdge.Right;
                    if (RowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing)
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.RowHeadersResizeRight;
                        if (RightToLeftInternal)
                        {
                            hti._mouseBarOffset = _layout.RowHeaders.Left - x - 1;
                        }
                        else
                        {
                            hti._mouseBarOffset = _layout.RowHeaders.Right - x - 1;
                        }
                    }
                }
            }

            if (_layout.Data.Contains(x, y))
            {
                hti._col = GetColumnIndexFromX(x, out int xColumnLeftEdge);
                hti._row = GetRowIndexFromY(y, out int yRowTopEdge);
                if (hti._col < 0 || hti._row < 0)
                {
                    return HitTestInfo.Nowhere;
                }
                Debug.Assert(xColumnLeftEdge == GetColumnXFromIndex(hti._col));
                Debug.Assert(yRowTopEdge == GetRowYFromIndex(hti._row));
                hti._type = DataGridViewHitTestType.Cell;
                hti._typeInternal = DataGridViewHitTestTypeInternal.Cell;
                hti._rowStart = yRowTopEdge;
                hti._colStart = xColumnLeftEdge;
                if (!ColumnHeadersVisible)
                {
                    int columnWidth = Columns[hti._col].Thickness;
                    if ((!RightToLeftInternal && xColumnLeftEdge + columnWidth - x < ColumnSizingHotZone) ||
                        (RightToLeftInternal && x - xColumnLeftEdge + columnWidth < ColumnSizingHotZone))
                    {
                        if (RightToLeftInternal)
                        {
                            hti._mouseBarOffset = xColumnLeftEdge - columnWidth - x + 1;
                        }
                        else
                        {
                            hti._mouseBarOffset = xColumnLeftEdge + columnWidth - x - 1;
                        }
                        DataGridViewColumn dataGridViewColumn = Columns[hti._col];
                        if (dataGridViewColumn.Resizable == DataGridViewTriState.True &&
                            (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.None || dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill))
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnResizeRight;
                        }
                        return hti;
                    }
                    else if ((!RightToLeftInternal && x - xColumnLeftEdge < ColumnSizingHotZone) ||
                             (RightToLeftInternal && xColumnLeftEdge - x < ColumnSizingHotZone))
                    {
                        DataGridViewColumn dataGridViewColumn = null;
                        if (hti._col != DisplayedBandsInfo.FirstDisplayedScrollingCol || DisplayedBandsInfo.LastTotallyDisplayedScrollingCol >= 0)
                        {
                            dataGridViewColumn = Columns.GetPreviousColumn(Columns[hti._col],
                                DataGridViewElementStates.Visible,
                                DataGridViewElementStates.None);
                        }
                        if (dataGridViewColumn != null)
                        {
                            hti._adjacentCol = dataGridViewColumn.Index;
                            if (RightToLeftInternal)
                            {
                                hti._mouseBarOffset = xColumnLeftEdge - x + 1;
                            }
                            else
                            {
                                hti._mouseBarOffset = xColumnLeftEdge - x - 1;
                            }
                            if (dataGridViewColumn.Resizable == DataGridViewTriState.True &&
                                (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.None || dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill))
                            {
                                hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnResizeLeft;
                            }
                            return hti;
                        }
                        else
                        {
                            if (RowHeadersVisible && RowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing)
                            {
                                hti._typeInternal = DataGridViewHitTestTypeInternal.RowHeadersResizeLeft;
                                if (RightToLeftInternal)
                                {
                                    hti._mouseBarOffset = xColumnLeftEdge - x;
                                }
                                else
                                {
                                    hti._mouseBarOffset = xColumnLeftEdge - x - 1;
                                }
                                return hti;
                            }
                        }
                    }
                }
                else if ((!RightToLeftInternal && x - xColumnLeftEdge < ColumnSizingHotZone) ||
                         (RightToLeftInternal && xColumnLeftEdge - x < ColumnSizingHotZone))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                    Debug.Assert(dataGridViewColumn != null);
                    if (hti._col == dataGridViewColumn.Index &&
                        RowHeadersVisible &&
                        RowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing)
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.RowHeadersResizeLeft;
                        if (RightToLeftInternal)
                        {
                            hti._mouseBarOffset = xColumnLeftEdge - x;
                        }
                        else
                        {
                            hti._mouseBarOffset = xColumnLeftEdge - x - 1;
                        }
                        return hti;
                    }
                }

                if (!RowHeadersVisible)
                {
                    int rowHeight = Rows.SharedRow(hti._row).GetHeight(hti._row);
                    if (yRowTopEdge + rowHeight - y < RowSizingHotZone)
                    {
                        if (RowIsResizable(hti._row) && AutoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
                        {
                            hti._typeInternal = DataGridViewHitTestTypeInternal.RowResizeBottom;
                            hti._mouseBarOffset = yRowTopEdge + rowHeight - y - 1;
                        }
                    }
                    else if (y - yRowTopEdge < RowSizingHotZone)
                    {
                        int indexTmp = -1;
                        if (hti._row != DisplayedBandsInfo.FirstDisplayedScrollingRow || DisplayedBandsInfo.NumDisplayedFrozenRows > 0)
                        {
                            indexTmp = Rows.GetPreviousRow(hti._row,
                                DataGridViewElementStates.Visible);
                        }
                        if (indexTmp != -1)
                        {
                            if (RowIsResizable(indexTmp) && AutoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
                            {
                                hti._typeInternal = DataGridViewHitTestTypeInternal.RowResizeTop;
                                hti._adjacentRow = indexTmp;
                                hti._mouseBarOffset = yRowTopEdge - y - 1;
                            }
                        }
                        else
                        {
                            if (ColumnHeadersVisible && ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.EnableResizing)
                            {
                                hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnHeadersResizeTop;
                                hti._mouseBarOffset = yRowTopEdge - y - 1;
                            }
                        }
                    }
                }
                else if (y - yRowTopEdge < RowSizingHotZone)
                {
                    int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                    Debug.Assert(rowIndex >= 0);
                    if (hti._row == rowIndex &&
                        ColumnHeadersVisible &&
                        ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.EnableResizing)
                    {
                        hti._typeInternal = DataGridViewHitTestTypeInternal.ColumnHeadersResizeTop;
                        hti._mouseBarOffset = yRowTopEdge - y - 1;
                    }
                }
            }

            return hti;
        }

        private void HorizScrollTimer_Tick(object sender, EventArgs e)
        {
            BeginInvoke(new MethodInvoker(HorizScrollTimerHandler));
        }

        private void HorizScrollTimerHandler()
        {
            Debug.Assert(_dataGridViewOper[OperationTrackColSelect] || _dataGridViewOper[OperationTrackCellSelect]);

            Point ptMouse = PointToClient(Control.MousePosition);
            HitTestInfo hti = HitTest(ptMouse.X, ptMouse.Y);
            int mouseX = ptMouse.X, mouseY = ptMouse.Y;
            if (GetOutOfBoundCorrectedHitTestInfo(ref hti, ref mouseX, ref mouseY, out int xOffset, out int yOffset))
            {
                if (xOffset != 0)
                {
                    int absXOffset = Math.Abs(xOffset), normOffset = xOffset / absXOffset;
                    ScrollColumns(normOffset);
                    _horizScrollTimer.Interval = GetColumnScrollRate(absXOffset);
                    if (_dataGridViewOper[OperationTrackColSelect])
                    {
                        hti = HitTest(ptMouse.X + (RightToLeftInternal ? 1 : -1) * (xOffset + normOffset), mouseY);
                        if (hti._col >= 0)
                        {
                            OnColumnSelectMouseMove(hti);
                        }
                    }
                    else if (_dataGridViewOper[OperationTrackCellSelect])
                    {
                        if (yOffset != 0)
                        {
                            hti = HitTest(ptMouse.X + (RightToLeftInternal ? 1 : -1) * (xOffset + normOffset), ptMouse.Y - yOffset - (yOffset / Math.Abs(yOffset)));
                        }
                        else
                        {
                            hti = HitTest(ptMouse.X + (RightToLeftInternal ? 1 : -1) * (xOffset + normOffset), mouseY);
                        }
                        if (hti._col >= 0 && hti._row >= 0)
                        {
                            OnCellSelectMouseMove(hti);
                        }
                    }
                }
                else
                {
                    if (_dataGridViewOper[OperationTrackColSelect] && hti._col >= 0)
                    {
                        OnColumnSelectMouseMove(hti);
                    }
                    else if (_dataGridViewOper[OperationTrackCellSelect] && hti._col >= 0 && hti._row >= 0)
                    {
                        OnCellSelectMouseMove(hti);
                    }
                    HorizScrollTimer.Enabled = false;
                }
            }
        }

        // Returns true for success, returns false when the OnDataError event cancels the operation.
        private bool InitializeEditingCellValue(ref DataGridViewCellStyle dataGridViewCellStyle, ref DataGridViewCell dataGridViewCell)
        {
            DataGridViewDataErrorEventArgs dgvdee = null;
            // Save unedited value so we can restore it later if parsing of new value fails
            _uneditedFormattedValue = dataGridViewCell.GetFormattedValue(_ptCurrentCell.Y, ref dataGridViewCellStyle, DataGridViewDataErrorContexts.Formatting);
            _dataGridViewState1[State1_IgnoringEditingChanges] = true;
            try
            {
                IDataGridViewEditingCell dataGridViewEditingCell = dataGridViewCell as IDataGridViewEditingCell;
                Debug.Assert(dataGridViewEditingCell != null);
                object currentFormattedValue = dataGridViewEditingCell.GetEditingCellFormattedValue(DataGridViewDataErrorContexts.Formatting);
                if ((currentFormattedValue is null && _uneditedFormattedValue != null) ||
                    (currentFormattedValue != null && _uneditedFormattedValue is null) ||
                    (currentFormattedValue != null && !_uneditedFormattedValue.Equals(currentFormattedValue)))
                {
                    Debug.Assert(_ptCurrentCell.X == dataGridViewCell.ColumnIndex);
                    dataGridViewCell = Rows[_ptCurrentCell.Y].Cells[_ptCurrentCell.X]; // unshare the edited cell
                    dataGridViewEditingCell = dataGridViewCell as IDataGridViewEditingCell;
                    dataGridViewEditingCell.EditingCellFormattedValue = _uneditedFormattedValue;
                    dataGridViewEditingCell.EditingCellValueChanged = false;
                }
            }
            catch (Exception exception)
            {
                if (ClientUtils.IsCriticalException(exception))
                {
                    throw;
                }
                dgvdee = new DataGridViewDataErrorEventArgs(exception, _ptCurrentCell.X,
                    _ptCurrentCell.Y,
                    DataGridViewDataErrorContexts.InitialValueRestoration);
                OnDataErrorInternal(dgvdee);
            }
            finally
            {
                _dataGridViewState1[State1_IgnoringEditingChanges] = false;
            }
            if (dgvdee != null)
            {
                if (dgvdee.ThrowException)
                {
                    throw dgvdee.Exception;
                }
                return !dgvdee.Cancel;
            }
            return true;
        }

        // Returns true for success, returns false when the OnDataError event cancels the operation.
        private bool InitializeEditingControlValue(ref DataGridViewCellStyle dataGridViewCellStyle, DataGridViewCell dataGridViewCell)
        {
            Debug.Assert(dataGridViewCell != null);
            Debug.Assert(EditingControl != null);

            DataGridViewDataErrorEventArgs dgvdee = null;
            object initialFormattedValue = dataGridViewCell.GetFormattedValue(_ptCurrentCell.Y, ref dataGridViewCellStyle, DataGridViewDataErrorContexts.Formatting);
            _dataGridViewState1[State1_EditingControlChanging] = true;
            _dataGridViewState1[State1_IgnoringEditingChanges] = true;
            try
            {
                dataGridViewCell.InitializeEditingControl(_ptCurrentCell.Y, initialFormattedValue, dataGridViewCellStyle);
                ((IDataGridViewEditingControl)EditingControl).EditingControlValueChanged = false;
            }
            catch (Exception exception)
            {
                if (ClientUtils.IsCriticalException(exception))
                {
                    throw;
                }
                dgvdee = new DataGridViewDataErrorEventArgs(exception, _ptCurrentCell.X,
                    _ptCurrentCell.Y,
                    DataGridViewDataErrorContexts.InitialValueRestoration);
                OnDataErrorInternal(dgvdee);
            }
            finally
            {
                _dataGridViewState1[State1_EditingControlChanging] = false;
                _dataGridViewState1[State1_IgnoringEditingChanges] = false;
            }
            if (dgvdee != null)
            {
                if (dgvdee.ThrowException)
                {
                    throw dgvdee.Exception;
                }
                return !dgvdee.Cancel;
            }

            // Save unedited value so we can restore it later if parsing of new value fails
            _uneditedFormattedValue = initialFormattedValue;
            return true;
        }

        public void InvalidateCell(DataGridViewCell dataGridViewCell)
        {
            if (dataGridViewCell is null)
            {
                throw new ArgumentNullException(nameof(dataGridViewCell));
            }
            if (dataGridViewCell.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_CellDoesNotBelongToDataGridView);
            }
            InvalidateCellPrivate(dataGridViewCell);
        }

        private void InvalidateCellPrivate(DataGridViewCell dataGridViewCell)
        {
            Debug.Assert(dataGridViewCell != null);
            Debug.Assert(dataGridViewCell.DataGridView == this);
            InvalidateCell(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex);
        }

        public void InvalidateCell(int columnIndex, int rowIndex)
        {
            if (columnIndex < -1 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }
            if (rowIndex < -1 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            InvalidateCellPrivate(columnIndex, rowIndex);
        }

        private void InvalidateCellPrivate(int columnIndex, int rowIndex)
        {
            if (IsHandleCreated)
            {
                Rectangle cellDisplayRect = GetCellAdjustedDisplayRectangle(columnIndex, rowIndex, true);
                if (!cellDisplayRect.IsEmpty)
                {
                    Invalidate(cellDisplayRect);
                }
            }
        }

        /// <summary>
        ///  Invalidate the painting region for the column specified.
        /// </summary>
        public void InvalidateColumn(int columnIndex)
        {
            if (columnIndex < 0 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }
            InvalidateColumnInternal(columnIndex);
        }

        internal void InvalidateColumnInternal(int columnIndex)
        {
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count);

            if (IsHandleCreated)
            {
                Rectangle columnDisplayRect = GetColumnDisplayRectanglePrivate(columnIndex, true);
                if (!columnDisplayRect.IsEmpty)
                {
                    Invalidate(columnDisplayRect);
                }
            }
        }

        private void InvalidateData()
        {
            if (IsHandleCreated)
            {
                Invalidate(_layout.Data);
            }
        }

        /// <summary>
        ///  Invalidates the scrollable area of the DataGridView.
        /// </summary>
        private void InvalidateInside()
        {
            if (IsHandleCreated)
            {
                Invalidate(_layout.Inside);
            }
        }

        /// <summary>
        ///  Invalidate the painting region for the row specified.
        /// </summary>
        public void InvalidateRow(int rowIndex)
        {
            if (rowIndex < 0 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            InvalidateRowPrivate(rowIndex);
        }

        private void InvalidateRowPrivate(int rowIndex)
        {
            Debug.Assert(rowIndex >= 0 && rowIndex < Rows.Count);

            if (IsHandleCreated)
            {
                Rectangle rowDisplayRect = GetRowDisplayRectanglePrivate(rowIndex, true);
                if (!rowDisplayRect.IsEmpty)
                {
                    Invalidate(rowDisplayRect);
                }
            }
        }

        private void InvalidateRowHeights()
        {
            Rows.InvalidateCachedRowsHeights();
            if (IsHandleCreated)
            {
                PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
                Invalidate();
            }
        }

        private void InvalidateRows(int lo, int hi)
        {
            Debug.Assert(lo <= hi);
            Debug.Assert(lo < Rows.Count);
            Debug.Assert(hi < Rows.Count);

            if (Rows.GetRowCount(DataGridViewElementStates.Visible) == 0)
            {
                return;
            }

            Rectangle rowDisplayRect, data;
            int top, bottom;

            data = _layout.Data;

            // If "lo" is not visible, then get the next visible row
            if ((Rows.GetRowState(lo) & DataGridViewElementStates.Visible) == 0)
            {
                lo = Rows.GetNextRow(lo, DataGridViewElementStates.Visible);
            }

            if (lo == -1)
            {
                // there are no visible rows below "lo" so there is nothing to invalidate.
                return;
            }

            // If "hi" is not visible, then get the previous visible row
            if ((Rows.GetRowState(hi) & DataGridViewElementStates.Visible) == 0)
            {
                hi = Rows.GetPreviousRow(hi, DataGridViewElementStates.Visible);
            }

            Debug.Assert(lo <= hi);
            Debug.Assert(lo > -1);

            rowDisplayRect = GetRowDisplayRectangle(lo, true /*cutOverflow*/);

            if (rowDisplayRect.IsEmpty)
            {
                // The top row is offscreen
                if ((Rows.GetRowState(lo) & DataGridViewElementStates.Frozen) != 0)
                {
                    // "lo" is a frozen row which is offscreen.
                    // This means that "lo" and any other row below it are offscreen.
                    return;
                }
                else if (DisplayedBandsInfo.NumDisplayedScrollingRows == 0)
                {
                    // "lo" and all the rows below are scrolling rows but no scrolling rows are displayed.
                    return;
                }
                else if (lo >= DisplayedBandsInfo.FirstDisplayedScrollingRow &&
                    Rows.GetRowCount(DataGridViewElementStates.Visible,
                                          DisplayedBandsInfo.FirstDisplayedScrollingRow,
                                          lo) >= DisplayedBandsInfo.NumDisplayedScrollingRows)
                {
                    // "lo" is a scrolling row whose coordinates are below the last visible row.
                    return;
                }
                else
                {
                    // "lo" is a scrolling row "behind" frozen rows.
                    // Start invalidating at the top of the first displayed scrolling row.
                    top = GetRowDisplayRectangle(DisplayedBandsInfo.FirstDisplayedScrollingRow, true /*cutOverflow*/).Top;
                }
            }
            else
            {
                top = rowDisplayRect.Top;
            }

            rowDisplayRect = GetRowDisplayRectangle(hi, true /*cutOverflow*/);

            if (rowDisplayRect.IsEmpty)
            {
                // The bottom row is offscreen.
                if ((Rows.GetRowState(hi) & DataGridViewElementStates.Frozen) == DataGridViewElementStates.Frozen)
                {
                    // "hi" is a frozen row offscreen and "lo" is a frozen row on screen.
                    // Invalidate all the way to the bottom
                    bottom = data.Bottom;
                }
                else if (hi > DisplayedBandsInfo.FirstDisplayedScrollingRow)
                {
                    // "hi" is a scrolling row offscreen which is beyond the firstDisplayedScrollingRow
                    // Invalidate all the way to the bottom again.
                    bottom = data.Bottom;
                }
                else if (Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) == 0)
                {
                    // "hi" is a scrolling row above the first displayed scrolling row and there are no frozen rows.
                    // There is nothing to invalidate.
                    return;
                }
                else
                {
                    // "hi" is a scrolling row which is "behind" the frozen rows.
                    // Invalidate all the way to the bottom of the frozen rows
                    // Compute the bottom of the last displayed frozen row.
                    // There may be invisible rows between the frozen rows.
                    bottom = 0;
                    for (int i = 0; i < DisplayedBandsInfo.NumDisplayedFrozenRows;)
                    {
                        if ((Rows.GetRowState(i) & DataGridViewElementStates.Visible) == 0)
                        {
                            continue;
                        }

                        if (i == DisplayedBandsInfo.NumDisplayedFrozenRows - 1)
                        {
                            bottom = GetRowDisplayRectangle(i, true /*cutOverflow*/).Bottom;
                            break;
                        }

                        i++;
                    }

                    if (bottom <= top)
                    {
                        // In this case both "lo" and "hi" are two scrolling rows behind the frozen rows.
                        // Nothing to invalidate.
                        return;
                    }
                }
            }
            else
            {
                bottom = rowDisplayRect.Bottom;
            }

            Invalidate(new Rectangle(data.X, top, data.Width, bottom - top));
        }

        private void InvalidateScrollBars()
        {
            // invalidate the horizontal and the vertical scrollbars
            // note that the scrollbars can be null - this happens when
            // the control has been disposed.
            if (_horizScrollBar != null && _horizScrollBar.Visible)
            {
                _horizScrollBar.Invalidate();
            }
            if (_vertScrollBar != null && _vertScrollBar.Visible)
            {
                _vertScrollBar.Invalidate();
            }
        }

        private bool IsColumnOutOfBounds(int columnIndex)
        {
            return columnIndex >= Columns.Count || columnIndex == -1;
        }

        private bool IsInnerCellOutOfBounds(int columnIndex, int rowIndex)
        {
            return columnIndex >= Columns.Count || rowIndex >= Rows.Count || columnIndex == -1 || rowIndex == -1;
        }

        private bool IsRowOutOfBounds(int rowIndex)
        {
            return rowIndex >= Rows.Count || rowIndex == -1;
        }

        protected override bool IsInputChar(char charCode)
        {
            if (EditingControl != null &&
                _dataGridViewState1[State1_ForwardCharMessage])
            {
                // Do not process key press in ProcessDialogChar.
                return true;
            }
            else
            {
                return base.IsInputChar(charCode);
            }
        }

        protected override bool IsInputKey(Keys keyData)
        {
            if ((keyData & Keys.Alt) == Keys.Alt)
            {
                return false;
            }
            switch (keyData & Keys.KeyCode)
            {
                case Keys.Escape:
                    {
                        return IsEscapeKeyEffective;
                    }

                case Keys.Tab:
                    {
                        return GetTabKeyEffective((keyData & Keys.Shift) == Keys.Shift, (keyData & Keys.Control) == Keys.Control);
                    }

                case Keys.A:
                    {
                        if ((keyData & (Keys.Control | Keys.Shift | Keys.Alt)) == Keys.Control)
                        {
                            return true;
                        }
                        break;
                    }

                case Keys.C:
                case Keys.Insert:
                    {
                        if ((keyData & (Keys.Control | Keys.Shift | Keys.Alt)) == Keys.Control)
                        {
                            return true;
                        }
                        break;
                    }

                case Keys.Space:
                    {
                        if ((keyData & (Keys.Control | Keys.Shift | Keys.Alt)) == Keys.Shift &&
                            (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect ||
                             SelectionMode == DataGridViewSelectionMode.RowHeaderSelect) &&
                            _ptCurrentCell.X != -1)
                        {
                            return true;
                        }
                        break;
                    }

                case Keys.Up:
                case Keys.Down:
                case Keys.Left:
                case Keys.Right:
                case Keys.Home:
                case Keys.End:
                case Keys.Next:
                case Keys.Prior:
                case Keys.Enter:
                case Keys.Delete:
                case Keys.D0:
                case Keys.NumPad0:
                case Keys.F2:
                case Keys.F3:
                    {
                        return true;
                    }
            }
            return base.IsInputKey(keyData);
        }

        /// <summary>
        ///  Determines if Scrollbars should be visible,
        ///  updates their bounds and the bounds of all
        ///  other regions in the dataGridView's Layout.
        /// </summary>
        private void LayoutScrollBars()
        {
            SuspendLayout();
            try
            {
                // Scrollbars are a tricky issue.
                // We need to see if we can cram our columns and rows
                // in without scrollbars and if they don't fit, we make
                // scrollbars visible and then fixup our regions for the
                // data.
                bool allowHorizScrollbar = ((_scrollBars == ScrollBars.Both) || (_scrollBars == ScrollBars.Horizontal)) &&
                                           _dataGridViewState2[State2_AllowHorizontalScrollbar];
                bool allowVertScrollbar = (_scrollBars == ScrollBars.Both) || (_scrollBars == ScrollBars.Vertical);
                bool needHorizScrollbarWithoutVertScrollbar = false;
                bool needHorizScrollbar = false;
                bool needVertScrollbar = false;
                bool rightToLeftInternal = RightToLeftInternal;
                int oldfirstDisplayedScrollingRow;

                int totalVisibleColCount = Columns.GetColumnCount(DataGridViewElementStates.Visible);
                int totalVisibleRowCount = Rows.GetRowCount(DataGridViewElementStates.Visible);
                int totalVisibleWidth = Columns.GetColumnsWidth(DataGridViewElementStates.Visible);
                int totalVisibleFrozenWidth = Columns.GetColumnsWidth(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);

                // Expensive call - dataGridView could have a mode where no row is resizable which would result in better perfs
                int totalVisibleHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible);
                int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);

                int horizScrollBarHeight = _horizScrollBar.Height = SystemInformation.HorizontalScrollBarHeight;
                int vertScrollBarWidth = _vertScrollBar.Width = SystemInformation.VerticalScrollBarWidth;

                if (allowHorizScrollbar &&
                    totalVisibleWidth > _layout.Data.Width && totalVisibleFrozenWidth < _layout.Data.Width &&
                    horizScrollBarHeight <= _layout.Data.Height)
                {
                    int oldDataHeight = _layout.Data.Height;
                    _layout.Data.Height -= horizScrollBarHeight;
                    Debug.Assert(_layout.Data.Height >= 0);
                    needHorizScrollbarWithoutVertScrollbar = needHorizScrollbar = true;
                    if (totalVisibleWidth - _layout.Data.Width <= vertScrollBarWidth ||
                        _layout.Data.Width - totalVisibleFrozenWidth <= vertScrollBarWidth)
                    {
                        // Would we still need a horizontal scrollbar if there were a vertical one?
                        oldfirstDisplayedScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                        ComputeVisibleRows();
                        if (DisplayedBandsInfo.NumTotallyDisplayedFrozenRows == Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) &&
                            DisplayedBandsInfo.NumTotallyDisplayedScrollingRows != totalVisibleRowCount - Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) &&
                            (totalVisibleHeight - totalVisibleFrozenHeight != ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight)))
                        {
                            needHorizScrollbar = (totalVisibleFrozenWidth < _layout.Data.Width - vertScrollBarWidth);
                        }
                        DisplayedBandsInfo.FirstDisplayedScrollingRow = oldfirstDisplayedScrollingRow;
                    }

                    if (needHorizScrollbar)
                    {
                        if (_layout.RowHeadersVisible)
                        {
                            _layout.RowHeaders.Height -= horizScrollBarHeight;
                            Debug.Assert(_layout.RowHeaders.Height >= 0);
                        }
                    }
                    else
                    {
                        // Restore old data height because turns out a horizontal scroll bar wouldn't make sense
                        _layout.Data.Height = oldDataHeight;
                    }
                }

                oldfirstDisplayedScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;

                ComputeVisibleRows();
                if (allowVertScrollbar &&
                    DisplayedBandsInfo.NumTotallyDisplayedFrozenRows == Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) &&
                    DisplayedBandsInfo.NumTotallyDisplayedScrollingRows != totalVisibleRowCount - Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) &&
                    (totalVisibleHeight - totalVisibleFrozenHeight != ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight)) &&
                    _layout.Data.Height > totalVisibleFrozenHeight &&
                    vertScrollBarWidth <= _layout.Data.Width)
                {
                    _layout.Data.Width -= vertScrollBarWidth;
                    Debug.Assert(_layout.Data.Width >= 0);
                    if (rightToLeftInternal)
                    {
                        _layout.Data.X += vertScrollBarWidth;
                    }
                    if (_layout.ColumnHeadersVisible)
                    {
                        _layout.ColumnHeaders.Width -= vertScrollBarWidth;
                        Debug.Assert(_layout.ColumnHeaders.Width >= 0);
                        if (rightToLeftInternal)
                        {
                            _layout.ColumnHeaders.X += vertScrollBarWidth;
                        }
                    }
                    needVertScrollbar = true;
                }

                DisplayedBandsInfo.FirstDisplayedScrollingCol = ComputeFirstVisibleScrollingColumn();
                // we compute the number of visible columns only after we set up the vertical scroll bar.
                ComputeVisibleColumns();

                if (allowHorizScrollbar &&
                    needVertScrollbar && !needHorizScrollbar &&
                    totalVisibleWidth > _layout.Data.Width && totalVisibleFrozenWidth < _layout.Data.Width &&
                    horizScrollBarHeight <= _layout.Data.Height)
                {
                    DisplayedBandsInfo.FirstDisplayedScrollingRow = oldfirstDisplayedScrollingRow;
                    if (_layout.ColumnHeadersVisible)
                    {
                        _layout.ColumnHeaders.Width += vertScrollBarWidth;
                        if (rightToLeftInternal)
                        {
                            _layout.ColumnHeaders.X -= vertScrollBarWidth;
                        }
                    }
                    _layout.Data.Width += vertScrollBarWidth;
                    if (rightToLeftInternal)
                    {
                        _layout.Data.X -= vertScrollBarWidth;
                    }
                    _layout.Data.Height -= horizScrollBarHeight;
                    Debug.Assert(_layout.Data.Height >= 0);
                    needVertScrollbar = false;

                    ComputeVisibleRows();
                    if (DisplayedBandsInfo.NumTotallyDisplayedFrozenRows == Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen) &&
                        DisplayedBandsInfo.NumTotallyDisplayedScrollingRows != totalVisibleRowCount &&
                        (totalVisibleHeight - totalVisibleFrozenHeight != ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight)) &&
                        _layout.Data.Height > totalVisibleFrozenHeight &&
                        vertScrollBarWidth <= _layout.Data.Width)
                    {
                        _layout.Data.Width -= vertScrollBarWidth;
                        Debug.Assert(_layout.Data.Width >= 0);
                        if (rightToLeftInternal)
                        {
                            _layout.Data.X += vertScrollBarWidth;
                        }
                        if (_layout.ColumnHeadersVisible)
                        {
                            _layout.ColumnHeaders.Width -= vertScrollBarWidth;
                            Debug.Assert(_layout.ColumnHeaders.Width >= 0);
                            if (rightToLeftInternal)
                            {
                                _layout.ColumnHeaders.X += vertScrollBarWidth;
                            }
                        }
                        needVertScrollbar = true;
                    }
                    if (needVertScrollbar)
                    {
                        needHorizScrollbar = true;
                    }
                    else
                    {
                        needHorizScrollbar = needHorizScrollbarWithoutVertScrollbar;
                    }
                }

                _layout.ResizeBoxRect = new Rectangle();
                if (needVertScrollbar && needHorizScrollbar)
                {
                    _layout.ResizeBoxRect = new Rectangle(
                        rightToLeftInternal ? _layout.Data.X - _vertScrollBar.Width : _layout.Data.Right,
                        _layout.Data.Bottom,
                        _vertScrollBar.Width,
                        _horizScrollBar.Height);
                }

                if (needHorizScrollbar && totalVisibleColCount > 0)
                {
                    int widthNotVisible = totalVisibleWidth - _layout.Data.Width;

                    _horizScrollBar.Minimum = 0;
                    _horizScrollBar.Maximum = totalVisibleWidth - totalVisibleFrozenWidth;
                    Debug.Assert(_horizScrollBar.Maximum > 0);
                    _horizScrollBar.SmallChange = 1;
                    _horizScrollBar.LargeChange = Math.Max(totalVisibleWidth - totalVisibleFrozenWidth - widthNotVisible, 0);
                    _horizScrollBar.Enabled = Enabled;
                    _horizScrollBar.Bounds = new Rectangle(
                        rightToLeftInternal ? _layout.Inside.X + _layout.ResizeBoxRect.Width : _layout.Inside.X,
                        _layout.Data.Bottom,
                        _layout.Inside.Width - _layout.ResizeBoxRect.Width,
                        _horizScrollBar.Height);
                    _horizScrollBar.Visible = true;
                    _horizScrollBar.Invalidate();
                }
                else
                {
                    _horizScrollBar.Visible = false;
                    HorizontalOffset = 0;

                    _horizScrollBar.Enabled = false;
                    _horizScrollBar.Minimum = 0;
                    _horizScrollBar.Maximum = 1;
                    _horizScrollBar.SmallChange = 1;
                    _horizScrollBar.LargeChange = 1;
                    _horizScrollBar.Value = 0;
                }

                if (needVertScrollbar)
                {
                    int vertScrollBarTop = _layout.Data.Y;
                    int vertScrollBarHeight = _layout.Data.Height;
                    if (_layout.ColumnHeadersVisible)
                    {
                        vertScrollBarTop = _layout.ColumnHeaders.Y;
                        vertScrollBarHeight += _layout.ColumnHeaders.Height;
                    }
                    else if (SingleHorizontalBorderAdded)
                    {
                        vertScrollBarTop--;
                        vertScrollBarHeight++;
                    }

                    _vertScrollBar.Minimum = 0;
                    _vertScrollBar.Maximum = totalVisibleHeight - totalVisibleFrozenHeight;
                    Debug.Assert(_vertScrollBar.Maximum > 0);
                    _vertScrollBar.Value = ComputeHeightOfScrolledOffRows();
                    _vertScrollBar.LargeChange = _layout.Data.Height - totalVisibleFrozenHeight;
                    _vertScrollBar.Bounds = new Rectangle(
                        rightToLeftInternal ? _layout.Data.X - _vertScrollBar.Width : _layout.Data.Right,
                        vertScrollBarTop,
                        _vertScrollBar.Width,
                        vertScrollBarHeight);
                    _vertScrollBar.Enabled = Enabled;
                    _vertScrollBar.Visible = true;
                    _vertScrollBar.Invalidate();

                    VerticalScrollingOffset = _vertScrollBar.Value;
                }
                else
                {
                    _vertScrollBar.Visible = false;
                    VerticalScrollingOffset = ComputeHeightOfScrolledOffRows();

                    _vertScrollBar.Enabled = false;
                    _vertScrollBar.Minimum = 0;
                    _vertScrollBar.Maximum = 1;
                    _vertScrollBar.LargeChange = 1;
                    _vertScrollBar.Value = 0;
                }
            }
            finally
            {
                ResumeLayout(false);
            }
        }

        private void MakeFirstDisplayedCellCurrentCell(bool includeNewRow)
        {
            // No current cell - try to set the first displayed cell to be the current one.
            Point firstDisplayedCellAddress = FirstDisplayedCellAddress;
            if (firstDisplayedCellAddress.X != -1 &&
                (includeNewRow ||
                 !AllowUserToAddRowsInternal ||
                 firstDisplayedCellAddress.Y != Rows.Count - 1))
            {
                bool success = SetAndSelectCurrentCellAddress(firstDisplayedCellAddress.X,
                                                              firstDisplayedCellAddress.Y,
                                                              true /*setAnchorCellAddress*/,
                                                              false /*validateCurrentCell*/,
                                                              false /*throughMouseClick*/,
                                                              true /*clearSelection*/,
                                                              false /*forceCurrentCellSelection (unused)*/);
                Debug.Assert(success);
            }
        }

        private static DataGridViewAutoSizeRowMode MapAutoSizeRowsModeToRowMode(DataGridViewAutoSizeRowsMode autoSizeRowsMode)
        {
            switch (autoSizeRowsMode)
            {
                case DataGridViewAutoSizeRowsMode.AllHeaders:
                    return DataGridViewAutoSizeRowMode.RowHeader;
                case DataGridViewAutoSizeRowsMode.DisplayedHeaders:
                    return DataGridViewAutoSizeRowMode.RowHeader;
                case DataGridViewAutoSizeRowsMode.AllCellsExceptHeaders:
                    return DataGridViewAutoSizeRowMode.AllCellsExceptHeader;
                case DataGridViewAutoSizeRowsMode.DisplayedCellsExceptHeaders:
                    return DataGridViewAutoSizeRowMode.AllCellsExceptHeader;
                case DataGridViewAutoSizeRowsMode.AllCells:
                    return DataGridViewAutoSizeRowMode.AllCells;
                case DataGridViewAutoSizeRowsMode.DisplayedCells:
                    return DataGridViewAutoSizeRowMode.AllCells;
                default:
                    Debug.Fail("Unexpected autoSizeRowsMode value in MapAutoSizeRowsModeToRowMode");
                    return DataGridViewAutoSizeRowMode.RowHeader;
            }
        }

        private void MoveColumnHeadersOrRowResize(MouseEventArgs e)
        {
            _lastRowSplitBar = _currentRowSplitBar;
            _currentRowSplitBar = e.Y;
            Rectangle lastSplitBarRect = CalcRowResizeFeedbackRect(_lastRowSplitBar);
            if (EditingControl != null &&
                !_dataGridViewState1[State1_EditingControlHidden] &&
                _editingPanel.Bounds.IntersectsWith(lastSplitBarRect))
            {
                _editingPanel.Invalidate();
                _editingPanel.Update();
                EditingControl.Invalidate();
                EditingControl.Update();
            }
            Invalidate(lastSplitBarRect);
            Invalidate(CalcRowResizeFeedbackRect(_currentRowSplitBar));
        }

        private void MapDataGridViewColumnToDataBoundField(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(DataSource != null, "this method should only be called when we have a data connection");
            Debug.Assert(dataGridViewColumn.DataPropertyName.Length != 0, "this method should be called only for columns which have DataPropertyName set");
            DataGridViewDataConnection conn = DataConnection;

            int boundColumnIndex = ((conn is null) ? -1 : conn.BoundColumnIndex(dataGridViewColumn.DataPropertyName));
            if (boundColumnIndex != -1)
            {
                dataGridViewColumn.IsDataBoundInternal = true;
                dataGridViewColumn.BoundColumnIndex = boundColumnIndex;
                dataGridViewColumn.BoundColumnConverter = conn.BoundColumnConverter(boundColumnIndex);
                dataGridViewColumn.ValueType = conn.BoundColumnValueType(boundColumnIndex);
                dataGridViewColumn.ReadOnly = conn.DataFieldIsReadOnly(dataGridViewColumn.BoundColumnIndex) || dataGridViewColumn.ReadOnly;
                InvalidateColumnInternal(dataGridViewColumn.Index);

                // Set the Sorting information on the data grid view according to the new DataPropertyName.
                // RefreshColumns() has its own routine for setting the Sorting information so don't do this step
                // if we are in RefreshColumns();
                if (dataGridViewColumn.SortMode != DataGridViewColumnSortMode.NotSortable &&
                    !_dataGridViewOper[OperationInRefreshColumns])
                {
                    dataGridViewColumn.HeaderCell.SortGlyphDirection = conn.BoundColumnSortOrder(boundColumnIndex);
                    if (SortedColumn is null && dataGridViewColumn.HeaderCell.SortGlyphDirection != SortOrder.None)
                    {
                        SortedColumn = dataGridViewColumn;
                        SortOrder = dataGridViewColumn.HeaderCell.SortGlyphDirection;
                        // no need to sort because the back end is already sorted....
                    }
                }
            }
            else
            {
                dataGridViewColumn.IsDataBoundInternal = false;
                dataGridViewColumn.BoundColumnIndex = -1;
                dataGridViewColumn.BoundColumnConverter = null;
                InvalidateColumnInternal(dataGridViewColumn.Index);
            }
        }

        private void MoveColumnRelocation(MouseEventArgs e, HitTestInfo hti)
        {
            _lastHeaderShadow = e.X;
            _dataGridViewState2[State2_ShowColumnRelocationInsertion] = ColumnRelocationTarget(e, hti, out _trackColumnEdge);
            Invalidate(Rectangle.Union(_layout.TopLeftHeader, _layout.ColumnHeaders));
        }

        private void MoveRowHeadersOrColumnResize(int x)
        {
            _lastColSplitBar = _currentColSplitBar;
            _currentColSplitBar = x;
            Rectangle lastSplitBarRect = CalcColResizeFeedbackRect(_lastColSplitBar);
            if (EditingControl != null &&
                !_dataGridViewState1[State1_EditingControlHidden] &&
                _editingPanel.Bounds.IntersectsWith(lastSplitBarRect))
            {
                _editingPanel.Invalidate();
                _editingPanel.Update();
                EditingControl.Invalidate();
                EditingControl.Update();
            }
            Invalidate(lastSplitBarRect);
            Invalidate(CalcColResizeFeedbackRect(_currentColSplitBar));
        }

        public virtual void NotifyCurrentCellDirty(bool dirty)
        {
            if (_dataGridViewState1[State1_IgnoringEditingChanges] == false)
            {
                // autosizing has no effect since edited value hasn't been committed
                // and autosizing code only looks at committed values.

                IsCurrentCellDirtyInternal = dirty;
                if (dirty && EditingControl != null && ((IDataGridViewEditingControl)EditingControl).RepositionEditingControlOnValueChange)
                {
                    PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                }
            }
        }

        internal void OnAddedColumn(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn.Index >= 0);
            Debug.Assert(dataGridViewColumn.DataGridView == this);

            if (dataGridViewColumn.DisplayIndex == -1 || dataGridViewColumn.DisplayIndex >= Columns.Count)
            {
                // Developer did not assign a DisplayIndex or picked a large number.
                // Choose the Index as the DisplayIndex.
                dataGridViewColumn.DisplayIndexInternal = dataGridViewColumn.Index;
                Columns.InvalidateCachedColumnsOrder();
            }

            CorrectColumnDisplayIndexesAfterInsertion(dataGridViewColumn);

            if (dataGridViewColumn.HasHeaderCell)
            {
                dataGridViewColumn.HeaderCell.DataGridView = this;
            }

            AdjustExpandingRows(dataGridViewColumn.Index, false /*fixedWidth*/);
            DataGridViewAutoSizeColumnMode autoSizeColumnMode = dataGridViewColumn.InheritedAutoSizeMode;
            Debug.Assert(autoSizeColumnMode != DataGridViewAutoSizeColumnMode.NotSet);
            bool fixedColumnWidth = autoSizeColumnMode == DataGridViewAutoSizeColumnMode.None ||
                                    autoSizeColumnMode == DataGridViewAutoSizeColumnMode.Fill;
            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                AutoResizeColumnHeadersHeight(dataGridViewColumn.Index, true /*fixedRowHeadersWidth*/, fixedColumnWidth);
            }

            if (!fixedColumnWidth)
            {
                // This is the first time the column autosizes. Save current column width for later reuse.
                dataGridViewColumn.CachedThickness = dataGridViewColumn.Thickness;
                AutoResizeColumnInternal(dataGridViewColumn.Index, (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode, true /*fixedHeight*/);

                if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                {
                    // Second round of column headers autosizing
                    AutoResizeColumnHeadersHeight(dataGridViewColumn.Index, true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
                }
            }

            // Raise the ColumnAdded event
            OnColumnAdded(new DataGridViewColumnEventArgs(dataGridViewColumn));
        }

        internal void OnAddedRow_PreNotification(int rowIndex)
        {
            Debug.Assert(rowIndex >= 0);

            if (AllowUserToAddRowsInternal && NewRowIndex == -1)
            {
                // The added row is necessarily the 'new row'
                // Set the this.newRowIndex variable as early as possible.
                Debug.Assert(rowIndex == Rows.Count - 1);
                NewRowIndex = rowIndex;
            }

            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);

#if DEBUG
            DataGridViewRow dataGridViewRowDebug = Rows.SharedRow(rowIndex);
            foreach (DataGridViewCell dataGridViewCell in dataGridViewRowDebug.Cells)
            {
                Debug.Assert(!dataGridViewCell.Selected);
                Debug.Assert(dataGridViewRowDebug.Index != -1 || !dataGridViewCell.HasValue);
            }
#endif

            // Update this.individualReadOnlyCells
            if ((rowState & DataGridViewElementStates.ReadOnly) == 0 &&
                !ReadOnly)
            {
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                foreach (DataGridViewCell dataGridViewCell in dataGridViewRow.Cells)
                {
                    if (!dataGridViewCell.OwningColumn.ReadOnly && IsSharedCellReadOnly(dataGridViewCell, rowIndex))
                    {
                        _individualReadOnlyCells.Add(dataGridViewCell);
                    }
                }
            }
        }

        internal void OnAddedRow_PostNotification(int rowIndex)
        {
            Debug.Assert(rowIndex >= 0);

            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);

            if ((rowState & DataGridViewElementStates.Visible) != 0)
            {
                bool rowDisplayed = (rowState & DataGridViewElementStates.Displayed) != 0;

                DataGridViewAutoSizeRowsModeInternal autoSizeRowsModeInternal = (DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode;

                bool autoSizeRow = false;
                // Auto size row if needed
                if (autoSizeRowsModeInternal != DataGridViewAutoSizeRowsModeInternal.None &&
                    !((autoSizeRowsModeInternal & DataGridViewAutoSizeRowsModeInternal.DisplayedRows) != 0 && !rowDisplayed))
                {
                    // this call may unshare the row.
                    int rowHeight = Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                    Rows.SharedRow(rowIndex).CachedThickness = rowHeight;
                    AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), false /*fixedWidth*/, true /*internalAutosizing*/);
                    autoSizeRow = true;
                }

                // Auto size columms also if needed
                DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter = DataGridViewAutoSizeColumnCriteriaInternal.AllRows;
                if (rowDisplayed)
                {
                    autoSizeColumnCriteriaFilter |= DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows;
                }
                bool columnAutoSized;
                if (Rows.GetRowCount(DataGridViewElementStates.Visible) > 1)
                {
                    // Columns can only expand, and not collapse.
                    columnAutoSized = AdjustExpandingColumns(autoSizeColumnCriteriaFilter, rowIndex);
                }
                else
                {
                    columnAutoSized = AutoResizeAllVisibleColumnsInternal(autoSizeColumnCriteriaFilter, true /*fixedHeight*/);
                }
                bool fixedColumnHeadersHeight = ColumnHeadersHeightSizeMode != DataGridViewColumnHeadersHeightSizeMode.AutoSize;
                bool rowHeadersAutoSize = _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.EnableResizing &&
                                          _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.DisableResizing;

                if (!rowHeadersAutoSize && !columnAutoSized)
                {
                    // No need to autosize the column headers when the row headers and columns don't change.
                    fixedColumnHeadersHeight = true;
                }

                // Auto size row headers
                if (rowHeadersAutoSize)
                {
                    AutoResizeRowHeadersWidth(rowIndex, _rowHeadersWidthSizeMode, fixedColumnHeadersHeight, true /*fixedRowsHeight*/);
                }

                // Auto size column headers
                if (!fixedColumnHeadersHeight)
                {
                    AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
                }

                if (autoSizeRow)
                {
                    // Second round of row autosizing
                    AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), true /*fixedWidth*/, true /*internalAutosizing*/);
                }

                if (rowHeadersAutoSize && !fixedColumnHeadersHeight)
                {
                    // Second round of row headers autosizing
                    AutoResizeRowHeadersWidth(rowIndex, _rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, true /*fixedRowsHeight*/);
                }
            }
        }

        internal void OnAddedRows_PreNotification(DataGridViewRow[] dataGridViewRows)
        {
            // Note: no row can be added that breaks the frozen row packing on the top

            foreach (DataGridViewRow dataGridViewRow in dataGridViewRows)
            {
                OnAddedRow_PreNotification(dataGridViewRow.Index);
            }
        }

        internal void OnAddedRows_PostNotification(DataGridViewRow[] dataGridViewRows)
        {
            foreach (DataGridViewRow dataGridViewRow in dataGridViewRows)
            {
                OnAddedRow_PostNotification(dataGridViewRow.Index);
            }
        }

        internal void OnAddingColumn(DataGridViewColumn dataGridViewColumn)
        {
            // throw an exception if the column to be added breaks the rules
            if (dataGridViewColumn is null)
            {
                throw new ArgumentNullException(nameof(dataGridViewColumn));
            }
            if (dataGridViewColumn.DataGridView != null)
            {
                throw new InvalidOperationException(SR.DataGridView_ColumnAlreadyBelongsToDataGridView);
            }

            if (!InInitialization &&
                dataGridViewColumn.SortMode == DataGridViewColumnSortMode.Automatic &&
                (SelectionMode == DataGridViewSelectionMode.FullColumnSelect ||
                 SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect))
            {
                throw new InvalidOperationException(string.Format(SR.DataGridViewColumn_SortModeAndSelectionModeClash, DataGridViewColumnSortMode.Automatic.ToString(), SelectionMode.ToString()));
            }

            if (dataGridViewColumn.Visible)
            {
                // Note that dataGridViewColumn.DataGridView is set later on, so dataGridViewColumn.InheritedAutoSizeMode should not be used

                // Make sure the column does not autosize based only on header while column headers are invisible
                if (!ColumnHeadersVisible &&
                    (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.ColumnHeader || (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.NotSet && AutoSizeColumnsMode == DataGridViewAutoSizeColumnsMode.ColumnHeader)))
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddAutoSizedColumn);
                }

                // Make sure the column is not frozen and auto fills
                if (dataGridViewColumn.Frozen &&
                    (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.Fill || (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.NotSet && AutoSizeColumnsMode == DataGridViewAutoSizeColumnsMode.Fill)))
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddAutoFillColumn);
                }

                // UsedFillWeight values need to be updated
                _dataGridViewState2[State2_UsedFillWeightsDirty] = true;
            }

            // Make sure the sum of the column weights does not exceed ushort.MaxValue
            float weightSum = Columns.GetColumnsFillWeight(DataGridViewElementStates.None) + dataGridViewColumn.FillWeight;
            if (weightSum > (float)ushort.MaxValue)
            {
                throw new InvalidOperationException(string.Format(SR.DataGridView_WeightSumCannotExceedLongMaxValue, ushort.MaxValue));
            }

            // check for correctness of frozen state - throws exception if state is incorrect.
            CorrectColumnFrozenState(dataGridViewColumn, Columns.Count);

            // prepare the existing rows by appending cells of correct type
            if (Rows.Count > 0)
            {
                // Only require a default cell type when there are rows to fill
                if (dataGridViewColumn.CellType is null)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddUntypedColumn);
                }

                if (dataGridViewColumn.CellTemplate.DefaultNewRowValue != null && NewRowIndex != -1)
                {
                    // New row needs to be unshared before addition of new cell with a Value != null
                    DataGridViewRow newRow = Rows[NewRowIndex];
                }

                int newColumnCount = Columns.Count + 1;

                try
                {
                    for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
                    {
                        DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                        if (dataGridViewRow.Cells.Count < newColumnCount)
                        {
                            DataGridViewCell dataGridViewCellNew = (DataGridViewCell)dataGridViewColumn.CellTemplate.Clone();
                            dataGridViewRow.Cells.AddInternal(dataGridViewCellNew);
                            if (rowIndex == NewRowIndex)
                            {
                                dataGridViewCellNew.SetValueInternal(rowIndex, dataGridViewCellNew.DefaultNewRowValue);
                            }
                            dataGridViewCellNew.DataGridView = this;
                            dataGridViewCellNew.OwningRow = dataGridViewRow;
                            dataGridViewCellNew.OwningColumn = dataGridViewColumn;

                            KeyboardToolTipStateMachine.Instance.Hook(dataGridViewCellNew, KeyboardToolTip);
                        }
                    }
                }
                catch
                {
                    for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
                    {
                        DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                        if (dataGridViewRow.Cells.Count == newColumnCount)
                        {
                            dataGridViewRow.Cells.RemoveAtInternal(newColumnCount - 1);
                        }
                        else
                        {
                            Debug.Assert(dataGridViewRow.Cells.Count < newColumnCount);
                            break;
                        }
                    }
                    throw;
                }
            }
        }

        internal void OnAddingColumns(DataGridViewColumn[] dataGridViewColumns)
        {
            // Make sure the sum of the column weights does not exceed ushort.MaxValue
            float weightSum = Columns.GetColumnsFillWeight(DataGridViewElementStates.None);
            Debug.Assert(weightSum <= (float)ushort.MaxValue);

            // throw an exception if any of the columns to be added breaks the rules
            Debug.Assert(dataGridViewColumns != null);
            foreach (DataGridViewColumn dataGridViewColumn in dataGridViewColumns)
            {
                if (dataGridViewColumn is null)
                {
                    throw new InvalidOperationException(SR.DataGridView_AtLeastOneColumnIsNull);
                }
                if (dataGridViewColumn.DataGridView != null)
                {
                    throw new InvalidOperationException(SR.DataGridView_ColumnAlreadyBelongsToDataGridView);
                }
                // Only require a default cell type when there are rows to fill
                if (Rows.Count > 0 && dataGridViewColumn.CellType is null)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddUntypedColumn);
                }

                if (!InInitialization &&
                    dataGridViewColumn.SortMode == DataGridViewColumnSortMode.Automatic &&
                    (SelectionMode == DataGridViewSelectionMode.FullColumnSelect ||
                     SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect))
                {
                    throw new InvalidOperationException(string.Format(SR.DataGridViewColumn_SortModeAndSelectionModeClash, DataGridViewColumnSortMode.Automatic.ToString(), SelectionMode.ToString()));
                }

                if (dataGridViewColumn.Visible)
                {
                    // Note that dataGridViewColumn.DataGridView is set later on, so dataGridViewColumn.InheritedAutoSizeMode should not be used

                    // Make sure the column does not autosize based only on header while column headers are invisible
                    if (!ColumnHeadersVisible &&
                        (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.ColumnHeader || (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.NotSet && AutoSizeColumnsMode == DataGridViewAutoSizeColumnsMode.ColumnHeader)))
                    {
                        throw new InvalidOperationException(SR.DataGridView_CannotAddAutoSizedColumn);
                    }

                    // Make sure the column is not frozen and auto fills
                    if (dataGridViewColumn.Frozen &&
                        (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.Fill || (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.NotSet && AutoSizeColumnsMode == DataGridViewAutoSizeColumnsMode.Fill)))
                    {
                        throw new InvalidOperationException(SR.DataGridView_CannotAddAutoFillColumn);
                    }

                    // UsedFillWeight values need to be updated
                    _dataGridViewState2[State2_UsedFillWeightsDirty] = true;
                }

                weightSum += dataGridViewColumn.FillWeight;
                if (weightSum > (float)ushort.MaxValue)
                {
                    throw new InvalidOperationException(string.Format(SR.DataGridView_WeightSumCannotExceedLongMaxValue, ushort.MaxValue));
                }
            }

            Debug.Assert(weightSum <= (float)ushort.MaxValue);

            // make sure no two columns are identical
            int columnCount = dataGridViewColumns.Length;
            for (int column1 = 0; column1 < columnCount - 1; column1++)
            {
                for (int column2 = column1 + 1; column2 < columnCount; column2++)
                {
                    if (dataGridViewColumns[column1] == dataGridViewColumns[column2])
                    {
                        throw new InvalidOperationException(SR.DataGridView_CannotAddIdenticalColumns);
                    }
                }
            }

            // check for correctness of frozen states - throws exception if any state is incorrect.
            CorrectColumnFrozenStates(dataGridViewColumns);

            // prepare the existing rows by appending cells of correct type
            if (Rows.Count > 0)
            {
                foreach (DataGridViewColumn dataGridViewColumn in dataGridViewColumns)
                {
                    Debug.Assert(dataGridViewColumn.CellType != null);
                    if (dataGridViewColumn.CellTemplate.DefaultNewRowValue != null && NewRowIndex != -1)
                    {
                        // New row needs to be unshared before addition of new cell with a Value != null
                        DataGridViewRow newRow = Rows[NewRowIndex];
                        break;
                    }
                }

                int previousColumnCount = Columns.Count;
                int addedColumnCount = 0;

                try
                {
                    foreach (DataGridViewColumn dataGridViewColumn in dataGridViewColumns)
                    {
                        addedColumnCount++;
                        Debug.Assert(dataGridViewColumn.CellType != null);
                        for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
                        {
                            DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                            if (dataGridViewRow.Cells.Count < previousColumnCount + addedColumnCount)
                            {
                                DataGridViewCell dataGridViewCellNew = (DataGridViewCell)dataGridViewColumn.CellTemplate.Clone();
                                int indexCell = dataGridViewRow.Cells.AddInternal(dataGridViewCellNew);
                                if (rowIndex == NewRowIndex)
                                {
                                    dataGridViewCellNew.Value = dataGridViewCellNew.DefaultNewRowValue;
                                }
                                dataGridViewCellNew.DataGridView = this;
                                dataGridViewCellNew.OwningRow = dataGridViewRow;
                                dataGridViewCellNew.OwningColumn = dataGridViewColumn;
                            }
                        }
                    }
                }
                catch
                {
                    for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
                    {
                        DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                        while (dataGridViewRow.Cells.Count > previousColumnCount)
                        {
                            dataGridViewRow.Cells.RemoveAtInternal(dataGridViewRow.Cells.Count - 1);
                        }
                    }
                    throw;
                }
            }
        }

        internal void OnAddingRow(DataGridViewRow dataGridViewRow, DataGridViewElementStates rowState, bool checkFrozenState)
        {
            // Note dataGridViewRow.DataGridView != null for duplication of shared rows.

            // throw an exception if the row to be added breaks the rules
            if (dataGridViewRow is null)
            {
                throw new ArgumentNullException(nameof(dataGridViewRow));
            }

            // !Do not check for dataGridViewRow.Selected flag. Caller does it instead!
            // !Do not check for dataGridViewRow.DataGridView != null. Caller does it instead!

            if (checkFrozenState)
            {
                // check for correctness of frozen state - throws exception if state is incorrect.
                CorrectRowFrozenState(dataGridViewRow, rowState, Rows.Count);
            }

            if (ReadOnly && dataGridViewRow.DataGridView is null && dataGridViewRow.ReadOnly)
            {
                // Clear the superfluous flag since the whole dataGridView is read-only
                dataGridViewRow.ReadOnly = false;
            }

            int columnIndex = 0;
            foreach (DataGridViewColumn dataGridViewColumn in Columns)
            {
                DataGridViewCell dataGridViewCell = dataGridViewRow.Cells[columnIndex];
                if ((ReadOnly || dataGridViewColumn.ReadOnly) && dataGridViewCell.StateIncludes(DataGridViewElementStates.ReadOnly))
                {
                    // Clear superfluous flag since the whole dataGridView or column is ReadOnly
                    dataGridViewCell.ReadOnlyInternal = false;
                }

                KeyboardToolTipStateMachine.Instance.Hook(dataGridViewCell, KeyboardToolTip);
                columnIndex++;
            }
        }

        internal void OnAddingRows(DataGridViewRow[] dataGridViewRows, bool checkFrozenStates)
        {
            // throw an exception if any of the rows to be added breaks the rules
            Debug.Assert(dataGridViewRows != null);

            foreach (DataGridViewRow dataGridViewRow in dataGridViewRows)
            {
                if (dataGridViewRow is null)
                {
                    throw new InvalidOperationException(SR.DataGridView_AtLeastOneRowIsNull);
                }

                if (dataGridViewRow.DataGridView != null)
                {
                    throw new InvalidOperationException(SR.DataGridView_RowAlreadyBelongsToDataGridView);
                }

                if (dataGridViewRow.Selected)
                {
                    throw new InvalidOperationException(SR.DataGridViewRowCollection_CannotAddOrInsertSelectedRow);
                }

                if (dataGridViewRow.Cells.Count > Columns.Count)
                {
                    throw new InvalidOperationException(SR.DataGridViewRowCollection_TooManyCells);
                }
            }

            // make sure no two rows are identical
            int rowCount = dataGridViewRows.Length;
            for (int row1 = 0; row1 < rowCount - 1; row1++)
            {
                for (int row2 = row1 + 1; row2 < rowCount; row2++)
                {
                    if (dataGridViewRows[row1] == dataGridViewRows[row2])
                    {
                        throw new InvalidOperationException(SR.DataGridView_CannotAddIdenticalRows);
                    }
                }
            }

            if (checkFrozenStates)
            {
                Debug.Assert(!AllowUserToAddRowsInternal);
                CorrectRowFrozenStates(dataGridViewRows, Rows.Count /*rowIndexInserted*/);
            }

            foreach (DataGridViewRow dataGridViewRow in dataGridViewRows)
            {
                CompleteCellsCollection(dataGridViewRow);
                OnAddingRow(dataGridViewRow, dataGridViewRow.State, false /*checkFrozenState*/);
            }
        }

        internal void OnAdvancedBorderStyleChanged(DataGridViewAdvancedBorderStyle dgvabs)
        {
            if (!_dataGridViewOper[OperationInBorderStyleChange])
            {
                if (dgvabs == AdvancedCellBorderStyle)
                {
                    OnCellBorderStyleChanged(EventArgs.Empty);
                }
                else if (dgvabs == AdvancedColumnHeadersBorderStyle)
                {
                    OnColumnHeadersBorderStyleChanged(EventArgs.Empty);
                }
                else if (dgvabs == AdvancedRowHeadersBorderStyle)
                {
                    OnRowHeadersBorderStyleChanged(EventArgs.Empty);
                }
            }
        }

        protected virtual void OnAllowUserToAddRowsChanged(EventArgs e)
        {
            PushAllowUserToAddRows();

            if (Events[s_allowUserToAddRowsChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAllowUserToDeleteRowsChanged(EventArgs e)
        {
            if (Events[s_allowUserToDeleteRowsChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAllowUserToOrderColumnsChanged(EventArgs e)
        {
            if (Events[s_allowUserToOrderColumnsChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAllowUserToResizeColumnsChanged(EventArgs e)
        {
            if (Events[s_allowUserToResizeColumnsChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAllowUserToResizeRowsChanged(EventArgs e)
        {
            if (Events[s_allowUserToResizeRowsChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAlternatingRowsDefaultCellStyleChanged(EventArgs e)
        {
            if (e is DataGridViewCellStyleChangedEventArgs dgvcsce && !dgvcsce.ChangeAffectsPreferredSize)
            {
                InvalidateData();
            }
            else
            {
                OnRowsGlobalAutoSize();
                if (EditingControl != null)
                {
                    PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                }
            }

            if (Events[s_alternatingRowsDefaultCellStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAutoGenerateColumnsChanged(EventArgs e)
        {
            if (AutoGenerateColumns && DataSource != null)
            {
                // refresh the list of columns and the rows
                RefreshColumnsAndRows();
            }
            if (Events[s_autoGenerateColumnsChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnAutoSizeColumnModeChanged(DataGridViewColumn dataGridViewColumn, DataGridViewAutoSizeColumnMode previousInheritedMode)
        {
            Debug.Assert(dataGridViewColumn != null);
            DataGridViewAutoSizeColumnModeEventArgs dgvascme = new DataGridViewAutoSizeColumnModeEventArgs(dataGridViewColumn, previousInheritedMode);
            OnAutoSizeColumnModeChanged(dgvascme);
        }

        protected virtual void OnAutoSizeColumnModeChanged(DataGridViewAutoSizeColumnModeEventArgs e)
        {
            DataGridViewColumn dataGridViewColumn = e.Column;
            if (e.Column is null)
            {
                throw new InvalidOperationException(string.Format(SR.InvalidNullArgument, "e.Column"));
            }
            DataGridViewAutoSizeColumnMode autoSizeColumnMode = dataGridViewColumn.InheritedAutoSizeMode;
            Debug.Assert(autoSizeColumnMode != DataGridViewAutoSizeColumnMode.NotSet);

            DataGridViewAutoSizeColumnMode previousInheritedMode = e.PreviousMode;
            bool previousInheritedModeAutoSized = previousInheritedMode != DataGridViewAutoSizeColumnMode.Fill &&
                                                  previousInheritedMode != DataGridViewAutoSizeColumnMode.None &&
                                                  previousInheritedMode != DataGridViewAutoSizeColumnMode.NotSet;

            if (autoSizeColumnMode == DataGridViewAutoSizeColumnMode.Fill ||
                previousInheritedMode == DataGridViewAutoSizeColumnMode.Fill)
            {
                // UsedFillWeight values need to be updated
                _dataGridViewState2[State2_UsedFillWeightsDirty] = true;
            }

            bool fixedHeight = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) == 0;

            if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.None)
            {
                if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.Fill)
                {
                    if (!previousInheritedModeAutoSized)
                    {
                        // Save current column width for later reuse
                        dataGridViewColumn.CachedThickness = dataGridViewColumn.Thickness;
                    }
                    AutoResizeColumnInternal(dataGridViewColumn.Index,
                                             (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode,
                                             fixedHeight);
                }
            }
            else if (dataGridViewColumn.Thickness != dataGridViewColumn.CachedThickness && previousInheritedModeAutoSized)
            {
                // Restoring cached column width
                dataGridViewColumn.ThicknessInternal = Math.Max(dataGridViewColumn.MinimumWidth, dataGridViewColumn.CachedThickness);
            }

            // Auto fill columns if needed
            PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);

            // Autosize rows and column headers if needed
            if (!fixedHeight)
            {
                AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                {
                    AutoResizeColumnHeadersHeight(dataGridViewColumn.Index, true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
                }

                // Column gets autosized with 1 degree of freedom this time.
                if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.None && autoSizeColumnMode != DataGridViewAutoSizeColumnMode.Fill)
                {
                    AutoResizeColumnInternal(dataGridViewColumn.Index,
                                             (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode,
                                             true /*fixedHeight*/);
                }
            }

            if (Events[s_autosizeColumnModeChangedEvent] is DataGridViewAutoSizeColumnModeEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAutoSizeColumnsModeChanged(DataGridViewAutoSizeColumnsModeEventArgs e)
        {
            DataGridViewAutoSizeColumnMode[] previousModes = e.PreviousModes;
            if (previousModes is null)
            {
                throw new ArgumentNullException(nameof(e.PreviousModes));
            }
            if (previousModes.Length != Columns.Count)
            {
                throw new ArgumentException(SR.DataGridView_PreviousModesHasWrongLength);
            }

            foreach (DataGridViewColumn dataGridViewColumn in Columns)
            {
                if (dataGridViewColumn.Visible)
                {
                    DataGridViewAutoSizeColumnMode autoSizeColumnMode = dataGridViewColumn.InheritedAutoSizeMode;
                    Debug.Assert(autoSizeColumnMode != DataGridViewAutoSizeColumnMode.NotSet);
                    DataGridViewAutoSizeColumnMode previousInheritedMode = previousModes[dataGridViewColumn.Index];
                    bool previousInheritedModeAutoSized = previousInheritedMode != DataGridViewAutoSizeColumnMode.Fill &&
                                                          previousInheritedMode != DataGridViewAutoSizeColumnMode.None &&
                                                          previousInheritedMode != DataGridViewAutoSizeColumnMode.NotSet;
                    if (autoSizeColumnMode == DataGridViewAutoSizeColumnMode.Fill ||
                        previousInheritedMode == DataGridViewAutoSizeColumnMode.Fill)
                    {
                        // UsedFillWeight values need to be updated
                        _dataGridViewState2[State2_UsedFillWeightsDirty] = true;
                    }

                    if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.None)
                    {
                        if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.Fill)
                        {
                            if (!previousInheritedModeAutoSized)
                            {
                                // Save current column width for later reuse
                                dataGridViewColumn.CachedThickness = dataGridViewColumn.Thickness;
                            }
                            AutoResizeColumnInternal(dataGridViewColumn.Index,
                                                     (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode,
                                                     (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) == 0 /*fixedHeight*/);
                        }
                    }
                    else if (dataGridViewColumn.Thickness != dataGridViewColumn.CachedThickness && previousInheritedModeAutoSized)
                    {
                        // Restoring cached column width
                        dataGridViewColumn.ThicknessInternal = Math.Max(dataGridViewColumn.MinimumWidth, dataGridViewColumn.CachedThickness);
                    }
                }
            }

            // Auto fill columns if needed
            PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);

            // Autosize rows and column headers if needed
            if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
            {
                AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                {
                    AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
                }

                // Second pass of column autosizing with 1 degree of freedom
                foreach (DataGridViewColumn dataGridViewColumn in Columns)
                {
                    DataGridViewAutoSizeColumnMode autoSizeColumnMode = dataGridViewColumn.InheritedAutoSizeMode;
                    Debug.Assert(autoSizeColumnMode != DataGridViewAutoSizeColumnMode.NotSet);

                    if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.None && autoSizeColumnMode != DataGridViewAutoSizeColumnMode.Fill)
                    {
                        AutoResizeColumnInternal(dataGridViewColumn.Index,
                                                 (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode,
                                                 true /*fixedHeight*/);
                    }
                }
            }

            if (Events[s_autosizeColumnsModeChangedEvent] is DataGridViewAutoSizeColumnsModeEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnAutoSizeRowsModeChanged(DataGridViewAutoSizeModeEventArgs e)
        {
            if (_autoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
            {
                // restore cached rows thickness
                RestoreRowsCachedThickness();
            }
            else
            {
                if (!e.PreviousModeAutoSized)
                {
                    // Save the rows thickness for later reuse
                    // Note that only visible rows are affected, contrary to columns in OnAutoSizeColumnsModeChanged where all columns are affected.
                    for (int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                        rowIndex != -1;
                        rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                    {
                        // this call may unshare the row.
                        int rowHeight = Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                        Rows.SharedRow(rowIndex).CachedThickness = rowHeight;
                    }
                }
                AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
            }

            if (Events[s_autosizeRowsModeChangedEvent] is DataGridViewAutoSizeModeEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnBackgroundColorChanged(EventArgs e)
        {
            InvalidateInside();

            if (Events[s_backgroundColorChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnBandContextMenuStripChanged(DataGridViewBand dataGridViewBand)
        {
            if (dataGridViewBand is DataGridViewColumn dataGridViewColumn)
            {
                DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
                OnColumnContextMenuStripChanged(dgvce);
            }
            else
            {
                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs((DataGridViewRow)dataGridViewBand);
                OnRowContextMenuStripChanged(dgvre);
            }
        }

        internal void OnBandDefaultCellStyleChanged(DataGridViewBand dataGridViewBand)
        {
            if (dataGridViewBand is DataGridViewColumn dataGridViewColumn)
            {
                DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
                OnColumnDefaultCellStyleChanged(dgvce);
            }
            else
            {
                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs((DataGridViewRow)dataGridViewBand);
                OnRowDefaultCellStyleChanged(dgvre);
            }
        }

        internal void OnBandDividerThicknessChanged(DataGridViewBand dataGridViewBand)
        {
            if (dataGridViewBand is DataGridViewColumn dataGridViewColumn)
            {
                DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
                OnColumnDividerWidthChanged(dgvce);
            }
            else
            {
                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs((DataGridViewRow)dataGridViewBand);
                OnRowDividerHeightChanged(dgvre);
            }
        }

        internal void OnBandHeaderCellChanged(DataGridViewBand dataGridViewBand)
        {
            if (dataGridViewBand is DataGridViewColumn dataGridViewColumn)
            {
                DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
                OnColumnHeaderCellChanged(dgvce);
            }
            else
            {
                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs((DataGridViewRow)dataGridViewBand);
                OnRowHeaderCellChanged(dgvre);
            }
        }

        internal void OnBandMinimumThicknessChanged(DataGridViewBand dataGridViewBand)
        {
            if (dataGridViewBand is DataGridViewColumn dataGridViewColumn)
            {
                DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
                OnColumnMinimumWidthChanged(dgvce);
            }
            else
            {
                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs((DataGridViewRow)dataGridViewBand);
                OnRowMinimumHeightChanged(dgvre);
            }
        }

        internal void OnBandThicknessChanged(DataGridViewBand dataGridViewBand)
        {
            if (dataGridViewBand is DataGridViewColumn dataGridViewColumn)
            {
                DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
                OnColumnWidthChanged(dgvce);
            }
            else
            {
                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs((DataGridViewRow)dataGridViewBand);
                OnRowHeightChanged(dgvre);
            }
        }

        internal void OnBandThicknessChanging()
        {
            if (InAdjustFillingColumns)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAlterAutoFillColumnParameter);
            }
        }

        protected override void OnBindingContextChanged(EventArgs e)
        {
            if (_dataGridViewState2[State2_InBindingContextChanged])
            {
                return;
            }

            _dataGridViewState2[State2_InBindingContextChanged] = true;
            try
            {
                if (DataConnection != null)
                {
                    CurrentCell = null;
                    try
                    {
                        DataConnection.SetDataConnection(DataSource, DataMember);
                    }
                    catch (ArgumentException)
                    {
                        if (DesignMode)
                        {
                            // If the DataMember became invalid at DesignTime then set it to String.Empty,
                            // regenerate the column collection and DO NOT send BindingContextChanged event.
                            DataMember = string.Empty;
                            RefreshColumnsAndRows();
                            return;
                        }
                        else
                        {
                            throw;
                        }
                    }
                    RefreshColumnsAndRows();
                    base.OnBindingContextChanged(e);
                    if (DataConnection.CurrencyManager != null)
                    {
                        OnDataBindingComplete(ListChangedType.Reset);
                    }
                }
                else
                {
                    base.OnBindingContextChanged(e);
                }
            }
            finally
            {
                _dataGridViewState2[State2_InBindingContextChanged] = false;
            }
        }

        protected virtual void OnBorderStyleChanged(EventArgs e)
        {
            if (Events[s_borderStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCancelRowEdit(QuestionEventArgs e)
        {
            if (Events[s_cancelRowEditEvent] is QuestionEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
                CorrectFocus(true /*onlyIfGridHasFocus*/);
            }
        }

        protected virtual void OnCellBeginEdit(DataGridViewCellCancelEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellBeginEditEvent] is DataGridViewCellCancelEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCellBorderStyleChanged(EventArgs e)
        {
            PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            Invalidate();

            if (Events[s_cellBorderStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellClickInternal(DataGridViewCellEventArgs e)
        {
            OnCellClick(e);
        }

        protected virtual void OnCellClick(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.ClickUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnClickInternal(e);
            }
            else
            {
                dataGridViewCell.OnClickInternal(e);
            }

            if (Events[s_cellClickEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellCommonChange(int columnIndex, int rowIndex)
        {
            if (columnIndex == -1)
            {
                // row or topleft header characteristic has changed
                OnRowHeaderGlobalAutoSize(rowIndex);
            }
            else
            {
                if (rowIndex == -1)
                {
                    // column header characteristic has changed
                    OnColumnHeaderGlobalAutoSize(columnIndex);
                }
                else
                {
                    // regular cell characteristic changed
                    InvalidateCellPrivate(columnIndex, rowIndex);

                    bool rowDisplayed = false;
                    if (rowIndex != -1)
                    {
                        rowDisplayed = (Rows.GetRowState(rowIndex) & DataGridViewElementStates.Displayed) != 0;
                    }

                    DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal = (DataGridViewAutoSizeColumnCriteriaInternal)Columns[columnIndex].InheritedAutoSizeMode;
                    bool autoSizeColumn = (autoSizeColumnCriteriaInternal & DataGridViewAutoSizeColumnCriteriaInternal.AllRows) != 0;
                    if (rowDisplayed)
                    {
                        autoSizeColumn |= (autoSizeColumnCriteriaInternal & DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows) != 0;
                    }

                    bool autoSizeRow = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0;
                    if (autoSizeRow)
                    {
                        AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), !autoSizeColumn /*fixedWidth*/, true /*internalAutosizing*/);
                    }
                    if (autoSizeColumn)
                    {
                        AutoResizeColumnInternal(columnIndex, autoSizeColumnCriteriaInternal, true /*fixedHeight*/);
                        if (autoSizeRow)
                        {
                            // Second round of row autosizing with 1 degree of freedom.
                            AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), true /*fixedWidth*/, true /*internalAutosizing*/);
                        }
                    }
                }
            }
        }

        internal void OnCellContentClickInternal(DataGridViewCellEventArgs e)
        {
            OnCellContentClick(e);
        }

        protected virtual void OnCellContentClick(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.ContentClickUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnContentClickInternal(e);
            }
            else
            {
                dataGridViewCell.OnContentClickInternal(e);
            }

            if (Events[s_cellContentClickEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellContentDoubleClickInternal(DataGridViewCellEventArgs e)
        {
            OnCellContentDoubleClick(e);
        }

        protected virtual void OnCellContentDoubleClick(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.ContentDoubleClickUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnContentDoubleClickInternal(e);
            }
            else
            {
                dataGridViewCell.OnContentDoubleClickInternal(e);
            }

            if (Events[s_cellContentDoubleClickEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellContextMenuStripChanged(DataGridViewCell dataGridViewCell)
        {
            DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(dataGridViewCell);
            OnCellContextMenuStripChanged(dgvce);
        }

        protected virtual void OnCellContextMenuStripChanged(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellContextMenuStripChangedEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal ContextMenuStrip OnCellContextMenuStripNeeded(int columnIndex, int rowIndex, ContextMenuStrip contextMenuStrip)
        {
            DataGridViewCellContextMenuStripNeededEventArgs dgvccmsne = new DataGridViewCellContextMenuStripNeededEventArgs(columnIndex, rowIndex, contextMenuStrip);
            OnCellContextMenuStripNeeded(dgvccmsne);
            return dgvccmsne.ContextMenuStrip;
        }

        protected virtual void OnCellContextMenuStripNeeded(DataGridViewCellContextMenuStripNeededEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellContextMenuStripNeededEvent] is DataGridViewCellContextMenuStripNeededEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCellDoubleClick(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.DoubleClickUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnDoubleClickInternal(e);
            }
            else
            {
                dataGridViewCell.OnDoubleClickInternal(e);
            }

            if (Events[s_cellDoubleClickEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCellEndEdit(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellEndEditEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellEnter(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex)
        {
            OnCellEnter(new DataGridViewCellEventArgs(columnIndex, rowIndex));
            if (dataGridViewCell != null)
            {
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    dataGridViewCell = null;
                }
                else
                {
                    Debug.Assert(rowIndex < Rows.Count && columnIndex < Columns.Count);
                    dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                }
            }
        }

        protected virtual void OnCellEnter(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            try
            {
                _noDimensionChangeCount++;

                if (Events[s_cellEnterEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
            }
        }

        internal void OnCellErrorTextChanged(DataGridViewCell dataGridViewCell)
        {
            Debug.Assert(dataGridViewCell.RowIndex >= -1);
            Debug.Assert(dataGridViewCell.ColumnIndex >= -1);
            DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(dataGridViewCell);
            OnCellErrorTextChanged(dgvce);
        }

        protected virtual void OnCellErrorTextChanged(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            UpdateCellErrorText(e.ColumnIndex, e.RowIndex);

            if (Events[s_cellErrorTextChangedEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal string OnCellErrorTextNeeded(int columnIndex, int rowIndex, string errorText)
        {
            Debug.Assert(columnIndex >= 0);
            Debug.Assert(rowIndex >= 0);
            DataGridViewCellErrorTextNeededEventArgs dgvcetne = new DataGridViewCellErrorTextNeededEventArgs(columnIndex, rowIndex, errorText);
            OnCellErrorTextNeeded(dgvcetne);
            return dgvcetne.ErrorText;
        }

        protected virtual void OnCellErrorTextNeeded(DataGridViewCellErrorTextNeededEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellErrorTextNeededEvent] is DataGridViewCellErrorTextNeededEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal DataGridViewCellFormattingEventArgs OnCellFormatting(int columnIndex, int rowIndex, object val, Type formattedValueType, DataGridViewCellStyle cellStyle)
        {
            DataGridViewCellFormattingEventArgs dgvcfe = new DataGridViewCellFormattingEventArgs(columnIndex,
                                                                                                 rowIndex,
                                                                                                 val,
                                                                                                 formattedValueType,
                                                                                                 cellStyle);
            OnCellFormatting(dgvcfe);
            return dgvcfe;
        }

        protected virtual void OnCellFormatting(DataGridViewCellFormattingEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellFormattingEvent] is DataGridViewCellFormattingEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellLeave(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex)
        {
            OnCellLeave(new DataGridViewCellEventArgs(columnIndex, rowIndex));
            if (dataGridViewCell != null)
            {
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    dataGridViewCell = null;
                }
                else
                {
                    Debug.Assert(rowIndex < Rows.Count && columnIndex < Columns.Count);
                    dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                }
            }
        }

        protected virtual void OnCellLeave(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            try
            {
                _noDimensionChangeCount++;

                if (Events[s_cellLeaveEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
            }
        }

        protected virtual void OnCellMouseClick(DataGridViewCellMouseEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.MouseClickUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnMouseClickInternal(e);
            }
            else
            {
                dataGridViewCell.OnMouseClickInternal(e);
            }
            _dataGridViewState2[State2_NextMouseUpIsDouble] = false;

            if (Events[s_cellMouseClickEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCellMouseDoubleClick(DataGridViewCellMouseEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.MouseDoubleClickUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnMouseDoubleClickInternal(e);
            }
            else
            {
                dataGridViewCell.OnMouseDoubleClickInternal(e);
            }
            _dataGridViewState2[State2_NextMouseUpIsDouble] = true;

            if (Events[s_cellMouseDoubleClickEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCellMouseDown(DataGridViewCellMouseEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }

            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);

            // Only left clicks for now
            Keys nModifier = ModifierKeys;
            bool isControlDown = (nModifier & Keys.Control) == Keys.Control && (nModifier & Keys.Alt) == 0;
            bool isShiftDown = (nModifier & Keys.Shift) == Keys.Shift;
            bool isAltDown = (nModifier & Keys.Alt) == Keys.Alt;

            Point ptGridCoord = ConvertCellToGridCoord(e.ColumnIndex, e.RowIndex, e.X, e.Y);

            HitTestInfo hti = HitTest(ptGridCoord.X, ptGridCoord.Y);

            if (!_dataGridViewState2[State2_MessageFromEditingCtrls] && e.Button == MouseButtons.Left)
            {
                Debug.Assert(hti.Type != DataGridViewHitTestType.None &&
                             hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                             hti.Type != DataGridViewHitTestType.VerticalScrollBar);
                Debug.Assert(_ptMouseDownCell.X == hti._col);
                Debug.Assert(_ptMouseDownCell.Y == hti._row);

                switch (hti._typeInternal)
                {
                    // Check for column/row (headers) resize
                    case DataGridViewHitTestTypeInternal.ColumnResizeLeft:
                    case DataGridViewHitTestTypeInternal.ColumnResizeRight:
                    case DataGridViewHitTestTypeInternal.RowResizeBottom:
                    case DataGridViewHitTestTypeInternal.RowResizeTop:
                    case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeLeft:
                    case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeRight:
                    case DataGridViewHitTestTypeInternal.RowHeadersResizeLeft:
                    case DataGridViewHitTestTypeInternal.RowHeadersResizeRight:
                    case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeTop:
                    case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeBottom:
                    case DataGridViewHitTestTypeInternal.ColumnHeadersResizeTop:
                    case DataGridViewHitTestTypeInternal.ColumnHeadersResizeBottom:
                        {
                            _dataGridViewOper[OperationResizingOperationAboutToStart] = (e.Clicks == 1);
                            break;
                        }
                }
            }

            try
            {
                if (e.RowIndex >= 0 && dataGridViewCell.MouseDownUnsharesRowInternal(e))
                {
                    DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                    GetCellInternal(e.ColumnIndex, e.RowIndex).OnMouseDownInternal(e);
                }
                else
                {
                    dataGridViewCell.OnMouseDownInternal(e);
                }

                if (Events[s_cellMouseDownEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                }

                if (!_dataGridViewState2[State2_MessageFromEditingCtrls] && e.Button == MouseButtons.Left)
                {
                    switch (hti._typeInternal)
                    {
                        // Check column resize
                        case DataGridViewHitTestTypeInternal.ColumnResizeLeft:
                        case DataGridViewHitTestTypeInternal.ColumnResizeRight:
                            {
                                int columnIndex = (hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnResizeRight) ? hti._col : hti._adjacentCol;
                                Debug.Assert(Columns[columnIndex].Resizable == DataGridViewTriState.True);
                                if (e.Clicks == 1)
                                {
                                    BeginMouseColumnResize(ptGridCoord.X, hti._mouseBarOffset, columnIndex);
                                }
                                break;
                            }

                        // Check row resize
                        case DataGridViewHitTestTypeInternal.RowResizeBottom:
                        case DataGridViewHitTestTypeInternal.RowResizeTop:
                            {
                                int rowIndex = (hti._typeInternal == DataGridViewHitTestTypeInternal.RowResizeBottom) ? hti._row : hti._adjacentRow;
                                if (e.Clicks == 1)
                                {
                                    BeginRowResize(ptGridCoord.Y, hti._mouseBarOffset, rowIndex);
                                }
                                break;
                            }

                        // Check for column header mouse down
                        case DataGridViewHitTestTypeInternal.ColumnHeader:
                        case DataGridViewHitTestTypeInternal.ColumnHeaderLeft:
                        case DataGridViewHitTestTypeInternal.ColumnHeaderRight:
                        case DataGridViewHitTestTypeInternal.FirstColumnHeaderLeft:
                            {
                                if (isAltDown && AllowUserToOrderColumns &&
                                    (SelectionMode == DataGridViewSelectionMode.FullColumnSelect ||
                                     SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect))
                                {
                                    BeginColumnRelocation(ptGridCoord.X, hti._col);
                                }
                                else
                                {
                                    OnColumnHeaderMouseDown(hti, isShiftDown, isControlDown);
                                }
                                break;
                            }

                        // Check for row header mouse down
                        case DataGridViewHitTestTypeInternal.RowHeader:
                            {
                                OnRowHeaderMouseDown(hti, isShiftDown, isControlDown);
                                break;
                            }

                        // Check for cell mouse down
                        case DataGridViewHitTestTypeInternal.Cell:
                            {
                                OnCellMouseDown(hti, isShiftDown, isControlDown);
                                break;
                            }

                        // Check for top/left header mouse down
                        case DataGridViewHitTestTypeInternal.TopLeftHeader:
                            {
                                OnTopLeftHeaderMouseDown();
                                break;
                            }

                        // Check for row headers resize
                        case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeLeft:
                        case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeRight:
                        case DataGridViewHitTestTypeInternal.RowHeadersResizeLeft:
                        case DataGridViewHitTestTypeInternal.RowHeadersResizeRight:
                            {
                                if (e.Clicks == 1)
                                {
                                    BeginRowHeadersResize(ptGridCoord.X, hti._mouseBarOffset);
                                }
                                break;
                            }

                        // Check for column headers resize
                        case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeTop:
                        case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeBottom:
                        case DataGridViewHitTestTypeInternal.ColumnHeadersResizeTop:
                        case DataGridViewHitTestTypeInternal.ColumnHeadersResizeBottom:
                            {
                                if (e.Clicks == 1)
                                {
                                    BeginColumnHeadersResize(ptGridCoord.Y, hti._mouseBarOffset);
                                }
                                break;
                            }
                    }
                    // Make sure that there is a current cell after this mouse down event.
                    if (_ptCurrentCell.X == -1)
                    {
                        MakeFirstDisplayedCellCurrentCell(true /*includeNewRow*/);
                    }
                }
            }
            finally
            {
                _dataGridViewOper[OperationResizingOperationAboutToStart] = false;
            }
        }

        private void OnCellMouseDown(HitTestInfo hti, bool isShiftDown, bool isControlDown)
        {
            Debug.Assert(hti.Type == DataGridViewHitTestType.Cell);
            // Only commit cell if the target cell is different from the current one.
            if (_ptCurrentCell.X >= 0 &&
                (_ptCurrentCell.X != hti._col || _ptCurrentCell.Y != hti._row))
            {
                Point ptOriginalCurrentCell = _ptCurrentCell;
                if (!CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit,
                    _ptCurrentCell.X != hti._col || _ptCurrentCell.Y != hti._row /*forCurrentCellChange*/,
                    _ptCurrentCell.Y != hti._row /*forCurrentRowChange*/))
                {
                    // Return silently if validating/commit/abort failed
                    return;
                }
                if (_ptCurrentCell != ptOriginalCurrentCell)
                {
                    // Somehow the fact that the current cell was committed altered the current cell value.
                    // To avoid unintentional multi-selections, we act as if Shift and Control keys were up.
                    isShiftDown = isControlDown = false;
                }
            }

            if (hti._col >= Columns.Count)
            {
                DataGridViewColumn dataGridViewLastVisibleColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible,
                                                                                              DataGridViewElementStates.None);
                if (_ptCurrentCell.X == -1 && dataGridViewLastVisibleColumn != null)
                {
                    // CurrentCell was reset because CommitEdit deleted column(s).
                    // Since the user clicked on a cell, we don't want to end up
                    // with no CurrentCell. We pick the last visible column in the grid.
                    hti._col = dataGridViewLastVisibleColumn.Index;
                }
                else
                {
                    return;
                }
            }
            if (hti._row >= Rows.Count)
            {
                int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
                if (_ptCurrentCell.X == -1 && lastVisibleRowIndex != -1)
                {
                    // CurrentCell was reset because CommitEdit deleted row(s).
                    // Since the user clicked on a cell, we don't want to end up
                    // with no CurrentCell. We pick the last visible row in the
                    // grid which may be the 'new row'.
                    hti._row = lastVisibleRowIndex;
                }
                else
                {
                    return;
                }
            }

            bool select = true;
            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        {
                            if (isControlDown &&
                                IsSharedCellSelected(Rows.SharedRow(hti._row).Cells[hti._col], hti._row) &&
                                (!isShiftDown || !MultiSelect))
                            {
                                select = false;
                            }
                            if (select)
                            {
                                if ((!MultiSelect || !isControlDown) && !(MultiSelect && isShiftDown))
                                {
                                    Debug.Assert(MultiSelect || _individualSelectedCells.Count <= 1);
                                    RemoveIndividuallySelectedCells(hti._col, hti._row);
                                }
                                if (MultiSelect)
                                {
                                    if (_dataGridViewOper[OperationTrackMouseMoves])
                                    {
                                        _dataGridViewOper[OperationTrackCellSelect] = true;
                                    }
                                    if (isShiftDown)
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, hti._col,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, hti._row);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(hti._col, hti._row, true);
                                    }
                                }
                                else
                                {
                                    SetSelectedCellCore(hti._col, hti._row, true);
                                }
                            }
                            else
                            {
                                SetSelectedCellCore(hti._col, hti._row, false);
                            }
                            bool success = SetCurrentCellAddressCore(hti._col, hti._row, !isShiftDown, false, true);
                            Debug.Assert(success);
                            break;
                        }

                    case DataGridViewSelectionMode.FullColumnSelect:
                        {
                            if (isControlDown && Columns[hti._col].Selected)
                            {
                                select = false;
                            }
                            if (select)
                            {
                                bool selectColumnRange = false;
                                _trackColumn = hti._col;
                                _trackColumnEdge = -1;
                                if (MultiSelect &&
                                    isShiftDown &&
                                    _ptAnchorCell.X > -1 &&
                                    Columns[_ptAnchorCell.X].Selected)
                                {
                                    selectColumnRange = true;
                                }
                                if (!MultiSelect || !isControlDown || isShiftDown)
                                {
                                    Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                                    int bandIndex = 0;
                                    bool switchedToBulkPaint = false;
                                    if (_selectedBandIndexes.Count > BulkPaintThreshold)
                                    {
                                        _inBulkPaintCount++;
                                        switchedToBulkPaint = true;
                                    }
                                    try
                                    {
                                        while (bandIndex < _selectedBandIndexes.Count)
                                        {
                                            if (_selectedBandIndexes[bandIndex] != hti._col)
                                            {
                                                // deselect currently selected column
                                                SetSelectedColumnCore(_selectedBandIndexes[bandIndex], false);
                                            }
                                            else
                                            {
                                                bandIndex++;
                                            }
                                        }
                                    }
                                    finally
                                    {
                                        if (switchedToBulkPaint)
                                        {
                                            ExitBulkPaint(-1, -1);
                                        }
                                    }
                                }
                                if (MultiSelect && _dataGridViewOper[OperationTrackMouseMoves])
                                {
                                    _dataGridViewOper[OperationTrackColSelect] = true;
                                }
                                if (selectColumnRange)
                                {
                                    if (Columns.DisplayInOrder(_ptAnchorCell.X, hti._col))
                                    {
                                        SelectColumnRange(_ptAnchorCell.X, hti._col, true);
                                    }
                                    else
                                    {
                                        SelectColumnRange(hti._col, _ptAnchorCell.X, true);
                                    }
                                }
                                else if (!_selectedBandIndexes.Contains(hti._col))
                                {
                                    SetSelectedColumnCore(hti._col, true);
                                }
                            }
                            else
                            {
                                Debug.Assert(_selectedBandIndexes.Contains(hti._col));
                                SetSelectedColumnCore(hti._col, false);
                            }
                            bool success = SetCurrentCellAddressCore(hti._col, hti._row, !isShiftDown, false, true);
                            Debug.Assert(success);
                            break;
                        }

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        {
                            if (isControlDown &&
                                (Columns[hti._col].Selected || IsSharedCellSelected(Rows.SharedRow(hti._row).Cells[hti._col], hti._row)) &&
                                (!isShiftDown || !MultiSelect))
                            {
                                select = false;
                            }
                            if (select)
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedColumnCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        RemoveIndividuallySelectedCells();
                                    }
                                    SetSelectedCellCore(hti._col, hti._row, true);
                                }
                                else
                                {
                                    if (!isControlDown && !isShiftDown)
                                    {
                                        bool switchedToBulkPaint = false;
                                        if (_selectedBandIndexes.Count > BulkPaintThreshold)
                                        {
                                            _inBulkPaintCount++;
                                            switchedToBulkPaint = true;
                                        }
                                        try
                                        {
                                            while (_selectedBandIndexes.Count > 0)
                                            {
                                                SetSelectedColumnCore(_selectedBandIndexes.HeadInt, false);
                                            }
                                            RemoveIndividuallySelectedCells(hti._col, hti._row);
                                        }
                                        finally
                                        {
                                            if (switchedToBulkPaint)
                                            {
                                                ExitBulkPaint(-1, -1);
                                            }
                                        }
                                    }
                                    if (_dataGridViewOper[OperationTrackMouseMoves])
                                    {
                                        _dataGridViewOper[OperationTrackCellSelect] = true;
                                    }
                                    if (isShiftDown)
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, hti._col,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, hti._row);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(hti._col, hti._row, true);
                                    }
                                }
                            }
                            else
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedColumnCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(hti._col, hti._row, false);
                                    }
                                }
                                else
                                {
                                    SetSelectedCellCore(hti._col, hti._row, false);
                                }
                            }
                            bool success = SetCurrentCellAddressCore(hti._col, hti._row, !isShiftDown, false, true);
                            Debug.Assert(success);
                            break;
                        }

                    case DataGridViewSelectionMode.FullRowSelect:
                        {
                            if (isControlDown &&
                                ((Rows.GetRowState(hti._row) & DataGridViewElementStates.Selected) != 0))
                            {
                                select = false;
                            }
                            if (select)
                            {
                                bool selectRowRange = false;
                                _trackRow = hti._row;
                                _trackRowEdge = -1;
                                if (MultiSelect &&
                                    isShiftDown &&
                                    _ptAnchorCell.Y > -1 && (Rows.GetRowState(_ptAnchorCell.Y) & DataGridViewElementStates.Selected) != 0)
                                {
                                    selectRowRange = true;
                                }

                                if (!MultiSelect || !isControlDown || isShiftDown)
                                {
                                    Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                                    int bandIndex = 0;
                                    bool switchedToBulkPaint = false;
                                    if (_selectedBandIndexes.Count > BulkPaintThreshold)
                                    {
                                        _inBulkPaintCount++;
                                        switchedToBulkPaint = true;
                                    }
                                    try
                                    {
                                        while (bandIndex < _selectedBandIndexes.Count)
                                        {
                                            if (_selectedBandIndexes[bandIndex] != hti._row)
                                            {
                                                // deselect currently selected row
                                                SetSelectedRowCore(_selectedBandIndexes[bandIndex], false);
                                            }
                                            else
                                            {
                                                bandIndex++;
                                            }
                                        }
                                    }
                                    finally
                                    {
                                        if (switchedToBulkPaint)
                                        {
                                            ExitBulkPaint(-1, -1);
                                        }
                                    }
                                }
                                if (MultiSelect && _dataGridViewOper[OperationTrackMouseMoves])
                                {
                                    _dataGridViewOper[OperationTrackRowSelect] = true;
                                }
                                if (selectRowRange)
                                {
                                    if (hti._row >= _ptAnchorCell.Y)
                                    {
                                        SelectRowRange(_ptAnchorCell.Y, hti._row, true);
                                    }
                                    else
                                    {
                                        SelectRowRange(hti._row, _ptAnchorCell.Y, true);
                                    }
                                }
                                else if ((Rows.GetRowState(hti._row) & DataGridViewElementStates.Selected) == 0)
                                {
                                    Debug.Assert(_selectedBandIndexes.Contains(hti._row) ==
                                                 ((Rows.GetRowState(hti._row) & DataGridViewElementStates.Selected) != 0));
                                    SetSelectedRowCore(hti._row, true);
                                }
                            }
                            else
                            {
                                Debug.Assert(_selectedBandIndexes.Contains(hti._row));
                                SetSelectedRowCore(hti._row, false);
                            }
                            bool success = SetCurrentCellAddressCore(hti._col, hti._row, !isShiftDown, false, true);
                            Debug.Assert(success);
                            break;
                        }

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        {
                            if (isControlDown &&
                                (((Rows.GetRowState(hti._row) & DataGridViewElementStates.Selected) != 0) ||
                                IsSharedCellSelected(Rows.SharedRow(hti._row).Cells[hti._col], hti._row)) &&
                                (!isShiftDown || !MultiSelect))
                            {
                                select = false;
                            }
                            if (select)
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedRowCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        RemoveIndividuallySelectedCells();
                                    }
                                    SetSelectedCellCore(hti._col, hti._row, true);
                                }
                                else
                                {
                                    if (!isControlDown && !isShiftDown)
                                    {
                                        bool switchedToBulkPaint = false;
                                        if (_selectedBandIndexes.Count > BulkPaintThreshold)
                                        {
                                            _inBulkPaintCount++;
                                            switchedToBulkPaint = true;
                                        }
                                        try
                                        {
                                            while (_selectedBandIndexes.Count > 0)
                                            {
                                                SetSelectedRowCore(_selectedBandIndexes.HeadInt, false);
                                            }
                                            RemoveIndividuallySelectedCells(hti._col, hti._row);
                                        }
                                        finally
                                        {
                                            if (switchedToBulkPaint)
                                            {
                                                ExitBulkPaint(-1, -1);
                                            }
                                        }
                                    }
                                    if (_dataGridViewOper[OperationTrackMouseMoves])
                                    {
                                        _dataGridViewOper[OperationTrackCellSelect] = true;
                                    }
                                    if (isShiftDown)
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, hti._col,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, hti._row);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(hti._col, hti._row, true);
                                    }
                                }
                            }
                            else
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedRowCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(hti._col, hti._row, false);
                                    }
                                }
                                else
                                {
                                    SetSelectedCellCore(hti._col, hti._row, false);
                                }
                            }

                            SetCurrentCellAddressCore(hti._col, hti._row, !isShiftDown, false, true);
                            break;
                        }
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
        }

        protected virtual void OnCellMouseEnter(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            _ptMouseEnteredCell.X = e.ColumnIndex;
            _ptMouseEnteredCell.Y = e.RowIndex;

            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.MouseEnterUnsharesRowInternal(e.RowIndex))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnMouseEnterInternal(e.RowIndex);
            }
            else
            {
                dataGridViewCell.OnMouseEnterInternal(e.RowIndex);
            }

            if (Events[s_cellMouseEnterEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCellMouseLeave(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            _ptMouseEnteredCell.X = -2;
            _ptMouseEnteredCell.Y = -2;

            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.MouseLeaveUnsharesRowInternal(e.RowIndex))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnMouseLeaveInternal(e.RowIndex);
            }
            else
            {
                dataGridViewCell.OnMouseLeaveInternal(e.RowIndex);
            }

            if (Events[s_cellMouseLeaveEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnCellMouseMove(DataGridViewCellMouseEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.MouseMoveUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnMouseMoveInternal(e);
            }
            else
            {
                dataGridViewCell.OnMouseMoveInternal(e);
            }

            if (Events[s_cellMouseMoveEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (!_dataGridViewState1[State1_ScrolledSinceMouseDown] &&
                !IsMouseOperationActive() &&
                AllowUserToOrderColumns &&
                SelectionMode != DataGridViewSelectionMode.FullColumnSelect &&
                SelectionMode != DataGridViewSelectionMode.ColumnHeaderSelect &&
                e.Button == MouseButtons.Left &&
                _ptMouseDownCell.Y == -1 &&
                _ptMouseDownCell.X >= 0 &&
                _ptMouseDownCell.X < Columns.Count)
            {
                Point ptGridCoord = ConvertCellToGridCoord(e.ColumnIndex, e.RowIndex, e.X, e.Y);

                HitTestInfo hti = HitTest(ptGridCoord.X, ptGridCoord.Y);

                Debug.Assert(hti.Type != DataGridViewHitTestType.None &&
                             hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                             hti.Type != DataGridViewHitTestType.VerticalScrollBar);

                switch (hti._typeInternal)
                {
                    // Check for column header mouse down
                    case DataGridViewHitTestTypeInternal.ColumnHeader:
                    case DataGridViewHitTestTypeInternal.ColumnHeaderLeft:
                    case DataGridViewHitTestTypeInternal.ColumnHeaderRight:
                    case DataGridViewHitTestTypeInternal.FirstColumnHeaderLeft:
                        {
                            Debug.Assert(!_dataGridViewState2[State2_MessageFromEditingCtrls]);
                            if (Math.Abs(_ptMouseDownGridCoord.X - ptGridCoord.X) >= DataGridView.s_dragSize.Width ||
                                Math.Abs(_ptMouseDownGridCoord.Y - ptGridCoord.Y) >= DataGridView.s_dragSize.Height)
                            {
                                BeginColumnRelocation(_ptMouseDownGridCoord.X, _ptMouseDownCell.X);
                            }
                            break;
                        }
                }
            }
        }

        protected virtual void OnCellMouseUp(DataGridViewCellMouseEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            DataGridViewCell dataGridViewCell = GetCellInternal(e.ColumnIndex, e.RowIndex);
            Debug.Assert(dataGridViewCell != null);
            if (e.RowIndex >= 0 && dataGridViewCell.MouseUpUnsharesRowInternal(e))
            {
                DataGridViewRow dataGridViewRow = Rows[e.RowIndex];
                GetCellInternal(e.ColumnIndex, e.RowIndex).OnMouseUpInternal(e);
            }
            else
            {
                dataGridViewCell.OnMouseUpInternal(e);
            }

            if (Events[s_cellMouseUpEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected internal virtual void OnCellPainting(DataGridViewCellPaintingEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellPaintingEvent] is DataGridViewCellPaintingEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal DataGridViewCellParsingEventArgs OnCellParsing(int rowIndex, int columnIndex, object formattedValue, Type valueType, DataGridViewCellStyle cellStyle)
        {
            DataGridViewCellParsingEventArgs dgvcpe = new DataGridViewCellParsingEventArgs(rowIndex, columnIndex,
                                                                                           formattedValue,
                                                                                           valueType,
                                                                                           cellStyle);
            OnCellParsing(dgvcpe);
            return dgvcpe;
        }

        protected virtual void OnCellParsing(DataGridViewCellParsingEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellParsingEvent] is DataGridViewCellParsingEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnCellSelectMouseMove(HitTestInfo hti)
        {
            Debug.Assert(MultiSelect);
            int oldEdgeColumnIndex = _ptCurrentCell.X;
            int oldEdgeRowIndex = _ptCurrentCell.Y;
            if ((hti._col != _ptCurrentCell.X || hti._row != _ptCurrentCell.Y) &&
                !CommitEditForOperation(hti._col, hti._row, true))
            {
                // Return silently if validating/commit/abort failed
                return;
            }
            _noSelectionChangeCount++;
            try
            {
                if (_ptAnchorCell.X == -1 || IsInnerCellOutOfBounds(hti._col, hti._row))
                {
                    return;
                }
                UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, hti._col,
                    _ptAnchorCell.Y, ref oldEdgeRowIndex, hti._row);
                if (hti._col != _ptCurrentCell.X || hti._row != _ptCurrentCell.Y)
                {
                    bool success = SetCurrentCellAddressCore(hti._col, hti._row, false, false, false);
                    Debug.Assert(success);
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
        }

        protected virtual void OnCellStateChanged(DataGridViewCellStateChangedEventArgs e)
        {
            // At this point we assume that only the Selected state has an influence on the rendering of the cell.
            // If there is a scenario where another state has an effect, then the dev will have to invalidate the cell by hand.
            DataGridViewCell dataGridViewCell = e.Cell;
            if (e.StateChanged == DataGridViewElementStates.Selected)
            {
                Debug.Assert(dataGridViewCell.RowIndex >= 0);
                if (_inBulkPaintCount == 0)
                {
                    InvalidateCellPrivate(dataGridViewCell);
                }
            }

            if (Events[s_cellStateChangedEvent] is DataGridViewCellStateChangedEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (e.StateChanged == DataGridViewElementStates.ReadOnly &&
                _ptCurrentCell.X == dataGridViewCell.ColumnIndex &&
                _ptCurrentCell.Y == dataGridViewCell.RowIndex &&
                dataGridViewCell.RowIndex > -1 &&
                !_dataGridViewOper[OperationInReadOnlyChange])
            {
                VerifyImeRestrictedModeChanged();

                if (!dataGridViewCell.ReadOnly &&
                    ColumnEditable(_ptCurrentCell.X) &&
                    !IsCurrentCellInEditMode &&
                    (EditMode == DataGridViewEditMode.EditOnEnter ||
                    (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null)))
                {
                    // Current cell becomes read/write. Enter editing mode.
                    BeginEditInternal(true /*selectAll*/);
                }
            }
        }

        internal void OnCellStyleChanged(DataGridViewCell dataGridViewCell)
        {
            DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(dataGridViewCell);
            OnCellStyleChanged(dgvce);
        }

        protected virtual void OnCellStyleChanged(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            OnCellCommonChange(e.ColumnIndex, e.RowIndex);

            if (Events[s_cellStyleChangedEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellStyleContentChanged(DataGridViewCellStyle dataGridViewCellStyle, DataGridViewCellStyle.DataGridViewCellStylePropertyInternal property)
        {
            Debug.Assert(dataGridViewCellStyle != null);
            switch (property)
            {
                case DataGridViewCellStyle.DataGridViewCellStylePropertyInternal.Font:
                    if ((dataGridViewCellStyle.Scope & DataGridViewCellStyleScopes.DataGridView) != 0 && _dataGridViewState1[State1_AmbientFont])
                    {
                        _dataGridViewState1[State1_AmbientFont] = false;
                    }
                    if ((dataGridViewCellStyle.Scope & DataGridViewCellStyleScopes.ColumnHeaders) != 0 && _dataGridViewState1[State1_AmbientColumnHeadersFont])
                    {
                        _dataGridViewState1[State1_AmbientColumnHeadersFont] = false;
                    }
                    if ((dataGridViewCellStyle.Scope & DataGridViewCellStyleScopes.RowHeaders) != 0 && _dataGridViewState1[State1_AmbientRowHeadersFont])
                    {
                        _dataGridViewState1[State1_AmbientRowHeadersFont] = false;
                    }
                    break;

                case DataGridViewCellStyle.DataGridViewCellStylePropertyInternal.ForeColor:
                    if ((dataGridViewCellStyle.Scope & DataGridViewCellStyleScopes.DataGridView) != 0 && _dataGridViewState1[State1_AmbientForeColor])
                    {
                        _dataGridViewState1[State1_AmbientForeColor] = false;
                    }
                    break;
            }

            DataGridViewCellStyleContentChangedEventArgs dgvcscce = new DataGridViewCellStyleContentChangedEventArgs(dataGridViewCellStyle,
                property != DataGridViewCellStyle.DataGridViewCellStylePropertyInternal.Color &&
                property != DataGridViewCellStyle.DataGridViewCellStylePropertyInternal.ForeColor /*changeAffectsPreferredSize*/);
            OnCellStyleContentChanged(dgvcscce);
        }

        protected virtual void OnCellStyleContentChanged(DataGridViewCellStyleContentChangedEventArgs e)
        {
            // We assume that when a color changes, it has no effect on the autosize of elements
            bool repositionEditingControl = false;

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.Cell) == DataGridViewCellStyleScopes.Cell && (e.CellStyleScope & DataGridViewCellStyleScopes.DataGridView) == 0)
            {
                // Same processing as in OnDefaultCellStyleChanged
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = true;
                    OnGlobalAutoSize();
                }
                else
                {
                    Invalidate();
                }
            }

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.Column) == DataGridViewCellStyleScopes.Column)
            {
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = true;
                    OnColumnsGlobalAutoSize();
                }
                else
                {
                    InvalidateData();
                }
            }

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.Row) == DataGridViewCellStyleScopes.Row && (e.CellStyleScope & DataGridViewCellStyleScopes.Rows) == 0 && (e.CellStyleScope & DataGridViewCellStyleScopes.AlternatingRows) == 0)
            {
                // Same processing as in OnRowsDefaultCellStyleChanged
                InvalidateData();
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = true;
                    // Autosize rows if needed
                    if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
                    {
                        AdjustShrinkingRows(_autoSizeRowsMode, false /*fixedWidth*/, true /*internalAutosizing*/);
                    }
                    // Auto size columms also if needed
                    // Impossible to figure out if DisplayedRows filter should be added or not. Adding it to be on the conservative side.
                    AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal.AllRows |
                                                        DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows,
                                                        true /*fixedHeight*/);
                    // Second round of rows autosizing
                    if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
                    {
                        AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                    }
                }
            }

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.DataGridView) == DataGridViewCellStyleScopes.DataGridView)
            {
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = e.ChangeAffectsPreferredSize;
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = false;
                    // OnDefaultCellStyleChanged will reposition the editing control.
                }
                OnDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.ColumnHeaders) == DataGridViewCellStyleScopes.ColumnHeaders)
            {
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = e.ChangeAffectsPreferredSize;
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = false;
                    // OnColumnHeadersDefaultCellStyleChanged will reposition the editing control.
                }
                OnColumnHeadersDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.RowHeaders) == DataGridViewCellStyleScopes.RowHeaders)
            {
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = e.ChangeAffectsPreferredSize;
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = false;
                    // OnRowHeadersDefaultCellStyleChanged will reposition the editing control.
                }
                OnRowHeadersDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.Rows) == DataGridViewCellStyleScopes.Rows)
            {
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = e.ChangeAffectsPreferredSize;
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = false;
                    // OnRowsDefaultCellStyleChanged will reposition the editing control.
                }
                OnRowsDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }

            if ((e.CellStyleScope & DataGridViewCellStyleScopes.AlternatingRows) == DataGridViewCellStyleScopes.AlternatingRows)
            {
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = e.ChangeAffectsPreferredSize;
                if (e.ChangeAffectsPreferredSize)
                {
                    repositionEditingControl = false;
                    // OnAlternatingRowsDefaultCellStyleChanged will reposition the editing control.
                }
                OnAlternatingRowsDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }

            if (repositionEditingControl && EditingControl != null)
            {
                PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
            }

            if (Events[s_cellStyleContentChangedEvent] is DataGridViewCellStyleContentChangedEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellToolTipTextChanged(DataGridViewCell dataGridViewCell)
        {
            DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(dataGridViewCell);
            OnCellToolTipTextChanged(dgvce);
        }

        protected virtual void OnCellToolTipTextChanged(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellTooltipTextChangedEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal string OnCellToolTipTextNeeded(int columnIndex, int rowIndex, string toolTipText)
        {
            DataGridViewCellToolTipTextNeededEventArgs dgvctttne = new DataGridViewCellToolTipTextNeededEventArgs(columnIndex, rowIndex, toolTipText);
            OnCellToolTipTextNeeded(dgvctttne);
            return dgvctttne.ToolTipText;
        }

        protected virtual void OnCellToolTipTextNeeded(DataGridViewCellToolTipTextNeededEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellTooltipTextNeededEvent] is DataGridViewCellToolTipTextNeededEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellValidated(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex)
        {
            OnCellValidated(new DataGridViewCellEventArgs(columnIndex, rowIndex));
            if (dataGridViewCell != null)
            {
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    dataGridViewCell = null;
                }
                else
                {
                    Debug.Assert(rowIndex < Rows.Count && columnIndex < Columns.Count);
                    dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                }
            }
        }

        protected virtual void OnCellValidated(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            try
            {
                _noDimensionChangeCount++;

                if (Events[s_cellValidatedEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                    CorrectFocus(true /*onlyIfGridHasFocus*/);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
            }
        }

        internal bool OnCellValidating(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex, DataGridViewDataErrorContexts context)
        {
            DataGridViewCell currentCell = dataGridViewCell ?? CurrentCellInternal;
            DataGridViewCellStyle dataGridViewCellStyle = currentCell.GetInheritedStyle(null, rowIndex, false);
            object val = currentCell.GetValueInternal(rowIndex);
            object editedFormattedValue = currentCell.GetEditedFormattedValue(val, rowIndex, ref dataGridViewCellStyle, context);
            DataGridViewCellValidatingEventArgs dgvcfvce = new DataGridViewCellValidatingEventArgs(columnIndex, rowIndex, editedFormattedValue);
            OnCellValidating(dgvcfvce);
            if (dataGridViewCell != null)
            {
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    dataGridViewCell = null;
                }
                else
                {
                    Debug.Assert(rowIndex < Rows.Count && columnIndex < Columns.Count);
                    dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                }
            }
            return dgvcfvce.Cancel;
        }

        protected virtual void OnCellValidating(DataGridViewCellValidatingEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            try
            {
                _noDimensionChangeCount++;
                _dataGridViewOper[OperationInCellValidating] = true;

                if (Events[s_cellValidatingEvent] is DataGridViewCellValidatingEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                    CorrectFocus(true /*onlyIfGridHasFocus*/);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
                _dataGridViewOper[OperationInCellValidating] = false;
            }
        }

        internal void OnCellValueChangedInternal(DataGridViewCellEventArgs e)
        {
            // For now, same effect as if the cell style had changed.
            OnCellValueChanged(e);
        }

        protected virtual void OnCellValueChanged(DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            OnCellCommonChange(e.ColumnIndex, e.RowIndex);

            if (Events[s_cellValueChangedEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal object OnCellValueNeeded(int columnIndex, int rowIndex)
        {
            DataGridViewCellValueEventArgs dgvcve = CellValueEventArgs;
            dgvcve.SetProperties(columnIndex, rowIndex, null);
            OnCellValueNeeded(dgvcve);
            return dgvcve.Value;
        }

        protected virtual void OnCellValueNeeded(DataGridViewCellValueEventArgs e)
        {
            if (e.ColumnIndex < 0 || e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex < 0 || e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }

            if (Events[s_cellValueNeededEvent] is DataGridViewCellValueEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnCellValuePushed(int columnIndex, int rowIndex, object value)
        {
            DataGridViewCellValueEventArgs dgvcve = CellValueEventArgs;
            dgvcve.SetProperties(columnIndex, rowIndex, value);
            OnCellValuePushed(dgvcve);
        }

        protected virtual void OnCellValuePushed(DataGridViewCellValueEventArgs e)
        {
            if (e.ColumnIndex < 0 || e.ColumnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException("e.ColumnIndex");
            }
            if (e.RowIndex < 0 || e.RowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException("e.RowIndex");
            }
            if (Events[s_cellValuePushedEvent] is DataGridViewCellValueEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnClearedRows()
        {
            // Raise the RowStateChanged(Displayed->false) events
            foreach (DataGridViewRow dataGridViewRow in _lstRows)
            {
                if (dataGridViewRow.Displayed)
                {
                    dataGridViewRow.Displayed = false;
                    DataGridViewRowStateChangedEventArgs dgvrsce = new DataGridViewRowStateChangedEventArgs(dataGridViewRow, DataGridViewElementStates.Displayed);
                    OnRowStateChanged(-1 /*rowIndex*/, dgvrsce);
                }
            }
            _lstRows.Clear();
        }

        internal void OnClearingColumns()
        {
            CurrentCell = null;

            // Rows need to be cleared first. There cannot be rows without also having columns.
            Rows.ClearInternal(false /*recreateNewRow*/);

            // Reset sort related variables.
            SortedColumn = null;
            SortOrder = SortOrder.None;

            // selectedBandIndexes, individualSelectedCells & individualReadOnlyCells cleared in OnClearingRows.
        }

        internal void OnClearingRows()
        {
            // Build a list of displayed rows in order to be able to raise their RowStateChanged(Displayed->false) events later on
            _lstRows.Clear();
            int numDisplayedRows = DisplayedBandsInfo.NumDisplayedFrozenRows + DisplayedBandsInfo.NumDisplayedScrollingRows;
            if (numDisplayedRows > 0)
            {
                _lstRows.Capacity = numDisplayedRows;
                int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Displayed);
                while (numDisplayedRows > 0 && rowIndex != -1)
                {
                    _lstRows.Add(Rows[rowIndex]);
                    numDisplayedRows--;
                    if (numDisplayedRows > 0)
                    {
                        rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Displayed);
                    }
                }
            }

            CurrentCell = null;

            NewRowIndex = -1;
            _dataGridViewState2[State2_RaiseSelectionChanged] = _selectedBandIndexes.Count > 0 ||
                                                                                _individualSelectedCells.Count > 0;
            _selectedBandIndexes.Clear();
            if (_selectedBandSnapshotIndexes != null)
            {
                _selectedBandSnapshotIndexes.Clear();
            }
            _individualSelectedCells.Clear();
            _individualReadOnlyCells.Clear();
        }

        protected virtual void OnColumnAdded(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            if (Events[s_columnAddedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnCollectionChanged_PreNotification(CollectionChangeEventArgs ccea)
        {
            // we need to map columns w/ DataPropertyName to bound columns
            if (DataSource != null && !_dataGridViewOper[OperationInRefreshColumns])
            {
                if (ccea.Action == CollectionChangeAction.Add)
                {
                    DataGridViewColumn dataGridViewColumn = (DataGridViewColumn)ccea.Element;
                    if (dataGridViewColumn.DataPropertyName.Length != 0)
                    {
                        MapDataGridViewColumnToDataBoundField(dataGridViewColumn);
                    }
                }
                else if (ccea.Action == CollectionChangeAction.Refresh)
                {
                    for (int i = 0; i < Columns.Count; i++)
                    {
                        if (Columns[i].DataPropertyName.Length != 0)
                        {
                            MapDataGridViewColumnToDataBoundField(Columns[i]);
                        }
                    }
                }
            }

            ResetUIState(false /*useRowShortcut*/, false /*computeVisibleRows*/);
        }

        internal void OnColumnCollectionChanged_PostNotification(DataGridViewColumn dataGridViewColumn)
        {
            if (Columns.Count != 0 && Rows.Count == 0)
            {
                if (DataSource != null && !_dataGridViewOper[OperationInRefreshColumns])
                {
                    // this will create the 'add new row' when AllowUserToAddRowsInternal == true
                    RefreshRows(true /*scrollIntoView*/);
                }
                else if (AllowUserToAddRowsInternal)
                {
                    AddNewRow(false);
                }
            }
            if (AutoSize && (dataGridViewColumn is null || dataGridViewColumn.Visible))
            {
                LayoutTransaction.DoLayout(ParentInternal, this, PropertyNames.Columns);
            }
        }

        internal void OnColumnCommonChange(int columnIndex)
        {
            OnColumnGlobalAutoSize(columnIndex);
        }

        protected virtual void OnColumnContextMenuStripChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            if (Events[s_columnContextMenuStripChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnDataPropertyNameChanged(DataGridViewColumn dataGridViewColumn)
        {
            OnColumnDataPropertyNameChanged(new DataGridViewColumnEventArgs(dataGridViewColumn));
        }

        protected virtual void OnColumnDataPropertyNameChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            // map the dataGridView column to some data field
            if (DataSource != null && e.Column.DataPropertyName.Length != 0 && !_dataGridViewOper[OperationInRefreshColumns])
            {
                MapDataGridViewColumnToDataBoundField(e.Column);
            }
            else if (DataSource != null && e.Column.DataPropertyName.Length == 0)
            {
                if (e.Column.IsDataBound)
                {
                    e.Column.IsDataBoundInternal = false;
                    e.Column.BoundColumnIndex = -1;
                    e.Column.BoundColumnConverter = null;
                    InvalidateColumnInternal(e.Column.Index);
                }
            }

            if (Events[s_columnDataPropertyNameChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnColumnDefaultCellStyleChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            OnColumnGlobalAutoSize(e.Column.Index);

            if (Events[s_columnDefaultCellStyleChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnDisplayIndexChanged(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);
            DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
            OnColumnDisplayIndexChanged(dgvce);
        }

        internal void OnColumnDisplayIndexChanging(DataGridViewColumn dataGridViewColumn, int newDisplayIndex)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(newDisplayIndex != dataGridViewColumn.DisplayIndex);

            if (_dataGridViewOper[OperationInDisplayIndexAdjustments])
            {
                // We are within columns display indexes adjustments. We do not allow changing display indexes while adjusting them.
                throw new InvalidOperationException(SR.DataGridView_CannotAlterDisplayIndexWithinAdjustments);
            }

            // Throws an exception if the requested move is illegal
            CorrectColumnFrozenStatesForMove(dataGridViewColumn, newDisplayIndex);

            try
            {
                _dataGridViewOper[OperationInDisplayIndexAdjustments] = true;

                // Move is legal - let's adjust the affected display indexes.
                if (newDisplayIndex < dataGridViewColumn.DisplayIndex)
                {
                    // DisplayIndex decreases. All columns with newDisplayIndex <= DisplayIndex < dataGridViewColumn.DisplayIndex
                    // get their DisplayIndex incremented.
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (newDisplayIndex <= dataGridViewColumnTmp.DisplayIndex && dataGridViewColumnTmp.DisplayIndex < dataGridViewColumn.DisplayIndex)
                        {
                            dataGridViewColumnTmp.DisplayIndexInternal = dataGridViewColumnTmp.DisplayIndex + 1;
                            dataGridViewColumnTmp.DisplayIndexHasChanged = true; // OnColumnDisplayIndexChanged needs to be raised later on
                        }
                    }
                }
                else
                {
                    // DisplayIndex increases. All columns with dataGridViewColumn.DisplayIndex < DisplayIndex <= newDisplayIndex
                    // get their DisplayIndex incremented.
                    foreach (DataGridViewColumn dataGridViewColumnTmp in Columns)
                    {
                        if (dataGridViewColumn.DisplayIndex < dataGridViewColumnTmp.DisplayIndex && dataGridViewColumnTmp.DisplayIndex <= newDisplayIndex)
                        {
                            dataGridViewColumnTmp.DisplayIndexInternal = dataGridViewColumnTmp.DisplayIndex - 1;
                            dataGridViewColumnTmp.DisplayIndexHasChanged = true; // OnColumnDisplayIndexChanged needs to be raised later on
                        }
                    }
                }
            }
            finally
            {
                _dataGridViewOper[OperationInDisplayIndexAdjustments] = false;
            }

            // Note that displayIndex of moved column is updated by caller.
        }

        protected virtual void OnColumnDisplayIndexChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }

            Debug.Assert(_dataGridViewOper[OperationInDisplayIndexAdjustments]);
#if DEBUG
            Debug.Assert(Columns.VerifyColumnDisplayIndexes());

#endif
            if (Events[s_columnDisplayIndexChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnDisplayIndexChanged_PreNotification()
        {
            Debug.Assert(_dataGridViewOper[OperationInDisplayIndexAdjustments]);

            // column.DisplayIndex changed - this may require a complete re-layout of the control
            Columns.InvalidateCachedColumnsOrder();

            PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            if (EditingControl != null)
            {
                PositionEditingControl(true, true, false);
            }
            Invalidate(Rectangle.Union(_layout.ColumnHeaders, _layout.Data));
        }

        internal void OnColumnDisplayIndexChanged_PostNotification()
        {
            // Notifications for adjusted display indexes.
            FlushDisplayIndexChanged(true /*raiseEvent*/);
        }

        protected virtual void OnColumnDividerDoubleClick(DataGridViewColumnDividerDoubleClickEventArgs e)
        {
            if (Events[s_columnDividerDoubleClickEvent] is DataGridViewColumnDividerDoubleClickEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (!e.Handled && e.Button == MouseButtons.Left && e.ColumnIndex < Columns.Count)
            {
                if (e.ColumnIndex == -1)
                {
                    AutoResizeRowHeadersWidth(DataGridViewRowHeadersWidthSizeMode.AutoSizeToDisplayedHeaders,
                                              true /*fixedColumnHeadersHeight*/,
                                              true /*fixedRowsHeight*/);
                }
                else
                {
                    DataGridViewAutoSizeColumnMode inheritedAutoSizeMode = Columns[e.ColumnIndex].InheritedAutoSizeMode;
                    if (inheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.None || inheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                    {
                        AutoResizeColumnInternal(e.ColumnIndex, DataGridViewAutoSizeColumnCriteriaInternal.Header | DataGridViewAutoSizeColumnCriteriaInternal.AllRows, true /*fixedHeight*/);
                    }
                    else
                    {
                        AutoResizeColumnInternal(e.ColumnIndex, (DataGridViewAutoSizeColumnCriteriaInternal)inheritedAutoSizeMode, true /*fixedHeight*/);
                    }
                }
            }
        }

        protected virtual void OnColumnDividerWidthChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            OnColumnGlobalAutoSize(e.Column.Index);

            if (Events[s_columnDividerWidthChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnFillWeightChanged(DataGridViewColumn dataGridViewColumn)
        {
            if (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
            {
                // UsedFillWeight properties need to be re-evaluated
                _dataGridViewState2[State2_UsedFillWeightsDirty] = true;
                // Adjust filling columns based on new weight of this column
                PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            }
        }

        internal void OnColumnFillWeightChanging(DataGridViewColumn dataGridViewColumn, float fillWeight)
        {
            if (InAdjustFillingColumns)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotAlterAutoFillColumnParameter);
            }

            // Make sure the sum of the column weights does not exceed ushort.MaxValue
            float weightSum = Columns.GetColumnsFillWeight(DataGridViewElementStates.None) - dataGridViewColumn.FillWeight + fillWeight;
            if (weightSum > (float)ushort.MaxValue)
            {
                throw new InvalidOperationException(string.Format(SR.DataGridView_WeightSumCannotExceedLongMaxValue, ushort.MaxValue));
            }
        }

        private void OnColumnGlobalAutoSize(int columnIndex)
        {
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count);

            if (!Columns[columnIndex].Visible)
            {
                return;
            }

            InvalidateColumnInternal(columnIndex);

            if (_noAutoSizeCount > 0)
            {
                return;
            }

            bool fixedHeight = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) == 0;

            DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal = (DataGridViewAutoSizeColumnCriteriaInternal)Columns[columnIndex].InheritedAutoSizeMode;
            if (autoSizeColumnCriteriaInternal != DataGridViewAutoSizeColumnCriteriaInternal.None &&
                autoSizeColumnCriteriaInternal != DataGridViewAutoSizeColumnCriteriaInternal.Fill)
            {
                AutoResizeColumnInternal(columnIndex, autoSizeColumnCriteriaInternal, fixedHeight);
            }

            // Autosize rows and column headers if needed
            if (!fixedHeight)
            {
                AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
            }
            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                AutoResizeColumnHeadersHeight(columnIndex, true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
            }
            if (!fixedHeight &&
                autoSizeColumnCriteriaInternal != DataGridViewAutoSizeColumnCriteriaInternal.None &&
                autoSizeColumnCriteriaInternal != DataGridViewAutoSizeColumnCriteriaInternal.Fill)
            {
                // Second round of column autosizing with 1 degree of freedom
                AutoResizeColumnInternal(columnIndex, autoSizeColumnCriteriaInternal, true /*fixedHeight*/);
            }
        }

        protected virtual void OnColumnHeaderCellChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }

            OnColumnHeaderGlobalAutoSize(e.Column.Index);

            if (Events[s_columnHeaderCellChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnColumnHeaderGlobalAutoSize(int columnIndex)
        {
            if (!ColumnHeadersVisible)
            {
                return;
            }

            InvalidateCellPrivate(columnIndex, -1);

            if (_noAutoSizeCount > 0)
            {
                return;
            }

            DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal = (DataGridViewAutoSizeColumnCriteriaInternal)Columns[columnIndex].InheritedAutoSizeMode;
            DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFiltered = autoSizeColumnCriteriaInternal & DataGridViewAutoSizeColumnCriteriaInternal.Header;
            bool fixedColumnWidth = autoSizeColumnCriteriaFiltered == 0;

            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                AutoResizeColumnHeadersHeight(columnIndex, true /*fixedRowHeadersWidth*/, fixedColumnWidth);
            }

            if (!fixedColumnWidth)
            {
                Debug.Assert(autoSizeColumnCriteriaInternal != DataGridViewAutoSizeColumnCriteriaInternal.None);
                Debug.Assert(autoSizeColumnCriteriaInternal != DataGridViewAutoSizeColumnCriteriaInternal.Fill);
                bool fixedHeight = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) == 0;
                AutoResizeColumnInternal(columnIndex, autoSizeColumnCriteriaInternal, fixedHeight);
                if (!fixedHeight)
                {
                    AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                    // Second round of column autosizing with 1 degree of freedom
                    AutoResizeColumnInternal(columnIndex, autoSizeColumnCriteriaInternal, true /*fixedHeight*/);
                }
                if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                {
                    // Second round of column headers autosizing with 1 degree of freedom
                    AutoResizeColumnHeadersHeight(columnIndex, true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
                }
            }
        }

        protected virtual void OnColumnHeaderMouseClick(DataGridViewCellMouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left &&
                SelectionMode != DataGridViewSelectionMode.FullColumnSelect &&
                SelectionMode != DataGridViewSelectionMode.ColumnHeaderSelect)
            {
                DataGridViewColumn dataGridViewColumn = Columns[e.ColumnIndex];

                if (CanSort(dataGridViewColumn))
                {
                    ListSortDirection direction = ListSortDirection.Ascending;

                    if (SortedColumn == dataGridViewColumn)
                    {
                        Debug.Assert(SortOrder != SortOrder.None);
                        if (SortOrder == SortOrder.Ascending)
                        {
                            direction = ListSortDirection.Descending;
                        }
                    }

                    if ((DataSource is null) ||
                        (DataSource != null &&
                         (DataConnection.List is IBindingList) &&
                         ((IBindingList)DataConnection.List).SupportsSorting &&
                         dataGridViewColumn.IsDataBound))
                    {
                        Sort(dataGridViewColumn, direction);
                    }
                }
            }

            if (Events[s_columnHeaderMouseClickEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnColumnHeaderMouseDoubleClick(DataGridViewCellMouseEventArgs e)
        {
            if (Events[s_columnHeaderMouseDoubleClickEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnColumnHeaderMouseDown(HitTestInfo hti, bool isShiftDown, bool isControlDown)
        {
            Debug.Assert(hti.Type == DataGridViewHitTestType.ColumnHeader);
            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.FullRowSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        break;

                    case DataGridViewSelectionMode.FullColumnSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        {
                            bool select = true;
                            if (isControlDown && Columns[hti._col].Selected)
                            {
                                select = false;
                            }
                            if (select)
                            {
                                int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                                if (rowIndex > -1 && hti._col != _ptCurrentCell.X)
                                {
                                    // Make sure we will be able to scroll into view
                                    int oldCurrentCellX = _ptCurrentCell.X;
                                    int oldCurrentCellY = _ptCurrentCell.Y;
                                    if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.CurrentCellChange,
                                                DataGridViewValidateCellInternal.Always /*validateCell*/,
                                                true /*fireCellLeave*/,
                                                true /*fireCellEnter*/,
                                                rowIndex != _ptCurrentCell.Y /*fireRowLeave*/,
                                                rowIndex != _ptCurrentCell.Y /*fireRowEnter*/,
                                                false /*fireLeave*/,
                                                EditMode != DataGridViewEditMode.EditOnEnter /*keepFocus*/,
                                                true /*resetCurrentCell*/,
                                                false /*resetAnchorCell*/))
                                    {
                                        // Just cancel operation silently instead of throwing InvalidOperationException
                                        return;
                                    }
                                    if (rowIndex != oldCurrentCellY && oldCurrentCellY != -1)
                                    {
                                        DataGridViewCell dataGridViewCellTmp = null;
                                        if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                        {
                                            return;
                                        }
                                        if (OnRowValidating(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY))
                                        {
                                            // Row validation was cancelled
                                            if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                            {
                                                return;
                                            }
                                            OnRowEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY, true /*canCreateNewRow*/, true /*validationFailureOccurred*/);
                                            if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                            {
                                                return;
                                            }
                                            OnCellEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);
                                            return;
                                        }
                                        if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                        {
                                            return;
                                        }
                                        OnRowValidated(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);
                                    }
                                }
                                if (IsColumnOutOfBounds(hti._col))
                                {
                                    return;
                                }

                                bool selectColumnRange = false;
                                _trackColumn = hti._col;
                                _trackColumnEdge = -1;
                                if (MultiSelect &&
                                    isShiftDown &&
                                    _ptAnchorCell.X > -1 &&
                                    Columns[_ptAnchorCell.X].Selected)
                                {
                                    selectColumnRange = true;
                                }
                                if (!MultiSelect || !isControlDown || isShiftDown)
                                {
                                    Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                                    int bandIndex = 0;
                                    bool switchedToBulkPaint = false;
                                    if (_selectedBandIndexes.Count > BulkPaintThreshold)
                                    {
                                        _inBulkPaintCount++;
                                        switchedToBulkPaint = true;
                                    }
                                    try
                                    {
                                        while (bandIndex < _selectedBandIndexes.Count)
                                        {
                                            if (_selectedBandIndexes[bandIndex] != hti._col)
                                            {
                                                // deselect currently selected column
                                                SetSelectedColumnCore(_selectedBandIndexes[bandIndex], false);
                                            }
                                            else
                                            {
                                                bandIndex++;
                                            }
                                        }
                                        if (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect)
                                        {
                                            RemoveIndividuallySelectedCells();
                                        }
                                        else
                                        {
                                            Debug.Assert(_individualSelectedCells.Count == 0);
                                        }
                                    }
                                    finally
                                    {
                                        if (switchedToBulkPaint)
                                        {
                                            ExitBulkPaint(-1, -1);
                                        }
                                    }
                                }
                                if (MultiSelect && _dataGridViewOper[OperationTrackMouseMoves])
                                {
                                    _dataGridViewOper[OperationTrackColSelect] = true;
                                }
                                if (selectColumnRange)
                                {
                                    if (Columns.DisplayInOrder(_ptAnchorCell.X, hti._col))
                                    {
                                        SelectColumnRange(_ptAnchorCell.X, hti._col, true);
                                    }
                                    else
                                    {
                                        SelectColumnRange(hti._col, _ptAnchorCell.X, true);
                                    }
                                }
                                else if (!_selectedBandIndexes.Contains(hti._col))
                                {
                                    SetSelectedColumnCore(hti._col, true);
                                }
                                // set current cell to the top most visible cell in the column
                                if (rowIndex != -1)
                                {
                                    if (hti._col != _ptCurrentCell.X)
                                    {
                                        if (IsInnerCellOutOfBounds(hti._col, rowIndex))
                                        {
                                            return;
                                        }
                                        bool success = ScrollIntoView(hti._col, rowIndex, false);
                                        Debug.Assert(success);
                                        if (IsInnerCellOutOfBounds(hti._col, rowIndex))
                                        {
                                            return;
                                        }
                                        success = SetCurrentCellAddressCore(hti._col, rowIndex, !isShiftDown, false, true);
                                        Debug.Assert(success);
                                    }
                                    else if (-1 != _ptCurrentCell.X)
                                    {
                                        // Potentially have to give focus back to the current edited cell.
                                        bool success = SetCurrentCellAddressCore(_ptCurrentCell.X, _ptCurrentCell.Y, false /*setAnchorCellAddress*/, false /*validateCurrentCell*/, false /*throughMouseClick*/);
                                        Debug.Assert(success);
                                    }
                                }
                                else
                                {
                                    Debug.Assert(CurrentCellAddress == new Point(-1, -1));
                                }
                            }
                            else
                            {
                                Debug.Assert(_selectedBandIndexes.Contains(hti._col));
                                SetSelectedColumnCore(hti._col, false);
                            }
                            break;
                        }
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
        }

        protected virtual void OnColumnHeadersBorderStyleChanged(EventArgs e)
        {
            PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            Invalidate();

            if (Events[s_columnHeadersBorderStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnColumnHeadersDefaultCellStyleChanged(EventArgs e)
        {
            if (ColumnHeadersVisible)
            {
                Invalidate(Rectangle.Union(_layout.TopLeftHeader, _layout.ColumnHeaders));

                if (!(e is DataGridViewCellStyleChangedEventArgs dgvcsce) || dgvcsce.ChangeAffectsPreferredSize)
                {
                    OnColumnHeadersGlobalAutoSize();
                    if (EditingControl != null)
                    {
                        PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                    }
                }
            }

            if (Events[s_columnHeadersDefaultCellStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnColumnHeadersGlobalAutoSize()
        {
            if (_noAutoSizeCount > 0)
            {
                return;
            }

            bool fixedRowHeadersWidth = _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing ||
                                        _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.DisableResizing;
            bool fixedColumnHeadersHeight = ColumnHeadersHeightSizeMode != DataGridViewColumnHeadersHeightSizeMode.AutoSize;

            if (!fixedColumnHeadersHeight)
            {
                AutoResizeColumnHeadersHeight(fixedRowHeadersWidth, false /*fixedColumnsWidth*/);
            }

            if (!fixedRowHeadersWidth)
            {
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, false /*fixedRowsHeight*/);
            }

            // Autosize columns
            bool columnAutoSized = AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal.Header, false /*fixedHeight*/);

            if (!fixedRowHeadersWidth || columnAutoSized)
            {
                // Autosize rows
                AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
            }

            if (!fixedColumnHeadersHeight)
            {
                // Second round of column headers autosizing
                AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
            }

            if (!fixedRowHeadersWidth)
            {
                // Second round of row headers autosizing
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, true /*fixedRowsHeight*/);
            }

            // Second round of columns autosizing
            AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal.Header, true /*fixedHeight*/);
        }

        protected virtual void OnColumnHeadersHeightChanged(EventArgs e)
        {
            if (EditingControl != null)
            {
                PositionEditingControl(true, false, false);
            }

            UpdateMouseEnteredCell(hti: null, e: null);

            OnColumnHeadersGlobalAutoSize();

            if (Events[s_columnHeadersHeightChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnColumnHeadersHeightSizeModeChanged(DataGridViewAutoSizeModeEventArgs e)
        {
            if (_columnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                if (!e.PreviousModeAutoSized)
                {
                    // Save current column headers height for later reuse
                    _cachedColumnHeadersHeight = ColumnHeadersHeight;
                }
                AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
            }
            else if (e.PreviousModeAutoSized)
            {
                ColumnHeadersHeight = _cachedColumnHeadersHeight;
            }

            if (Events[s_columnHeadersHeightSizeModeChangedEvent] is DataGridViewAutoSizeModeEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnHidden(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);
            if (dataGridViewColumn.Displayed)
            {
                dataGridViewColumn.Displayed = false;
                DataGridViewColumnStateChangedEventArgs dgvrsce = new DataGridViewColumnStateChangedEventArgs(dataGridViewColumn, DataGridViewElementStates.Displayed);
                OnColumnStateChanged(dgvrsce);
            }
        }

        internal void OnColumnMinimumWidthChanging(DataGridViewColumn dataGridViewColumn, int minimumWidth)
        {
            if (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill && dataGridViewColumn.Width < minimumWidth)
            {
                // Force the filled column's width to be minimumWidth
                try
                {
                    _dataGridViewState2[State2_UsedFillWeightsDirty] = true;
                    dataGridViewColumn.DesiredMinimumWidth = minimumWidth;
                    PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
                }
                finally
                {
                    dataGridViewColumn.DesiredMinimumWidth = 0;
                }
                Debug.Assert(dataGridViewColumn.Width == minimumWidth);
            }
        }

        protected virtual void OnColumnMinimumWidthChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            if (e.Column.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
            {
                // Column's width may adjust smaller
                PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            }

            if (Events[s_columnMinimumWidthChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnNameChanged(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);
            DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
            OnColumnNameChanged(dgvce);
        }

        protected virtual void OnColumnNameChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            // Check if the column name is used as is in the column header
            DataGridViewColumn dataGridViewColumn = e.Column;

            if (dataGridViewColumn.HasHeaderCell && dataGridViewColumn.HeaderCell.Value is string &&
                string.Compare((string)dataGridViewColumn.HeaderCell.Value, dataGridViewColumn.Name, false, CultureInfo.InvariantCulture) == 0)
            {
                InvalidateCellPrivate(dataGridViewColumn.Index, -1);

                DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal = (DataGridViewAutoSizeColumnCriteriaInternal)dataGridViewColumn.InheritedAutoSizeMode;
                DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFiltered = autoSizeColumnCriteriaInternal & DataGridViewAutoSizeColumnCriteriaInternal.Header;
                bool fixedColumnWidth = autoSizeColumnCriteriaFiltered == 0 || !ColumnHeadersVisible;
                if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                {
                    AutoResizeColumnHeadersHeight(dataGridViewColumn.Index, true /*fixedRowHeadersWidth*/, fixedColumnWidth);
                }
                if (!fixedColumnWidth)
                {
                    bool fixedHeight = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) == 0;
                    AutoResizeColumnInternal(dataGridViewColumn.Index, autoSizeColumnCriteriaInternal, fixedHeight);
                    if (!fixedHeight)
                    {
                        AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                        // Second round of column autosizing
                        AutoResizeColumnInternal(dataGridViewColumn.Index, autoSizeColumnCriteriaInternal, true /*fixedHeight*/);
                    }
                    if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                    {
                        // Second round of column headers autosizing
                        AutoResizeColumnHeadersHeight(dataGridViewColumn.Index, true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
                    }
                }
            }

            if (Events[s_columnNameChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnColumnRemoved(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(dataGridViewColumn.DataGridView is null);
            OnColumnRemoved(new DataGridViewColumnEventArgs(dataGridViewColumn));
        }

        protected virtual void OnColumnRemoved(DataGridViewColumnEventArgs e)
        {
            if (Events[s_columnRemovedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnColumnSelectMouseMove(HitTestInfo hti)
        {
            Debug.Assert(hti._col >= 0);
            Debug.Assert(MultiSelect);

            if (_ptCurrentCell.X != -1 &&
                hti._col != _ptCurrentCell.X &&
                !CommitEditForOperation(hti._col, _ptCurrentCell.Y, true))
            {
                // Return silently if validating/commit/abort failed
                return;
            }
            if (IsColumnOutOfBounds(hti._col))
            {
                return;
            }

            _noSelectionChangeCount++;
            try
            {
                if (_trackColumnEdge >= 0 && (Columns.DisplayInOrder(_trackColumn, _trackColumnEdge) || _trackColumnEdge == _trackColumn) && Columns.DisplayInOrder(_trackColumnEdge, hti._col))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[_trackColumnEdge], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(dataGridViewColumn.Index, hti._col, true);
                    _trackColumnEdge = hti._col;
                }
                else if (_trackColumnEdge >= 0 && Columns.DisplayInOrder(_trackColumn, _trackColumnEdge) && Columns.DisplayInOrder(hti._col, _trackColumnEdge) && (Columns.DisplayInOrder(_trackColumn, hti._col) || hti._col == _trackColumn))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[hti._col], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(dataGridViewColumn.Index, _trackColumnEdge, false);
                    _trackColumnEdge = hti._col;
                }
                else if (_trackColumnEdge == -1 && Columns.DisplayInOrder(_trackColumn, hti._col))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[_trackColumn], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(dataGridViewColumn.Index, hti._col, true);
                    _trackColumnEdge = hti._col;
                }
                else if (_trackColumnEdge >= 0 && (Columns.DisplayInOrder(_trackColumnEdge, _trackColumn) || _trackColumnEdge == _trackColumn) && Columns.DisplayInOrder(hti._col, _trackColumnEdge))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[_trackColumnEdge], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(hti._col, dataGridViewColumn.Index, true);
                    _trackColumnEdge = hti._col;
                }
                else if (_trackColumnEdge >= 0 && Columns.DisplayInOrder(_trackColumnEdge, _trackColumn) && Columns.DisplayInOrder(_trackColumnEdge, hti._col) && (Columns.DisplayInOrder(hti._col, _trackColumn) || hti._col == _trackColumn))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[hti._col], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(_trackColumnEdge, dataGridViewColumn.Index, false);
                    _trackColumnEdge = hti._col;
                }
                else if (_trackColumnEdge == -1 && Columns.DisplayInOrder(hti._col, _trackColumn))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[_trackColumn], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(hti._col, dataGridViewColumn.Index, true);
                    _trackColumnEdge = hti._col;
                }
                else if (_trackColumnEdge >= 0 && Columns.DisplayInOrder(_trackColumn, _trackColumnEdge) && Columns.DisplayInOrder(hti._col, _trackColumn))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[_trackColumn], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(dataGridViewColumn.Index, _trackColumnEdge, false);
                    dataGridViewColumn = Columns.GetPreviousColumn(Columns[_trackColumn], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(hti._col, dataGridViewColumn.Index, true);
                    _trackColumnEdge = hti._col;
                }
                else if (_trackColumnEdge >= 0 && Columns.DisplayInOrder(_trackColumn, hti._col) && Columns.DisplayInOrder(_trackColumnEdge, _trackColumn))
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[_trackColumn], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(_trackColumnEdge, dataGridViewColumn.Index, false);
                    dataGridViewColumn = Columns.GetNextColumn(Columns[_trackColumn], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectColumnRange(dataGridViewColumn.Index, hti._col, true);
                    _trackColumnEdge = hti._col;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }

            if (_ptCurrentCell.X != -1 && hti._col != _ptCurrentCell.X)
            {
                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(hti._col))
                {
                    return;
                }
                bool success = SetCurrentCellAddressCore(hti._col,
                    _ptCurrentCell.Y,
                    false /*setAnchorCellAddress*/,
                    false /*validateCurrentCell*/,
                    false /*throughMouseClick*/);
                Debug.Assert(success);
            }
        }

        private void OnColumnsGlobalAutoSize()
        {
            InvalidateData();

            if (_noAutoSizeCount > 0)
            {
                return;
            }

            // Auto-size columms if needed
            bool fixedHeight = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) == 0;
            bool columnAutoSized = AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal.AllRows | DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows, fixedHeight);
            // Autosize rows if needed
            if (!fixedHeight)
            {
                if (columnAutoSized)
                {
                    AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                }
                // Second round of columns autosizing
                AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal.AllRows | DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows, true /*fixedHeight*/);
            }
        }

        internal void OnColumnSortModeChanged(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn != null);
            DataGridViewColumnEventArgs dgvce = new DataGridViewColumnEventArgs(dataGridViewColumn);
            OnColumnSortModeChanged(dgvce);
        }

        protected virtual void OnColumnSortModeChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            DataGridViewColumn dataGridViewColumn = e.Column;

            if (dataGridViewColumn.HasHeaderCell)
            {
                if (dataGridViewColumn.SortMode == DataGridViewColumnSortMode.NotSortable ||
                    (dataGridViewColumn.SortMode == DataGridViewColumnSortMode.Programmatic && SortedColumn == dataGridViewColumn))
                {
                    dataGridViewColumn.HeaderCell.SortGlyphDirection = SortOrder.None;
                    // This call will trigger OnSortGlyphDirectionChanged which in turn does
                    // this.sortedColumn = null; and InvalidateCellPrivate(e.Column.Index, -1);
                }
                // Potential resizing of the column headers and/or affected column.
                DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaInternal = (DataGridViewAutoSizeColumnCriteriaInternal)dataGridViewColumn.InheritedAutoSizeMode;
                DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFiltered = autoSizeColumnCriteriaInternal & DataGridViewAutoSizeColumnCriteriaInternal.Header;
                bool fixedColumnWidth = autoSizeColumnCriteriaFiltered == 0 || !ColumnHeadersVisible;
                if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                {
                    AutoResizeColumnHeadersHeight(dataGridViewColumn.Index, true /*fixedRowHeadersWidth*/, fixedColumnWidth);
                }
                if (!fixedColumnWidth)
                {
                    bool fixedHeight = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) == 0;
                    AutoResizeColumnInternal(dataGridViewColumn.Index, autoSizeColumnCriteriaInternal, fixedHeight);
                    if (!fixedHeight)
                    {
                        AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                        // Second round of column autosizing
                        AutoResizeColumnInternal(dataGridViewColumn.Index, autoSizeColumnCriteriaInternal, true /*fixedHeight*/);
                    }
                    if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                    {
                        // Second round of column headers autosizing
                        AutoResizeColumnHeadersHeight(dataGridViewColumn.Index, true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
                    }
                }
            }

            if (Events[s_columnSortModeChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnColumnStateChanged(DataGridViewColumnStateChangedEventArgs e)
        {
            // column.Frozen | .Visible changed - this may require a complete re-layout of the control
            DataGridViewColumn dataGridViewColumn = e.Column;
            switch (e.StateChanged)
            {
                // At this point we assume that only the Selected state has an influence on the rendering of the column.
                // If there is a customer scenario where another state has an influence, the dev must invalidate the column by hand.
                // case DataGridViewElementStates.ReadOnly:
                // case DataGridViewElementStates.Resizable:

                case DataGridViewElementStates.Selected:
                    if (dataGridViewColumn.Visible && _inBulkPaintCount == 0)
                    {
                        InvalidateColumnInternal(dataGridViewColumn.Index);
                    }
                    break;

                case DataGridViewElementStates.Frozen:
                    if (dataGridViewColumn.Visible)
                    {
                        if (dataGridViewColumn.Frozen)
                        {
                            // visible column became frozen
                            if (_horizontalOffset >= dataGridViewColumn.Thickness)
                            {
                                Debug.Assert(Columns.DisplayInOrder(dataGridViewColumn.Index, DisplayedBandsInfo.FirstDisplayedScrollingCol));
                                _horizontalOffset -= dataGridViewColumn.Thickness;
                            }
                            else
                            {
                                _horizontalOffset = FirstDisplayedScrollingColumnHiddenWidth = 0;
                            }
                        }
                        else
                        {
                            // column was unfrozen - make it the first visible scrolling column if there is room
                            _horizontalOffset = FirstDisplayedScrollingColumnHiddenWidth = 0;
                        }
                        if (_horizScrollBar.Enabled)
                        {
                            _horizScrollBar.Value = _horizontalOffset;
                        }

                        // UsedFillWeight values need to be updated
                        _dataGridViewState2[State2_UsedFillWeightsDirty] = true;

                        PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, true /*repositionEditingControl*/);
                        Invalidate();
                    }
                    break;

                case DataGridViewElementStates.Visible:
                    if (!dataGridViewColumn.Visible && dataGridViewColumn.Displayed)
                    {
                        // Displayed column becomes invisible. Turns off the Displayed state.
                        dataGridViewColumn.Displayed = false;
                    }

                    // UsedFillWeight values need to be updated
                    _dataGridViewState2[State2_UsedFillWeightsDirty] = true;

                    PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, true /*repositionEditingControl*/);

                    bool autoSizeRows = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0 ||
                                        ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.Header) != 0 &&
                                        RowHeadersVisible);
                    bool autoSizeColumn = false;
                    DataGridViewAutoSizeColumnMode autoSizeColumnMode = dataGridViewColumn.InheritedAutoSizeMode;
                    Debug.Assert(autoSizeColumnMode != DataGridViewAutoSizeColumnMode.NotSet);
                    if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.None &&
                        autoSizeColumnMode != DataGridViewAutoSizeColumnMode.Fill)
                    {
                        // Column autosizes
                        int width = dataGridViewColumn.ThicknessInternal;
                        if (dataGridViewColumn.Visible)
                        {
                            // Cache column's width before potential autosizing occurs
                            dataGridViewColumn.CachedThickness = width;
                            AutoResizeColumnInternal(dataGridViewColumn.Index, (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode, !autoSizeRows /*fixedHeight*/);
                            autoSizeColumn = true;
                        }
                        else if (width != dataGridViewColumn.CachedThickness)
                        {
                            // Columns that are made invisible in the collection take their non-autosized width
                            dataGridViewColumn.ThicknessInternal = Math.Max(dataGridViewColumn.MinimumWidth, dataGridViewColumn.CachedThickness);
                        }
                    }

                    if (autoSizeRows)
                    {
                        if (dataGridViewColumn.Visible)
                        {
                            AdjustExpandingRows(dataGridViewColumn.Index, true /*fixedWidth*/);
                        }
                        else
                        {
                            AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                        }
                        if (autoSizeColumn)
                        {
                            // Second round of column autosizing
                            AutoResizeColumnInternal(dataGridViewColumn.Index, (DataGridViewAutoSizeColumnCriteriaInternal)autoSizeColumnMode, true /*fixedHeight*/);
                        }
                    }
                    else
                    {
                        Invalidate();
                    }
                    break;
            }

            if (Events[s_columnStateChangedEvent] is DataGridViewColumnStateChangedEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (e.StateChanged == DataGridViewElementStates.ReadOnly &&
                dataGridViewColumn.Index == _ptCurrentCell.X &&
                !_dataGridViewOper[OperationInReadOnlyChange])
            {
                VerifyImeRestrictedModeChanged();

                if (!dataGridViewColumn.ReadOnly &&
                    ColumnEditable(_ptCurrentCell.X) &&
                    (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.ReadOnly) == 0 &&
                     !IsCurrentCellInEditMode &&
                     (EditMode == DataGridViewEditMode.EditOnEnter ||
                      (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null)))
                {
                    // Current column becomes read/write. Enter editing mode.
                    BeginEditInternal(true /*selectAll*/);
                }
            }
        }

        internal void OnColumnToolTipTextChanged(DataGridViewColumn dataGridViewColumn)
        {
            OnColumnToolTipTextChanged(new DataGridViewColumnEventArgs(dataGridViewColumn));
        }

        protected virtual void OnColumnToolTipTextChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            if (Events[s_columnTooltipTextChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnColumnWidthChanged(DataGridViewColumnEventArgs e)
        {
            if (e.Column.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }
            Columns.InvalidateCachedColumnsWidths();

            // don't do any layout logic if the handle was not created already
            if (e.Column.Visible && IsHandleCreated)
            {
                PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);

                Rectangle rightArea = _layout.Data;
                if (_layout.ColumnHeadersVisible)
                {
                    rightArea = Rectangle.Union(rightArea, _layout.ColumnHeaders);
                }
                else if (SingleHorizontalBorderAdded)
                {
                    rightArea.Y--;
                    rightArea.Height++;
                }
                if (rightArea.Width > 0 && rightArea.Height > 0)
                {
                    int leftEdge = GetColumnXFromIndex(e.Column.Index);
                    if (RightToLeftInternal)
                    {
                        rightArea.Width -= rightArea.Right - leftEdge;
                    }
                    else
                    {
                        rightArea.Width -= leftEdge - rightArea.X;
                        rightArea.X = leftEdge;
                    }
                    if (rightArea.Width > 0 && rightArea.Height > 0)
                    {
                        Invalidate(rightArea);
                    }
                }

                if (EditingControl != null)
                {
                    PositionEditingControl(_ptCurrentCell.X != e.Column.Index, true, false);
                }

                UpdateMouseEnteredCell(hti: null, e: null);

                if (AutoSize)
                {
                    LayoutTransaction.DoLayout(ParentInternal, this, PropertyNames.Columns);
                }
            }

            if (Events[s_columnWidthChangedEvent] is DataGridViewColumnEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (!InAdjustFillingColumns)
            {
                // Autosize rows and column headers if needed
                OnColumnGlobalAutoSize(e.Column.Index);
            }
        }

        internal void OnCommonCellContentClick(int columnIndex, int rowIndex, bool doubleClick)
        {
            if (_ptMouseDownCell.X == -2 ||
                (_dataGridViewState2[State2_CellMouseDownInContentBounds] &&
                 _ptMouseDownCell.X == columnIndex && _ptMouseDownCell.Y == rowIndex &&
                 (_ptMouseDownCell.X == -1 || _ptMouseDownCell.Y == -1 ||
                  (columnIndex == _ptCurrentCell.X && rowIndex == _ptCurrentCell.Y))))
            {
                DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(columnIndex, rowIndex);
                if (doubleClick)
                {
                    OnCellContentDoubleClick(dgvce);
                }
                else
                {
                    OnCellContentClick(dgvce);
                }
            }
        }

        protected virtual void OnCurrentCellChanged(EventArgs e)
        {
            VerifyImeRestrictedModeChanged();
            if (Events[s_currentCellChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (CurrentCell != null && (ShowCellToolTips || (ShowCellErrors && !string.IsNullOrEmpty(CurrentCell?.ErrorText))))
            {
                ActivateToolTip(false /*activate*/, String.Empty, CurrentCell.ColumnIndex, CurrentCell.RowIndex);
                KeyboardToolTipStateMachine.Instance.NotifyAboutGotFocus(CurrentCell);
            }
        }

        protected virtual void OnCurrentCellDirtyStateChanged(EventArgs e)
        {
            if (RowHeadersVisible && ShowEditingIcon)
            {
                // Force the pencil to appear in the row header
                InvalidateCellPrivate(-1, _ptCurrentCell.Y);
            }
            if (IsCurrentCellDirty && NewRowIndex == _ptCurrentCell.Y)
            {
                Debug.Assert(AllowUserToAddRowsInternal);
                // First time the 'new' row gets edited.
                // It becomes a regular row and a new 'new' row is appened.
                NewRowIndex = -1;
                AddNewRow(true /*createdByEditing*/);
            }

            if (Events[s_currentCellDirtyStateChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected override void OnCursorChanged(EventArgs e)
        {
            base.OnCursorChanged(e);
            if (!_dataGridViewState2[State2_IgnoreCursorChange])
            {
                _oldCursor = Cursor;
            }
        }

        internal void OnDataBindingComplete(ListChangedType listChangedType)
        {
            OnDataBindingComplete(new DataGridViewBindingCompleteEventArgs(listChangedType));
        }

        protected virtual void OnDataBindingComplete(DataGridViewBindingCompleteEventArgs e)
        {
            if (Events[s_dataBindingCompleteEvent] is DataGridViewBindingCompleteEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnDataError(bool displayErrorDialogIfNoHandler, DataGridViewDataErrorEventArgs e)
        {
            if (!_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                if (!(Events[s_dataErrorEvent] is DataGridViewDataErrorEventHandler eh))
                {
                    if (displayErrorDialogIfNoHandler)
                    {
                        string errorText;
                        if (e.Exception is null)
                        {
                            errorText = SR.DataGridView_ErrorMessageText_NoException;
                        }
                        else
                        {
                            errorText = string.Format(SR.DataGridView_ErrorMessageText_WithException, e.Exception);
                        }
                        if (RightToLeftInternal)
                        {
                            MessageBox.Show(errorText, SR.DataGridView_ErrorMessageCaption, MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1, MessageBoxOptions.RightAlign | MessageBoxOptions.RtlReading);
                        }
                        else
                        {
                            MessageBox.Show(errorText, SR.DataGridView_ErrorMessageCaption, MessageBoxButtons.OK, MessageBoxIcon.Error);
                        }
                        CorrectFocus(true /*onlyIfGridHasFocus*/);
                    }
                }
                else
                {
                    eh(this, e);
                    CorrectFocus(true /*onlyIfGridHasFocus*/);
                }
            }
        }

        internal void OnDataErrorInternal(DataGridViewDataErrorEventArgs e)
        {
            OnDataError(!DesignMode /*displayErrorDialogIfNoHandler*/, e);
        }

        internal void OnDataGridViewElementStateChanged(DataGridViewElement element, int index, DataGridViewElementStates elementState)
        {
            if (element is DataGridViewColumn dataGridViewColumn)
            {
                DataGridViewColumnStateChangedEventArgs dgvcsce = new DataGridViewColumnStateChangedEventArgs(dataGridViewColumn, elementState);

                OnColumnStateChanged(dgvcsce);
            }
            else
            {
                if (element is DataGridViewRow dataGridViewRow)
                {
                    if (Events[s_rowStateChangedEvent] is DataGridViewRowStateChangedEventHandler eh && dataGridViewRow.DataGridView != null && dataGridViewRow.Index == -1)
                    {
                        dataGridViewRow = Rows[index];
                    }

                    DataGridViewRowStateChangedEventArgs dgvrsce = new DataGridViewRowStateChangedEventArgs(dataGridViewRow, elementState);

                    OnRowStateChanged(dataGridViewRow.Index == -1 ? index : dataGridViewRow.Index, dgvrsce);
                }
                else
                {
                    if (element is DataGridViewCell dataGridViewCell)
                    {
                        DataGridViewCellStateChangedEventArgs dgvcsce = new DataGridViewCellStateChangedEventArgs(dataGridViewCell, elementState);

                        OnCellStateChanged(dgvcsce);
                    }
                }
            }

            if ((elementState & DataGridViewElementStates.Selected) == DataGridViewElementStates.Selected)
            {
                if (_noSelectionChangeCount > 0)
                {
                    _dataGridViewState2[State2_RaiseSelectionChanged] = true;
                }
                else
                {
                    OnSelectionChanged(EventArgs.Empty);
                }
            }
        }

        internal void OnDataGridViewElementStateChanging(DataGridViewElement element, int index, DataGridViewElementStates elementState)
        {
            if (element is DataGridViewColumn dataGridViewColumn)
            {
                // column.Frozen | .Visible | .ReadOnly changing
                switch (elementState)
                {
                    case DataGridViewElementStates.Frozen:
                    case DataGridViewElementStates.Visible:
                        if (elementState == DataGridViewElementStates.Visible)
                        {
                            if (!dataGridViewColumn.Visible &&
                                dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.ColumnHeader &&
                                !ColumnHeadersVisible)
                            {
                                throw new InvalidOperationException(SR.DataGridView_CannotMakeAutoSizedColumnVisible);
                            }
                            else if (!dataGridViewColumn.Visible &&
                                dataGridViewColumn.Frozen &&
                                dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                            {
                                // alternative: throw new InvalidOperationException(SR.DataGridView_CannotMakeAutoFillColumnVisible);
                                //              DataGridView_CannotMakeAutoFillColumnVisible=The column cannot be made visible because its autosizing mode is Fill and it is frozen.
                                // Removing the Fill auto size mode when frozen column becomes visible (instead of throwing an exception)
                                dataGridViewColumn.AutoSizeMode = DataGridViewAutoSizeColumnMode.None;
                            }
                            else if (dataGridViewColumn.Visible && _ptCurrentCell.X == dataGridViewColumn.Index)
                            {
                                // Column of the current cell is made invisible. Trying to reset the current cell. May throw an exception.
                                ResetCurrentCell();
                                // Microsoft: Should the current cell be set to some cell after the operation?
                            }
                        }
                        if (elementState == DataGridViewElementStates.Frozen &&
                            !dataGridViewColumn.Frozen &&
                            dataGridViewColumn.Visible &&
                            dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill)
                        {
                            // Removing the Fill auto size mode when visible column becomes frozen (instead of throwing an exception)
                            dataGridViewColumn.AutoSizeMode = DataGridViewAutoSizeColumnMode.None;
                        }
                        CorrectColumnFrozenStates(dataGridViewColumn, elementState == DataGridViewElementStates.Frozen);
                        break;

                    case DataGridViewElementStates.ReadOnly:
                        if (_ptCurrentCell.X == dataGridViewColumn.Index &&
                            IsCurrentCellInEditMode &&
                            !dataGridViewColumn.ReadOnly &&
                            !_dataGridViewOper[OperationInReadOnlyChange])
                        {
                            Debug.Assert(!ReadOnly);
                            // Column becomes read-only. Exit editing mode.
                            if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit,
                                        DataGridViewValidateCellInternal.Always /*validateCell*/,
                                        false /*fireCellLeave*/,
                                        false /*fireCellEnter*/,
                                        false /*fireRowLeave*/,
                                        false /*fireRowEnter*/,
                                        false /*fireLeave*/,
                                        true /*keepFocus*/,
                                        false /*resetCurrentCell*/,
                                        false /*resetAnchorCell*/))
                            {
                                throw new InvalidOperationException(SR.DataGridView_CommitFailedCannotCompleteOperation);
                            }
                        }
                        break;

                    default:
                        Debug.Fail("Unexpected DataGridViewElementStates param in DataGridView.OnDataGridViewElementStateChanging");
                        break;
                }
            }
            else
            {
                if (element is DataGridViewRow dataGridViewRow)
                {
                    // row.Frozen | .Visible | .ReadOnly changing
                    int rowIndex = ((dataGridViewRow.Index > -1) ? dataGridViewRow.Index : index);
                    switch (elementState)
                    {
                        case DataGridViewElementStates.Frozen:
                        case DataGridViewElementStates.Visible:
                            if (elementState == DataGridViewElementStates.Visible && _ptCurrentCell.Y == rowIndex)
                            {
                                Debug.Assert((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) != 0);
                                // Row of the current cell is made invisible.
                                if (DataSource != null)
                                {
                                    Debug.Assert(DataConnection != null);
                                    Debug.Assert(DataConnection.CurrencyManager != null);
                                    Debug.Assert(DataConnection.CurrencyManager.Position == _ptCurrentCell.Y);
                                    // the row associated with the currency manager's position cannot be made invisble.
                                    throw new InvalidOperationException(SR.DataGridView_CurrencyManagerRowCannotBeInvisible);
                                }
                                // Trying to reset the current cell. May throw an exception.
                                ResetCurrentCell();
                                // Microsoft: Should the current cell be set to some cell after the operation?
                            }
                            CorrectRowFrozenStates(dataGridViewRow, rowIndex, elementState == DataGridViewElementStates.Frozen);
                            break;

                        case DataGridViewElementStates.ReadOnly:
                            if (_ptCurrentCell.Y == rowIndex &&
                                (Rows.GetRowState(rowIndex) & DataGridViewElementStates.ReadOnly) == 0 &&
                                !ReadOnly &&
                                IsCurrentCellInEditMode &&
                                !_dataGridViewOper[OperationInReadOnlyChange])
                            {
                                // Row becomes read-only. Exit editing mode.
                                if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit,
                                            DataGridViewValidateCellInternal.Always /*validateCell*/,
                                            false /*fireCellLeave*/,
                                            false /*fireCellEnter*/,
                                            false /*fireRowLeave*/,
                                            false /*fireRowEnter*/,
                                            false /*fireLeave*/,
                                            true /*keepFocus*/,
                                            false /*resetCurrentCell*/,
                                            false /*resetAnchorCell*/))
                                {
                                    throw new InvalidOperationException(SR.DataGridView_CommitFailedCannotCompleteOperation);
                                }
                            }
                            break;

                        default:
                            Debug.Fail("Unexpected DataGridViewElementStates param in DataGridView.OnDataGridViewElementStateChanging");
                            break;
                    }
                }
                else
                {
                    if (element is DataGridViewCell dataGridViewCell)
                    {
                        // cell.ReadOnly changing
                        switch (elementState)
                        {
                            case DataGridViewElementStates.ReadOnly:
                                if (_ptCurrentCell.X == dataGridViewCell.ColumnIndex &&
                                    _ptCurrentCell.Y == dataGridViewCell.RowIndex &&
                                    IsCurrentCellInEditMode &&
                                    !dataGridViewCell.ReadOnly &&
                                    !_dataGridViewOper[OperationInReadOnlyChange])
                                {
                                    Debug.Assert(!Columns[dataGridViewCell.ColumnIndex].ReadOnly);
                                    Debug.Assert(!Rows[dataGridViewCell.RowIndex].ReadOnly);
                                    Debug.Assert(!ReadOnly);
                                    // Current cell becomes read-only. Exit editing mode.
                                    if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit,
                                                DataGridViewValidateCellInternal.Always /*validateCell*/,
                                                false /*fireCellLeave*/,
                                                false /*fireCellEnter*/,
                                                false /*fireRowLeave*/,
                                                false /*fireRowEnter*/,
                                                false /*fireLeave*/,
                                                true /*keepFocus*/,
                                                false /*resetCurrentCell*/,
                                                false /*resetAnchorCell*/))
                                    {
                                        throw new InvalidOperationException(SR.DataGridView_CommitFailedCannotCompleteOperation);
                                    }
                                }
                                break;

                            default:
                                Debug.Fail("Unexpected DataGridViewElementStates param in DataGridView.OnDataGridViewElementStateChanging");
                                break;
                        }
                    }
                    else
                    {
                        Debug.Fail("Unexpected DataGridViewElement type in DataGridView.OnDataGridViewElementStateChanging");
                    }
                }
            }
        }

        protected virtual void OnDataMemberChanged(EventArgs e)
        {
            RefreshColumnsAndRows();

            if (Events[s_dataMemberChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (DataConnection != null && DataConnection.CurrencyManager != null)
            {
                OnDataBindingComplete(ListChangedType.Reset);
            }
        }

        protected virtual void OnDataSourceChanged(EventArgs e)
        {
            RefreshColumnsAndRows();
            InvalidateRowHeights();

            if (Events[s_dataSourceChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (DataConnection != null && DataConnection.CurrencyManager != null)
            {
                OnDataBindingComplete(ListChangedType.Reset);
            }
        }

        protected virtual void OnDefaultCellStyleChanged(EventArgs e)
        {
            if (e is DataGridViewCellStyleChangedEventArgs dgvcsce && !dgvcsce.ChangeAffectsPreferredSize)
            {
                Invalidate();
            }
            else
            {
                OnGlobalAutoSize();
                if (EditingControl != null)
                {
                    PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                }
            }

            if (Events[s_defaultCellStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnDefaultValuesNeeded(DataGridViewRowEventArgs e)
        {
            if (Events[s_defaultValuesNeededEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected override void OnDoubleClick(EventArgs e)
        {
            base.OnDoubleClick(e);

            if (!_dataGridViewState2[State2_MessageFromEditingCtrls] && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                if (e is MouseEventArgs me)
                {
                    HitTestInfo hti = HitTest(me.X, me.Y);
                    if (hti.Type != DataGridViewHitTestType.None &&
                        hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                        hti.Type != DataGridViewHitTestType.VerticalScrollBar &&
                        me.Button == MouseButtons.Left)
                    {
                        OnCellDoubleClick(new DataGridViewCellEventArgs(hti._col, hti._row));
                    }
                }
            }
        }

        protected virtual void OnEditingControlShowing(DataGridViewEditingControlShowingEventArgs e)
        {
            if (Events[s_editingControlShowingEvent] is DataGridViewEditingControlShowingEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnEditModeChanged(EventArgs e)
        {
            if (Focused &&
                EditMode == DataGridViewEditMode.EditOnEnter &&
                _ptCurrentCell.X > -1 &&
                !IsCurrentCellInEditMode)
            {
                // New edit mode is EditOnEnter and there is an editable current cell, try to go to edit mode.
                BeginEditInternal(true /*selectAll*/);
            }

            if (Events[s_editModeChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected override void OnEnabledChanged(EventArgs e)
        {
            base.OnEnabledChanged(e);
            if (GetAnyDisposingInHierarchy())
            {
                return;
            }

            if (IsHandleCreated && Enabled)
            {
                if (_vertScrollBar != null && _vertScrollBar.Visible)
                {
                    int totalVisibleHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible);
                    int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    _vertScrollBar.Maximum = totalVisibleHeight - totalVisibleFrozenHeight;

                    _vertScrollBar.Enabled = true;
                }
                if (_horizScrollBar != null && _horizScrollBar.Visible)
                {
                    _horizScrollBar.Enabled = true;
                }
            }
        }

        protected override void OnEnter(EventArgs e)
        {
            if (EditingControl != null && EditingControl.ContainsFocus)
            {
                return;
            }

            base.OnEnter(e);

            // There are cases when a control is on the designer and it still receives the OnEnter event.
            // Guard against this.
            if (DesignMode)
            {
                return;
            }

            _dataGridViewState1[State1_LeavingWithTabKey] = false;

            if (_ptCurrentCell.X > -1)
            {
                DataGridViewCell dataGridViewCell = null;
                // We're re-entering a row we already entered earlier. The first time we entered the row,
                // the DataGridView didn't have focus. This time it does. We don't want to recreate the new row a second time.
                OnRowEnter(ref dataGridViewCell, _ptCurrentCell.X, _ptCurrentCell.Y, false /*canCreateNewRow*/, false /*validationFailureOccurred*/);
                if (_ptCurrentCell.X == -1)
                {
                    return;
                }
                OnCellEnter(ref dataGridViewCell, _ptCurrentCell.X, _ptCurrentCell.Y);

                // Force repainting of the current collumn's header cell to highlight it
                if (SelectionMode == DataGridViewSelectionMode.FullRowSelect)
                {
                    InvalidateCellPrivate(_ptCurrentCell.X, -1);
                }
            }
            else if (!_dataGridViewOper[OperationInMouseDown])
            {
                // Focus is given to the DataGridView control via a the TAB key.
                MakeFirstDisplayedCellCurrentCell(true /*includeNewRow*/);
            }

            if (_ptCurrentCell.X > -1 &&
                !IsCurrentCellInEditMode)
            {
                if (EditMode == DataGridViewEditMode.EditOnEnter ||
                   (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null))
                {
                    BeginEditInternal(true /*selectAll*/);
                    if (_ptCurrentCell.X > -1 && CurrentCellInternal.EditType is null && !_dataGridViewOper[OperationInMouseDown])
                    {
                        // The current cell does not have an edit type so the data grid view did not put an edit control on top.
                        // We should invalidate the current cell so that the dataGridView repaints the focus around the current cell.
                        // But do that only if the dataGridView did not get the focus via mouse.
                        InvalidateCellPrivate(_ptCurrentCell.X /*columnIndex*/, _ptCurrentCell.Y /*rowIndex*/);
                    }
                }
                else if (!_dataGridViewOper[OperationInMouseDown])
                {
                    // When the focus is given to the DataGridView control via mouse
                    // the dataGridView changes selection so it invalidates the current cell anyway
                    //
                    // In any other case Invalidate the current cell so the dataGridView repaints the focus around the current cell
                    InvalidateCellPrivate(_ptCurrentCell.X /*columnIndex*/, _ptCurrentCell.Y /*rowIndex*/);
                }
            }

            // Draw focus rectangle around the grid
            if (IsGridFocusRectangleEnabled())
            {
                InvalidateRectangleEdges(GetGridFocusRectangle());
            }
        }

        protected override void OnFontChanged(EventArgs e)
        {
            base.OnFontChanged(e);

            if (GetAnyDisposingInHierarchy())
            {
                return;
            }

            // Change may be due to an ambient font change.
            if (_dataGridViewState1[State1_AmbientColumnHeadersFont] &&
                ColumnHeadersDefaultCellStyle.Font != base.Font)
            {
                ColumnHeadersDefaultCellStyle.Font = base.Font;
                _dataGridViewState1[State1_AmbientColumnHeadersFont] = true;
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = true;
                OnColumnHeadersDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }

            if (_dataGridViewState1[State1_AmbientRowHeadersFont] &&
                RowHeadersDefaultCellStyle.Font != base.Font)
            {
                RowHeadersDefaultCellStyle.Font = base.Font;
                _dataGridViewState1[State1_AmbientRowHeadersFont] = true;
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = true;
                OnRowHeadersDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }

            if (_dataGridViewState1[State1_AmbientFont] &&
                DefaultCellStyle.Font != base.Font)
            {
                DefaultCellStyle.Font = base.Font;
                _dataGridViewState1[State1_AmbientFont] = true;
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = true;
                OnDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }
        }

        protected override void OnForeColorChanged(EventArgs e)
        {
            base.OnForeColorChanged(e);
            if (GetAnyDisposingInHierarchy())
            {
                return;
            }

            // Change may be due to an ambient forecolor change.
            if (_dataGridViewState1[State1_AmbientForeColor] && DefaultCellStyle.ForeColor != base.ForeColor)
            {
                DefaultCellStyle.ForeColor = base.ForeColor;
                _dataGridViewState1[State1_AmbientForeColor] = true;
                CellStyleChangedEventArgs.ChangeAffectsPreferredSize = false;
                OnDefaultCellStyleChanged(CellStyleChangedEventArgs);
            }
        }

        private void OnGlobalAutoSize()
        {
            Invalidate();

            if (_noAutoSizeCount > 0)
            {
                return;
            }

            bool autoSizeRowHeaders = _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.EnableResizing &&
                                      _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.DisableResizing;
            if (autoSizeRowHeaders)
            {
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode,
                                          ColumnHeadersHeightSizeMode != DataGridViewColumnHeadersHeightSizeMode.AutoSize /*fixedColumnHeadersHeight*/,
                                          _autoSizeRowsMode == DataGridViewAutoSizeRowsMode.None /*fixedRowsHeight*/);
            }

            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                AutoResizeColumnHeadersHeight(fixedRowHeadersWidth: true, fixedColumnsWidth: false);
            }
            if (_autoSizeRowsMode != DataGridViewAutoSizeRowsMode.None)
            {
                AdjustShrinkingRows(_autoSizeRowsMode, false /*fixedWidth*/, true /*internalAutosizing*/);
            }

            AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal.Header | DataGridViewAutoSizeColumnCriteriaInternal.AllRows | DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows, true /*fixedHeight*/);

            if (autoSizeRowHeaders &&
                (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize || _autoSizeRowsMode != DataGridViewAutoSizeRowsMode.None))
            {
                // Second round of row headers autosizing
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, true /*fixedRowsHeight*/);
            }
            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                // Second round of column headers autosizing
                AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
            }
            if (_autoSizeRowsMode != DataGridViewAutoSizeRowsMode.None)
            {
                // Second round of rows autosizing
                AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
            }
        }

        protected override void OnGotFocus(EventArgs e)
        {
            base.OnGotFocus(e);
            if (_ptCurrentCell.X != -1)
            {
                InvalidateCell(_ptCurrentCell.X, _ptCurrentCell.Y);
            }

            // Inform Accessibility that our current cell contains the focus.
            if (!_dataGridViewOper[OperationInCurrentCellChange] &&
                (!_dataGridViewOper[OperationInEndEdit] || EditMode != DataGridViewEditMode.EditOnEnter) &&
                (!_dataGridViewOper[OperationInMouseDown] || EditMode != DataGridViewEditMode.EditOnEnter) &&
                _ptCurrentCell.X > -1)
            {
                // The name is misleading ( the current cell did not change ).
                // However, AccessibilityNotifyCurrentCellChanged is now a public method so we can't change its name
                // to better reflect its purpose.
                AccessibilityNotifyCurrentCellChanged(_ptCurrentCell);
                if (CurrentCell != null && (ShowCellToolTips || (ShowCellErrors && !string.IsNullOrEmpty(CurrentCell.ErrorText))))
                {
                    ActivateToolTip(false /*activate*/, String.Empty, CurrentCell.ColumnIndex, CurrentCell.RowIndex);
                    KeyboardToolTipStateMachine.Instance.NotifyAboutGotFocus(CurrentCell);
                }
            }
        }

        protected virtual void OnGridColorChanged(EventArgs e)
        {
            InvalidateInside();

            if (Events[s_gridColorChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected override void OnHandleCreated(EventArgs e)
        {
            base.OnHandleCreated(e);

            if (_layout._dirty)
            {
                PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            }
            if (_ptCurrentCell.X == -1)
            {
                MakeFirstDisplayedCellCurrentCell(false /*includeNewRow*/);
            }
            else
            {
                ScrollIntoView(_ptCurrentCell.X, _ptCurrentCell.Y, false /*forCurrentCellChange*/);
            }

            // do the AutoSize work that was skipped during initialization
            if (_dataGridViewState2[State2_AutoSizedWithoutHandle])
            {
                _dataGridViewState2[State2_AutoSizedWithoutHandle] = false;
                OnGlobalAutoSize();
            }
            SystemEvents.UserPreferenceChanged += new UserPreferenceChangedEventHandler(OnUserPreferenceChanged);
        }

        protected override void OnHandleDestroyed(EventArgs e)
        {
            SystemEvents.UserPreferenceChanged -= new UserPreferenceChangedEventHandler(OnUserPreferenceChanged);
            base.OnHandleDestroyed(e);
        }

        internal void OnInsertedColumn_PreNotification(DataGridViewColumn dataGridViewColumn)
        {
            // Fix the OldFirstDisplayedScrollingCol
            DisplayedBandsInfo.CorrectColumnIndexAfterInsertion(dataGridViewColumn.Index, 1);

            // Fix the Index of all following columns
            CorrectColumnIndexesAfterInsertion(dataGridViewColumn, 1);

            // Same effect as appending a column
            OnAddedColumn(dataGridViewColumn);
        }

        internal void OnInsertedColumn_PostNotification(Point newCurrentCell)
        {
            // Update current cell if needed
            if (newCurrentCell.X != -1)
            {
                Debug.Assert(_ptCurrentCell.X == -1);
                bool success = SetAndSelectCurrentCellAddress(newCurrentCell.X,
                                                              newCurrentCell.Y,
                                                              true,
                                                              false,
                                                              false,
                                                              false /*clearSelection*/,
                                                              Columns.GetColumnCount(DataGridViewElementStates.Visible) == 1 /*forceCurrentCellSelection*/);
                Debug.Assert(success);
            }
        }

        internal void OnInsertedRow_PreNotification(int rowIndex, int insertionCount)
        {
            Debug.Assert(rowIndex >= 0);
            Debug.Assert(insertionCount > 0);

            // Fix the OldFirstDisplayedScrollingRow
            DisplayedBandsInfo.CorrectRowIndexAfterInsertion(rowIndex, insertionCount);

            // Fix the Index of all following rows
            CorrectRowIndexesAfterInsertion(rowIndex, insertionCount);

            // Next, same effect as adding a row
            OnAddedRow_PreNotification(rowIndex);
        }

        internal void OnInsertedRow_PostNotification(int rowIndex, Point newCurrentCell, bool lastInsertion)
        {
            Debug.Assert(rowIndex >= 0);

            // Same effect as adding a row
            OnAddedRow_PostNotification(rowIndex);

            // Update current cell if needed
            if (lastInsertion && newCurrentCell.Y != -1)
            {
                Debug.Assert(_ptCurrentCell.X == -1);
                bool success = SetAndSelectCurrentCellAddress(newCurrentCell.X,
                                                              newCurrentCell.Y,
                                                              true,
                                                              false,
                                                              false,
                                                              false /*clearSelection*/,
                                                              Rows.GetRowCount(DataGridViewElementStates.Visible) == 1 /*forceCurrentCellSelection*/);
                Debug.Assert(success);
            }
        }

        internal void OnInsertedRows_PreNotification(int rowIndex, DataGridViewRow[] dataGridViewRows)
        {
            Debug.Assert(rowIndex >= 0);
            Debug.Assert(dataGridViewRows != null);
            Debug.Assert(dataGridViewRows.Length > 0);

            // Fix the OldFirstDisplayedScrollingRow
            DisplayedBandsInfo.CorrectRowIndexAfterInsertion(rowIndex, dataGridViewRows.Length);

            // Fix the Index of all following rows
            CorrectRowIndexesAfterInsertion(rowIndex, dataGridViewRows.Length);

            // Next, same effect as adding the rows
            OnAddedRows_PreNotification(dataGridViewRows);
        }

        internal void OnInsertedRows_PostNotification(DataGridViewRow[] dataGridViewRows, Point newCurrentCell)
        {
            Debug.Assert(dataGridViewRows != null);
            Debug.Assert(dataGridViewRows.Length > 0);

            // Same effect as adding the rows
            OnAddedRows_PostNotification(dataGridViewRows);

            // Update current cell if needed
            if (newCurrentCell.Y != -1)
            {
                Debug.Assert(_ptCurrentCell.X == -1);
                bool success = SetAndSelectCurrentCellAddress(newCurrentCell.X, newCurrentCell.Y, true, false, false, false /*clearSelection*/, false /*forceCurrentCellSelection*/);
                Debug.Assert(success);
            }
        }

        internal void OnInsertingColumn(int columnIndexInserted, DataGridViewColumn dataGridViewColumn, out Point newCurrentCell)
        {
            Debug.Assert(dataGridViewColumn != null);

            if (dataGridViewColumn.DataGridView != null)
            {
                throw new InvalidOperationException(SR.DataGridView_ColumnAlreadyBelongsToDataGridView);
            }

            if (!InInitialization &&
                dataGridViewColumn.SortMode == DataGridViewColumnSortMode.Automatic &&
                (SelectionMode == DataGridViewSelectionMode.FullColumnSelect ||
                 SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect))
            {
                throw new InvalidOperationException(string.Format(SR.DataGridViewColumn_SortModeAndSelectionModeClash, DataGridViewColumnSortMode.Automatic.ToString(), SelectionMode.ToString()));
            }

            if (dataGridViewColumn.Visible)
            {
                // Note that dataGridViewColumn.DataGridView is set later on, so dataGridViewColumn.InheritedAutoSizeMode should not be used

                // Make sure the column does not autosize based only on header while column headers are invisible
                if (!ColumnHeadersVisible &&
                    (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.ColumnHeader || (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.NotSet && AutoSizeColumnsMode == DataGridViewAutoSizeColumnsMode.ColumnHeader)))
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddAutoSizedColumn);
                }

                // Make sure the column is not frozen and auto fills
                if (dataGridViewColumn.Frozen &&
                    (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.Fill || (dataGridViewColumn.AutoSizeMode == DataGridViewAutoSizeColumnMode.NotSet && AutoSizeColumnsMode == DataGridViewAutoSizeColumnsMode.Fill)))
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddAutoFillColumn);
                }
            }

            // check for correctness of frozen state - throws exception if state is incorrect.
            CorrectColumnFrozenState(dataGridViewColumn, columnIndexInserted);

            // Reset current cell if there is one, no matter the relative position of the columns involved
            if (_ptCurrentCell.X != -1)
            {
                newCurrentCell = new Point(columnIndexInserted <= _ptCurrentCell.X ? _ptCurrentCell.X + 1 : _ptCurrentCell.X,
                     _ptCurrentCell.Y);
                ResetCurrentCell();
            }
            else
            {
                newCurrentCell = new Point(-1, -1);
            }

            // prepare the existing rows by inserting cells of correct type
            if (Rows.Count > 0)
            {
                // Only require a default cell type when there are rows to fill
                if (dataGridViewColumn.CellType is null)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAddUntypedColumn);
                }

                if (dataGridViewColumn.CellTemplate.DefaultNewRowValue != null && NewRowIndex != -1)
                {
                    // New row needs to be unshared before addition of new cell with a Value != null
                    DataGridViewRow newRow = Rows[NewRowIndex];
                }

                int newColumnCount = Columns.Count + 1;

                try
                {
                    for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
                    {
                        DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                        if (dataGridViewRow.Cells.Count < newColumnCount)
                        {
                            DataGridViewCell dataGridViewCellNew = (DataGridViewCell)dataGridViewColumn.CellTemplate.Clone();
                            dataGridViewRow.Cells.InsertInternal(columnIndexInserted, dataGridViewCellNew);
                            if (rowIndex == NewRowIndex)
                            {
                                dataGridViewCellNew.Value = dataGridViewCellNew.DefaultNewRowValue;
                            }
                            dataGridViewCellNew.DataGridView = this;
                            dataGridViewCellNew.OwningRow = dataGridViewRow;
                            dataGridViewCellNew.OwningColumn = dataGridViewColumn;
                        }
                    }
                }
                catch
                {
                    // An error occurred while inserting the cells. Revert all the insertions.
                    for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
                    {
                        DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                        if (dataGridViewRow.Cells.Count == newColumnCount)
                        {
                            dataGridViewRow.Cells.RemoveAtInternal(columnIndexInserted);
                        }
                        else
                        {
                            Debug.Assert(dataGridViewRow.Cells.Count < newColumnCount);
                            break;
                        }
                    }
                    throw;
                }
            }

            // Update the indexes of selected columns to compensate for the insertion of this column
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.FullColumnSelect:
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    int columnEntries = _selectedBandIndexes.Count;
                    int columnEntry = 0;
                    while (columnEntry < columnEntries)
                    {
                        int columnIndex = _selectedBandIndexes[columnEntry];
                        if (columnIndexInserted <= columnIndex)
                        {
                            _selectedBandIndexes[columnEntry] = columnIndex + 1;
                        }
                        columnEntry++;
                    }
                    if (_selectedBandSnapshotIndexes != null)
                    {
                        columnEntries = _selectedBandSnapshotIndexes.Count;
                        columnEntry = 0;
                        while (columnEntry < columnEntries)
                        {
                            int columnIndex = _selectedBandSnapshotIndexes[columnEntry];
                            if (columnIndexInserted <= columnIndex)
                            {
                                _selectedBandSnapshotIndexes[columnEntry] = columnIndex + 1;
                            }
                            columnEntry++;
                        }
                    }
                    break;
            }
        }

        internal void OnInsertingRow(int rowIndexInserted,
                                     DataGridViewRow dataGridViewRow,
                                     DataGridViewElementStates rowState,
                                     ref Point newCurrentCell,
                                     bool firstInsertion,
                                     int insertionCount,
                                     bool force)
        {
            // Reset the current cell's address if it's after the inserted row.
            if (firstInsertion)
            {
                if (_ptCurrentCell.Y != -1 && rowIndexInserted <= _ptCurrentCell.Y)
                {
                    newCurrentCell = new Point(_ptCurrentCell.X, _ptCurrentCell.Y + insertionCount);
                    if (force)
                    {
                        // When force is true, the underlying data was already added, therefore we need to avoid accessing any back-end data
                        // since we might be off by 1 row.
                        _dataGridViewState1[State1_TemporarilyResetCurrentCell] = true;
                        bool success = SetCurrentCellAddressCore(-1, -1, true /*setAnchorCellAddress*/, false /*validateCurrentCell*/, false);
                        Debug.Assert(success);
                    }
                    else
                    {
                        ResetCurrentCell();
                    }
                }
                else
                {
                    newCurrentCell = new Point(-1, -1);
                }
            }
            else
            {
                if (newCurrentCell.Y != -1)
                {
                    newCurrentCell.Y += insertionCount;
                }
            }

            // For now same checks as for OnAddingRow
            OnAddingRow(dataGridViewRow, rowState, false /*checkFrozenState*/);

            // check for correctness of frozen state - throws exception if state is incorrect.
            CorrectRowFrozenState(dataGridViewRow, rowState, rowIndexInserted);

            // Update the indexes of selected rows to compensate for the insertion of this row
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    int rowEntries = _selectedBandIndexes.Count;
                    int rowEntry = 0;
                    while (rowEntry < rowEntries)
                    {
                        int rowIndex = _selectedBandIndexes[rowEntry];
                        if (rowIndexInserted <= rowIndex)
                        {
                            _selectedBandIndexes[rowEntry] = rowIndex + insertionCount;
                        }
                        rowEntry++;
                    }
                    if (_selectedBandSnapshotIndexes != null)
                    {
                        rowEntries = _selectedBandSnapshotIndexes.Count;
                        rowEntry = 0;
                        while (rowEntry < rowEntries)
                        {
                            int rowIndex = _selectedBandSnapshotIndexes[rowEntry];
                            if (rowIndexInserted <= rowIndex)
                            {
                                _selectedBandSnapshotIndexes[rowEntry] = rowIndex + insertionCount;
                            }
                            rowEntry++;
                        }
                    }
                    break;
            }
        }

        internal void OnInsertingRows(int rowIndexInserted, DataGridViewRow[] dataGridViewRows, ref Point newCurrentCell)
        {
            Debug.Assert(dataGridViewRows != null);

            // Reset the current cell's address if it's after the inserted row.
            if (_ptCurrentCell.Y != -1 && rowIndexInserted <= _ptCurrentCell.Y)
            {
                newCurrentCell = new Point(_ptCurrentCell.X, _ptCurrentCell.Y + dataGridViewRows.Length);
                ResetCurrentCell();
            }
            else
            {
                newCurrentCell = new Point(-1, -1);
            }

            // For now almost same checks as for OnAddingRows
            // OnAddingRows checks for Selected status of rows.
            OnAddingRows(dataGridViewRows, false /*checkFrozenStates*/);

            // Check for Frozen state correctness
            CorrectRowFrozenStates(dataGridViewRows, rowIndexInserted);

            // Update the indexes of selected rows to compensate for the insertion of this row
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    int rowEntries = _selectedBandIndexes.Count;
                    int rowEntry = 0;
                    while (rowEntry < rowEntries)
                    {
                        int rowIndex = _selectedBandIndexes[rowEntry];
                        if (rowIndexInserted <= rowIndex)
                        {
                            _selectedBandIndexes[rowEntry] = rowIndex + dataGridViewRows.Length;
                        }
                        rowEntry++;
                    }
                    if (_selectedBandSnapshotIndexes != null)
                    {
                        rowEntries = _selectedBandSnapshotIndexes.Count;
                        rowEntry = 0;
                        while (rowEntry < rowEntries)
                        {
                            int rowIndex = _selectedBandSnapshotIndexes[rowEntry];
                            if (rowIndexInserted <= rowIndex)
                            {
                                _selectedBandSnapshotIndexes[rowEntry] = rowIndex + dataGridViewRows.Length;
                            }
                            rowEntry++;
                        }
                    }
                    break;
            }
        }

        [EditorBrowsable(EditorBrowsableState.Advanced)]
        protected override void OnKeyDown(KeyEventArgs e)
        {
            base.OnKeyDown(e);
            if (e.Handled)
            {
                return;
            }

            // Forward key down to current cell if any
            if (_ptCurrentCell.X != -1)
            {
                DataGridViewCell dataGridViewCell = CurrentCellInternal;
                Debug.Assert(dataGridViewCell != null);
                if (dataGridViewCell.KeyDownUnsharesRowInternal(e, _ptCurrentCell.Y))
                {
                    DataGridViewRow dataGridViewRow = Rows[_ptCurrentCell.Y];
                    CurrentCellInternal.OnKeyDownInternal(e, _ptCurrentCell.Y);
                }
                else
                {
                    dataGridViewCell.OnKeyDownInternal(e, _ptCurrentCell.Y);
                }
            }

            if (!e.Handled)
            {
                switch (e.KeyData & Keys.KeyCode)
                {
                    case Keys.A:
                    case Keys.C:
                    case Keys.D0:
                    case Keys.NumPad0:
                    case Keys.Delete:
                    case Keys.Down:
                    case Keys.F2:
                    case Keys.F3:
                    case Keys.F10:
                    case Keys.End:
                    case Keys.Enter:
                    case Keys.Escape:
                    case Keys.Home:
                    case Keys.Insert:
                    case Keys.Left:
                    case Keys.Next:
                    case Keys.Prior:
                    case Keys.Right:
                    case Keys.Space:
                    case Keys.Tab:
                    case Keys.Up:
                        {
                            e.Handled = ProcessDataGridViewKey(e);
                            break;
                        }
                }
            }
        }

        [EditorBrowsable(EditorBrowsableState.Advanced)]
        protected override void OnKeyPress(KeyPressEventArgs e)
        {
            base.OnKeyPress(e);
            if (e.Handled)
            {
                return;
            }

            // Forward key press to current cell if any
            if (_ptCurrentCell.X != -1)
            {
                DataGridViewCell dataGridViewCell = CurrentCellInternal;
                Debug.Assert(dataGridViewCell != null);
                if (dataGridViewCell.KeyPressUnsharesRowInternal(e, _ptCurrentCell.Y))
                {
                    DataGridViewRow dataGridViewRow = Rows[_ptCurrentCell.Y];
                    CurrentCellInternal.OnKeyPressInternal(e, _ptCurrentCell.Y);
                }
                else
                {
                    dataGridViewCell.OnKeyPressInternal(e, _ptCurrentCell.Y);
                }
            }
        }

        [EditorBrowsable(EditorBrowsableState.Advanced)]
        protected override void OnKeyUp(KeyEventArgs e)
        {
            base.OnKeyUp(e);
            if (e.Handled)
            {
                return;
            }

            if (_dataGridViewOper[OperationTrackKeyboardColResize] && (e.KeyData & Keys.Alt) != Keys.Alt)
            {
                EndColumnResize(_currentColSplitBar);
                ResetKeyboardTrackingState();
                return;
            }

            // Forward key up to current cell if any
            if (_ptCurrentCell.X != -1)
            {
                DataGridViewCell dataGridViewCell = CurrentCellInternal;
                Debug.Assert(dataGridViewCell != null);
                if (dataGridViewCell.KeyUpUnsharesRowInternal(e, _ptCurrentCell.Y))
                {
                    DataGridViewRow dataGridViewRow = Rows[_ptCurrentCell.Y];
                    CurrentCellInternal.OnKeyUpInternal(e, _ptCurrentCell.Y);
                }
                else
                {
                    dataGridViewCell.OnKeyUpInternal(e, _ptCurrentCell.Y);
                }
            }
        }

        protected override void OnLayout(LayoutEventArgs e)
        {
            if (_dataGridViewState1[State1_EditingControlChanging])
            {
                return;
            }

            base.OnLayout(e);
            PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            if (RightToLeftInternal)
            {
                Invalidate();
            }
            if (EditingControl != null)
            {
                PositionEditingControl(true, true, false);
            }
        }

        protected override void OnLeave(EventArgs e)
        {
            if (_ptCurrentCell.X > -1 && !_dataGridViewState1[State1_LeavingWithTabKey])
            {
                DataGridViewCell dataGridViewCell = null;
                OnCellLeave(ref dataGridViewCell, _ptCurrentCell.X, _ptCurrentCell.Y);
                if (_ptCurrentCell.X == -1)
                {
                    return;
                }
                OnRowLeave(ref dataGridViewCell, _ptCurrentCell.X, _ptCurrentCell.Y);
            }

            if (!_dataGridViewState1[State1_LeavingWithTabKey])
            {
                base.OnLeave(e);

                // invalidate the current cell so the data grid view does not paint the focus rectangle any longer
                if (_ptCurrentCell.X > -1 && _ptCurrentCell.Y > -1)
                {
                    InvalidateCellPrivate(_ptCurrentCell.X /*columnIndex*/, _ptCurrentCell.Y /*rowIndex*/);
                }
            }

            // Erase focus rectangle around the grid
            if (IsGridFocusRectangleEnabled())
            {
                InvalidateRectangleEdges(GetGridFocusRectangle());
            }
        }

        protected override void OnLostFocus(EventArgs e)
        {
            base.OnLostFocus(e);
            if (_ptCurrentCell.X != -1)
            {
                InvalidateCell(_ptCurrentCell.X, _ptCurrentCell.Y);
            }

            if (CurrentCell != null)
            {
                KeyboardToolTipStateMachine.Instance.NotifyAboutLostFocus(CurrentCell);
            }
        }

        protected override void OnMouseClick(MouseEventArgs e)
        {
            bool mouseClickRaised = false;

            if (!_dataGridViewState2[State2_MessageFromEditingCtrls] &&
                !_dataGridViewOper[OperationInDispose] && !IsDisposed &&
                !_dataGridViewOper[OperationTrackColResize] &&
                !_dataGridViewOper[OperationTrackRowResize] &&
                !_dataGridViewOper[OperationTrackColHeadersResize] &&
                !_dataGridViewOper[OperationTrackRowHeadersResize])
            {
                HitTestInfo hti = HitTest(e.X, e.Y);

                if (_ptMouseDownCell.X == hti._col &&
                    _ptMouseDownCell.Y == hti._row &&
                    (e.Button != MouseButtons.Left ||
                     _ptMouseDownCell.X == -1 ||
                     _ptMouseDownCell.Y == -1 ||
                     (_ptMouseDownCell.X == _ptCurrentCell.X &&
                      _ptMouseDownCell.Y == _ptCurrentCell.Y)))
                {
                    DataGridViewCellMouseEventArgs dgvcme = null;
                    if (hti.Type != DataGridViewHitTestType.None &&
                        hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                        hti.Type != DataGridViewHitTestType.VerticalScrollBar)
                    {
                        int mouseX = e.X - hti.ColumnX;
                        if (RightToLeftInternal)
                        {
                            mouseX += ((hti._col == -1) ? RowHeadersWidth : Columns[hti._col].Thickness);
                        }
                        dgvcme = new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, e.Y - hti.RowY, e);
                        RecordCellMouseClick(dgvcme);
                        if (e.Button == MouseButtons.Left)
                        {
                            OnCellClick(new DataGridViewCellEventArgs(hti._col, hti._row));
                        }
                        base.OnMouseClick(e);
                        mouseClickRaised = true;
                        if (dgvcme.ColumnIndex < Columns.Count && dgvcme.RowIndex < Rows.Count)
                        {
                            OnCellMouseClick(dgvcme);
                        }
                    }
                    else
                    {
                        base.OnMouseClick(e);
                        mouseClickRaised = true;
                    }

                    if (!_dataGridViewOper[OperationTrackColRelocation])
                    {
                        switch (hti._typeInternal)
                        {
                            case DataGridViewHitTestTypeInternal.ColumnHeader:
                            case DataGridViewHitTestTypeInternal.ColumnHeaderLeft:
                            case DataGridViewHitTestTypeInternal.ColumnHeaderRight:
                            case DataGridViewHitTestTypeInternal.FirstColumnHeaderLeft:
                                {
                                    Debug.Assert(dgvcme != null);
                                    if (dgvcme.ColumnIndex < Columns.Count && dgvcme.RowIndex < Rows.Count)
                                    {
                                        OnColumnHeaderMouseClick(dgvcme);
                                    }
                                    break;
                                }

                            case DataGridViewHitTestTypeInternal.RowHeader:
                                {
                                    Debug.Assert(dgvcme != null);
                                    if (dgvcme.ColumnIndex < Columns.Count && dgvcme.RowIndex < Rows.Count)
                                    {
                                        OnRowHeaderMouseClick(dgvcme);
                                    }
                                    break;
                                }
                        }
                    }
                }
            }
            if (!mouseClickRaised)
            {
                base.OnMouseClick(e);
            }
        }

        protected override void OnMouseDoubleClick(MouseEventArgs e)
        {
            base.OnMouseDoubleClick(e);

            if (!_dataGridViewState2[State2_MessageFromEditingCtrls] &&
                !_dataGridViewOper[OperationTrackColResize] &&
                !_dataGridViewOper[OperationTrackRowResize] &&
                !_dataGridViewOper[OperationTrackColHeadersResize] &&
                !_dataGridViewOper[OperationTrackRowHeadersResize])
            {
                HitTestInfo hti = HitTest(e.X, e.Y);

                if (_ptMouseDownCell.X == hti._col && _ptMouseDownCell.Y == hti._row)
                {
                    DataGridViewCellMouseEventArgs dgvcme = null;
                    if (hti.Type != DataGridViewHitTestType.None &&
                        hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                        hti.Type != DataGridViewHitTestType.VerticalScrollBar)
                    {
                        int mouseX = e.X - hti.ColumnX;
                        if (RightToLeftInternal)
                        {
                            mouseX += ((hti._col == -1) ? RowHeadersWidth : Columns[hti._col].Thickness);
                        }
                        dgvcme = new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, e.Y - hti.RowY, e);
                        OnCellMouseDoubleClick(dgvcme);
                    }

                    if (!_dataGridViewOper[OperationTrackColRelocation])
                    {
                        switch (hti._typeInternal)
                        {
                            case DataGridViewHitTestTypeInternal.ColumnHeader:
                            case DataGridViewHitTestTypeInternal.ColumnHeaderLeft:
                            case DataGridViewHitTestTypeInternal.ColumnHeaderRight:
                            case DataGridViewHitTestTypeInternal.FirstColumnHeaderLeft:
                                {
                                    Debug.Assert(dgvcme != null);
                                    if (dgvcme.ColumnIndex < Columns.Count && dgvcme.RowIndex < Rows.Count)
                                    {
                                        OnColumnHeaderMouseDoubleClick(dgvcme);
                                    }
                                    break;
                                }

                            case DataGridViewHitTestTypeInternal.ColumnResizeLeft:
                            case DataGridViewHitTestTypeInternal.ColumnResizeRight:
                                {
                                    int columnIndex = (hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnResizeRight) ? hti._col : hti._adjacentCol;
                                    if (columnIndex < Columns.Count)
                                    {
                                        HandledMouseEventArgs hme = new HandledMouseEventArgs(e.Button, e.Clicks, e.X, e.Y, e.Delta, false /*defaultHandledValue*/);
                                        DataGridViewColumnDividerDoubleClickEventArgs dgvcddce = new DataGridViewColumnDividerDoubleClickEventArgs(columnIndex, hme);
                                        Debug.Assert(Columns[columnIndex].Resizable == DataGridViewTriState.True);
                                        OnColumnDividerDoubleClick(dgvcddce);
                                    }
                                    break;
                                }

                            case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeTop:
                            case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeBottom:
                            case DataGridViewHitTestTypeInternal.ColumnHeadersResizeTop:
                            case DataGridViewHitTestTypeInternal.ColumnHeadersResizeBottom:
                                {
                                    HandledMouseEventArgs hme = new HandledMouseEventArgs(e.Button, e.Clicks, e.X, e.Y, e.Delta, false /*defaultHandledValue*/);
                                    DataGridViewRowDividerDoubleClickEventArgs dgvrddce = new DataGridViewRowDividerDoubleClickEventArgs(-1, hme);
                                    Debug.Assert(_columnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.EnableResizing);
                                    OnRowDividerDoubleClick(dgvrddce);
                                    break;
                                }

                            case DataGridViewHitTestTypeInternal.RowHeader:
                                {
                                    Debug.Assert(dgvcme != null);
                                    if (dgvcme.ColumnIndex < Columns.Count && dgvcme.RowIndex < Rows.Count)
                                    {
                                        OnRowHeaderMouseDoubleClick(dgvcme);
                                    }
                                    break;
                                }

                            case DataGridViewHitTestTypeInternal.RowResizeBottom:
                            case DataGridViewHitTestTypeInternal.RowResizeTop:
                                {
                                    int rowIndex = (hti._typeInternal == DataGridViewHitTestTypeInternal.RowResizeBottom) ? hti._row : hti._adjacentRow;
                                    if (rowIndex < Rows.Count)
                                    {
                                        HandledMouseEventArgs hme = new HandledMouseEventArgs(e.Button, e.Clicks, e.X, e.Y, e.Delta, false /*defaultHandledValue*/);
                                        DataGridViewRowDividerDoubleClickEventArgs dgvrddce = new DataGridViewRowDividerDoubleClickEventArgs(rowIndex, hme);
                                        Debug.Assert(Rows[rowIndex].Resizable == DataGridViewTriState.True);
                                        OnRowDividerDoubleClick(dgvrddce);
                                    }
                                    break;
                                }

                            case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeLeft:
                            case DataGridViewHitTestTypeInternal.TopLeftHeaderResizeRight:
                            case DataGridViewHitTestTypeInternal.RowHeadersResizeLeft:
                            case DataGridViewHitTestTypeInternal.RowHeadersResizeRight:
                                {
                                    HandledMouseEventArgs hme = new HandledMouseEventArgs(e.Button, e.Clicks, e.X, e.Y, e.Delta, false /*defaultHandledValue*/);
                                    DataGridViewColumnDividerDoubleClickEventArgs dgvcddce = new DataGridViewColumnDividerDoubleClickEventArgs(-1, hme);
                                    Debug.Assert(_rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing);
                                    OnColumnDividerDoubleClick(dgvcddce);
                                    break;
                                }
                        }
                    }
                }
            }
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            if (!_dataGridViewState2[State2_MessageFromEditingCtrls])
            {
                _dataGridViewOper[OperationTrackMouseMoves] = true;
            }

            base.OnMouseDown(e);

            if (_dataGridViewState2[State2_MessageFromEditingCtrls])
            {
                return;
            }

            if (_ptMouseDownCell.X != -2)
            {
                // Happens when user pushes the mouse wheel down while the left mouse button is already down
                Debug.Assert(_ptMouseDownCell.Y != -2);
                return;
            }

            HitTestInfo hti = HitTest(e.X, e.Y);

            if (hti.Type != DataGridViewHitTestType.None &&
                hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                hti.Type != DataGridViewHitTestType.VerticalScrollBar)
            {
                _ptMouseDownCell.X = hti._col;
                _ptMouseDownCell.Y = hti._row;
                _ptMouseDownGridCoord = new Point(e.X, e.Y);
                int mouseX = e.X - hti.ColumnX;
                if (RightToLeftInternal)
                {
                    mouseX += ((hti._col == -1) ? RowHeadersWidth : Columns[hti._col].Thickness);
                }
                DataGridViewCellMouseEventArgs dgvcme = new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, e.Y - hti.RowY, e);
                OnCellMouseDown(dgvcme);
            }
        }

        protected override void OnMouseEnter(EventArgs e)
        {
            if (!_dataGridViewState2[State2_MouseOverRemovedEditingCtrl] &&
                !_dataGridViewState2[State2_MouseOverRemovedEditingPanel] &&
                _dataGridViewState2[State2_MouseEnterExpected] &&
                !_toolTipControl.Activated)
            {
                base.OnMouseEnter(e);
            }

            _dataGridViewState2[State2_MouseOverRemovedEditingCtrl] = false;
            _dataGridViewState2[State2_MouseOverRemovedEditingPanel] = false;
            _dataGridViewState2[State2_MouseEnterExpected] = false;
        }

        protected override void OnMouseLeave(EventArgs e)
        {
            // when the mouse leaves the dataGridView control, reset the cursor to the previously cached one
            if (_dataGridViewState1[State1_CustomCursorSet])
            {
                _dataGridViewState1[State1_CustomCursorSet] = false;
                CursorInternal = _oldCursor;
            }

            bool mouseOverEditingControl = MouseOverEditingControl;
            bool mouseOverEditingPanel = MouseOverEditingPanel;
            bool mouseOverToolTipControl = _toolTipControl.Activated && ClientRectangle.Contains(PointToClient(Control.MousePosition));

            if (!mouseOverEditingPanel && !mouseOverEditingControl && !mouseOverToolTipControl && _ptMouseEnteredCell.X != -2)
            {
                if (_ptMouseEnteredCell.X >= -1 && _ptMouseEnteredCell.X < Columns.Count &&
                    _ptMouseEnteredCell.Y >= -1 && _ptMouseEnteredCell.Y < Rows.Count)
                {
                    DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(_ptMouseEnteredCell.X, _ptMouseEnteredCell.Y);
                    OnCellMouseLeave(dgvce);
                }
                else
                {
                    _ptMouseEnteredCell.X = _ptMouseEnteredCell.Y = -2;
                }
            }

            ResetTrackingState();
            _dataGridViewOper[OperationTrackMouseMoves] = false;

            if (!mouseOverEditingPanel && !mouseOverEditingControl && !mouseOverToolTipControl && !MouseOverScrollBar)
            {
                _toolTipControl.Activate(false /*activate*/);
                base.OnMouseLeave(e);
                _dataGridViewState2[State2_MouseEnterExpected] = true;
            }
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            base.OnMouseMove(e);

            HitTestInfo hti = HitTest(e.X, e.Y);

            UpdateMouseEnteredCell(hti, e);

            // We need to give UI feedback when the user is resizing a column
            if (_dataGridViewOper[OperationTrackColResize])
            {
                MoveRowHeadersOrColumnResize(e.X);
            }
            else if (_dataGridViewOper[OperationTrackRowResize])
            {
                MoveColumnHeadersOrRowResize(e);
            }
            else if (_dataGridViewOper[OperationTrackColRelocation])
            {
                MoveColumnRelocation(e, hti);
            }
            else if (_dataGridViewOper[OperationTrackColHeadersResize])
            {
                MoveColumnHeadersOrRowResize(e);
            }
            else if (_dataGridViewOper[OperationTrackRowHeadersResize])
            {
                MoveRowHeadersOrColumnResize(e.X);
            }

            if (_dataGridViewOper[OperationTrackColResize] ||
                _dataGridViewOper[OperationTrackRowHeadersResize] ||
                ((hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnResizeLeft ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.TopLeftHeaderResizeLeft ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.TopLeftHeaderResizeRight ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnResizeRight ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.RowHeadersResizeLeft ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.RowHeadersResizeRight) &&
                !_dataGridViewOper[OperationTrackColHeadersResize] &&
                !_dataGridViewOper[OperationTrackColRelocation] &&
                !_dataGridViewOper[OperationTrackColSelect] &&
                !_dataGridViewOper[OperationTrackRowSelect] &&
                !_dataGridViewOper[OperationTrackCellSelect]))
            {
                if (!_dataGridViewState1[State1_CustomCursorSet])
                {
                    _dataGridViewState1[State1_CustomCursorSet] = true;
                    _oldCursor = Cursor;
                }
                CursorInternal = Cursors.SizeWE;
                return;
            }
            else if (_dataGridViewOper[OperationTrackRowResize] ||
                _dataGridViewOper[OperationTrackColHeadersResize] ||
                ((hti._typeInternal == DataGridViewHitTestTypeInternal.RowResizeBottom ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.TopLeftHeaderResizeTop ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.TopLeftHeaderResizeBottom ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.RowResizeTop ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeadersResizeTop ||
                hti._typeInternal == DataGridViewHitTestTypeInternal.ColumnHeadersResizeBottom) &&
                !_dataGridViewOper[OperationTrackRowHeadersResize] &&
                !_dataGridViewOper[OperationTrackColRelocation] &&
                !_dataGridViewOper[OperationTrackColSelect] &&
                !_dataGridViewOper[OperationTrackRowSelect] &&
                !_dataGridViewOper[OperationTrackCellSelect]))
            {
                if (!_dataGridViewState1[State1_CustomCursorSet])
                {
                    _dataGridViewState1[State1_CustomCursorSet] = true;
                    _oldCursor = Cursor;
                }
                CursorInternal = Cursors.SizeNS;
                return;
            }
            /* Whidbey

*/
            else if (_dataGridViewState1[State1_CustomCursorSet])
            {
                _dataGridViewState1[State1_CustomCursorSet] = false;
                CursorInternal = _oldCursor;
            }

            if (_dataGridViewOper[OperationTrackColSelect] ||
                _dataGridViewOper[OperationTrackRowSelect] ||
                _dataGridViewOper[OperationTrackCellSelect])
            {
                int mouseX = e.X, mouseY = e.Y;
                if (GetOutOfBoundCorrectedHitTestInfo(ref hti, ref mouseX, ref mouseY, out int xOffset, out int yOffset))
                {
                    if (xOffset == 0)
                    {
                        if (_horizScrollTimer != null && _horizScrollTimer.Enabled)
                        {
                            // Mouse's X came in-bound - need to stop the horizontal scroll timer
                            _horizScrollTimer.Enabled = false;
                        }
                    }
                    else if (_horizScrollTimer is null || !_horizScrollTimer.Enabled)
                    {
                        // Need to start delayed horizontal scroll
                        HorizScrollTimer.Interval = GetColumnScrollRate(Math.Abs(xOffset));
                        HorizScrollTimer.Enabled = true;
                    }

                    if (yOffset == 0)
                    {
                        if (_vertScrollTimer != null && _vertScrollTimer.Enabled)
                        {
                            // Mouse's Y came in-bound - need to stop the vertical scroll timer
                            _vertScrollTimer.Enabled = false;
                        }
                    }
                    else if (_vertScrollTimer is null || !_vertScrollTimer.Enabled)
                    {
                        // Need to start delayed vertical scroll
                        VertScrollTimer.Interval = GetRowScrollRate(Math.Abs(yOffset));
                        VertScrollTimer.Enabled = true;
                    }

                    if (HorizScrollTimer.Enabled || VertScrollTimer.Enabled)
                    {
                        return;
                    }

                    if (/*!this.dataGridViewState1[State1_ScrolledSinceMouseDown] && */
                        hti.Type != DataGridViewHitTestType.None &&
                        hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                        hti.Type != DataGridViewHitTestType.VerticalScrollBar)
                    {
                        if (_dataGridViewOper[OperationTrackColSelect] && hti._col >= 0)
                        {
                            OnColumnSelectMouseMove(hti);
                        }
                        else if (_dataGridViewOper[OperationTrackRowSelect] && hti._row >= 0)
                        {
                            OnRowSelectMouseMove(hti);
                        }
                        else if (_dataGridViewOper[OperationTrackCellSelect] && hti._col >= 0 && hti._row >= 0)
                        {
                            OnCellSelectMouseMove(hti);
                        }
                    }
                }
            }
#if DEBUG
            else
            {
                Debug.Assert(_vertScrollTimer is null || !_vertScrollTimer.Enabled);
                Debug.Assert(_horizScrollTimer is null || !_horizScrollTimer.Enabled);
            }
#endif
            if (!_toolTipControl.Activated)
            {
                //
                // After processing the MouseMove event, the tool tip is still not activated.
                // Reset the tool tip cell.
                _ptToolTipCell = new Point(-1, -1);
            }
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            if (!_dataGridViewState2[State2_MessageFromEditingCtrls])
            {
                _dataGridViewState1[State1_ScrolledSinceMouseDown] = false;

                HitTestInfo hti = HitTest(e.X, e.Y);

                if (!IsMouseOperationActive())
                {
                    if (hti.Type != DataGridViewHitTestType.None &&
                        hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                        hti.Type != DataGridViewHitTestType.VerticalScrollBar)
                    {
                        int mouseX = e.X - hti.ColumnX;
                        if (RightToLeftInternal)
                        {
                            mouseX += ((hti._col == -1) ? RowHeadersWidth : Columns[hti._col].Thickness);
                        }
                        DataGridViewCellMouseEventArgs dgvcme;
                        if (_dataGridViewState2[State2_NextMouseUpIsDouble])
                        {
                            MouseEventArgs meTmp = new MouseEventArgs(e.Button, 2, e.X, e.Y, e.Delta);
                            dgvcme = new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, e.Y - hti.RowY, meTmp);
                        }
                        else
                        {
                            dgvcme = new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, e.Y - hti.RowY, e);
                        }
                        if (hti._col >= 0 && _ptMouseDownCell.X == hti._col &&
                            hti._row >= 0 && _ptMouseDownCell.Y == hti._row &&
                            EditMode == DataGridViewEditMode.EditOnEnter &&
                            EditingControl != null)
                        {
                            OnClick(e);
                            OnMouseClick(e);
                        }

                        CorrectFocus(true /*onlyIfGridHasFocus*/);

                        if (dgvcme.ColumnIndex < Columns.Count && dgvcme.RowIndex < Rows.Count)
                        {
                            OnCellMouseUp(dgvcme);
                        }
                    }
                    else if (hti.Type == DataGridViewHitTestType.None)
                    {
                        // VS Whidbey
                        CorrectFocus(true /*onlyIfGridHasFocus*/);
                    }
                }
                else
                {
                    if (_dataGridViewOper[OperationTrackColResize])
                    {
                        EndColumnResize(e);
                    }

                    if (_dataGridViewOper[OperationTrackRowResize])
                    {
                        EndRowResize(e);
                    }

                    if (_dataGridViewOper[OperationTrackColRelocation])
                    {
                        EndColumnRelocation(e, hti);
                    }

                    if (_dataGridViewOper[OperationTrackColHeadersResize])
                    {
                        EndColumnHeadersResize(e);
                    }

                    if (_dataGridViewOper[OperationTrackRowHeadersResize])
                    {
                        EndRowHeadersResize(e);
                    }

                    // VS Whidbey
                    CorrectFocus(true /*onlyIfGridHasFocus*/);

                    // Updating the hit test info since the EndXXX operation above may have invalidated the previously
                    // determined hti.
                    hti = HitTest(e.X, e.Y);
                    if (hti.Type != DataGridViewHitTestType.None &&
                        hti.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                        hti.Type != DataGridViewHitTestType.VerticalScrollBar)
                    {
                        int mouseX = e.X - hti.ColumnX;
                        if (RightToLeftInternal)
                        {
                            mouseX += ((hti._col == -1) ? RowHeadersWidth : Columns[hti._col].Thickness);
                        }
                        OnCellMouseUp(new DataGridViewCellMouseEventArgs(hti._col, hti._row, mouseX, e.Y - hti.RowY, e));
                    }
                }

                ResetTrackingState();
            }
            base.OnMouseUp(e);
        }

        protected override void OnMouseWheel(MouseEventArgs e)
        {
            base.OnMouseWheel(e);

            HandledMouseEventArgs hme = e as HandledMouseEventArgs;
            if (hme != null && hme.Handled)
            {
                // The application event handler handled the scrolling - don't do anything more.
                return;
            }

            if ((ModifierKeys & (Keys.Shift | Keys.Alt)) != 0 || MouseButtons != MouseButtons.None)
            {
                return; // Do not scroll when Shift or Alt key is down, or when a mouse button is down.
            }

            bool verticalScroll = ((ModifierKeys & Keys.Control) == 0);

            ScrollBar sb = (verticalScroll ? (ScrollBar)_vertScrollBar : (ScrollBar)_horizScrollBar);

            if (!sb.Visible || !sb.Enabled)
            {
                return; // Do not scroll when the corresponding scrollbar is invisible or disabled
            }

            if (hme != null)
            {
                hme.Handled = true;
            }

            int wheelScrollLines = SystemInformation.MouseWheelScrollLines;
            if (wheelScrollLines == 0)
            {
                return; // Do not scroll when the user system setting is 0 lines per notch
            }

            Debug.Assert(_cumulativeVerticalWheelDelta > -NativeMethods.WHEEL_DELTA);
            Debug.Assert(_cumulativeVerticalWheelDelta < NativeMethods.WHEEL_DELTA);
            Debug.Assert(_cumulativeHorizontalWheelDelta > -NativeMethods.WHEEL_DELTA);
            Debug.Assert(_cumulativeHorizontalWheelDelta < NativeMethods.WHEEL_DELTA);

            float partialNotches;

            if (verticalScroll)
            {
                _cumulativeVerticalWheelDelta += e.Delta;
                partialNotches = (float)_cumulativeVerticalWheelDelta / (float)NativeMethods.WHEEL_DELTA;
            }
            else
            {
                _cumulativeHorizontalWheelDelta += e.Delta;
                partialNotches = (float)_cumulativeHorizontalWheelDelta / (float)NativeMethods.WHEEL_DELTA;
            }

            int fullNotches = (int)partialNotches;

            if (wheelScrollLines == -1)
            {
                // Equivalent to large change scrolls
                if (fullNotches != 0)
                {
                    if (_ptCurrentCell.X >= 0 &&
                        !CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                    false /*forCurrentCellChange*/, false /*forCurrentRowChange*/))
                    {
                        // Could not commit edited cell value
                        return;
                    }
                    if (verticalScroll)
                    {
                        int originalVerticalOffset = VerticalOffset;
                        VerticalOffset -= fullNotches * _vertScrollBar.LargeChange;
                        if (Math.Abs(VerticalOffset - originalVerticalOffset) >= Math.Abs(fullNotches * _vertScrollBar.LargeChange))
                        {
                            _cumulativeVerticalWheelDelta -= fullNotches * NativeMethods.WHEEL_DELTA;
                        }
                        else
                        {
                            _cumulativeVerticalWheelDelta = 0;
                        }
                    }
                    else
                    {
                        int originalHorizontalOffset = HorizontalOffset;
                        HorizontalOffset -= fullNotches * _horizScrollBar.LargeChange;
                        if (Math.Abs(HorizontalOffset - originalHorizontalOffset) >= Math.Abs(fullNotches * _horizScrollBar.LargeChange))
                        {
                            _cumulativeHorizontalWheelDelta -= fullNotches * NativeMethods.WHEEL_DELTA;
                        }
                        else
                        {
                            _cumulativeHorizontalWheelDelta = 0;
                        }
                    }
                }
            }
            else
            {
                // Evaluate number of bands to scroll
                int scrollBands = (int)((float)wheelScrollLines * partialNotches);
                if (scrollBands != 0)
                {
                    if (_ptCurrentCell.X >= 0 &&
                        !CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                    false /*forCurrentCellChange*/, false /*forCurrentRowChange*/))
                    {
                        // Could not commit edited cell value
                        return;
                    }
                    int absScrollBands;
                    if (verticalScroll)
                    {
                        if (scrollBands > 0)
                        {
                            absScrollBands = scrollBands;
                            while (_vertScrollBar.Value != _vertScrollBar.Minimum && absScrollBands > 0)
                            {
                                ScrollRowsByCount(-1, ScrollEventType.SmallDecrement);
                                absScrollBands--;
                            }
                            if (_vertScrollBar.Value == _vertScrollBar.Minimum)
                            {
                                _cumulativeVerticalWheelDelta = 0;
                            }
                            else
                            {
                                _cumulativeVerticalWheelDelta -= (int)((float)scrollBands * ((float)NativeMethods.WHEEL_DELTA / (float)wheelScrollLines));
                            }
                        }
                        else
                        {
                            absScrollBands = -scrollBands;
                            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                            int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                            while (absScrollBands > 0 &&
                                   _vertScrollBar.Value + Rows.SharedRow(DisplayedBandsInfo.FirstDisplayedScrollingRow).GetHeight(DisplayedBandsInfo.FirstDisplayedScrollingRow) <=
                                   _vertScrollBar.Maximum - ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight))
                            {
                                ScrollRowsByCount(1, ScrollEventType.SmallIncrement);
                                // Assuming totalVisibleFrozenHeight is unchanged by scrolling operation
                                Debug.Assert(totalVisibleFrozenHeight == Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen));
                                Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                                absScrollBands--;
                            }
                            if (_vertScrollBar.Value + Rows.SharedRow(DisplayedBandsInfo.FirstDisplayedScrollingRow).GetHeight(DisplayedBandsInfo.FirstDisplayedScrollingRow) >
                                _vertScrollBar.Maximum - ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight))
                            {
                                _cumulativeVerticalWheelDelta = 0;
                            }
                            else
                            {
                                _cumulativeVerticalWheelDelta -= (int)((float)scrollBands * ((float)NativeMethods.WHEEL_DELTA / (float)wheelScrollLines));
                            }
                        }
                    }
                    else
                    {
                        int extremeScrollBarValue, scrollBand;
                        if (scrollBands > 0)
                        {
                            extremeScrollBarValue = _horizScrollBar.Minimum;
                            scrollBand = -1;
                        }
                        else
                        {
                            extremeScrollBarValue = _horizScrollBar.Maximum;
                            scrollBand = 1;
                        }
                        absScrollBands = Math.Abs(scrollBands);
                        while (_horizScrollBar.Value != extremeScrollBarValue && absScrollBands > 0)
                        {
                            ScrollColumns(scrollBand);
                            absScrollBands--;
                        }
                        if (_horizScrollBar.Value == extremeScrollBarValue)
                        {
                            _cumulativeHorizontalWheelDelta = 0;
                        }
                        else
                        {
                            _cumulativeHorizontalWheelDelta -= (int)((float)scrollBands * ((float)NativeMethods.WHEEL_DELTA / (float)wheelScrollLines));
                        }
                    }
                }
            }
        }

        internal void OnMouseWheelInternal(MouseEventArgs e)
        {
            // Notification forwarded from editing control
            OnMouseWheel(e);
        }

        protected virtual void OnMultiSelectChanged(EventArgs e)
        {
            if (Events[s_multiselectChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnNewRowNeeded(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }
            if (Events[s_newRowNeededEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            try
            {
                // We can't paint if we are disposed.
                if (_dataGridViewOper[OperationInDispose] || IsDisposed)
                {
                    return;
                }

                if (_layout._dirty)
                {
                    PerformLayoutPrivate(false /*useRowShortcut*/, true /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
                }

                Graphics g = e.GraphicsInternal;
                Rectangle clipRect = e.ClipRectangle;
                Rectangle gridRect = GetGridRectangle();

                if (_currentRowSplitBar != -1)
                {
                    clipRect = Rectangle.Union(clipRect, CalcRowResizeFeedbackRect(_currentRowSplitBar));
                }
                else if (_currentColSplitBar != -1)
                {
                    clipRect = Rectangle.Union(clipRect, CalcColResizeFeedbackRect(_currentColSplitBar));
                }

                if (clipRect.IntersectsWith(gridRect))
                {
                    using var clipScope = new GraphicsClipScope(g);
                    g.SetClip(gridRect);
                    PaintBackground(g, clipRect, gridRect);
                    PaintGrid(g, gridRect, clipRect, SingleVerticalBorderAdded, SingleHorizontalBorderAdded);
                }

                PaintBorder(g, clipRect, _layout.ClientRectangle);
                if (clipRect.IntersectsWith(_layout.ResizeBoxRect))
                {
                    g.FillRectangle(SystemBrushes.Control, _layout.ResizeBoxRect);
                }

                // Draw focus rectangle around the grid
                if (Focused && IsGridFocusRectangleEnabled())
                {
                    if (SystemInformation.HighContrast)
                    {
                        ControlPaint.DrawHighContrastFocusRectangle(g, GetGridFocusRectangle(), SystemColors.ActiveCaptionText);
                    }
                    else
                    {
                        ControlPaint.DrawFocusRectangle(g, GetGridFocusRectangle());
                    }
                }

                base.OnPaint(e); // raise paint event
            }
            catch (Exception ex)
            {
#if DEBUG
                Debug.Fail("DataGridView.OnPaint exception: " + ex.Message + " stack trace " + ex.StackTrace);
#endif
                if (ClientUtils.IsCriticalException(ex))
                {
                    throw;
                }
            }
        }

        // Determines if a focus rectangle may be drawn along the perimeter of the DataGridView control
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private bool IsGridFocusRectangleEnabled()
        {
            return ShowFocusCues && CurrentCell is null;
        }

        // Creates a rectangle by merging row headers, column headers
        // and cells rectangles (from layout data)
        private Rectangle GetGridRectangle()
        {
            Rectangle gridRect = _layout.Data;
            if (_layout.RowHeadersVisible)
            {
                gridRect = Rectangle.Union(gridRect, _layout.RowHeaders);
            }
            else if (SingleVerticalBorderAdded)
            {
                if (!RightToLeftInternal)
                {
                    gridRect.X--;
                }
                gridRect.Width++;
            }

            if (_layout.ColumnHeadersVisible)
            {
                gridRect = Rectangle.Union(gridRect, _layout.ColumnHeaders);
            }
            else if (SingleHorizontalBorderAdded)
            {
                if (gridRect.Y == _layout.Data.Y)
                {
                    gridRect.Y--;
                    gridRect.Height++;
                }
            }

            return gridRect;
        }

        // Creates a grid focus rectangle
        private Rectangle GetGridFocusRectangle()
        {
            Rectangle focusRect = GetGridRectangle();
            focusRect.Inflate(1 - FocusRectOffset, 1 - FocusRectOffset);
            return focusRect;
        }

        private void InvalidateGridFocusOnScroll(int change, ScrollOrientation orientation)
        {
            if (change == 0)
            {
                return;
            }

            Rectangle focusRect = GetGridFocusRectangle();

            if (orientation == ScrollOrientation.HorizontalScroll)
            {
                // Scroll right
                if (change > 0)
                {
                    focusRect.Width -= change;
                }
                // Scroll left
                else
                {
                    focusRect.X -= change;
                    focusRect.Width += change;
                }
            }
            else
            {
                // Scroll down
                if (change > 0)
                {
                    focusRect.Height -= change;
                }
                // Scroll up
                else
                {
                    focusRect.Y -= change;
                    focusRect.Height += change;
                }
            }

            InvalidateRectangleEdges(focusRect);
        }

        private void InvalidateRectangleEdges(Rectangle rect)
        {
            // Left edge
            Rectangle edge = rect;
            edge.Width = 1;
            Invalidate(edge);

            // Right edge
            edge.X += rect.Width - 1;
            Invalidate(edge);

            // Top edge
            edge = rect;
            edge.Height = 1;
            Invalidate(edge);

            // Bottom edge
            edge.Y += rect.Height - 1;
            Invalidate(edge);
        }

        internal override void OnParentBecameInvisible()
        {
            base.OnParentBecameInvisible();
            if (GetState(States.Visible))
            {
                // This control became invisible too - Update the Displayed properties of the bands.
                OnVisibleChangedPrivate();
            }
        }

        protected virtual void OnReadOnlyChanged(EventArgs e)
        {
            if (Events[s_readOnlyChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            VerifyImeRestrictedModeChanged();

            if (!ReadOnly &&
                _ptCurrentCell.X != -1 &&
                ColumnEditable(_ptCurrentCell.X) &&
                !IsCurrentCellInEditMode &&
                (EditMode == DataGridViewEditMode.EditOnEnter ||
                 (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null)) &&
                !Rows[_ptCurrentCell.Y].Cells[_ptCurrentCell.X].ReadOnly) // Unshares the row
            {
                // Current cell becomes read/write. Enter editing mode.
                BeginEditInternal(true /*selectAll*/);
            }
        }

        internal void OnRemovedColumn_PreNotification(DataGridViewColumn dataGridViewColumn)
        {
            Debug.Assert(dataGridViewColumn.Index >= 0);
            Debug.Assert(dataGridViewColumn.DataGridView is null);

            // Clear the potential header sort glyph
            if (dataGridViewColumn.HasHeaderCell)
            {
                dataGridViewColumn.HeaderCell.SortGlyphDirectionInternal = SortOrder.None;
            }
            // Intentionally keep the DisplayIndex intact after detaching the column.
            CorrectColumnIndexesAfterDeletion(dataGridViewColumn);

            CorrectColumnDisplayIndexesAfterDeletion(dataGridViewColumn);

            // Fix the OldFirstDisplayedScrollingCol
            DisplayedBandsInfo.CorrectRowIndexAfterDeletion(dataGridViewColumn.Index);

            // Raise the ColumnRemoved event
            OnColumnRemoved(dataGridViewColumn);
        }

        internal void OnRemovedColumn_PostNotification(DataGridViewColumn dataGridViewColumn, Point newCurrentCell)
        {
            // Update current cell if needed
            if (newCurrentCell.X != -1)
            {
                Debug.Assert(_ptCurrentCell.X == -1);
                bool success = SetAndSelectCurrentCellAddress(newCurrentCell.X,
                                                              newCurrentCell.Y,
                                                              true,
                                                              false,
                                                              false,
                                                              false /*clearSelection*/,
                                                              false /*forceCurrentCellSelection*/);
                Debug.Assert(success);
            }

            // Raise SelectionChanged event if needed
            FlushSelectionChanged();

            // Raise ColumnStateChanged event for Displayed state of deleted column
            OnColumnHidden(dataGridViewColumn);

            // Columns that are removed from the collection take their non-autosized width
            // Note that in some edge cases, the dev could have changed:
            //     - the grid's AutoSizeColumnsMode
            //     - the column's Width or AutoSizeMode
            // in a ColumnRemoved event handler for example, in which case using the CachedThickness may be wrong.
            // At least we make sure the column is not sized smaller than its minimum width.
            DataGridViewAutoSizeColumnMode autoSizeColumnMode = dataGridViewColumn.GetInheritedAutoSizeMode(this);
            Debug.Assert(autoSizeColumnMode != DataGridViewAutoSizeColumnMode.NotSet);
            if (autoSizeColumnMode != DataGridViewAutoSizeColumnMode.None &&
                autoSizeColumnMode != DataGridViewAutoSizeColumnMode.Fill &&
                dataGridViewColumn.ThicknessInternal != dataGridViewColumn.CachedThickness)
            {
                dataGridViewColumn.ThicknessInternal = Math.Max(dataGridViewColumn.MinimumWidth, dataGridViewColumn.CachedThickness);
            }

            // Autosize rows if needed
            AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
        }

        internal void OnRemovedRow_PreNotification(int rowIndexDeleted)
        {
            // Fix the OldFirstDisplayedScrollingRow
            DisplayedBandsInfo.CorrectRowIndexAfterDeletion(rowIndexDeleted);

            CorrectRowIndexesAfterDeletion(rowIndexDeleted);
            ComputeVisibleRows();
        }

        internal void OnRemovedRow_PostNotification(DataGridViewRow dataGridViewRow, Point newCurrentCell)
        {
            // Update current cell if needed
            if (newCurrentCell.Y != -1)
            {
                Debug.Assert(_ptCurrentCell.X == -1);
                bool success = SetAndSelectCurrentCellAddress(newCurrentCell.X,
                                                              newCurrentCell.Y,
                                                              true /*setAnchorCellAddress*/,
                                                              false /*validateCurrentCell*/,
                                                              false /*throughMouseClick*/,
                                                              false /*clearSelection*/,
                                                              false /*forceCurrentCellSelection*/);
                Debug.Assert(success);
            }

            // Raise SelectionChange event if needed
            FlushSelectionChanged();

            bool rowDisplayed = dataGridViewRow.DataGridView is null && dataGridViewRow.Displayed;

            // Raise RowStateChanged event for Displayed state of deleted row
            if (rowDisplayed)
            {
                dataGridViewRow.Displayed = false;
                DataGridViewRowStateChangedEventArgs dgvrsce = new DataGridViewRowStateChangedEventArgs(dataGridViewRow, DataGridViewElementStates.Displayed);
                OnRowStateChanged(-1 /*rowIndex*/, dgvrsce);
            }

            // Rows that are removed from the collection take their non-autosized height
            // Note that in some edge cases, the dev could have changed:
            //     - the grid's AutoSizeRowsMode
            //     - the row's Height
            // in a RowsRemoved event handler for example, in which case using the CachedThickness may be wrong.
            // At least we make sure the row is not sized smaller than its minimum height.
            if (_autoSizeRowsMode != DataGridViewAutoSizeRowsMode.None && dataGridViewRow.ThicknessInternal != dataGridViewRow.CachedThickness)
            {
                dataGridViewRow.ThicknessInternal = Math.Max(dataGridViewRow.MinimumHeight, dataGridViewRow.CachedThickness);
            }

            // Auto size columms also if needed
            DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter = DataGridViewAutoSizeColumnCriteriaInternal.AllRows;
            if (rowDisplayed)
            {
                autoSizeColumnCriteriaFilter |= DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows;
            }
            bool columnAutoSized = AutoResizeAllVisibleColumnsInternal(autoSizeColumnCriteriaFilter, true /*fixedHeight*/);
            bool fixedColumnHeadersHeight = ColumnHeadersHeightSizeMode != DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            bool fixedRowHeadersWidth = _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing ||
                                        _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.DisableResizing;

            if (fixedRowHeadersWidth && !columnAutoSized)
            {
                // No need to autosize the column headers when the row headers and columns don't change.
                fixedColumnHeadersHeight = true;
            }

            // Auto size column headers
            if (!fixedColumnHeadersHeight)
            {
                AutoResizeColumnHeadersHeight(fixedRowHeadersWidth, true /*fixedColumnsWidth*/);
            }

            // Auto size row headers
            if (!fixedRowHeadersWidth)
            {
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, true /*fixedRowsHeight*/);
            }

            if (!fixedColumnHeadersHeight && !fixedRowHeadersWidth)
            {
                // Second round of column headers autosizing
                AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
            }
        }

        internal void OnRemovingColumn(DataGridViewColumn dataGridViewColumn, out Point newCurrentCell, bool force)
        {
            Debug.Assert(dataGridViewColumn != null);
            Debug.Assert(dataGridViewColumn.Index >= 0 && dataGridViewColumn.Index < Columns.Count);

            _dataGridViewState1[State1_TemporarilyResetCurrentCell] = false;
            int columnIndex = dataGridViewColumn.Index;

            // Reset the current cell's address if there is one.
            if (_ptCurrentCell.X != -1)
            {
                int newX = _ptCurrentCell.X;
                if (columnIndex == _ptCurrentCell.X)
                {
                    DataGridViewColumn dataGridViewColumnNext = Columns.GetNextColumn(
                        Columns[columnIndex],
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.None);
                    if (dataGridViewColumnNext != null)
                    {
                        if (dataGridViewColumnNext.Index > columnIndex)
                        {
                            newX = dataGridViewColumnNext.Index - 1;
                        }
                        else
                        {
                            newX = dataGridViewColumnNext.Index;
                        }
                    }
                    else
                    {
                        DataGridViewColumn dataGridViewColumnPrevious = Columns.GetPreviousColumn(
                            Columns[columnIndex],
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None);
                        if (dataGridViewColumnPrevious != null)
                        {
                            if (dataGridViewColumnPrevious.Index > columnIndex)
                            {
                                newX = dataGridViewColumnPrevious.Index - 1;
                            }
                            else
                            {
                                newX = dataGridViewColumnPrevious.Index;
                            }
                        }
                        else
                        {
                            newX = -1;
                        }
                    }
                }
                else if (columnIndex < _ptCurrentCell.X)
                {
                    newX = _ptCurrentCell.X - 1;
                }
                newCurrentCell = new Point(newX, (newX == -1) ? -1 : _ptCurrentCell.Y);
                if (columnIndex == _ptCurrentCell.X)
                {
                    // Left cell is not validated since cancelling validation wouldn't have any effect anyways.
                    bool success = SetCurrentCellAddressCore(-1, -1, true /*setAnchorCellAddress*/, false /*validateCurrentCell*/, false);
                    Debug.Assert(success);
                }
                else if (force)
                {
                    // Underlying data of deleted column is gone. It cannot be accessed anymore.
                    // Do not end editing mode so that CellValidation doesn't get raised, since that event needs the current formatted value.
                    _dataGridViewState1[State1_TemporarilyResetCurrentCell] = true;
                    bool success = SetCurrentCellAddressCore(-1, -1, true /*setAnchorCellAddress*/, false /*validateCurrentCell*/, false);
                    Debug.Assert(success);
                }
                else
                {
                    // Quit editing mode and set the current cell to its new location once everything is in sync again.
                    ResetCurrentCell();
                }
            }
            else
            {
                newCurrentCell = new Point(-1, -1);
            }

            // If the last column is removed, delete all the rows first.
            if (Columns.Count == 1)
            {
                Debug.Assert(columnIndex == 0);
                Rows.ClearInternal(false /*recreateNewRow*/);
            }

            // Prepare the existing rows by removing cells at correct index
            int newColumnCount = Columns.Count - 1;

            for (int rowIndex = 0; rowIndex < Rows.Count; rowIndex++)
            {
                DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                if (dataGridViewRow.Cells.Count > newColumnCount)
                {
                    KeyboardToolTipStateMachine.Instance.Unhook(dataGridViewRow.Cells[columnIndex], KeyboardToolTip);
                    dataGridViewRow.Cells.RemoveAtInternal(columnIndex);
                }
            }

            // Detach column header cell
            if (dataGridViewColumn.HasHeaderCell)
            {
                dataGridViewColumn.HeaderCell.DataGridView = null;
            }

            // Reset sort related variables.
            if (dataGridViewColumn == SortedColumn)
            {
                SortedColumn = null;
                SortOrder = SortOrder.None;

                if (dataGridViewColumn.IsDataBound)
                {
                    // If the column being removed is the sorted column and it is also the dataBound column
                    // then see if there is another dataBound column which has the same property name as the sorted column.
                    // If so, then make that dataGridViewColumn the sorted column in the data grid view.
                    for (int i = 0; i < Columns.Count; i++)
                    {
                        if (dataGridViewColumn != Columns[i] &&
                            Columns[i].SortMode != DataGridViewColumnSortMode.NotSortable &&
                            string.Compare(dataGridViewColumn.DataPropertyName,
                                           Columns[i].DataPropertyName,
                                           true /*ignoreCase*/,
                                           CultureInfo.InvariantCulture) == 0)
                        {
                            Debug.Assert(Columns[i].IsDataBound, "two columns w/ the same DataPropertyName should be DataBound at the same time");
                            Debug.Assert(Columns[i].HeaderCell.SortGlyphDirection == dataGridViewColumn.HeaderCell.SortGlyphDirection, "DataBound columns should have the same SortGlyphDirection as the one on the DataGridView");
                            SortedColumn = Columns[i];
                            SortOrder = Columns[i].HeaderCell.SortGlyphDirection;
                            break;
                        }
                    }
                }
            }

            // Is deleted column scrolled off screen?
            if (dataGridViewColumn.Visible &&
                !dataGridViewColumn.Frozen &&
                DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0)
            {
                // Deleted column is part of scrolling columns.
                if (DisplayedBandsInfo.FirstDisplayedScrollingCol == dataGridViewColumn.Index)
                {
                    // Deleted column is first scrolling column
                    _horizontalOffset -= FirstDisplayedScrollingColumnHiddenWidth;
                    FirstDisplayedScrollingColumnHiddenWidth = 0;
                }
                else if (Columns.DisplayInOrder(DisplayedBandsInfo.FirstDisplayedScrollingCol, dataGridViewColumn.Index))
                {
                    // Deleted column is displayed after first scrolling column
                    if (_horizScrollBar.Enabled)
                    {
                        int newHorizontalOffset = _horizScrollBar.Maximum - _horizScrollBar.LargeChange - dataGridViewColumn.Thickness;
                        if (newHorizontalOffset >= 0 && newHorizontalOffset < _horizScrollBar.Value)
                        {
                            _horizontalOffset = newHorizontalOffset;
                            FirstDisplayedScrollingColumnHiddenWidth = GetNegOffsetFromHorizontalOffset(_horizontalOffset);
                        }
                    }
                    else
                    {
                        _horizontalOffset = FirstDisplayedScrollingColumnHiddenWidth = 0;
                    }
                }
                else
                {
                    // Deleted column is displayed before first scrolling column
                    Debug.Assert(_horizontalOffset >= dataGridViewColumn.Thickness);
                    _horizontalOffset -= dataGridViewColumn.Thickness;
                }

                if (_horizScrollBar.Enabled)
                {
                    _horizScrollBar.Value = _horizontalOffset;
                }
            }

            bool raiseSelectionChanged = false;

            // Update the indexes of selected columns or individual cells to compensate for the removal of this column
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.FullColumnSelect:
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    int columnEntries = _selectedBandIndexes.Count;
                    int columnEntry = 0;
                    while (columnEntry < columnEntries)
                    {
                        int columnIndexSelected = _selectedBandIndexes[columnEntry];
                        if (columnIndex == columnIndexSelected)
                        {
                            _selectedBandIndexes.RemoveAt(columnEntry);
                            columnEntries--;
                            raiseSelectionChanged = true;
                        }
                        else
                        {
                            if (columnIndex < columnIndexSelected)
                            {
                                _selectedBandIndexes[columnEntry] = columnIndexSelected - 1;
                            }
                            columnEntry++;
                        }
                    }
                    break;
            }

            _dataGridViewState2[State2_RaiseSelectionChanged] |= _individualSelectedCells.RemoveAllCellsAtBand(true /*column*/, columnIndex) > 0 ||
                                                                                 raiseSelectionChanged;
            _individualReadOnlyCells.RemoveAllCellsAtBand(true /*column*/, columnIndex);
        }

        internal void OnRemovingRow(int rowIndexDeleted, out Point newCurrentCell, bool force)
        {
            // if force is true, the row needs to be deleted no matter what. The underlying data row was already deleted.

            Debug.Assert(rowIndexDeleted >= 0 && rowIndexDeleted < Rows.Count);

            if (rowIndexDeleted >= 0 && rowIndexDeleted < Rows.Count)
            {
                foreach (DataGridViewCell cell in Rows[rowIndexDeleted].Cells)
                {
                    KeyboardToolTipStateMachine.Instance.Unhook(cell, KeyboardToolTip);
                }
            }

            _dataGridViewState1[State1_TemporarilyResetCurrentCell] = false;
            newCurrentCell = new Point(-1, -1);

            // Reset the current cell's address if it's on the deleted row, or after it.
            if (_ptCurrentCell.Y != -1 && rowIndexDeleted <= _ptCurrentCell.Y)
            {
                int newY;
                if (rowIndexDeleted == _ptCurrentCell.Y)
                {
                    int rowIndexPrevious = Rows.GetPreviousRow(rowIndexDeleted, DataGridViewElementStates.Visible);
                    int rowIndexNext = Rows.GetNextRow(rowIndexDeleted, DataGridViewElementStates.Visible);
                    if (rowIndexPrevious > -1 && AllowUserToAddRowsInternal)
                    {
                        Debug.Assert(NewRowIndex != -1);
                        Debug.Assert(NewRowIndex == Rows.Count - 1);
                        if (rowIndexNext > -1 && rowIndexNext < Rows.Count - 1)
                        {
                            newY = rowIndexNext - 1;
                        }
                        else
                        {
                            newY = rowIndexPrevious;
                        }
                    }
                    else
                    {
                        if (rowIndexNext > -1)
                        {
                            newY = rowIndexNext - 1;
                        }
                        else
                        {
                            newY = rowIndexPrevious;
                        }
                    }
                    // Since the current row is deleted, the dirty states need to be reset
                    IsCurrentCellDirtyInternal = false;
                    IsCurrentRowDirtyInternal = false;
                }
                else
                {
                    Debug.Assert(rowIndexDeleted < _ptCurrentCell.Y);
                    newY = _ptCurrentCell.Y - 1;
                }
                newCurrentCell = new Point(_ptCurrentCell.X, newY);
                if (rowIndexDeleted == _ptCurrentCell.Y)
                {
                    // Left cell is not validated since cancelling validation wouldn't have any effect anyways.
                    bool success = SetCurrentCellAddressCore(-1, -1, true /*setAnchorCellAddress*/, false /*validateCurrentCell*/, false);
                    Debug.Assert(success);
                }
                else if (force)
                {
                    // Underlying data of deleted row is gone. It cannot be accessed anymore.
                    // Do not end editing mode so that CellValidation doesn't get raised, since that event needs the current formatted value.
                    _dataGridViewState1[State1_TemporarilyResetCurrentCell] = true;
                    bool success = SetCurrentCellAddressCore(-1, -1, true /*setAnchorCellAddress*/, false /*validateCurrentCell*/, false);
                    Debug.Assert(success);
                }
                else
                {
                    // Quit editing mode and set the current cell to its new location once everything is in sync again.
                    ResetCurrentCell();
                }
            }

            bool raiseSelectionChanged = false;

            // Update the indexes of selected rows to compensate for the removal of this row
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    int rowEntries = _selectedBandIndexes.Count;
                    int rowEntry = 0;
                    while (rowEntry < rowEntries)
                    {
                        int rowIndex = _selectedBandIndexes[rowEntry];
                        if (rowIndexDeleted == rowIndex)
                        {
                            raiseSelectionChanged = true;
                            _selectedBandIndexes.RemoveAt(rowEntry);
                            rowEntries--;
                        }
                        else
                        {
                            if (rowIndexDeleted < rowIndex)
                            {
                                _selectedBandIndexes[rowEntry] = rowIndex - 1;
                            }
                            rowEntry++;
                        }
                    }
                    if (_selectedBandSnapshotIndexes != null)
                    {
                        rowEntries = _selectedBandSnapshotIndexes.Count;
                        rowEntry = 0;
                        while (rowEntry < rowEntries)
                        {
                            int rowIndex = _selectedBandSnapshotIndexes[rowEntry];
                            if (rowIndexDeleted == rowIndex)
                            {
                                _selectedBandSnapshotIndexes.RemoveAt(rowEntry);
                                rowEntries--;
                            }
                            else
                            {
                                if (rowIndexDeleted < rowIndex)
                                {
                                    _selectedBandSnapshotIndexes[rowEntry] = rowIndex - 1;
                                }
                                rowEntry++;
                            }
                        }
                    }
                    break;
            }

            _dataGridViewState2[State2_RaiseSelectionChanged] |= _individualSelectedCells.RemoveAllCellsAtBand(false /*column*/, rowIndexDeleted) > 0 ||
                                                                                 raiseSelectionChanged;
            _individualReadOnlyCells.RemoveAllCellsAtBand(false /*column*/, rowIndexDeleted);
        }

        internal void OnReplacedCell(DataGridViewRow dataGridViewRow, int columnIndex)
        {
            DataGridViewCell dataGridViewCell = dataGridViewRow.Cells[columnIndex];
            if (_dataGridViewState2[State2_ReplacedCellSelected])
            {
                _individualSelectedCells.Add(dataGridViewCell);
            }
            if (_dataGridViewState2[State2_ReplacedCellReadOnly])
            {
                _individualReadOnlyCells.Add(dataGridViewCell);
            }

            // AutoSize column and row if needed
            OnCellCommonChange(columnIndex, dataGridViewRow.Index);

            if (_ptCurrentCellCache.X != -1)
            {
                if (!IsInnerCellOutOfBounds(_ptCurrentCellCache.X, _ptCurrentCellCache.Y))
                {
                    SetCurrentCellAddressCore(_ptCurrentCellCache.X, _ptCurrentCellCache.Y, false, false, false);
                }
                _ptCurrentCellCache.X = -1;
                _ptCurrentCellCache.Y = -1;
            }
        }

        internal void OnReplacingCell(DataGridViewRow dataGridViewRow, int columnIndex)
        {
            if (_ptCurrentCell.X == dataGridViewRow.Index &&
                _ptCurrentCell.Y == columnIndex)
            {
                // Trying to replace the current cell. Exiting editing mode first (if needed).
                // Remember to reset the current cell in OnReplacedCell notification
                _ptCurrentCellCache.X = _ptCurrentCell.X;
                _ptCurrentCellCache.Y = _ptCurrentCell.Y;
                // This may fail and throw an exception
                ResetCurrentCell();
            }
            else
            {
                _ptCurrentCellCache.X = -1;
                _ptCurrentCellCache.Y = -1;
            }
            DataGridViewCell dataGridViewCell = dataGridViewRow.Cells[columnIndex];
            _dataGridViewState2[State2_ReplacedCellSelected] = _individualSelectedCells.Contains(dataGridViewCell);
            if (_dataGridViewState2[State2_ReplacedCellSelected])
            {
                _individualSelectedCells.Remove(dataGridViewCell);
            }
            _dataGridViewState2[State2_ReplacedCellReadOnly] = _individualReadOnlyCells.Contains(dataGridViewCell);
            if (_dataGridViewState2[State2_ReplacedCellReadOnly])
            {
                _individualReadOnlyCells.Remove(dataGridViewCell);
            }
        }

        protected override void OnResize(EventArgs e)
        {
            int borderWidth = BorderWidth;
            Rectangle right;
            Rectangle bottom;
            Rectangle oldClientRectangle = _layout.ClientRectangle;
            Rectangle oldGridFocusRectangle = GetGridFocusRectangle();

            right = new Rectangle(oldClientRectangle.X + oldClientRectangle.Width - borderWidth,
                oldClientRectangle.Y,
                borderWidth,
                oldClientRectangle.Height);
            bottom = new Rectangle(oldClientRectangle.X,
                oldClientRectangle.Y + oldClientRectangle.Height - borderWidth,
                oldClientRectangle.Width,
                borderWidth);

            if (!IsMinimized)
            {
                // When owning form is minimized, act as if it had a normal size
                _normalClientRectangle = ClientRectangle;
            }

            Rectangle newClientRectangle = _normalClientRectangle;
            Rectangle newGridFocusRectangle = DisplayRectangle;
            newGridFocusRectangle.Inflate(1 - borderWidth - FocusRectOffset, 1 - borderWidth - FocusRectOffset);

            if (newClientRectangle.Width != oldClientRectangle.Width)
            {
                Invalidate(right);
                right = new Rectangle(newClientRectangle.X + newClientRectangle.Width - borderWidth,
                    newClientRectangle.Y,
                    borderWidth,
                    newClientRectangle.Height);
                Invalidate(right);
            }
            if (newClientRectangle.Height != oldClientRectangle.Height)
            {
                Invalidate(bottom);
                bottom = new Rectangle(newClientRectangle.X,
                    newClientRectangle.Y + newClientRectangle.Height - borderWidth,
                    newClientRectangle.Width,
                    borderWidth);
                Invalidate(bottom);
            }

            // Invalidate grid focus rectangle
            if (Focused && IsGridFocusRectangleEnabled() && oldGridFocusRectangle != newGridFocusRectangle)
            {
                right = new Rectangle(oldGridFocusRectangle.X + oldGridFocusRectangle.Width - 1,
                    oldGridFocusRectangle.Y,
                    1,
                    oldGridFocusRectangle.Height);
                Invalidate(right);

                bottom = new Rectangle(oldGridFocusRectangle.X,
                    oldGridFocusRectangle.Y + oldGridFocusRectangle.Height - 1,
                    oldGridFocusRectangle.Width,
                    1);
                Invalidate(bottom);

                InvalidateRectangleEdges(newGridFocusRectangle);
            }

            //also, invalidate the ResizeBoxRect
            if (!_layout.ResizeBoxRect.IsEmpty)
            {
                Invalidate(_layout.ResizeBoxRect);
            }
            _layout.ClientRectangle = newClientRectangle;

            int oldfirstDisplayedScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
            base.OnResize(e);
            if (oldfirstDisplayedScrollingRow != DisplayedBandsInfo.FirstDisplayedScrollingRow)
            {
                Invalidate();
            }
        }

        protected override void OnRightToLeftChanged(EventArgs e)
        {
            _dataGridViewState2[State2_RightToLeftValid] = false;
            base.OnRightToLeftChanged(e);
            CorrectFocus(true /*onlyIfGridHasFocus*/);
            PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
        }

        internal void OnRowCollectionChanged_PostNotification(bool recreateNewRow,
                                                              bool allowSettingCurrentCell,
                                                              CollectionChangeAction cca,
                                                              DataGridViewRow dataGridViewRow,
                                                              int rowIndex)
        {
            if (recreateNewRow &&
                cca == CollectionChangeAction.Refresh &&
                Columns.Count != 0 &&
                Rows.Count == 0 &&
                AllowUserToAddRowsInternal)
            {
                AddNewRow(false);
            }

            if (cca == CollectionChangeAction.Refresh)
            {
                FlushSelectionChanged();
            }

            if ((cca == CollectionChangeAction.Refresh || cca == CollectionChangeAction.Add) &&
                _ptCurrentCell.X == -1 && allowSettingCurrentCell && !InSortOperation)
            {
                MakeFirstDisplayedCellCurrentCell(false /*includeNewRow*/);
            }

            if (AutoSize)
            {
                bool invalidatePreferredSizeCache = true;
                switch (cca)
                {
                    case CollectionChangeAction.Add:
                        Debug.Assert(rowIndex >= 0);
                        DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
                        invalidatePreferredSizeCache = ((rowState & DataGridViewElementStates.Visible) != 0);
                        break;
                    case CollectionChangeAction.Remove:
                        invalidatePreferredSizeCache = dataGridViewRow.DataGridView is null && dataGridViewRow.Visible;
                        break;
                        // case CollectionChangeAction.Refresh: invalidatePreferredSizeCache stays true
                }
                if (invalidatePreferredSizeCache)
                {
                    LayoutTransaction.DoLayout(ParentInternal, this, PropertyNames.Rows);
                }
            }
        }

        protected virtual void OnRowContextMenuStripChanged(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }
            if (Events[s_rowContextMenuStripChangedEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal ContextMenuStrip OnRowContextMenuStripNeeded(int rowIndex, ContextMenuStrip contextMenuStrip)
        {
            DataGridViewRowContextMenuStripNeededEventArgs dgvrcmsne = new DataGridViewRowContextMenuStripNeededEventArgs(rowIndex, contextMenuStrip);
            OnRowContextMenuStripNeeded(dgvrcmsne);
            return dgvrcmsne.ContextMenuStrip;
        }

        protected virtual void OnRowContextMenuStripNeeded(DataGridViewRowContextMenuStripNeededEventArgs e)
        {
            if (Events[s_rowContextMenuStripNeededEvent] is DataGridViewRowContextMenuStripNeededEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowDefaultCellStyleChanged(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }

            OnRowGlobalAutoSize(e.Row.Index);

            if (Events[s_rowDefaultCellStyleChangedEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowDirtyStateNeeded(QuestionEventArgs e)
        {
            if (Events[s_rowDirtyStateNeededEvent] is QuestionEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowDividerDoubleClick(DataGridViewRowDividerDoubleClickEventArgs e)
        {
            if (Events[s_rowDividerDoubleClickEvent] is DataGridViewRowDividerDoubleClickEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (!e.Handled && e.Button == MouseButtons.Left && e.RowIndex < Rows.Count)
            {
                if (e.RowIndex == -1)
                {
                    AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
                }
                else
                {
                    if (_autoSizeRowsMode == DataGridViewAutoSizeRowsMode.None)
                    {
                        AutoResizeRowInternal(e.RowIndex, DataGridViewAutoSizeRowMode.AllCells, true /*fixedWidth*/, true /*internalAutosizing*/);
                    }
                    else
                    {
                        AutoResizeRowInternal(e.RowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), true /*fixedWidth*/, true /*internalAutosizing*/);
                    }
                }
            }
        }

        protected virtual void OnRowDividerHeightChanged(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }

            OnRowGlobalAutoSize(e.Row.Index);

            if (Events[s_rowDividerHeightChangedEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnRowEnter(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex, bool canCreateNewRow, bool validationFailureOccurred)
        {
            Debug.Assert(columnIndex >= 0 && rowIndex >= 0);

            if (!validationFailureOccurred)
            {
                _dataGridViewState1[State1_NewRowEdited] = false;
            }
            if (rowIndex < Rows.Count &&
                columnIndex < Columns.Count)
            {
                bool calledAddNewOnTheDataConnection = false;
                if (!validationFailureOccurred && AllowUserToAddRowsInternal && NewRowIndex == rowIndex)
                {
                    _dataGridViewState1[State1_NewRowEdited] = true;

                    if (canCreateNewRow)
                    {
                        DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs(Rows[NewRowIndex]);
                        if (VirtualMode || DataSource != null)
                        {
                            if (DataConnection != null && DataConnection.InterestedInRowEvents)
                            {
                                DataConnection.OnNewRowNeeded();
                                calledAddNewOnTheDataConnection = true;
                            }
                            if (VirtualMode)
                            {
                                OnNewRowNeeded(dgvre);
                            }
                        }

                        // AllowUserToAddRowsInternal can become FALSE while adding a row.
                        // NOTE: we don't need to invalidate if AllowUserToAddRowsInternal changed to FALSE.
                        //
                        if (AllowUserToAddRowsInternal)
                        {
                            OnDefaultValuesNeeded(dgvre);
                            InvalidateRowPrivate(NewRowIndex);
                        }
#if DEBUG
                        else
                        {
                            Debug.Assert(NewRowIndex == -1, "newRowIndex and AllowUserToAddRowsInternal became out of sync");
                        }
#endif //
                    }
                }

                if (calledAddNewOnTheDataConnection && rowIndex > Rows.Count - 1)
                {
                    // Calling AddNew on the DataConnection can result in the entire list being wiped out.
                    //
                    rowIndex = Math.Min(rowIndex, Rows.Count - 1);
                }

                DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(columnIndex, rowIndex);
                OnRowEnter(dgvce);
                if (DataConnection != null &&
                    DataConnection.InterestedInRowEvents &&
                    !DataConnection.PositionChangingOutsideDataGridView &&
                    !DataConnection.ListWasReset &&
                    (!calledAddNewOnTheDataConnection || DataConnection.List.Count > 0))
                {
                    DataConnection.OnRowEnter(dgvce);
                }

                if (dataGridViewCell != null)
                {
                    if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                    {
                        dataGridViewCell = null;
                    }
                    else
                    {
                        Debug.Assert(rowIndex < Rows.Count && columnIndex < Columns.Count);
                        dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                    }
                }
            }
        }

        protected virtual void OnRowEnter(DataGridViewCellEventArgs e)
        {
            try
            {
                _noDimensionChangeCount++;

                if (Events[s_rowEnterEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                    CorrectFocus(true /*onlyIfGridHasFocus*/);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
            }
        }

        internal void OnRowErrorTextChanged(DataGridViewRow dataGridViewRow)
        {
            DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs(dataGridViewRow);
            OnRowErrorTextChanged(dgvre);
        }

        protected virtual void OnRowErrorTextChanged(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }
            UpdateRowErrorText(e.Row.Index);

            if (Events[s_rowErrorTextChangedEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal string OnRowErrorTextNeeded(int rowIndex, string errorText)
        {
            Debug.Assert(rowIndex >= 0);
            DataGridViewRowErrorTextNeededEventArgs dgvretne = new DataGridViewRowErrorTextNeededEventArgs(rowIndex, errorText);
            OnRowErrorTextNeeded(dgvretne);
            return dgvretne.ErrorText;
        }

        protected virtual void OnRowErrorTextNeeded(DataGridViewRowErrorTextNeededEventArgs e)
        {
            if (Events[s_rowErrorTextNeededEvent] is DataGridViewRowErrorTextNeededEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnRowGlobalAutoSize(int rowIndex)
        {
            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
            if ((rowState & DataGridViewElementStates.Visible) == 0)
            {
                return;
            }

            InvalidateRowPrivate(rowIndex);

            if (_noAutoSizeCount > 0)
            {
                return;
            }

            DataGridViewAutoSizeRowsModeInternal autoSizeRowsModeInternal = (DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode;
            bool autoSizeRow = false;
            bool rowDisplayed = (rowState & DataGridViewElementStates.Displayed) != 0;
            if (autoSizeRowsModeInternal != DataGridViewAutoSizeRowsModeInternal.None &&
                !((autoSizeRowsModeInternal & DataGridViewAutoSizeRowsModeInternal.DisplayedRows) != 0 && !rowDisplayed))
            {
                AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), false /*fixedWidth*/, true /*internalAutosizing*/);
                autoSizeRow = true;
            }

            // Auto size columms also if needed
            DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter = DataGridViewAutoSizeColumnCriteriaInternal.AllRows;
            if (rowDisplayed)
            {
                autoSizeColumnCriteriaFilter |= DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows;
            }
            AutoResizeAllVisibleColumnsInternal(autoSizeColumnCriteriaFilter, true /*fixedHeight*/);

            bool fixedRowHeadersWidth = _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing ||
                                        _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.DisableResizing;
            // Auto size column headers
            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                AutoResizeColumnHeadersHeight(fixedRowHeadersWidth, true /*fixedColumnsWidth*/);
            }

            // Auto size row headers
            if (!fixedRowHeadersWidth)
            {
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, true /*fixedRowsHeight*/);
            }

            if (autoSizeRow)
            {
                // Second round of row autosizing
                AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), true /*fixedWidth*/, true /*internalAutosizing*/);
            }

            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize && !fixedRowHeadersWidth)
            {
                // Second round of column headers autosizing
                AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
            }
        }

        protected virtual void OnRowHeaderCellChanged(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }

            OnRowHeaderGlobalAutoSize(e.Row.Index);

            if (Events[s_rowHeaderCellChangedEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnRowHeaderGlobalAutoSize(int rowIndex)
        {
            if (!RowHeadersVisible)
            {
                return;
            }

            InvalidateCellPrivate(-1, rowIndex);

            if (_noAutoSizeCount > 0)
            {
                return;
            }

            bool rowDisplayed = false;
            if (rowIndex != -1)
            {
                rowDisplayed = (Rows.GetRowState(rowIndex) & DataGridViewElementStates.Displayed) != 0;
            }

            bool fixedColumnHeadersHeight = rowIndex != -1 || ColumnHeadersHeightSizeMode != DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            bool fixedRowHeight = rowIndex == -1 ||
                                  ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.Header) == 0) ||
                                  ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.DisplayedRows) != 0 && rowIndex != -1 && !rowDisplayed);

            bool autoSizeRowHeaders = false;
            if (_rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders ||
                (_rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.AutoSizeToDisplayedHeaders && rowIndex != -1 && rowDisplayed) ||
                (_rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.EnableResizing && _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.DisableResizing && rowIndex == -1) ||
                (_rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.AutoSizeToFirstHeader && rowIndex != -1 && rowIndex == Rows.GetFirstRow(DataGridViewElementStates.Visible)))
            {
                AutoResizeRowHeadersWidth(rowIndex,
                                          _rowHeadersWidthSizeMode,
                                          fixedColumnHeadersHeight,
                                          fixedRowHeight);
                autoSizeRowHeaders = true;
            }
            if (!fixedColumnHeadersHeight)
            {
                AutoResizeColumnHeadersHeight(-1, true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
            }
            if (!fixedRowHeight)
            {
                AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), true /*fixedWidth*/, true /*internalAutosizing*/);
            }

            if (autoSizeRowHeaders && (!fixedColumnHeadersHeight || !fixedRowHeight))
            {
                // Second round of row headers autosizing
                AutoResizeRowHeadersWidth(rowIndex,
                                          _rowHeadersWidthSizeMode,
                                          true /*fixedColumnHeadersHeight*/,
                                          true /*fixedRowHeight*/);
            }
        }

        protected virtual void OnRowHeaderMouseClick(DataGridViewCellMouseEventArgs e)
        {
            if (Events[s_rowHeaderMouseClickEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowHeaderMouseDoubleClick(DataGridViewCellMouseEventArgs e)
        {
            if (Events[s_rowHeaderMouseDoubleClickEvent] is DataGridViewCellMouseEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnRowHeaderMouseDown(HitTestInfo hti, bool isShiftDown, bool isControlDown)
        {
            Debug.Assert(hti.Type == DataGridViewHitTestType.RowHeader);
            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.FullColumnSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        break;

                    case DataGridViewSelectionMode.FullRowSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        {
                            bool select = true;
                            if (isControlDown &&
                                ((Rows.GetRowState(hti._row) & DataGridViewElementStates.Selected) != 0))
                            {
                                select = false;
                            }
                            if (select)
                            {
                                DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
                                if (dataGridViewColumn != null && hti._row != _ptCurrentCell.Y)
                                {
                                    int oldCurrentCellX = _ptCurrentCell.X;
                                    int oldCurrentCellY = _ptCurrentCell.Y;
                                    // Make sure we will be able to scroll into view
                                    if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.CurrentCellChange,
                                        DataGridViewValidateCellInternal.Always /*validateCell*/,
                                        true /*fireCellLeave*/,
                                        true /*fireCellEnter*/,
                                        hti._row != _ptCurrentCell.Y /*fireRowLeave*/,
                                        hti._row != _ptCurrentCell.Y /*fireRowEnter*/,
                                        false /*fireLeave*/,
                                        EditMode != DataGridViewEditMode.EditOnEnter /*keepFocus*/,
                                        true /*resetCurrentCell*/,
                                        false /*resetAnchorCell*/))
                                    {
                                        // Just cancel operation silently instead of throwing InvalidOperationException
                                        return;
                                    }
                                    if (oldCurrentCellY != -1)
                                    {
                                        DataGridViewCell dataGridViewCellTmp = null;
                                        if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                        {
                                            return;
                                        }
                                        if (OnRowValidating(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY))
                                        {
                                            // Row validation was cancelled
                                            if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                            {
                                                return;
                                            }
                                            OnRowEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY, true /*canCreateNewRow*/, true /*validationFailureOccurred*/);
                                            if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                            {
                                                return;
                                            }
                                            OnCellEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);
                                            return;
                                        }
                                        if (IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                        {
                                            return;
                                        }
                                        OnRowValidated(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);

                                        // Row validation was not cancelled, but operation needs to be re-evaluated.
                                        if (hti._row >= Rows.Count)
                                        {
                                            int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
                                            if (_ptCurrentCell.X == -1 && lastVisibleRowIndex != -1)
                                            {
                                                // CurrentCell was reset because commit deleted row(s).
                                                // Since the user wants to select a row, we don't want to
                                                // end up with no CurrentCell. We pick the last visible
                                                // row in the grid which may be the 'new row'.
                                                if (IsColumnOutOfBounds(oldCurrentCellX))
                                                {
                                                    return;
                                                }
                                                bool success = SetAndSelectCurrentCellAddress(oldCurrentCellX,
                                                                                              lastVisibleRowIndex,
                                                                                              true,
                                                                                              false,
                                                                                              false,
                                                                                              false /*clearSelection*/,
                                                                                              false /*forceCurrentCellSelection*/);
                                                Debug.Assert(success);
                                            }
                                            return;
                                        }
                                        else if ((Rows.GetRowState(hti._row) & DataGridViewElementStates.Visible) == 0)
                                        {
                                            return;
                                        }
                                    }
                                }
                                bool selectRowRange = false;
                                _trackRow = hti._row;
                                _trackRowEdge = -1;
                                if (MultiSelect &&
                                    isShiftDown &&
                                    _ptAnchorCell.Y > -1 &&
                                    (Rows.GetRowState(_ptAnchorCell.Y) & DataGridViewElementStates.Selected) != 0)
                                {
                                    selectRowRange = true;
                                }
                                if (!MultiSelect || !isControlDown || isShiftDown)
                                {
                                    Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                                    int bandIndex = 0;
                                    bool switchedToBulkPaint = false;
                                    if (_selectedBandIndexes.Count > BulkPaintThreshold)
                                    {
                                        _inBulkPaintCount++;
                                        switchedToBulkPaint = true;
                                    }
                                    try
                                    {
                                        while (bandIndex < _selectedBandIndexes.Count)
                                        {
                                            if (_selectedBandIndexes[bandIndex] != hti._row)
                                            {
                                                // deselect currently selected row
                                                SetSelectedRowCore(_selectedBandIndexes[bandIndex], false);
                                            }
                                            else
                                            {
                                                bandIndex++;
                                            }
                                        }

                                        if (SelectionMode == DataGridViewSelectionMode.RowHeaderSelect)
                                        {
                                            RemoveIndividuallySelectedCells();
                                        }
                                        else
                                        {
                                            Debug.Assert(_individualSelectedCells.Count == 0);
                                        }
                                    }
                                    finally
                                    {
                                        if (switchedToBulkPaint)
                                        {
                                            ExitBulkPaint(-1, -1);
                                        }
                                    }
                                }
                                if (MultiSelect && _dataGridViewOper[OperationTrackMouseMoves])
                                {
                                    _dataGridViewOper[OperationTrackRowSelect] = true;
                                }
                                if (selectRowRange)
                                {
                                    if (hti._row >= _ptAnchorCell.Y)
                                    {
                                        SelectRowRange(_ptAnchorCell.Y, hti._row, true);
                                    }
                                    else
                                    {
                                        SelectRowRange(hti._row, _ptAnchorCell.Y, true);
                                    }
                                }
                                else if ((Rows.GetRowState(hti._row) & DataGridViewElementStates.Selected) == 0)
                                {
                                    Debug.Assert(_selectedBandIndexes.Contains(hti._row) ==
                                                 ((Rows.GetRowState(hti._row) & DataGridViewElementStates.Selected) != 0));
                                    SetSelectedRowCore(hti._row, true);
                                }
                                if (dataGridViewColumn != null)
                                {
                                    if (hti._row != _ptCurrentCell.Y)
                                    {
                                        if (IsInnerCellOutOfBounds(dataGridViewColumn.Index, hti._row))
                                        {
                                            return;
                                        }
                                        // set current cell to the left most visible cell in the row
                                        bool success = ScrollIntoView(dataGridViewColumn.Index, hti._row, false);
                                        Debug.Assert(success);
                                        if (IsInnerCellOutOfBounds(dataGridViewColumn.Index, hti._row))
                                        {
                                            return;
                                        }
                                        success = SetCurrentCellAddressCore(dataGridViewColumn.Index, hti._row, !selectRowRange, false, true);
                                        Debug.Assert(success);
                                    }
                                    else if (-1 != _ptCurrentCell.Y)
                                    {
                                        // Potentially have to give focus back to the current edited cell.
                                        bool success = SetCurrentCellAddressCore(_ptCurrentCell.X, _ptCurrentCell.Y,
                                                                                false /*setAnchorCellAddress*/,
                                                                                false /*validateCurrentCell*/,
                                                                                false /*throughMouseClick*/);
                                        Debug.Assert(success);
                                    }
                                }
                                else
                                {
                                    Debug.Assert(CurrentCellAddress == new Point(-1, -1));
                                }
                            }
                            else
                            {
                                Debug.Assert(_selectedBandIndexes.Contains(hti._row));
                                SetSelectedRowCore(hti._row, false);
                            }
                            break;
                        }
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
        }

        protected virtual void OnRowHeadersBorderStyleChanged(EventArgs e)
        {
            PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, false /*repositionEditingControl*/);
            Invalidate();

            if (Events[s_rowHeadersBorderStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowHeadersDefaultCellStyleChanged(EventArgs e)
        {
            if (RowHeadersVisible)
            {
                Invalidate(Rectangle.Union(_layout.TopLeftHeader, _layout.RowHeaders));

                if (!(e is DataGridViewCellStyleChangedEventArgs dgvcsce) || dgvcsce.ChangeAffectsPreferredSize)
                {
                    OnRowHeadersGlobalAutoSize(false /*expandingRows*/);
                    if (EditingControl != null)
                    {
                        PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                    }
                }
            }

            if (Events[s_rowHeadersDefaultCellStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnRowHeadersGlobalAutoSize(bool expandingRows)
        {
            if (_noAutoSizeCount > 0)
            {
                return;
            }

            bool fixedRowsHeight = (((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.Header) == 0 ||
                                   !RowHeadersVisible;
            bool autoSizeRowHeaders = _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.EnableResizing &&
                                      _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.DisableResizing;
            if (autoSizeRowHeaders)
            {
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, fixedRowsHeight);
            }

            if (!fixedRowsHeight)
            {
                if (expandingRows)
                {
                    AdjustExpandingRows(-1, true /*fixedWidth*/);
                }
                else
                {
                    AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                }

                if (autoSizeRowHeaders)
                {
                    // Second round of row headers autosizing
                    AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, true /*fixedRowsHeight*/);
                }
            }
        }

        protected virtual void OnRowHeadersWidthChanged(EventArgs e)
        {
            if (RowHeadersVisible)
            {
                if (EditingControl != null)
                {
                    PositionEditingControl(true, false, false);
                }

                UpdateMouseEnteredCell(hti: null, e: null);

                OnRowHeadersGlobalAutoSize(false /*expandingRows*/);
            }

            if (Events[s_rowHeadersWidthChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowHeadersWidthSizeModeChanged(DataGridViewAutoSizeModeEventArgs e)
        {
            if (_rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.EnableResizing &&
                _rowHeadersWidthSizeMode != DataGridViewRowHeadersWidthSizeMode.DisableResizing)
            {
                if (!e.PreviousModeAutoSized)
                {
                    // Save current row headers width for later reuse
                    _cachedRowHeadersWidth = RowHeadersWidth;
                }
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode,
                                          true /*fixedColumnHeadersHeight*/,
                                          true /*fixedRowsHeight*/);
            }
            else if (e.PreviousModeAutoSized)
            {
                RowHeadersWidth = _cachedRowHeadersWidth;
            }

            if (Events[s_rowHeadersWidthSizeModeChangedEvent] is DataGridViewAutoSizeModeEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowHeightChanged(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }
            UpdateRowHeightInfoPrivate(e.Row.Index, false, false /*invalidInAdjustFillingColumns*/);

            if (Events[s_rowHeightChangedEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            OnRowGlobalAutoSize(e.Row.Index);
        }

        internal DataGridViewRowHeightInfoNeededEventArgs OnRowHeightInfoNeeded(int rowIndex, int height, int minimumHeight)
        {
            DataGridViewRowHeightInfoNeededEventArgs dgvrhine = RowHeightInfoNeededEventArgs;
            dgvrhine.SetProperties(rowIndex, height, minimumHeight);
            OnRowHeightInfoNeeded(dgvrhine);
            return dgvrhine;
        }

        protected virtual void OnRowHeightInfoNeeded(DataGridViewRowHeightInfoNeededEventArgs e)
        {
            if (Events[s_rowHeightInfoNeededEvent] is DataGridViewRowHeightInfoNeededEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private bool OnRowHeightInfoPushed(int rowIndex, int height, int minimumHeight)
        {
            Debug.Assert(rowIndex != -1);
            Debug.Assert(_autoSizeRowsMode == DataGridViewAutoSizeRowsMode.None);
            if (VirtualMode || DataSource != null)
            {
                DataGridViewRowHeightInfoPushedEventArgs dgvrhipe = new DataGridViewRowHeightInfoPushedEventArgs(rowIndex, height, minimumHeight);
                OnRowHeightInfoPushed(dgvrhipe);
                if (dgvrhipe.Handled)
                {
                    UpdateRowHeightInfoPrivate(rowIndex, false, true /*invalidInAdjustFillingColumns*/);
                    return true;
                }
            }
            return false;
        }

        protected virtual void OnRowHeightInfoPushed(DataGridViewRowHeightInfoPushedEventArgs e)
        {
            if (Events[s_rowHeightInfoPushedEvent] is DataGridViewRowHeightInfoPushedEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnRowLeave(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex)
        {
            Debug.Assert(columnIndex >= 0 && rowIndex >= 0);
            if (rowIndex < Rows.Count && columnIndex < Columns.Count)
            {
                DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(columnIndex, rowIndex);
                OnRowLeave(dgvce);
                if (dataGridViewCell != null)
                {
                    if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                    {
                        dataGridViewCell = null;
                    }
                    else
                    {
                        Debug.Assert(rowIndex < Rows.Count && columnIndex < Columns.Count);
                        dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                    }
                }
            }
        }

        protected virtual void OnRowLeave(DataGridViewCellEventArgs e)
        {
            try
            {
                _noDimensionChangeCount++;

                if (Events[s_rowLeaveEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                    CorrectFocus(true /*onlyIfGridHasFocus*/);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
            }
        }

        protected virtual void OnRowMinimumHeightChanged(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }
            if (Events[s_rowMinimumHeightChangeEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected internal virtual void OnRowPostPaint(DataGridViewRowPostPaintEventArgs e)
        {
            if (Events[s_rowPostPaintEvent] is DataGridViewRowPostPaintEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected internal virtual void OnRowPrePaint(DataGridViewRowPrePaintEventArgs e)
        {
            if (Events[s_rowPrePaintEvent] is DataGridViewRowPrePaintEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnRowsAddedInternal(int rowIndex, int rowCount)
        {
            OnRowsAdded(new DataGridViewRowsAddedEventArgs(rowIndex, rowCount));
        }

        protected virtual void OnRowsAdded(DataGridViewRowsAddedEventArgs e)
        {
            if (Events[s_rowsAddedEvent] is DataGridViewRowsAddedEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowsDefaultCellStyleChanged(EventArgs e)
        {
            if (e is DataGridViewCellStyleChangedEventArgs dgvcsce && !dgvcsce.ChangeAffectsPreferredSize)
            {
                InvalidateData();
            }
            else
            {
                OnRowsGlobalAutoSize();
                if (EditingControl != null)
                {
                    PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                }
            }

            if (Events[s_rowsDefaultCellStyleChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnRowSelectMouseMove(HitTestInfo hti)
        {
            Debug.Assert(hti._row >= 0);
            Debug.Assert(MultiSelect);

            if (_ptCurrentCell.Y != -1 &&
                hti._row != _ptCurrentCell.Y &&
                !CommitEditForOperation(_ptCurrentCell.X, hti._row, true))
            {
                // Return silently if validating/commit/abort failed
                return;
            }
            if (IsRowOutOfBounds(hti._row))
            {
                return;
            }

            _noSelectionChangeCount++;
            try
            {
                if (_trackRowEdge >= _trackRow && hti._row > _trackRowEdge && _trackRowEdge >= 0)
                {
                    SelectRowRange(Rows.GetNextRow(_trackRowEdge, DataGridViewElementStates.Visible),
                        hti._row, true);
                    _trackRowEdge = hti._row;
                }
                else if (_trackRowEdge > _trackRow && hti._row < _trackRowEdge && hti._row >= _trackRow && _trackRowEdge >= 0)
                {
                    SelectRowRange(Rows.GetNextRow(hti._row, DataGridViewElementStates.Visible),
                        _trackRowEdge, false);
                    _trackRowEdge = hti._row;
                }
                else if (hti._row > _trackRow && _trackRowEdge == -1)
                {
                    SelectRowRange(Rows.GetNextRow(_trackRow, DataGridViewElementStates.Visible),
                        hti._row, true);
                    _trackRowEdge = hti._row;
                }
                else if (_trackRowEdge <= _trackRow && hti._row < _trackRowEdge && _trackRowEdge >= 0)
                {
                    SelectRowRange(hti._row,
                        Rows.GetPreviousRow(_trackRowEdge, DataGridViewElementStates.Visible),
                        true);
                    _trackRowEdge = hti._row;
                }
                else if (_trackRowEdge < _trackRow && hti._row > _trackRowEdge && hti._row <= _trackRow && _trackRowEdge >= 0)
                {
                    SelectRowRange(_trackRowEdge,
                        Rows.GetPreviousRow(hti._row, DataGridViewElementStates.Visible),
                        false);
                    _trackRowEdge = hti._row;
                }
                else if (hti._row < _trackRow && _trackRowEdge == -1)
                {
                    SelectRowRange(hti._row,
                        Rows.GetPreviousRow(_trackRow, DataGridViewElementStates.Visible),
                        true);
                    _trackRowEdge = hti._row;
                }
                else if (_trackRowEdge > _trackRow && hti._row < _trackRow)
                {
                    SelectRowRange(Rows.GetNextRow(_trackRow, DataGridViewElementStates.Visible),
                        _trackRowEdge, false);
                    SelectRowRange(hti._row,
                        Rows.GetPreviousRow(_trackRow, DataGridViewElementStates.Visible),
                        true);
                    _trackRowEdge = hti._row;
                }
                else if (hti._row > _trackRow && _trackRowEdge < _trackRow && _trackRowEdge >= 0)
                {
                    SelectRowRange(_trackRowEdge,
                        Rows.GetPreviousRow(_trackRow, DataGridViewElementStates.Visible),
                        false);
                    SelectRowRange(Rows.GetNextRow(_trackRow, DataGridViewElementStates.Visible),
                        hti._row, true);
                    _trackRowEdge = hti._row;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }

            if (_ptCurrentCell.Y != -1 && hti._row != _ptCurrentCell.Y)
            {
                if (IsRowOutOfBounds(hti._row))
                {
                    return;
                }
                bool success = SetCurrentCellAddressCore(_ptCurrentCell.X,
                    hti._row,
                    false /*setAnchorCellAddress*/,
                    false /*validateCurrentCell*/,
                    false /*throughMouseClick*/);
                Debug.Assert(success);
            }
        }

        private void OnRowsGlobalAutoSize()
        {
            InvalidateData();

            if (_noAutoSizeCount > 0)
            {
                return;
            }

            // Autosize rows if needed
            if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
            {
                AdjustShrinkingRows(_autoSizeRowsMode, false /*fixedWidth*/, true /*internalAutosizing*/);
            }

            // Auto size columms also if needed
            AutoResizeAllVisibleColumnsInternal(DataGridViewAutoSizeColumnCriteriaInternal.AllRows |
                                                DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows,
                                                true /*fixedHeight*/);

            bool fixedRowHeadersWidth = _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.EnableResizing ||
                                        _rowHeadersWidthSizeMode == DataGridViewRowHeadersWidthSizeMode.DisableResizing;
            // Auto size column headers
            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
            {
                AutoResizeColumnHeadersHeight(fixedRowHeadersWidth, true /*fixedColumnsWidth*/);
            }

            // Auto size row headers
            if (!fixedRowHeadersWidth)
            {
                AutoResizeRowHeadersWidth(_rowHeadersWidthSizeMode, true /*fixedColumnHeadersHeight*/, true /*fixedRowsHeight*/);
            }

            // Second round of rows autosizing
            if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
            {
                AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
            }

            // Second round of column headers autosizing
            if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize && !fixedRowHeadersWidth)
            {
                AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnsWidth*/);
            }
        }

        internal void OnRowsRemovedInternal(int rowIndex, int rowCount)
        {
            OnRowsRemoved(new DataGridViewRowsRemovedEventArgs(rowIndex, rowCount));
        }

        protected virtual void OnRowsRemoved(DataGridViewRowsRemovedEventArgs e)
        {
            if (Events[s_rowsRemovedEvent] is DataGridViewRowsRemovedEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnRowStateChanged(int rowIndex, DataGridViewRowStateChangedEventArgs e)
        {
            Debug.Assert(rowIndex >= -1);

            // If row.Frozen changed, we need to update the vertical scroll bar
            // A hidden row may become visible and vice-versa, we'd better repaint the whole control
            DataGridViewRow dataGridViewRow = e.Row;
            DataGridViewElementStates newState = DataGridViewElementStates.None;
            bool rowVisible = false;
            if (rowIndex >= 0)
            {
                newState = Rows.GetRowState(rowIndex);
                rowVisible = ((newState & DataGridViewElementStates.Visible) != 0);
            }
            switch (e.StateChanged)
            {
                // At this point we assume that only the Selected state has an influence on the rendering of the row.
                // If there is a customer scenario where another state has an influence, the dev will have to invalidate the row by hand.
                // case DataGridViewElementStates.ReadOnly:
                // case DataGridViewElementStates.Resizable:

                case DataGridViewElementStates.Selected:
                    if (rowVisible && _inBulkPaintCount == 0)
                    {
                        InvalidateRowPrivate(rowIndex);
                    }
                    break;

                case DataGridViewElementStates.Frozen:
                    if (rowVisible)
                    {
                        if ((newState & DataGridViewElementStates.Frozen) == 0)
                        {
                            // row was unfrozen - make it the first visible scrolling row if there is room
                            FirstVisibleScrollingRowTempted(rowIndex);
                        }
                        PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, true /*repositionEditingControl*/);
                        Invalidate();
                    }
                    break;

                case DataGridViewElementStates.Visible:
                    {
                        if (!rowVisible && (newState & DataGridViewElementStates.Displayed) != 0)
                        {
                            // Displayed row becomes invisible. Turns off the Displayed state.
                            Rows.SetRowState(rowIndex, DataGridViewElementStates.Displayed, false);
                        }

                        PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, true /*invalidInAdjustFillingColumns*/, true /*repositionEditingControl*/);
                        Invalidate();

                        bool rowDisplayed = (Rows.GetRowState(rowIndex) & DataGridViewElementStates.Displayed) != 0;
                        DataGridViewAutoSizeRowsModeInternal autoSizeRowsModeInternal = (DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode;

                        bool autoSizeRow = false;

                        if (autoSizeRowsModeInternal != DataGridViewAutoSizeRowsModeInternal.None)
                        {
                            int height = dataGridViewRow.ThicknessInternal;
                            if (rowVisible)
                            {
                                // Cache row's height before potential autosizing occurs
                                // Valid operation even for shared rows
                                dataGridViewRow.CachedThickness = height;
                                if (!((autoSizeRowsModeInternal & DataGridViewAutoSizeRowsModeInternal.DisplayedRows) != 0 && !rowDisplayed))
                                {
                                    AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), false /*fixedWidth*/, true /*internalAutosizing*/);
                                    autoSizeRow = true;
                                }
                            }
                            else if (height != dataGridViewRow.CachedThickness)
                            {
                                // Rows that are made invisible in the collection take their non-autosized height
                                // Not calling OnRowHeightInfoPushed(...) because rows are autosized
                                // Make sure the affected row is unshared
                                if (dataGridViewRow.Index == -1)
                                {
                                    dataGridViewRow = Rows[rowIndex];
                                }
                                dataGridViewRow.ThicknessInternal = Math.Max(dataGridViewRow.MinimumHeight, dataGridViewRow.CachedThickness);
                            }
                        }

                        // Auto size columms also if needed
                        DataGridViewAutoSizeColumnCriteriaInternal autoSizeColumnCriteriaFilter = DataGridViewAutoSizeColumnCriteriaInternal.AllRows;
                        if (rowDisplayed)
                        {
                            autoSizeColumnCriteriaFilter |= DataGridViewAutoSizeColumnCriteriaInternal.DisplayedRows;
                        }
                        if (rowVisible && Rows.GetRowCount(DataGridViewElementStates.Visible) > 1)
                        {
                            // Columns can only expand, and not collapse.
                            AdjustExpandingColumns(autoSizeColumnCriteriaFilter, rowIndex);
                        }
                        else
                        {
                            AutoResizeAllVisibleColumnsInternal(autoSizeColumnCriteriaFilter, true /*fixedHeight*/);
                        }

                        if (autoSizeRow)
                        {
                            // Second round of row autosizing
                            AutoResizeRowInternal(rowIndex, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), true /*fixedWidth*/, true /*internalAutosizing*/);
                        }
                        break;
                    }
            }

            if (Events[s_rowStateChangedEvent] is DataGridViewRowStateChangedEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }

            if (e.StateChanged == DataGridViewElementStates.ReadOnly &&
                rowIndex == _ptCurrentCell.Y &&
                !_dataGridViewOper[OperationInReadOnlyChange])
            {
                VerifyImeRestrictedModeChanged();

                if ((newState & DataGridViewElementStates.ReadOnly) == 0 &&
                    !ReadOnly &&
                    !Columns[_ptCurrentCell.X].ReadOnly &&
                    ColumnEditable(_ptCurrentCell.X) &&
                    !IsCurrentCellInEditMode &&
                    (EditMode == DataGridViewEditMode.EditOnEnter ||
                    (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null)))
                {
                    // Current row becomes read/write. Enter editing mode.
                    BeginEditInternal(true /*selectAll*/);
                }
            }
        }

        internal void OnRowUnshared(DataGridViewRow dataGridViewRow)
        {
            if (-1 != _ptCurrentCell.X && dataGridViewRow.Index == _ptCurrentCell.Y && EditingControl != null)
            {
                CurrentCellInternal.CacheEditingControl();
            }
            DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs(dataGridViewRow);
            OnRowUnshared(dgvre);
        }

        protected virtual void OnRowUnshared(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }
            if (Events[s_rowUnsharedEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private bool OnRowValidating(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex)
        {
            DataGridViewCellCancelEventArgs dgvcce = new DataGridViewCellCancelEventArgs(columnIndex, rowIndex);
            OnRowValidating(dgvcce);
            if (!dgvcce.Cancel)
            {
                if (DataConnection != null &&
                    DataConnection.InterestedInRowEvents &&
                    !DataConnection.PositionChangingOutsideDataGridView &&
                    !DataConnection.ListWasReset)
                {
                    DataConnection.OnRowValidating(dgvcce);
                }
            }
            if (dataGridViewCell != null && rowIndex < Rows.Count && columnIndex < Columns.Count)
            {
                dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
            }
            return dgvcce.Cancel;
        }

        protected virtual void OnRowValidating(DataGridViewCellCancelEventArgs e)
        {
            try
            {
                _noDimensionChangeCount++;

                if (Events[s_rowValidatingEvent] is DataGridViewCellCancelEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                    CorrectFocus(true /*onlyIfGridHasFocus*/);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
            }
        }

        private void OnRowValidated(ref DataGridViewCell dataGridViewCell, int columnIndex, int rowIndex)
        {
            IsCurrentRowDirtyInternal = false;
            _dataGridViewState1[State1_NewRowCreatedByEditing] = false;
            if (rowIndex == NewRowIndex)
            {
                // Stop displaying the default cell values on the 'new row'.
                InvalidateRowPrivate(rowIndex);
            }

            DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(columnIndex, rowIndex);
            OnRowValidated(dgvce);
            if (dataGridViewCell != null)
            {
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    dataGridViewCell = null;
                }
                else
                {
                    Debug.Assert(rowIndex < Rows.Count && columnIndex < Columns.Count);
                    dataGridViewCell = Rows.SharedRow(rowIndex).Cells[columnIndex];
                }
            }
        }

        protected virtual void OnRowValidated(DataGridViewCellEventArgs e)
        {
            try
            {
                _noDimensionChangeCount++;

                if (Events[s_rowValidatedEvent] is DataGridViewCellEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
                {
                    eh(this, e);
                    CorrectFocus(true /*onlyIfGridHasFocus*/);
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
            }
        }

        private void RefreshByCurrentPos(int oldValue, int newValue)
        {
            Point pt = PointToScreen(Location);
            int step = newValue - oldValue;

            // horizontal scrool left
            if (pt.X < 0 && step < 0)
            {
                Invalidate(new Rectangle(new Point(-pt.X, ColumnHeadersHeight),
                                         new Size(-step, ClientSize.Height)));
            }

            pt.X += Width;
            pt.Y += Height;
            Rectangle rect = Screen.GetBounds(pt);

            // horizontal scrool right
            if (pt.X > rect.Right && step > 0)
            {
                Invalidate(new Rectangle(new Point(ClientSize.Width - (pt.X - rect.Right) - step, ColumnHeadersHeight),
                                         new Size(step, ClientSize.Height)));
            }

            // vertical scrool up
            if (pt.Y < 0 && step < 0)
            {
                Invalidate(new Rectangle(new Point(0, -pt.Y),
                                         new Size(-step, ClientSize.Width)));
            }

            // vertical scrool down
            if (pt.Y > rect.Bottom && step > 0)
            {
                Invalidate(new Rectangle(new Point(0, ColumnHeadersHeight),
                                         new Size(ClientSize.Width, ClientSize.Height - (pt.Y - rect.Bottom) - step)));
            }
        }

        private void OnScroll(ScrollEventType scrollEventType, int oldValue, int newValue, ScrollOrientation orientation)
        {
            ScrollEventArgs se = new ScrollEventArgs(scrollEventType, oldValue, newValue, orientation);
            OnScroll(se);
            RefreshByCurrentPos(oldValue, newValue);
            if (Focused && IsGridFocusRectangleEnabled())
            {
                InvalidateGridFocusOnScroll(newValue - oldValue, orientation);
            }
            if (ScrollOrientation.VerticalScroll == orientation)
            {
                if (se.NewValue != newValue)
                {
                    try
                    {
                        _dataGridViewState2[State2_StopRaisingVerticalScroll] = true;
                        int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                        int rowIndexPrevious = rowIndex;
                        newValue = se.NewValue;
                        while (rowIndex != -1 && newValue > 0)
                        {
                            rowIndexPrevious = rowIndex;
                            rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                            newValue--;
                        }
                        if (rowIndex != -1)
                        {
                            rowIndexPrevious = rowIndex;
                        }
                        if (rowIndexPrevious != -1)
                        {
                            FirstDisplayedScrollingRowIndex = rowIndexPrevious;
                        }
                    }
                    finally
                    {
                        _dataGridViewState2[State2_StopRaisingVerticalScroll] = false;
                    }
                }
            }
            else
            {
                if (se.NewValue != newValue)
                {
                    try
                    {
                        _dataGridViewState2[State2_StopRaisingHorizontalScroll] = true;
                        HorizontalOffset = se.NewValue;
                    }
                    finally
                    {
                        _dataGridViewState2[State2_StopRaisingHorizontalScroll] = false;
                    }
                }
            }
        }

        protected virtual void OnScroll(ScrollEventArgs e)
        {
            if (Events[s_scrollEvent] is ScrollEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnSelectionChanged(EventArgs e)
        {
            _dataGridViewState2[State2_RaiseSelectionChanged] = false;

            if (Events[s_selectionChangedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal bool OnSortCompare(DataGridViewColumn dataGridViewSortedColumn, object value1, object value2, int rowIndex1, int rowIndex2, out int sortResult)
        {
            DataGridViewSortCompareEventArgs dgvsce = new DataGridViewSortCompareEventArgs(dataGridViewSortedColumn, value1, value2, rowIndex1, rowIndex2);
            OnSortCompare(dgvsce);
            sortResult = dgvsce.SortResult;
            return dgvsce.Handled;
        }

        protected virtual void OnSortCompare(DataGridViewSortCompareEventArgs e)
        {
            if (Events[s_sortCompareEvent] is DataGridViewSortCompareEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnSorted(EventArgs e)
        {
            if (Events[s_sortedEvent] is EventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        internal void OnSortGlyphDirectionChanged(DataGridViewColumnHeaderCell dataGridViewColumnHeaderCell)
        {
            Debug.Assert(dataGridViewColumnHeaderCell != null);

            if (dataGridViewColumnHeaderCell.OwningColumn == SortedColumn)
            {
                if (dataGridViewColumnHeaderCell.SortGlyphDirection == SortOrder.None)
                {
                    SortedColumn = null;
                    DataGridViewColumn dataGridViewColumn = dataGridViewColumnHeaderCell.OwningColumn;

                    if (dataGridViewColumn.IsDataBound)
                    {
                        // If the column whose SortGlyphChanges is the sorted column and it is also the dataBound column
                        // then see if there is another dataBound column which has the same property name as the sorted column.
                        // If so, then make that dataGridViewColumn the sorted column in the data grid view.
                        for (int i = 0; i < Columns.Count; i++)
                        {
                            if (dataGridViewColumn != Columns[i] &&
                                Columns[i].SortMode != DataGridViewColumnSortMode.NotSortable &&
                                string.Compare(dataGridViewColumn.DataPropertyName,
                                               Columns[i].DataPropertyName,
                                               true /*ignoreCase*/,
                                               CultureInfo.InvariantCulture) == 0)
                            {
                                Debug.Assert(Columns[i].IsDataBound, "two columns w/ the same DataPropertyName should be DataBound at the same time");
                                SortedColumn = Columns[i];
                                break;
                            }
                        }
                    }
                }

                SortOrder = SortedColumn != null ? SortedColumn.HeaderCell.SortGlyphDirection : SortOrder.None;
            }

            InvalidateCellPrivate(dataGridViewColumnHeaderCell);
        }

        private void OnTopLeftHeaderMouseDown()
        {
            if (MultiSelect)
            {
                SelectAll();
                if (-1 != _ptCurrentCell.X)
                {
                    // Potentially have to give focus back to the current edited cell.
                    bool success = SetCurrentCellAddressCore(_ptCurrentCell.X, _ptCurrentCell.Y,
                                                             false /*setAnchorCellAddress*/,
                                                             false /*validateCurrentCell*/,
                                                             false /*throughMouseClick*/);
                    Debug.Assert(success);
                }
            }
        }

        protected virtual void OnUserAddedRow(DataGridViewRowEventArgs e)
        {
            if (e.Row.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_RowDoesNotBelongToDataGridView, "e.Row");
            }
            if (Events[s_userAddedRowEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnUserDeletedRow(DataGridViewRowEventArgs e)
        {
            if (Events[s_userDeletedRowEvent] is DataGridViewRowEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        protected virtual void OnUserDeletingRow(DataGridViewRowCancelEventArgs e)
        {
            if (Events[s_userDeletingRowEvent] is DataGridViewRowCancelEventHandler eh && !_dataGridViewOper[OperationInDispose] && !IsDisposed)
            {
                eh(this, e);
            }
        }

        private void OnUserPreferenceChanged(object sender, UserPreferenceChangedEventArgs e)
        {
            if (e.Category == UserPreferenceCategory.Color ||
                e.Category == UserPreferenceCategory.Locale ||
                e.Category == UserPreferenceCategory.General ||
                e.Category == UserPreferenceCategory.Window ||
                e.Category == UserPreferenceCategory.VisualStyle)
            {
                OnGlobalAutoSize();
                if (e.Category == UserPreferenceCategory.Window)
                {
                    _cachedEditingControl = null;
                    if (EditingControl != null)
                    {
                        // The editing control may not adapt well to the new system rendering,
                        // so instead of caching it into the this.cachedEditingControl variable
                        // next time editing mode is exited, simply discard the control.
                        _dataGridViewState2[State2_DiscardEditingControl] = true;
                    }
                    PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, false /*invalidInAdjustFillingColumns*/, true /*repositionEditingControl*/);
                }
            }
        }

        protected override void OnValidating(CancelEventArgs e)
        {
            // Avoid Cell/Row Validation events when the grid or its editing control gets the focus
            if (!BecomingActiveControl && (EditingControl is null || !EditingControl.BecomingActiveControl))
            {
                if (!_dataGridViewState1[State1_LeavingWithTabKey])
                {
                    if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.LeaveControl,
                                 DataGridViewValidateCellInternal.Always,
                                 false /*fireCellLeave*/,
                                 false /*fireCellEnter*/,
                                 false /*fireRowLeave*/,
                                 false /*fireRowEnter*/,
                                 false /*fireLeave*/,
                                 false /*keepFocus*/,
                                 false /*resetCurrentCell*/,
                                 false /*resetAnchorCell unused here*/))
                    {
                        e.Cancel = true;
                        return;
                    }
                }

                if (_ptCurrentCell.X >= 0)
                {
                    DataGridViewCell dataGridViewCellTmp = null;
                    if (OnRowValidating(ref dataGridViewCellTmp, _ptCurrentCell.X, _ptCurrentCell.Y))
                    {
                        // Row validation was cancelled
                        e.Cancel = true;
                        return;
                    }
                    if (_ptCurrentCell.X == -1)
                    {
                        return;
                    }
                    OnRowValidated(ref dataGridViewCellTmp, _ptCurrentCell.X, _ptCurrentCell.Y);
                    // Row validation was not cancelled, but does operation need to be re-evaluated.
                    if (DataSource != null &&
                        _ptCurrentCell.X >= 0 &&
                        AllowUserToAddRowsInternal &&
                        NewRowIndex == _ptCurrentCell.Y)
                    {
                        // Current cell needs to be moved to the row just above the 'new row' if possible.
                        int rowIndex = Rows.GetPreviousRow(_ptCurrentCell.Y, DataGridViewElementStates.Visible);
                        if (rowIndex > -1)
                        {
                            bool success = SetAndSelectCurrentCellAddress(_ptCurrentCell.X, rowIndex,
                                true /*setAnchorCellAddress*/,
                                false /*validateCurrentCell*/,
                                false /*throughMouseClick*/,
                                false /*clearSelection*/,
                                false /*forceCurrentCellSelection*/);
                            Debug.Assert(success);
                        }
                        else
                        {
                            bool success = SetCurrentCellAddressCore(-1, -1,
                                true /*setAnchorCellAddress*/,
                                false /*validateCurrentCell*/,
                                false /*throughMouseClick*/);
                            Debug.Assert(success);
                        }
                    }
                }
            }
            base.OnValidating(e);
        }

        protected override void OnVisibleChanged(EventArgs e)
        {
            base.OnVisibleChanged(e);
            OnVisibleChangedPrivate();
        }

        private void OnVisibleChangedPrivate()
        {
            int rowIndexTmp;

            if (Visible)
            {
                // Make sure all displayed bands get the Displayed state: 1 & 2 for rows

                // 1. Make sure all displayed frozen rows have their Displayed state set to true
                int numDisplayedFrozenRows = DisplayedBandsInfo.NumDisplayedFrozenRows;
                if (numDisplayedFrozenRows > 0)
                {
                    rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    while (numDisplayedFrozenRows > 0)
                    {
                        Debug.Assert(rowIndexTmp != -1);
                        if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0)
                        {
#if DEBUG
                            int numDisplayedFrozenRowsDbg = numDisplayedFrozenRows;
                            while (numDisplayedFrozenRowsDbg > 0)
                            {
                                Debug.Assert(rowIndexTmp != -1);
                                Debug.Assert((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0);
                                rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                                numDisplayedFrozenRowsDbg--;
                            }
#endif
                            return; // rows' Displayed states are already up-to-date. OnHandleCreated already did the job.
                        }
                        else
                        {
                            Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, true);
                            rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                            numDisplayedFrozenRows--;
                        }
                    }
                }

                // 2. Make sure all displayed scrolling rows have their Displayed state set to true
                rowIndexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                if (rowIndexTmp > -1)
                {
                    Debug.Assert((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Visible) != 0);
                    int numDisplayedScrollingRows = DisplayedBandsInfo.NumDisplayedScrollingRows;
                    Debug.Assert(numDisplayedScrollingRows > 0);
                    while (numDisplayedScrollingRows > 0)
                    {
                        Debug.Assert(rowIndexTmp != -1);
                        if ((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0)
                        {
#if DEBUG
                            int numDisplayedScrollingRowsDbg = numDisplayedScrollingRows;
                            while (numDisplayedScrollingRowsDbg > 0)
                            {
                                Debug.Assert(rowIndexTmp != -1);
                                Debug.Assert((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) != 0);
                                rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                                numDisplayedScrollingRowsDbg--;
                            }
#endif
                            return; // rows' Displayed states are already up-to-date. OnHandleCreated already did the job.
                        }
                        else
                        {
                            Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, true);
                            rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                            numDisplayedScrollingRows--;
                        }
                    }
                }
            }
            else
            {
                // Make sure all displayed bands lose the Displayed state
                UpdateRowsDisplayedState(false /*displayed*/);
            }

            UpdateColumnsDisplayedState(Visible /*displayed*/);
        }

        protected virtual void PaintBackground(Graphics graphics, Rectangle clipBounds, Rectangle gridBounds)
        {
            // Paint potential block below rows
            Rectangle rcBelowRows = gridBounds;

            // Remaining cell images on DataGridView
            int visibleRowsHeight = Rows.GetRowsHeight(DataGridViewElementStates.Displayed);
            if (_layout.ColumnHeadersVisible)
            {
                rcBelowRows.Y += _layout.ColumnHeaders.Height;
                rcBelowRows.Height -= _layout.ColumnHeaders.Height;
            }
            else if (SingleHorizontalBorderAdded && visibleRowsHeight > 0)
            {
                rcBelowRows.Y++;
                rcBelowRows.Height--;
            }

            rcBelowRows.Y += visibleRowsHeight;
            rcBelowRows.Height -= visibleRowsHeight;
            if (rcBelowRows.Width > 0 && rcBelowRows.Height > 0)
            {
                using var brush = BackgroundColor.GetCachedSolidBrushScope();
                graphics.FillRectangle(brush, rcBelowRows);
            }

            // Paint potential block next to column headers and rows
            // Remaining cell images on DataGridView
            int visibleColumnsWidth = Columns.GetColumnsWidth(DataGridViewElementStates.Displayed);
            Rectangle rcNextRows = gridBounds;
            if (Columns.Count > 0)
            {
                if (_layout.RowHeadersVisible)
                {
                    if (!RightToLeftInternal)
                    {
                        rcNextRows.X += _layout.RowHeaders.Width;
                    }
                    rcNextRows.Width -= _layout.RowHeaders.Width;
                }
                else if (SingleVerticalBorderAdded && visibleColumnsWidth > 0)
                {
                    if (!RightToLeftInternal)
                    {
                        rcNextRows.X++;
                    }
                    rcNextRows.Width--;
                }
            }
            int rowsWidth = visibleColumnsWidth - _horizontalOffset;
            if (!RightToLeftInternal)
            {
                rcNextRows.X += rowsWidth;
            }

            rcNextRows.Width -= rowsWidth;
            if (rcBelowRows.Height > 0)
            {
                rcNextRows.Height = gridBounds.Height - rcBelowRows.Height;
            }

            if (rcNextRows.Width > 0 && rcNextRows.Height > 0)
            {
                using var brush = BackgroundColor.GetCachedSolidBrushScope();
                graphics.FillRectangle(brush, rcNextRows);
            }
        }

        private void PaintBorder(Graphics g, Rectangle clipRect, Rectangle bounds)
        {
            Debug.Assert(bounds.Left == 0);
            Debug.Assert(bounds.Top == 0);
            if (BorderStyle == BorderStyle.None)
            {
                return;
            }

            bool paintingNeeded = false;
            int borderWidth = BorderWidth;
            // Does the clipRect intersect with the top edge?
            Rectangle edge = new Rectangle(0, 0, bounds.Width, borderWidth);
            paintingNeeded = clipRect.IntersectsWith(edge);
            if (!paintingNeeded)
            {
                // Does the clipRect intersect with the bottom edge?
                edge.Y = bounds.Height - borderWidth;
                paintingNeeded = clipRect.IntersectsWith(edge);
                if (!paintingNeeded)
                {
                    // Does the clipRect intersect with the left edge?
                    edge.Y = 0;
                    edge.Height = bounds.Height;
                    edge.Width = borderWidth;
                    paintingNeeded = clipRect.IntersectsWith(edge);
                    if (!paintingNeeded)
                    {
                        // Does the clipRect intersect with the right edge?
                        edge.X = bounds.Width - borderWidth;
                        paintingNeeded = clipRect.IntersectsWith(edge);
                    }
                }
            }

            if (paintingNeeded)
            {
                if (BorderStyle == BorderStyle.Fixed3D)
                {
                    if (Application.RenderWithVisualStyles)
                    {
                        using var pen = VisualStyleInformation.TextControlBorder.GetCachedPenScope();
                        g.DrawRectangle(pen, new Rectangle(0, 0, bounds.Width - 1, bounds.Height - 1));
                    }
                    else
                    {
                        ControlPaint.DrawBorder3D(g, bounds, Border3DStyle.Sunken);
                    }
                }
                else if (BorderStyle == BorderStyle.FixedSingle)
                {
                    using var pen = SystemColors.ControlText.GetCachedPenScope();
                    g.DrawRectangle(pen, new Rectangle(0, 0, bounds.Width - 1, bounds.Height - 1));
                }
                else
                {
                    Debug.Fail("DataGridView.PaintBorder - Unexpected BorderStyle value.");
                }
            }
        }

        private void PaintColumnHeaders(Graphics g, Rectangle clipBounds, bool singleBorderAdded)
        {
            if (g.IsVisible(_layout.ColumnHeaders))
            {
                Rectangle bandBounds, cellBounds;
                bandBounds = cellBounds = _layout.ColumnHeaders;
                bandBounds.Height = cellBounds.Height = _columnHeadersHeight;
                int cx = 0;
                bool isFirstDisplayedColumn = true, isLastVisibleColumn = false;
                DataGridViewCell cell;
                DataGridViewCellStyle inheritedCellStyle = new DataGridViewCellStyle();
                DataGridViewAdvancedBorderStyle dataGridViewAdvancedBorderStylePlaceholder = new DataGridViewAdvancedBorderStyle(), dgvabsEffective;
                DataGridViewColumn dataGridViewColumnNext = null;

                // first paint the visible frozen columns
                DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                while (dataGridViewColumn != null)
                {
                    cell = dataGridViewColumn.HeaderCell;
                    cellBounds.Width = dataGridViewColumn.Thickness;
                    if (singleBorderAdded && isFirstDisplayedColumn)
                    {
                        cellBounds.Width++;
                    }
                    Debug.Assert(cellBounds.Width > 0);
                    if (RightToLeftInternal)
                    {
                        cellBounds.X = bandBounds.Right - cx - cellBounds.Width;
                    }
                    else
                    {
                        cellBounds.X = bandBounds.X + cx;
                    }

                    BuildInheritedColumnHeaderCellStyle(inheritedCellStyle, cell);

                    dataGridViewColumnNext = Columns.GetNextColumn(dataGridViewColumn,
                        DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen,
                        DataGridViewElementStates.None);
                    if (dataGridViewColumnNext is null)
                    {
                        isLastVisibleColumn = (DisplayedBandsInfo.FirstDisplayedScrollingCol < 0);
                    }

                    dgvabsEffective = AdjustColumnHeaderBorderStyle(AdvancedColumnHeadersBorderStyle, dataGridViewAdvancedBorderStylePlaceholder,
                                                                    isFirstDisplayedColumn, isLastVisibleColumn);

                    // Microsoft: should paintSelectionBackground be dev-settable?
                    cell.PaintWork(g,
                                   clipBounds,
                                   cellBounds,
                                   -1,
                                   dataGridViewColumn.State,
                                   inheritedCellStyle,
                                   dgvabsEffective,
                                   DataGridViewPaintParts.Background | DataGridViewPaintParts.Border | DataGridViewPaintParts.ContentBackground | DataGridViewPaintParts.ContentForeground | DataGridViewPaintParts.ErrorIcon | DataGridViewPaintParts.SelectionBackground);

                    cx += cellBounds.Width;
                    if (cx >= bandBounds.Width)
                    {
                        break;
                    }

                    dataGridViewColumn = dataGridViewColumnNext;
                    isFirstDisplayedColumn = false;
                }

                // then paint the visible scrolling ones
                Rectangle scrollingBounds = bandBounds;
                if (!RightToLeftInternal)
                {
                    scrollingBounds.X -= FirstDisplayedScrollingColumnHiddenWidth;
                }
                scrollingBounds.Width += FirstDisplayedScrollingColumnHiddenWidth;

                if (DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0 && cx < scrollingBounds.Width)
                {
                    Region clipRegion = null;
                    if (FirstDisplayedScrollingColumnHiddenWidth > 0)
                    {
                        clipRegion = g.Clip;
                        Rectangle rowRect = bandBounds;
                        if (!RightToLeftInternal)
                        {
                            rowRect.X += cx;
                        }
                        rowRect.Width -= cx;
                        g.SetClip(rowRect);
                    }

                    dataGridViewColumn = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
                    while (dataGridViewColumn != null)
                    {
                        Debug.Assert(dataGridViewColumn.Visible && !dataGridViewColumn.Frozen);

                        cell = dataGridViewColumn.HeaderCell;
                        cellBounds.Width = dataGridViewColumn.Thickness;
                        if (singleBorderAdded && isFirstDisplayedColumn)
                        {
                            cellBounds.Width++;
                        }
                        Debug.Assert(cellBounds.Width > 0);
                        if (RightToLeftInternal)
                        {
                            cellBounds.X = scrollingBounds.Right - cx - cellBounds.Width;
                        }
                        else
                        {
                            cellBounds.X = scrollingBounds.X + cx;
                        }

                        BuildInheritedColumnHeaderCellStyle(inheritedCellStyle, cell);

                        dataGridViewColumnNext = Columns.GetNextColumn(dataGridViewColumn,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None);
                        isLastVisibleColumn = (dataGridViewColumnNext is null);

                        dgvabsEffective = AdjustColumnHeaderBorderStyle(AdvancedColumnHeadersBorderStyle, dataGridViewAdvancedBorderStylePlaceholder,
                                                                        isFirstDisplayedColumn, isLastVisibleColumn);

                        cell.PaintWork(g,
                                       clipBounds,
                                       cellBounds,
                                       -1,
                                       dataGridViewColumn.State,
                                       inheritedCellStyle,
                                       dgvabsEffective,
                                       DataGridViewPaintParts.Background | DataGridViewPaintParts.Border | DataGridViewPaintParts.ContentBackground | DataGridViewPaintParts.ContentForeground | DataGridViewPaintParts.ErrorIcon | DataGridViewPaintParts.SelectionBackground);

                        cx += cellBounds.Width;
                        if (cx >= scrollingBounds.Width)
                        {
                            break;
                        }

                        dataGridViewColumn = dataGridViewColumnNext;
                        isFirstDisplayedColumn = false;
                    }

                    if (FirstDisplayedScrollingColumnHiddenWidth > 0)
                    {
                        Debug.Assert(clipRegion != null);
                        g.Clip = clipRegion;
                        clipRegion.Dispose();
                    }
                }
            }
        }

        private void PaintGrid(Graphics g,
            Rectangle gridBounds,
            Rectangle clipRect,
            bool singleVerticalBorderAdded,
            bool singleHorizontalBorderAdded)
        {
            Rectangle rc = gridBounds;

            if (_layout.TopLeftHeader.Width > 0 &&
                (clipRect.IntersectsWith(_layout.TopLeftHeader) || _lastHeaderShadow != -1))
            {
                if (Columns.Count > 0 || Rows.Count > 0)
                {
                    using (Region clipRegion = g.Clip)
                    {
                        g.SetClip(_layout.TopLeftHeader);
                        PaintTopLeftHeaderCell(g);
                        g.Clip = clipRegion;
                    }
                }
            }

            if (_layout.ColumnHeadersVisible)
            {
                Rectangle columnHeadersClip = _layout.ColumnHeaders;
                if (singleVerticalBorderAdded)
                {
                    columnHeadersClip.Width++;
                }
                if (clipRect.IntersectsWith(columnHeadersClip) || _lastHeaderShadow != -1)
                {
                    using (Region clipRegion = g.Clip)
                    {
                        g.SetClip(columnHeadersClip);
                        PaintColumnHeaders(g, columnHeadersClip, singleVerticalBorderAdded);
                        g.Clip = clipRegion;
                    }
                }
                int columnHeadersHeight = _layout.ColumnHeaders.Height;
                rc.Y += columnHeadersHeight;
                rc.Height -= columnHeadersHeight;

                if (_lastHeaderShadow != -1)
                {
                    DrawColHeaderShadow(g, _lastHeaderShadow);
                }
            }

            if (rc.Height > 0)
            {
                PaintRows(g, rc, clipRect, /*singleVerticalBorderAdded, */ singleHorizontalBorderAdded);
            }

            if (_currentRowSplitBar != -1)
            {
                Debug.Assert(_dataGridViewOper[OperationTrackColHeadersResize] || _dataGridViewOper[OperationTrackRowResize]);
                DrawRowSplitBar(_currentRowSplitBar);
            }
            else if (_currentColSplitBar != -1)
            {
                Debug.Assert(_dataGridViewOper[OperationTrackRowHeadersResize] ||
                    _dataGridViewOper[OperationTrackColResize] ||
                    _dataGridViewOper[OperationTrackKeyboardColResize]);
                DrawColSplitBar(_currentColSplitBar);
            }
        }

        private void PaintRows(Graphics g,
            Rectangle boundingRect,
            Rectangle clipRect,
            /*bool singleVerticalBorderAdded,*/
            bool singleHorizontalBorderAdded)
        {
            int cy = 0;
            Rectangle rowBounds;
            DataGridViewRow dataGridViewRow;
            bool isFirstDisplayedRow = true;
            int indexTmp, indexTmpNext;

            // paint visible none-scrolling rows
            indexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            while (indexTmp != -1)
            {
                rowBounds = boundingRect;

                // DataGridView AutoSizeRowsMode does not work properly after column sort
                // Should unshared the row and set the thickness to a perfect value
                // every time user scroll to display the specific row.

                DataGridViewAutoSizeRowsModeInternal autoSizeRowsModeInternal = (DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode;
                // Auto size row if needed
                if (autoSizeRowsModeInternal != DataGridViewAutoSizeRowsModeInternal.None)
                {
                    // this call may unshare the row.
                    int rowHeight = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                    Rows.SharedRow(indexTmp).CachedThickness = rowHeight;
                    AutoResizeRowInternal(indexTmp, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), false /*fixedWidth*/, true /*internalAutosizing*/);
                }

                rowBounds.Height = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                if (isFirstDisplayedRow && singleHorizontalBorderAdded)
                {
                    rowBounds.Height++;
                }
                rowBounds.Y = boundingRect.Y + cy;

                indexTmpNext = Rows.GetNextRow(indexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);

                if (clipRect.IntersectsWith(rowBounds))
                {
                    dataGridViewRow = Rows.SharedRow(indexTmp);
                    dataGridViewRow.Paint(g,
                        clipRect,
                        rowBounds,
                        indexTmp,
                        Rows.GetRowState(indexTmp),
                        isFirstDisplayedRow,
                        (indexTmpNext == -1) && (DisplayedBandsInfo.FirstDisplayedScrollingRow == -1));
                }
                cy += rowBounds.Height;
                if (cy >= boundingRect.Height)
                {
                    break;
                }
                indexTmp = indexTmpNext;
                isFirstDisplayedRow = false;
            }

            // paint scrolling rows
            if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0 && cy < boundingRect.Height)
            {
                indexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                Debug.Assert((Rows.GetRowState(indexTmp) & DataGridViewElementStates.Frozen) == 0);
                Debug.Assert((Rows.GetRowState(indexTmp) & DataGridViewElementStates.Visible) != 0);
                while (indexTmp != -1)
                {
                    rowBounds = boundingRect;

                    // DataGridView AutoSizeRowsMode does not work properly after column sort
                    // Should unshared the row and set the thickness to a perfect value
                    // every time user scroll to display the specific row.

                    DataGridViewAutoSizeRowsModeInternal autoSizeRowsModeInternal = (DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode;
                    // Auto size row if needed
                    if (autoSizeRowsModeInternal != DataGridViewAutoSizeRowsModeInternal.None)
                    {
                        // this call may unshare the row.
                        int rowHeight = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                        Rows.SharedRow(indexTmp).CachedThickness = rowHeight;
                        AutoResizeRowInternal(indexTmp, MapAutoSizeRowsModeToRowMode(_autoSizeRowsMode), false /*fixedWidth*/, true /*internalAutosizing*/);
                    }

                    rowBounds.Height = Rows.SharedRow(indexTmp).GetHeight(indexTmp);
                    if (isFirstDisplayedRow && singleHorizontalBorderAdded)
                    {
                        rowBounds.Height++;
                    }
                    rowBounds.Y = boundingRect.Y + cy;

                    indexTmpNext = Rows.GetNextRow(indexTmp, DataGridViewElementStates.Visible);

                    if (clipRect.IntersectsWith(rowBounds))
                    {
                        dataGridViewRow = Rows.SharedRow(indexTmp);
                        dataGridViewRow.Paint(g,
                            clipRect,
                            rowBounds,
                            indexTmp,
                            Rows.GetRowState(indexTmp),
                            isFirstDisplayedRow,
                            indexTmpNext == -1);
                    }
                    cy += rowBounds.Height;
                    if (cy >= boundingRect.Height)
                    {
                        break;
                    }
                    indexTmp = indexTmpNext;
                    isFirstDisplayedRow = false;
                }
            }
        }

        private void PaintTopLeftHeaderCell(Graphics g)
        {
            if (g.IsVisible(_layout.TopLeftHeader))
            {
                DataGridViewCell cell = TopLeftHeaderCell;
                DataGridViewCellStyle inheritedCellStyle = new DataGridViewCellStyle();
                BuildInheritedColumnHeaderCellStyle(inheritedCellStyle, cell);
                Rectangle cellBounds = _layout.TopLeftHeader;
                cellBounds.Width = RowHeadersWidth;
                cellBounds.Height = _columnHeadersHeight;
                // Microsoft: Should paintSelectionBackground be dev-settable?
                cell.PaintWork(g,
                               _layout.TopLeftHeader,
                               cellBounds,
                               -1,
                               cell.State,
                               inheritedCellStyle,
                               AdjustedTopLeftHeaderBorderStyle,
                               DataGridViewPaintParts.Background | DataGridViewPaintParts.Border | DataGridViewPaintParts.ContentBackground | DataGridViewPaintParts.ContentForeground | DataGridViewPaintParts.ErrorIcon | DataGridViewPaintParts.SelectionBackground);
            }
        }

        private void PerformLayoutPrivate(bool useRowShortcut,
                                          bool computeVisibleRows,
                                          bool invalidInAdjustFillingColumns,
                                          bool repositionEditingControl)
        {
            _inPerformLayoutCount++;
            try
            {
                if (invalidInAdjustFillingColumns && InAdjustFillingColumns)
                {
                    throw new InvalidOperationException(SR.DataGridView_CannotAlterAutoFillColumnParameter);
                }

                if (IsHandleCreated)
                {
                    bool columnsAdjusted = false;
                    if (useRowShortcut)
                    {
                        ComputeLayoutShortcut(computeVisibleRows);
                    }
                    else
                    {
                        columnsAdjusted = ComputeLayout();
                    }
                    FlushDisplayedChanged();
                    if (columnsAdjusted && _inPerformLayoutCount < 3)
                    {
                        // Some columns were auto-filled, the rows and column headers may need to be autosized.
                        if ((((DataGridViewAutoSizeRowsModeInternal)_autoSizeRowsMode) & DataGridViewAutoSizeRowsModeInternal.AllColumns) != 0)
                        {
                            AdjustShrinkingRows(_autoSizeRowsMode, true /*fixedWidth*/, true /*internalAutosizing*/);
                        }
                        if (ColumnHeadersHeightSizeMode == DataGridViewColumnHeadersHeightSizeMode.AutoSize)
                        {
                            AutoResizeColumnHeadersHeight(true /*fixedRowHeadersWidth*/, true /*fixedColumnWidth*/);
                        }
                    }
                    if (repositionEditingControl && EditingControl != null)
                    {
                        PositionEditingControl(true /*setLocation*/, false /*setSize*/, false /*setFocus*/);
                    }
                }
                else
                {
                    DisplayedBandsInfo.FirstDisplayedFrozenCol = -1;
                    DisplayedBandsInfo.FirstDisplayedFrozenRow = -1;
                    DisplayedBandsInfo.FirstDisplayedScrollingRow = -1;
                    DisplayedBandsInfo.FirstDisplayedScrollingCol = -1;
                    DisplayedBandsInfo.NumDisplayedFrozenRows = 0;
                    DisplayedBandsInfo.NumDisplayedFrozenCols = 0;
                    DisplayedBandsInfo.NumDisplayedScrollingRows = 0;
                    DisplayedBandsInfo.NumDisplayedScrollingCols = 0;
                    DisplayedBandsInfo.NumTotallyDisplayedFrozenRows = 0;
                    DisplayedBandsInfo.NumTotallyDisplayedScrollingRows = 0;
                    DisplayedBandsInfo.LastDisplayedScrollingRow = -1;
                    DisplayedBandsInfo.LastTotallyDisplayedScrollingCol = -1;
                    if (_layout != null)
                    {
                        _layout._dirty = true;
                    }
                }
            }
            finally
            {
                _inPerformLayoutCount--;
                Debug.Assert(_inPerformLayoutCount >= 0);
            }
        }

        private void PopulateNewRowWithDefaultValues()
        {
            if (NewRowIndex != -1)
            {
                DataGridViewRow newRow = Rows.SharedRow(NewRowIndex);
                DataGridViewCellCollection newRowCells = newRow.Cells;
                foreach (DataGridViewCell dataGridViewCell in newRowCells)
                {
                    if (dataGridViewCell.DefaultNewRowValue != null)
                    {
                        newRow = Rows[NewRowIndex]; // unshare the 'new row'.
                        newRowCells = newRow.Cells;
                        break;
                    }
                }
                foreach (DataGridViewCell dataGridViewCell in newRowCells)
                {
                    dataGridViewCell.SetValueInternal(NewRowIndex, dataGridViewCell.DefaultNewRowValue);
                }
            }
        }

        private void PositionEditingControl(bool setLocation, bool setSize, bool setFocus)
        {
            Debug.Assert(EditingControl != null);

            if (!IsHandleCreated)
            {
                return;
            }

#if DEBUG
            DataGridViewCell dataGridViewCell = CurrentCellInternal;
            Debug.Assert(dataGridViewCell != null);
            Debug.Assert(dataGridViewCell.ColumnIndex == _ptCurrentCell.X);
            Debug.Assert(dataGridViewCell.RowIndex == _ptCurrentCell.Y || dataGridViewCell.RowIndex == -1);
#endif

            Rectangle editingZone = _layout.Data;
            if (editingZone.Width == 0 || editingZone.Height == 0)
            {
                return;
            }

            _dataGridViewState1[State1_EditingControlChanging] = true;

            try
            {
                int leftEdge = GetColumnXFromIndex(_ptCurrentCell.X);
                if (RightToLeftInternal)
                {
                    leftEdge -= Columns[_ptCurrentCell.X].Width - 1;
                }
                Rectangle cellBounds = new Rectangle(leftEdge, GetRowYFromIndex(_ptCurrentCell.Y),
                                                     Columns[_ptCurrentCell.X].Width, Rows.SharedRow(_ptCurrentCell.Y).GetHeight(_ptCurrentCell.Y));
                Rectangle cellClip = cellBounds;
                // Need to clip the zones of the frozen columns and rows and headers.
                if (!Columns[_ptCurrentCell.X].Frozen)
                {
                    int totalVisibleFrozenWidth = Columns.GetColumnsWidth(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    if (!RightToLeftInternal)
                    {
                        editingZone.X += totalVisibleFrozenWidth;
                    }
                    editingZone.Width = Math.Max(0, editingZone.Width - totalVisibleFrozenWidth);
                }
                if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Frozen) == 0)
                {
                    int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    editingZone.Y += totalVisibleFrozenHeight;
                }
                cellClip.Intersect(editingZone);

                if (cellClip.Width == 0 || cellClip.Height == 0)
                {
                    // we cannot simply make the control invisible because we want it to keep the focus.
                    // (and Control::CanFocus returns false if the control is not visible).
                    // So we place the editing control to the right of the DataGridView.
                    Debug.Assert(EditingControl != null);
                    _editingPanel.Location = new Point(Width + 1, 0);
                    _dataGridViewState1[State1_EditingControlHidden] = true;
                }
                else
                {
                    bool singleVerticalBorderAdded = SingleVerticalBorderAdded;
                    bool singleHorizontalBorderAdded = SingleHorizontalBorderAdded;
                    bool isFirstDisplayedColumn = FirstDisplayedColumnIndex == _ptCurrentCell.X;
                    bool isFirstDisplayedRow = FirstDisplayedRowIndex == _ptCurrentCell.Y;

                    if (singleVerticalBorderAdded && isFirstDisplayedColumn)
                    {
                        if (!RightToLeftInternal)
                        {
                            cellBounds.X--;
                            cellClip.X--;
                        }
                        cellBounds.Width++;
                        cellClip.Width++;
                    }
                    if (singleHorizontalBorderAdded && isFirstDisplayedRow)
                    {
                        cellBounds.Y--;
                        cellClip.Y--;
                        cellBounds.Height++;
                        cellClip.Height++;
                    }

                    CurrentCellInternal.PositionEditingControl(
                        setLocation || _dataGridViewState1[State1_EditingControlHidden],
                        setSize || _dataGridViewState1[State1_EditingControlHidden],
                        cellBounds, cellClip, InheritedEditingCellStyle,
                        singleVerticalBorderAdded, singleHorizontalBorderAdded,
                        isFirstDisplayedColumn, isFirstDisplayedRow);
                    _dataGridViewState1[State1_EditingControlHidden] = false;
                }
                _editingPanel.Visible = true;
                if (setFocus)
                {
                    CorrectFocus(false /*onlyIfGridHasFocus*/);
                }
            }
            finally
            {
                _dataGridViewState1[State1_EditingControlChanging] = false;
            }
        }

        protected bool ProcessAKey(Keys keyData)
        {
            if ((keyData & (Keys.Shift | Keys.Control | Keys.Alt)) == Keys.Control &&
                MultiSelect)
            {
                SelectAll();
                return true;
            }
            return false;
        }

        protected bool ProcessDeleteKey(Keys keyData)
        {
            if (AllowUserToDeleteRowsInternal)
            {
                if (EditingControl != null)
                {
                    // editing control gets a chance to handle the Delete key first
                    return false;
                }
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.FullRowSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        int remainingSelectedRows = 0;
                        try
                        {
                            _selectedBandSnapshotIndexes = new DataGridViewIntLinkedList(_selectedBandIndexes);
                            while (_selectedBandSnapshotIndexes.Count > remainingSelectedRows)
                            {
                                int rowIndex = _selectedBandSnapshotIndexes[remainingSelectedRows];
                                Debug.Assert(rowIndex >= 0);
                                if (rowIndex == NewRowIndex || rowIndex >= Rows.Count)
                                {
                                    remainingSelectedRows++;
                                }
                                else
                                {
                                    DataGridViewRowCancelEventArgs dgvrce = new DataGridViewRowCancelEventArgs(Rows[rowIndex]);
                                    OnUserDeletingRow(dgvrce);
                                    if (!dgvrce.Cancel)
                                    {
                                        DataGridViewRow dataGridViewRow = Rows[rowIndex];
                                        if (DataSource != null)
                                        {
                                            int dataGridRowsCount = Rows.Count;
#if DEBUG
                                            int dataGridViewRowsCount = Rows.Count;           // the number of rows in the dataGridView row collection not counting the AddNewRow
                                            int rowCount = DataConnection.CurrencyManager.List.Count;
                                            if (AllowUserToAddRowsInternal)
                                            {
                                                if (NewRowIndex < rowCount)
                                                {
                                                    // the user did not type inside the 'add new row'
                                                    Debug.Assert(rowCount == dataGridViewRowsCount, "out of sync in AddNewTransaction when the user did not type in the 'add new row'");
                                                }
                                                else
                                                {
                                                    dataGridViewRowsCount--;
                                                }
                                            }

                                            Debug.Assert(rowCount == dataGridViewRowsCount, "out of sync");
#endif
                                            DataGridViewDataErrorEventArgs dgvdee = null;
                                            try
                                            {
                                                DataConnection.DeleteRow(rowIndex);
                                            }
                                            catch (Exception exception)
                                            {
                                                if (ClientUtils.IsCriticalException(exception))
                                                {
                                                    throw;
                                                }
                                                // this is tricky.
                                                // the back-end threw an exception. At that stage, we did not delete the dataGridView row
                                                // from our collection of dataGridView rows.
                                                // So all we do is to throw the exception if the user wants. Otherwise we don't do anything.
                                                dgvdee = new DataGridViewDataErrorEventArgs(exception,
                                                                                            -1,
                                                                                            rowIndex,
                                                                                            // null,
                                                                                            // null,
                                                                                            DataGridViewDataErrorContexts.RowDeletion);
                                                OnDataErrorInternal(dgvdee);

                                                if (dgvdee.ThrowException)
                                                {
                                                    throw dgvdee.Exception;
                                                }
                                                else
                                                {
                                                    remainingSelectedRows++;
                                                }
                                            }

                                            if (dataGridRowsCount != Rows.Count)
                                            {
                                                Debug.Assert(dataGridViewRow.Index == -1);
                                                DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs(dataGridViewRow);
                                                OnUserDeletedRow(dgvre);
                                            }
                                            else if (dgvdee is null)
                                            {
                                                remainingSelectedRows++;
                                            }
                                        }
                                        else
                                        {
                                            Rows.RemoveAtInternal(rowIndex, false /*force*/);
                                            Debug.Assert(dataGridViewRow.Index == -1);
                                            DataGridViewRowEventArgs dgvre = new DataGridViewRowEventArgs(dataGridViewRow);
                                            OnUserDeletedRow(dgvre);
                                        }
                                    }
                                    else
                                    {
                                        remainingSelectedRows++;
                                    }
                                }
                            }
                        }
                        finally
                        {
                            _selectedBandSnapshotIndexes = null;
                        }
                        return true;
                }
            }
            return false;
        }

        /// <summary>
        ///  Gets or sets a value that indicates whether a key should be processed
        ///  further.
        /// </summary>
        protected override bool ProcessDialogKey(Keys keyData)
        {
            Keys key = (keyData & Keys.KeyCode);

            if (key == Keys.Enter)
            {
                if (ProcessEnterKey(keyData))
                {
                    return true;
                }
            }
            else if (key == Keys.Escape)
            {
                bool keyEffective = IsEscapeKeyEffective;
                bool ret = base.ProcessDialogKey(keyData);
                if (!keyEffective)
                {
                    // This call may perform Click of Cancel button of form.
                    if (Focused)
                    {
                        // Make sure the current cell is in editing mode if needed.
                        if (_ptCurrentCell.X > -1 &&
                            !IsCurrentCellInEditMode &&
                            (EditMode == DataGridViewEditMode.EditOnEnter ||
                            (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null)))
                        {
                            BeginEditInternal(true /*selectAll*/);
                        }
                    }
                }
                return ret;
            }
            else if (key == Keys.D0 || key == Keys.NumPad0)
            {
                if (ProcessZeroKey(keyData))
                {
                    return true;
                }
            }
            else if (key == Keys.C || key == Keys.Insert)
            {
                if (ProcessInsertKey(keyData))
                {
                    return true;
                }
            }
            else if (key == Keys.Tab)
            {
                if (ProcessTabKey(keyData))
                {
                    return true;
                }
                else
                {
                    if (EditingControl != null)
                    {
                        _dataGridViewState1[State1_LeavingWithTabKey] = true;
                        if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.LeaveControl,
                                     DataGridViewValidateCellInternal.Always,
                                     true /*fireCellLeave*/,
                                     true /*fireCellEnter*/,
                                     true /*fireRowLeave*/,
                                     true /*fireRowEnter*/,
                                     true /*fireLeave*/,
                                     false /*keepFocus*/,
                                     false /*resetCurrentCell*/,
                                     false /*resetAnchorCell unused here*/))
                        {
                            return true;
                        }
                    }

                    keyData &= ~Keys.Control;
                    bool ret = false;

                    ret = base.ProcessDialogKey(keyData);

                    if (_dataGridViewState1[State1_LeavingWithTabKey] && Focused)
                    {
                        // There was no other control to tab to. The CellLeave, RowLeave, Leave events were raised.
                        // Since the DataGridView control still has the focus, Enter, RowEnter, CellEnter events need to be raised.
                        OnEnter(EventArgs.Empty);
                    }

                    return ret;
                }
            }
            return base.ProcessDialogKey(keyData);
        }

        protected bool ProcessDownKey(Keys keyData)
        {
            return ProcessDownKeyInternal(keyData, out bool moved);
        }

        private bool ProcessDownKeyInternal(Keys keyData, out bool moved)
        {
            bool success;
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
            if (firstVisibleColumnIndex == -1 || lastVisibleRowIndex == -1)
            {
                moved = false;
                return false;
            }
            int nextVisibleRowIndex = -1;
            if (_ptCurrentCell.Y != -1)
            {
                nextVisibleRowIndex = Rows.GetNextRow(_ptCurrentCell.Y, DataGridViewElementStates.Visible);
            }
            moved = true;

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        // SetCurrentCellAddressCore can fail if by navigating to a cell
                                        // the list under the DataGridView changes.
                                        // In this case set moved to false so the users that call ProcessDownKey
                                        // will commit the data.
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (MultiSelect)
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        Debug.Assert(_ptAnchorCell.Y >= 0);
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptCurrentCell.X == -1 || _ptAnchorCell.X == -1 ||
                                            IsRowOutOfBounds(lastVisibleRowIndex))
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, lastVisibleRowIndex);
                                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, false, false, false);
                                        if (!success)
                                        {
                                            moved = false;
                                        }
                                    }
                                    else
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(lastVisibleRowIndex))
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, lastVisibleRowIndex, true);
                                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, true, false, false);
                                        if (!success)
                                        {
                                            moved = false;
                                        }
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedCellCore(_ptCurrentCell.X, lastVisibleRowIndex, true);
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (nextVisibleRowIndex == -1)
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, nextVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if (MultiSelect)
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, nextVisibleRowIndex);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, nextVisibleRowIndex, true);
                                    }
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextVisibleRowIndex, !MultiSelect, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (nextVisibleRowIndex == -1)
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, nextVisibleRowIndex, true /*forCurrentCellChange*/))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedCellCore(_ptCurrentCell.X, nextVisibleRowIndex, true);
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X,
                                        nextVisibleRowIndex,
                                        true  /*setAnchorCellAddress*/,
                                        false /*validateCurrentCell*/,
                                        false /*throughMouseClick*/);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (MultiSelect)
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptAnchorCell.Y == -1 || _ptCurrentCell.X == -1 ||
                                            IsRowOutOfBounds(lastVisibleRowIndex))
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        ClearSelection();
                                        Debug.Assert(_ptAnchorCell.Y >= 0);
                                        SelectRowRange(_ptAnchorCell.Y, lastVisibleRowIndex, true);
                                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, false, false, false);
                                        if (!success)
                                        {
                                            moved = false;
                                        }
                                    }
                                    else
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(lastVisibleRowIndex))
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        SetSelectedRowCore(_ptCurrentCell.Y, false);
                                        SetSelectedRowCore(lastVisibleRowIndex, true);
                                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, true, false, false);
                                        if (!success)
                                        {
                                            moved = false;
                                        }
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedRowCore(lastVisibleRowIndex, true);
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (nextVisibleRowIndex == -1)
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, nextVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    ClearSelection();
                                    if (MultiSelect)
                                    {
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        if (nextVisibleRowIndex >= _ptAnchorCell.Y)
                                        {
                                            SelectRowRange(_ptAnchorCell.Y, nextVisibleRowIndex, true);
                                        }
                                        else
                                        {
                                            SelectRowRange(nextVisibleRowIndex, _ptAnchorCell.Y, true);
                                        }
                                    }
                                    else
                                    {
                                        SetSelectedRowCore(nextVisibleRowIndex, true);
                                    }
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextVisibleRowIndex, !MultiSelect, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (nextVisibleRowIndex == -1)
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, nextVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedRowCore(nextVisibleRowIndex, true);
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (MultiSelect)
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        Debug.Assert(_ptAnchorCell.Y >= 0);
                                        if (_ptAnchorCell.Y == -1 || _ptCurrentCell.Y == -1 ||
                                            IsRowOutOfBounds(lastVisibleRowIndex))
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                        {
                                            ClearSelection();
                                            SelectRowRange(_ptAnchorCell.Y, lastVisibleRowIndex, true);
                                        }
                                        else
                                        {
                                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                                _ptAnchorCell.Y, ref oldEdgeRowIndex, lastVisibleRowIndex);
                                        }
                                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, false, false, false);
                                        if (!success)
                                        {
                                            moved = false;
                                        }
                                    }
                                    else
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptCurrentCell.Y == -1 || IsRowOutOfBounds(lastVisibleRowIndex))
                                        {
                                            moved = false;
                                            return true;
                                        }
                                        if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                        {
                                            SetSelectedRowCore(_ptCurrentCell.Y, false);
                                            SetSelectedRowCore(lastVisibleRowIndex, true);
                                        }
                                        else
                                        {
                                            SetSelectedCellCore(_ptCurrentCell.X, _ptCurrentCell.Y, false);
                                            SetSelectedCellCore(_ptCurrentCell.X, lastVisibleRowIndex, true);
                                        }
                                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, true, false, false);
                                        if (!success)
                                        {
                                            moved = false;
                                        }
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsRowOutOfBounds(lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SetSelectedRowCore(lastVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, lastVisibleRowIndex, true);
                                    }
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (nextVisibleRowIndex == -1)
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, nextVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsRowOutOfBounds(nextVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        if (MultiSelect)
                                        {
                                            if (_ptAnchorCell.Y == -1)
                                            {
                                                moved = false;
                                                return true;
                                            }
                                            if (nextVisibleRowIndex >= _ptAnchorCell.Y)
                                            {
                                                SelectRowRange(_ptAnchorCell.Y, nextVisibleRowIndex, true);
                                            }
                                            else
                                            {
                                                SelectRowRange(nextVisibleRowIndex, _ptAnchorCell.Y, true);
                                            }
                                        }
                                        else
                                        {
                                            SetSelectedRowCore(nextVisibleRowIndex, true);
                                        }
                                    }
                                    else
                                    {
                                        if (MultiSelect)
                                        {
                                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                                            if (_ptAnchorCell.X == -1)
                                            {
                                                moved = false;
                                                return true;
                                            }
                                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                                _ptAnchorCell.Y, ref oldEdgeRowIndex, nextVisibleRowIndex);
                                        }
                                        else
                                        {
                                            ClearSelection();
                                            SetSelectedCellCore(_ptCurrentCell.X, nextVisibleRowIndex, true);
                                        }
                                    }
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextVisibleRowIndex, !MultiSelect, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, lastVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                                else
                                {
                                    if (nextVisibleRowIndex == -1)
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, nextVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsRowOutOfBounds(nextVisibleRowIndex))
                                    {
                                        moved = false;
                                        return true;
                                    }
                                    if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SetSelectedRowCore(nextVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, nextVisibleRowIndex, true);
                                    }
                                    success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextVisibleRowIndex, true, false, false);
                                    if (!success)
                                    {
                                        moved = false;
                                    }
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                {
                                    moved = false;
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                if (!success)
                                {
                                    moved = false;
                                }
                            }
                            else
                            {
                                if (!ScrollIntoView(_ptCurrentCell.X, lastVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(lastVisibleRowIndex))
                                {
                                    moved = false;
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(_ptCurrentCell.X, lastVisibleRowIndex, true, false, false);
                                if (!success)
                                {
                                    moved = false;
                                }
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, lastVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, lastVisibleRowIndex))
                                {
                                    moved = false;
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                                if (!success)
                                {
                                    moved = false;
                                }
                            }
                            else
                            {
                                if (nextVisibleRowIndex == -1)
                                {
                                    moved = false;
                                    return true;
                                }
                                if (!ScrollIntoView(_ptCurrentCell.X, nextVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextVisibleRowIndex))
                                {
                                    moved = false;
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextVisibleRowIndex, true, false, false);
                                if (!success)
                                {
                                    moved = false;
                                }
                            }
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessEndKey(Keys keyData)
        {
            DataGridViewColumn dataGridViewColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible,
                DataGridViewElementStates.None);
            int lastVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
            if (lastVisibleColumnIndex == -1 || firstVisibleRowIndex == -1)
            {
                return false;
            }

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(lastVisibleColumnIndex, lastVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, lastVisibleRowIndex))
                            {
                                return true;
                            }
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (MultiSelect && _ptAnchorCell.X >= 0)
                                {
                                    int oldEdgeColumnIndex = _ptCurrentCell.X;
                                    int oldEdgeRowIndex = _ptCurrentCell.Y;
                                    UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, lastVisibleColumnIndex,
                                        _ptAnchorCell.Y, ref oldEdgeRowIndex, lastVisibleRowIndex);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, lastVisibleRowIndex, true);
                                }
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                ClearSelection();
                                SetSelectedCellCore(lastVisibleColumnIndex, lastVisibleRowIndex, true);
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(lastVisibleColumnIndex, lastVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, lastVisibleRowIndex))
                            {
                                return true;
                            }
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (MultiSelect && _ptAnchorCell.X >= 0)
                                {
                                    if (_ptCurrentCell.Y > -1 &&
                                        (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SelectRowRange(_ptCurrentCell.Y, lastVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, lastVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, lastVisibleRowIndex);
                                    }
                                }
                                else
                                {
                                    if (_ptCurrentCell.Y > -1 &&
                                        (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SetSelectedRowCore(lastVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(lastVisibleColumnIndex, lastVisibleRowIndex, true);
                                    }
                                }
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                if (_ptCurrentCell.Y > -1 &&
                                    (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(lastVisibleRowIndex, true);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, lastVisibleRowIndex, true);
                                }
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(lastVisibleColumnIndex, lastVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, lastVisibleRowIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (MultiSelect && _ptCurrentCell.X >= 0)
                                {
                                    SelectColumnRange(_ptAnchorCell.X, lastVisibleColumnIndex, true);
                                }
                                else
                                {
                                    SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                }
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, lastVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, lastVisibleRowIndex))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X >= 0 && Columns[_ptCurrentCell.X].Selected)
                                {
                                    ClearSelection();
                                    if (MultiSelect)
                                    {
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        SelectColumnRange(_ptAnchorCell.X, lastVisibleColumnIndex, true);
                                    }
                                    SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                }
                                else
                                {
                                    if (MultiSelect && _ptCurrentCell.X >= 0)
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, lastVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, lastVisibleRowIndex);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(lastVisibleColumnIndex, lastVisibleRowIndex, true);
                                    }
                                }
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, lastVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, lastVisibleRowIndex))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X >= 0 && Columns[_ptCurrentCell.X].Selected)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, lastVisibleRowIndex, true);
                                }
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(lastVisibleColumnIndex, lastVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, lastVisibleRowIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (MultiSelect && _ptCurrentCell.Y >= 0)
                                {
                                    if (_ptAnchorCell.Y == -1)
                                    {
                                        return true;
                                    }
                                    SelectRowRange(_ptAnchorCell.Y, lastVisibleRowIndex, true);
                                }
                                else
                                {
                                    SetSelectedRowCore(lastVisibleRowIndex, true);
                                }

                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                SetSelectedRowCore(lastVisibleRowIndex, true);
                                SetCurrentCellAddressCore(lastVisibleColumnIndex, lastVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessEnterKey(Keys keyData)
        {
            // When Enter is pressed, no matter Ctrl is also pressed or not,
            // changes in a cell should be commited.
            // Therefore, commitRow should be always true, and useless here.

            bool moved = false, ret = true;//, commitRow = true;
            if ((keyData & Keys.Control) == 0)
            {
                // Enter behaves like down arrow - it commits the potential editing and goes down one cell.
                // commitRow = false;
                keyData &= ~Keys.Shift;
                ret = ProcessDownKeyInternal(keyData, out moved);
            }

            if (!moved)
            {
                DataGridViewCell dataGridViewCurrentCell = null;
                // Try to commit the potential editing
                if (EditMode == DataGridViewEditMode.EditOnEnter)
                {
                    if (_ptCurrentCell.X != -1)
                    {
                        dataGridViewCurrentCell = CurrentCellInternal;
                        DataGridViewDataErrorEventArgs dgvdee = CommitEdit(ref dataGridViewCurrentCell,
                            DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit,
                            DataGridViewValidateCellInternal.WhenChanged,
                            false /*fireCellLeave*/,
                            false /*fireCellEnter*/,
                            false /*fireRowLeave*/,
                            false /*fireRowEnter*/,
                            false /*fireLeave*/);
                        if (null != dgvdee)
                        {
                            if (dgvdee.ThrowException)
                            {
                                throw dgvdee.Exception;
                            }
                        }
                    }
                }
                else
                {
                    EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit,
                        DataGridViewValidateCellInternal.WhenChanged /*validateCell*/,
                        false /*fireCellLeave*/,
                        false /*fireCellEnter*/,
                        false /*fireRowLeave*/,
                        false /*fireRowEnter*/,
                        false /*fireLeave*/,
                        true /*keepFocus*/,
                        true /*resetCurrentCell unused here*/,
                        true /*resetAnchorCell unused here*/);
                }
                if (/*commitRow && */IsCurrentRowDirty)
                {
                    dataGridViewCurrentCell = null;
                    int columnIndex = _ptCurrentCell.X;
                    int rowIndex = _ptCurrentCell.Y;
                    if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                    {
                        return ret;
                    }
                    if (!OnRowValidating(ref dataGridViewCurrentCell, columnIndex, rowIndex))
                    {
                        if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                        {
                            return ret;
                        }
                        OnRowValidated(ref dataGridViewCurrentCell, columnIndex, rowIndex);
                    }
                }
            }
            return ret;
        }

        protected bool ProcessEscapeKey(Keys keyData)
        {
            if (IsEscapeKeyEffective)
            {
                if (IsMouseOperationActive())
                {
                    ResetTrackingState();
                }
                else
                {
                    CancelEdit(true /*endEdit, DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.InitialValueRestoration*/);
                }
                return true;
            }
            return false;
        }

        protected bool ProcessF2Key(Keys keyData)
        {
            if (_ptCurrentCell.X != -1 &&
                !IsCurrentCellInEditMode &&
                ModifierKeys == 0)
            {
                Debug.Assert(_ptCurrentCell.Y != -1);
                Debug.Assert(CurrentCellInternal != null);
                Debug.Assert(EditMode != DataGridViewEditMode.EditOnEnter ||
                    (IsSharedCellReadOnly(CurrentCellInternal, _ptCurrentCell.Y) || !ColumnEditable(_ptCurrentCell.X)));
                if (ColumnEditable(_ptCurrentCell.X) &&
                    !IsSharedCellReadOnly(CurrentCellInternal, _ptCurrentCell.Y) &&
                    (EditMode == DataGridViewEditMode.EditOnKeystrokeOrF2 ||
                     EditMode == DataGridViewEditMode.EditOnF2))
                {
                    bool success = ScrollIntoView(_ptCurrentCell.X, _ptCurrentCell.Y, false);
                    Debug.Assert(success);
                    BeginEditInternal(EditMode == DataGridViewEditMode.EditOnF2 /*selectAll*/);
                    return true;
                }
            }
            return false;
        }

        /// <summary>
        ///  Sorts the current column.
        ///  'UseLegacyAccessibilityFeatures2' accessibility switch
        ///  should be set to false to enable the feature.
        /// </summary>
        protected bool ProcessF3Key(Keys keyData)
        {
            if (_ptCurrentCell.X != -1)
            {
                DataGridViewColumn dataGridViewColumn = Columns[_ptCurrentCell.X];
                if (dataGridViewColumn != null && CanSort(dataGridViewColumn))
                {
                    ListSortDirection listSortDirection = SortedColumn == dataGridViewColumn && SortOrder == SortOrder.Ascending ?
                        ListSortDirection.Descending : ListSortDirection.Ascending;

                    Sort(dataGridViewColumn, listSortDirection);
                    return true;
                }
            }
            return false;
        }

        protected bool ProcessHomeKey(Keys keyData)
        {
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            if (firstVisibleColumnIndex == -1 || firstVisibleRowIndex == -1)
            {
                return false;
            }

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (MultiSelect && _ptAnchorCell.X >= 0)
                                {
                                    int oldEdgeColumnIndex = _ptCurrentCell.X;
                                    int oldEdgeRowIndex = _ptCurrentCell.Y;
                                    UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, firstVisibleColumnIndex,
                                        _ptAnchorCell.Y, ref oldEdgeRowIndex, firstVisibleRowIndex);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                }
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                ClearSelection();
                                SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (MultiSelect && _ptAnchorCell.X >= 0)
                                {
                                    if (_ptCurrentCell.Y > -1 &&
                                        (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SelectRowRange(firstVisibleRowIndex, _ptAnchorCell.Y, true);
                                    }
                                    else
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, firstVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, firstVisibleRowIndex);
                                    }
                                }
                                else
                                {
                                    if (_ptCurrentCell.Y > -1 &&
                                        (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SetSelectedRowCore(firstVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    }
                                }
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                if (_ptCurrentCell.Y > -1 &&
                                    (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(firstVisibleRowIndex, true);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                }
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (MultiSelect && _ptCurrentCell.X >= 0)
                                {
                                    if (_ptAnchorCell.X == -1)
                                    {
                                        return true;
                                    }
                                    SelectColumnRange(firstVisibleColumnIndex, _ptAnchorCell.X, true);
                                }
                                else
                                {
                                    SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                }
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (!ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X >= 0 && Columns[_ptCurrentCell.X].Selected)
                                {
                                    ClearSelection();
                                    if (MultiSelect)
                                    {
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        SelectColumnRange(firstVisibleColumnIndex, _ptAnchorCell.X, true);
                                    }
                                    SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                }
                                else
                                {
                                    if (MultiSelect && _ptCurrentCell.X >= 0)
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, firstVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, firstVisibleRowIndex);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    }
                                }
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, !MultiSelect, false, false);
                            }
                            else
                            {
                                if (!ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X >= 0 && Columns[_ptCurrentCell.X].Selected)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                }
                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if ((keyData & Keys.Control) == 0)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (!ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, true))
                            {
                                return true;
                            }
                            if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            SetSelectedRowCore(firstVisibleRowIndex, true);
                            SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessInsertKey(Keys keyData)
        {
            if (((keyData & (Keys.Shift | Keys.Control | Keys.Alt)) == Keys.Control ||
                 ((keyData & (Keys.Shift | Keys.Control | Keys.Alt)) == (Keys.Control | Keys.Shift) && (keyData & Keys.KeyCode) == Keys.C)) &&
                ClipboardCopyMode != DataGridViewClipboardCopyMode.Disable)
            {
                DataObject dataObject = GetClipboardContent();
                if (dataObject != null)
                {
                    Clipboard.SetDataObject(dataObject);
                    return true;
                }
            }
            return false;
        }

        protected override bool ProcessKeyEventArgs(ref Message m)
        {
            if (m.Msg == (int)User32.WM.SYSKEYDOWN || m.Msg == (int)User32.WM.KEYDOWN)
            {
                if (_ptCurrentCell.X != -1)
                {
                    DataGridViewCell dataGridViewCell = CurrentCellInternal;
                    Debug.Assert(dataGridViewCell != null);

                    if (!IsCurrentCellInEditMode &&
                        ColumnEditable(_ptCurrentCell.X) &&
                        !IsSharedCellReadOnly(dataGridViewCell, _ptCurrentCell.Y) &&
                        (EditMode == DataGridViewEditMode.EditOnKeystroke || EditMode == DataGridViewEditMode.EditOnKeystrokeOrF2))
                    {
                        KeyEventArgs ke = new KeyEventArgs((Keys)(unchecked((int)(long)m.WParam)) | ModifierKeys);
                        if (ke.KeyCode != Keys.ProcessKey || (int)m.LParam != 0x01) // Changing IME context does not trigger editing mode
                        {
                            Type editControlType = dataGridViewCell.EditType;
                            Type editingCellInterface = null;
                            if (editControlType is null)
                            {
                                // Current cell does not have an editing control. Does it implement IDataGridViewEditingCell?
                                editingCellInterface = dataGridViewCell.GetType().GetInterface("System.Windows.Forms.IDataGridViewEditingCell");
                            }

                            if ((editControlType != null || editingCellInterface is null) &&
                                dataGridViewCell.KeyEntersEditMode(ke))
                            {
                                // Cell wants to go to edit mode
                                bool success = ScrollIntoView(_ptCurrentCell.X, _ptCurrentCell.Y, false);
                                Debug.Assert(success);
                                if (BeginEditInternal(!(ke.KeyCode == Keys.F2 && ModifierKeys == 0 && EditMode == DataGridViewEditMode.EditOnKeystrokeOrF2) /*selectAll*/))
                                {
                                    // Forward the key message to the editing control if any
                                    if (EditingControl != null)
                                    {
                                        User32.SendMessageW(EditingControl, (User32.WM)m.Msg, m.WParam, m.LParam);
                                        _dataGridViewState1[State1_ForwardCharMessage] = true;
                                        return true;
                                    }
                                }
                            }
                        }
                    }
                }
            }
            else if (_dataGridViewState1[State1_ForwardCharMessage] &&
                     (m.Msg == (int)User32.WM.SYSCHAR || m.Msg == (int)User32.WM.CHAR || m.Msg == (int)User32.WM.IME_CHAR))
            {
                _dataGridViewState1[State1_ForwardCharMessage] = false;
                if (EditingControl != null)
                {
                    User32.SendMessageW(EditingControl, (User32.WM)m.Msg, m.WParam, m.LParam);
                    return true;
                }
            }
            return base.ProcessKeyEventArgs(ref m);
        }

        protected override bool ProcessKeyPreview(ref Message m)
        {
            bool dataGridViewWantsInputKey;
            KeyEventArgs ke = new KeyEventArgs((Keys)((int)m.WParam) | ModifierKeys);

            // Refactor the special keys into two parts.
            // 1. Escape and Space exist in both WM_CHAR and WM_KEYDOWN, WM_KEYUP.
            // 2. Other special keys do not exist in WM_CHAR message, and character code of WM_CHAR may have overlapped
            // w/ some of the key code. (Like character code of lowcase "q" is 0x71, it's overlapped w/ Keys.F2). This
            // may introduce problem when handling them.
            if (m.Msg == (int)User32.WM.CHAR)
            {
                switch (ke.KeyCode)
                {
                    case Keys.Escape:
                    case Keys.Space:
                        dataGridViewWantsInputKey = true;
                        break;

                    default:
                        dataGridViewWantsInputKey = false;
                        break;
                }
            }
            else
            {
                switch (ke.KeyCode)
                {
                    case Keys.Delete:
                    case Keys.Down:
                    case Keys.End:
                    case Keys.Enter:
                    case Keys.Escape:
                    case Keys.F2:
                    case Keys.F3:
                    case Keys.Home:
                    case Keys.Left:
                    case Keys.Next:
                    case Keys.Prior:
                    case Keys.Right:
                    case Keys.Space:
                    case Keys.Tab:
                    case Keys.Up:
                        dataGridViewWantsInputKey = true;
                        break;

                    default:
                        dataGridViewWantsInputKey = false;
                        break;
                }
            }

            if (EditingControl != null && (m.Msg == (int)User32.WM.KEYDOWN || m.Msg == (int)User32.WM.SYSKEYDOWN))
            {
                _dataGridViewState2[State2_CurrentCellWantsInputKey] = ((IDataGridViewEditingControl)EditingControl).EditingControlWantsInputKey(ke.KeyData, dataGridViewWantsInputKey);
            }

            if (_dataGridViewState2[State2_CurrentCellWantsInputKey])
            {
                return base.ProcessKeyPreview(ref m);
            }

            if (dataGridViewWantsInputKey)
            {
                if (m.Msg == (int)User32.WM.KEYDOWN || m.Msg == (int)User32.WM.SYSKEYDOWN)
                {
                    if (ProcessDataGridViewKey(ke))
                    {
                        return true;
                        // Ctrl-Tab will be sent as a tab paired w/ a control on the KeyUp message
                    }
                    else
                    {
                        _dataGridViewState2[State2_CurrentCellWantsInputKey] = true;
                    }
                }
                else
                {
                    return true;
                }
            }
            return base.ProcessKeyPreview(ref m);
        }

        private bool? ProcessColumnResize(Keys keyData, int step)
        {
            if ((keyData & Keys.Alt) == Keys.Alt && AllowUserToResizeColumns && _ptCurrentCell.X != -1)
            {
                if (_currentColSplitBar == -1)
                {
                    DataGridViewColumn dataGridViewColumn = Columns[_ptCurrentCell.X];
                    if (dataGridViewColumn != null && dataGridViewColumn.Resizable == DataGridViewTriState.True &&
                        (dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.None || dataGridViewColumn.InheritedAutoSizeMode == DataGridViewAutoSizeColumnMode.Fill))
                    {
                        BeginKeyboardColumnResize(_ptCurrentCell.X);
                        return true;
                    }
                    return false;
                }
                else
                {
                    int x = _currentColSplitBar + step;
                    if (_dataGridViewOper[OperationTrackKeyboardColResize] && _resizeClipRectangle.Contains(x, _resizeClipRectangle.Top))
                    {
                        MoveRowHeadersOrColumnResize(x);
                        return true;
                    }
                    return false;
                }
            }

            return null;
        }

        /// <summary>
        ///  Activates keyboard tooltip.
        /// </summary>
        protected bool ProcessControlShiftF10Keys(Keys keyData)
        {
            if (CurrentCell is null || _ptCurrentCell.X == -1 || _ptCurrentCell.Y == -1)
            {
                return false;
            }

            DataGridViewCell dataGridViewCell = CurrentCell;

            ActivateToolTip(false /*activate*/, String.Empty, dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex);
            if (KeyboardToolTip.IsActivatedByKeyboard)
            {
                KeyboardToolTipStateMachine.Instance.NotifyAboutLostFocus(dataGridViewCell);
            }
            else
            {
                KeyboardToolTipStateMachine.Instance.NotifyAboutGotFocus(dataGridViewCell);
            }

            return true;
        }

        protected bool ProcessLeftKey(Keys keyData)
        {
            if (RightToLeftInternal)
            {
                return ProcessRightKeyPrivate(keyData);
            }
            else
            {
                return ProcessLeftKeyPrivate(keyData);
            }
        }

        private bool ProcessLeftKeyPrivate(Keys keyData)
        {
            bool? resizeResult = ProcessColumnResize(keyData, -_keyboardResizeStep);
            if (resizeResult.HasValue)
            {
                return resizeResult.Value;
            }

            bool success;
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            if (firstVisibleColumnIndex == -1 || firstVisibleRowIndex == -1)
            {
                return false;
            }
            int previousVisibleColumnIndex = -1;
            if (_ptCurrentCell.X != -1)
            {
                dataGridViewColumn = Columns.GetPreviousColumn(Columns[_ptCurrentCell.X],
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
                if (dataGridViewColumn != null)
                {
                    previousVisibleColumnIndex = dataGridViewColumn.Index;
                }
            }

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (previousVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(previousVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(previousVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    if (MultiSelect)
                                    {
                                        Debug.Assert(_ptAnchorCell.X >= 0);
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, previousVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    }
                                    success = SetCurrentCellAddressCore(previousVisibleColumnIndex, _ptCurrentCell.Y, !MultiSelect, false, false);
                                    Debug.Assert(success);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (previousVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(previousVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(previousVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedCellCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    success = SetCurrentCellAddressCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (previousVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(previousVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(previousVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    if (MultiSelect)
                                    {
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        if (Columns.DisplayInOrder(_ptAnchorCell.X, previousVisibleColumnIndex))
                                        {
                                            SelectColumnRange(_ptAnchorCell.X, previousVisibleColumnIndex, true);
                                        }
                                        else
                                        {
                                            SelectColumnRange(previousVisibleColumnIndex, _ptAnchorCell.X, true);
                                        }
                                    }
                                    else
                                    {
                                        SetSelectedColumnCore(previousVisibleColumnIndex, true);
                                    }
                                    success = SetCurrentCellAddressCore(previousVisibleColumnIndex, _ptCurrentCell.Y, !MultiSelect, false, false);
                                    Debug.Assert(success);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (previousVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(previousVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(previousVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedColumnCore(previousVisibleColumnIndex, true);
                                    success = SetCurrentCellAddressCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (previousVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(previousVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsColumnOutOfBounds(previousVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        ClearSelection();
                                        if (MultiSelect)
                                        {
                                            if (_ptAnchorCell.X == -1)
                                            {
                                                return true;
                                            }
                                            if (Columns.DisplayInOrder(_ptAnchorCell.X, previousVisibleColumnIndex))
                                            {
                                                SelectColumnRange(_ptAnchorCell.X, previousVisibleColumnIndex, true);
                                            }
                                            else
                                            {
                                                SelectColumnRange(previousVisibleColumnIndex, _ptAnchorCell.X, true);
                                            }
                                        }
                                        SetSelectedColumnCore(previousVisibleColumnIndex, true);
                                    }
                                    else
                                    {
                                        if (MultiSelect)
                                        {
                                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                                            if (_ptAnchorCell.X == -1)
                                            {
                                                return true;
                                            }
                                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, previousVisibleColumnIndex,
                                                _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                        }
                                        else
                                        {
                                            ClearSelection();
                                            SetSelectedCellCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true);
                                        }
                                    }
                                    success = SetCurrentCellAddressCore(previousVisibleColumnIndex, _ptCurrentCell.Y, !MultiSelect, false, false);
                                    Debug.Assert(success);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (previousVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(previousVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsColumnOutOfBounds(previousVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        ClearSelection();
                                        SetSelectedColumnCore(previousVisibleColumnIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    }
                                    success = SetCurrentCellAddressCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessLeftMost((keyData & Keys.Shift) == Keys.Shift, firstVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedRowCore(firstVisibleRowIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (previousVisibleColumnIndex == -1)
                                {
                                    return true;
                                }
                                if (!ScrollIntoView(previousVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(previousVisibleColumnIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(previousVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        // Ctrl Left <==> Home
        // Shift Ctrl Left <==> Shift Home
        private bool ProcessLeftMost(bool shift, int firstVisibleColumnIndex, int firstVisibleRowIndex)
        {
            bool success;

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if (shift)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (MultiSelect)
                                {
                                    if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    Debug.Assert(_ptAnchorCell.X >= 0);
                                    int oldEdgeColumnIndex = _ptCurrentCell.X;
                                    int oldEdgeRowIndex = _ptCurrentCell.Y;
                                    if (_ptAnchorCell.X == -1 || _ptCurrentCell.X == -1 ||
                                        IsColumnOutOfBounds(firstVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, firstVisibleColumnIndex,
                                        _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, false, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(firstVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(firstVisibleColumnIndex))
                                {
                                    return true;
                                }
                                ClearSelection();
                                SetSelectedCellCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true);
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if (shift)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (MultiSelect)
                                {
                                    if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptAnchorCell.X == -1 || _ptCurrentCell.Y == -1 ||
                                        IsColumnOutOfBounds(firstVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    Debug.Assert(_ptAnchorCell.X >= 0);
                                    SelectColumnRange(firstVisibleColumnIndex, _ptAnchorCell.X, true);
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, false, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsColumnOutOfBounds(firstVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    SetSelectedColumnCore(_ptCurrentCell.X, false);
                                    SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(firstVisibleColumnIndex))
                                {
                                    return true;
                                }
                                ClearSelection();
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if (shift)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (MultiSelect)
                                {
                                    if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptAnchorCell.X == -1 || _ptCurrentCell.X == -1 ||
                                        IsColumnOutOfBounds(firstVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    Debug.Assert(_ptAnchorCell.X >= 0);
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        ClearSelection();
                                        SelectColumnRange(firstVisibleColumnIndex, _ptAnchorCell.X, true);
                                    }
                                    else
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, firstVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, false, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 ||
                                        IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        SetSelectedColumnCore(_ptCurrentCell.X, false);
                                        SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(_ptCurrentCell.X, _ptCurrentCell.Y, false);
                                        SetSelectedCellCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    }
                                    success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X == -1 || IsColumnOutOfBounds(firstVisibleColumnIndex))
                                {
                                    return true;
                                }
                                if (Columns[_ptCurrentCell.X].Selected)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true);
                                }
                                success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            ClearSelection();
                            SetSelectedRowCore(firstVisibleRowIndex, true);
                            success = ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                            Debug.Assert(success);
                            if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            success = SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            Debug.Assert(success);
                        }
                        else
                        {
                            if (!ScrollIntoView(firstVisibleColumnIndex, _ptCurrentCell.Y, true))
                            {
                                return true;
                            }
                            if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(firstVisibleColumnIndex))
                            {
                                return true;
                            }
                            success = SetCurrentCellAddressCore(firstVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                            Debug.Assert(success);
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessNextKey(Keys keyData)
        {
            bool success;
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            if (firstVisibleColumnIndex == -1)
            {
                return false;
            }
            int nextScreenVisibleRowIndexTmp, nextScreenVisibleRowIndex = -1, jumpRows = 0;
            if (_ptCurrentCell.Y == -1)
            {
                nextScreenVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                if (nextScreenVisibleRowIndex == -1)
                {
                    return false;
                }
            }
            else
            {
                nextScreenVisibleRowIndex = _ptCurrentCell.Y;
            }

            if ((Rows.GetRowState(nextScreenVisibleRowIndex) & DataGridViewElementStates.Frozen) != 0)
            {
                if (DisplayedBandsInfo.FirstDisplayedScrollingRow > 0)
                {
                    int firstDisplayedScrollingRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                    Debug.Assert(firstDisplayedScrollingRowIndex != -1);
                    if (!ScrollIntoView(_ptCurrentCell.X == -1 ? firstVisibleColumnIndex : _ptCurrentCell.X,
                        firstDisplayedScrollingRowIndex, true))
                    {
                        return true;
                    }
                    jumpRows = Rows.GetRowCount(DataGridViewElementStates.Visible,
                        _ptCurrentCell.Y,
                        firstDisplayedScrollingRowIndex) - 1;
                }
                else
                {
                    jumpRows = DisplayedBandsInfo.NumTotallyDisplayedFrozenRows;
                }
            }
            jumpRows += DisplayedBandsInfo.NumTotallyDisplayedScrollingRows;

            nextScreenVisibleRowIndexTmp = nextScreenVisibleRowIndex;
            Debug.Assert(nextScreenVisibleRowIndexTmp != -1);
            if (jumpRows == 0)
            {
                jumpRows = 1;
            }
            while (jumpRows > 0 && nextScreenVisibleRowIndexTmp != -1)
            {
                nextScreenVisibleRowIndexTmp = Rows.GetNextRow(nextScreenVisibleRowIndex, DataGridViewElementStates.Visible);
                if (nextScreenVisibleRowIndexTmp != -1)
                {
                    nextScreenVisibleRowIndex = nextScreenVisibleRowIndexTmp;
                    jumpRows--;
                }
            }

            _noSelectionChangeCount++;
            try
            {
                if (_ptCurrentCell.X == -1)
                {
                    ClearSelection();
                    switch (SelectionMode)
                    {
                        case DataGridViewSelectionMode.CellSelect:
                        case DataGridViewSelectionMode.ColumnHeaderSelect:
                        case DataGridViewSelectionMode.RowHeaderSelect:
                            SetSelectedCellCore(firstVisibleColumnIndex, nextScreenVisibleRowIndex, true);
                            break;
                        case DataGridViewSelectionMode.FullRowSelect:
                            SetSelectedRowCore(nextScreenVisibleRowIndex, true);
                            break;
                        case DataGridViewSelectionMode.FullColumnSelect:
                            SetSelectedColumnCore(firstVisibleColumnIndex, true);
                            break;
                    }
                    success = ScrollIntoView(firstVisibleColumnIndex, nextScreenVisibleRowIndex, false);
                    Debug.Assert(success);
                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, nextScreenVisibleRowIndex))
                    {
                        return true;
                    }

                    SetCurrentCellAddressCore(firstVisibleColumnIndex, nextScreenVisibleRowIndex, true, false, false);
                    return true;
                }

                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, nextScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextScreenVisibleRowIndex))
                        {
                            return true;
                        }
                        if ((keyData & Keys.Shift) == Keys.Shift && MultiSelect)
                        {
                            Debug.Assert(_ptAnchorCell.Y >= 0);
                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                            if (_ptAnchorCell.Y == -1)
                            {
                                return true;
                            }
                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                _ptAnchorCell.Y, ref oldEdgeRowIndex, nextScreenVisibleRowIndex);
                        }
                        else
                        {
                            ClearSelection();
                            SetSelectedCellCore(_ptCurrentCell.X, nextScreenVisibleRowIndex, true);
                        }
                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextScreenVisibleRowIndex, false, false, false);
                        Debug.Assert(success);
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, nextScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextScreenVisibleRowIndex))
                        {
                            return true;
                        }
                        ClearSelection();
                        if ((keyData & Keys.Shift) == Keys.Shift && MultiSelect)
                        {
                            Debug.Assert(_ptAnchorCell.Y >= 0);
                            if (_ptAnchorCell.Y == -1)
                            {
                                return true;
                            }
                            if (_ptAnchorCell.Y < nextScreenVisibleRowIndex)
                            {
                                SelectRowRange(_ptAnchorCell.Y, nextScreenVisibleRowIndex, true);
                            }
                            else
                            {
                                SelectRowRange(nextScreenVisibleRowIndex, _ptAnchorCell.Y, true);
                            }
                        }
                        else
                        {
                            SetSelectedRowCore(nextScreenVisibleRowIndex, true);
                        }
                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextScreenVisibleRowIndex, false, false, false);
                        return true;

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, nextScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextScreenVisibleRowIndex))
                        {
                            return true;
                        }
                        if ((keyData & Keys.Shift) == Keys.Shift && MultiSelect)
                        {
                            Debug.Assert(_ptAnchorCell.Y >= 0);
                            if (_ptAnchorCell.Y == -1)
                            {
                                return true;
                            }
                            if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                            {
                                ClearSelection();
                                if (_ptAnchorCell.Y < nextScreenVisibleRowIndex)
                                {
                                    SelectRowRange(_ptAnchorCell.Y, nextScreenVisibleRowIndex, true);
                                }
                                else
                                {
                                    SelectRowRange(nextScreenVisibleRowIndex, _ptAnchorCell.Y, true);
                                }
                            }
                            else
                            {
                                int oldEdgeColumnIndex = _ptCurrentCell.X;
                                int oldEdgeRowIndex = _ptCurrentCell.Y;
                                UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                    _ptAnchorCell.Y, ref oldEdgeRowIndex, nextScreenVisibleRowIndex);
                            }
                        }
                        else
                        {
                            if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                            {
                                ClearSelection();
                                SetSelectedRowCore(nextScreenVisibleRowIndex, true);
                            }
                            else
                            {
                                ClearSelection();
                                SetSelectedCellCore(_ptCurrentCell.X, nextScreenVisibleRowIndex, true);
                            }
                        }
                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextScreenVisibleRowIndex, !MultiSelect, false, false);
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, nextScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(nextScreenVisibleRowIndex))
                        {
                            return true;
                        }
                        success = SetCurrentCellAddressCore(_ptCurrentCell.X, nextScreenVisibleRowIndex, true, false, false);
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessPriorKey(Keys keyData)
        {
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            if (firstVisibleColumnIndex == -1)
            {
                return false;
            }
            int previousScreenVisibleRowIndexTmp, previousScreenVisibleRowIndex = -1;
            if (_ptCurrentCell.Y == -1)
            {
                previousScreenVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                if (previousScreenVisibleRowIndex == -1)
                {
                    return false;
                }
            }
            else
            {
                previousScreenVisibleRowIndex = _ptCurrentCell.Y;
            }

            int jumpRows;
            if ((Rows.GetRowState(previousScreenVisibleRowIndex) & DataGridViewElementStates.Frozen) != 0)
            {
                jumpRows = DisplayedBandsInfo.NumTotallyDisplayedFrozenRows;
            }
            else
            {
                jumpRows = DisplayedBandsInfo.NumTotallyDisplayedScrollingRows;
            }
            if (jumpRows == 0)
            {
                jumpRows = 1;
            }
            previousScreenVisibleRowIndexTmp = previousScreenVisibleRowIndex;
            Debug.Assert(previousScreenVisibleRowIndexTmp != -1);
            while (jumpRows > 0 && previousScreenVisibleRowIndexTmp != -1)
            {
                previousScreenVisibleRowIndexTmp = Rows.GetPreviousRow(previousScreenVisibleRowIndex, DataGridViewElementStates.Visible);
                if (previousScreenVisibleRowIndexTmp != -1)
                {
                    previousScreenVisibleRowIndex = previousScreenVisibleRowIndexTmp;
                }
                jumpRows--;
            }

            if ((Rows.GetRowState(previousScreenVisibleRowIndex) & DataGridViewElementStates.Frozen) != 0)
            {
                // Make sure the first scrolling row is visible if any
                int firstDisplayedScrollingRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                if (firstDisplayedScrollingRowIndex != -1 &&
                    !ScrollIntoView(_ptCurrentCell.X == -1 ? firstVisibleColumnIndex : _ptCurrentCell.X,
                    firstDisplayedScrollingRowIndex, true))
                {
                    return true;
                }
                // Also, first visible frozen row should become current one - there is no reason to jump to another frozen row.
                previousScreenVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            }
            Debug.Assert(previousScreenVisibleRowIndex != -1);

            _noSelectionChangeCount++;
            try
            {
                if (_ptCurrentCell.X == -1)
                {
                    ClearSelection();
                    switch (SelectionMode)
                    {
                        case DataGridViewSelectionMode.CellSelect:
                        case DataGridViewSelectionMode.ColumnHeaderSelect:
                        case DataGridViewSelectionMode.RowHeaderSelect:
                            SetSelectedCellCore(firstVisibleColumnIndex, previousScreenVisibleRowIndex, true);
                            break;
                        case DataGridViewSelectionMode.FullRowSelect:
                            SetSelectedRowCore(previousScreenVisibleRowIndex, true);
                            break;
                        case DataGridViewSelectionMode.FullColumnSelect:
                            SetSelectedColumnCore(firstVisibleColumnIndex, true);
                            break;
                    }

                    ScrollIntoView(firstVisibleColumnIndex, previousScreenVisibleRowIndex, false);
                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, previousScreenVisibleRowIndex))
                    {
                        return true;
                    }

                    SetCurrentCellAddressCore(firstVisibleColumnIndex, previousScreenVisibleRowIndex, true, false, false);
                    return true;
                }

                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, previousScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousScreenVisibleRowIndex))
                        {
                            return true;
                        }
                        if ((keyData & Keys.Shift) == Keys.Shift && MultiSelect)
                        {
                            Debug.Assert(_ptAnchorCell.Y >= 0);
                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                            if (_ptAnchorCell.X == -1)
                            {
                                return true;
                            }
                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                _ptAnchorCell.Y, ref oldEdgeRowIndex, previousScreenVisibleRowIndex);
                        }
                        else
                        {
                            ClearSelection();
                            SetSelectedCellCore(_ptCurrentCell.X, previousScreenVisibleRowIndex, true);
                        }
                        SetCurrentCellAddressCore(_ptCurrentCell.X, previousScreenVisibleRowIndex, false, false, false);
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, previousScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousScreenVisibleRowIndex))
                        {
                            return true;
                        }
                        ClearSelection();
                        if ((keyData & Keys.Shift) == Keys.Shift && MultiSelect)
                        {
                            Debug.Assert(_ptAnchorCell.Y >= 0);
                            if (_ptAnchorCell.Y == -1)
                            {
                                return true;
                            }
                            if (_ptAnchorCell.Y < previousScreenVisibleRowIndex)
                            {
                                SelectRowRange(_ptAnchorCell.Y, previousScreenVisibleRowIndex, true);
                            }
                            else
                            {
                                SelectRowRange(previousScreenVisibleRowIndex, _ptAnchorCell.Y, true);
                            }
                        }
                        else
                        {
                            SetSelectedRowCore(previousScreenVisibleRowIndex, true);
                        }
                        SetCurrentCellAddressCore(_ptCurrentCell.X, previousScreenVisibleRowIndex, false, false, false);
                        return true;

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, previousScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousScreenVisibleRowIndex))
                        {
                            return true;
                        }
                        if ((keyData & Keys.Shift) == Keys.Shift && MultiSelect)
                        {
                            Debug.Assert(_ptAnchorCell.Y >= 0);
                            if (_ptAnchorCell.Y == -1)
                            {
                                return true;
                            }
                            if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                            {
                                ClearSelection();
                                if (_ptAnchorCell.Y < previousScreenVisibleRowIndex)
                                {
                                    SelectRowRange(_ptAnchorCell.Y, previousScreenVisibleRowIndex, true);
                                }
                                else
                                {
                                    SelectRowRange(previousScreenVisibleRowIndex, _ptAnchorCell.Y, true);
                                }
                            }
                            else
                            {
                                int oldEdgeColumnIndex = _ptCurrentCell.X;
                                int oldEdgeRowIndex = _ptCurrentCell.Y;
                                UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                    _ptAnchorCell.Y, ref oldEdgeRowIndex, previousScreenVisibleRowIndex);
                            }
                        }
                        else
                        {
                            if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                            {
                                ClearSelection();
                                SetSelectedRowCore(previousScreenVisibleRowIndex, true);
                            }
                            else
                            {
                                ClearSelection();
                                SetSelectedCellCore(_ptCurrentCell.X, previousScreenVisibleRowIndex, true);
                            }
                        }

                        SetCurrentCellAddressCore(_ptCurrentCell.X, previousScreenVisibleRowIndex, !MultiSelect, false, false);
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if (!ScrollIntoView(_ptCurrentCell.X, previousScreenVisibleRowIndex, true))
                        {
                            return true;
                        }
                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousScreenVisibleRowIndex))
                        {
                            return true;
                        }

                        SetCurrentCellAddressCore(_ptCurrentCell.X, previousScreenVisibleRowIndex, true, false, false);
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessRightKey(Keys keyData)
        {
            if (RightToLeftInternal)
            {
                return ProcessLeftKeyPrivate(keyData);
            }
            else
            {
                return ProcessRightKeyPrivate(keyData);
            }
        }

        private bool ProcessRightKeyPrivate(Keys keyData)
        {
            bool? resizeResult = ProcessColumnResize(keyData, _keyboardResizeStep);
            if (resizeResult.HasValue)
            {
                return resizeResult.Value;
            }

            bool success;
            DataGridViewColumn dataGridViewColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible,
                DataGridViewElementStates.None);
            int lastVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            if (lastVisibleColumnIndex == -1 || firstVisibleRowIndex == -1)
            {
                return false;
            }
            int nextVisibleColumnIndex = -1;
            if (_ptCurrentCell.X != -1)
            {
                dataGridViewColumn = Columns.GetNextColumn(Columns[_ptCurrentCell.X],
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
                if (dataGridViewColumn != null)
                {
                    nextVisibleColumnIndex = dataGridViewColumn.Index;
                }
            }

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (nextVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(nextVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(nextVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    if (MultiSelect)
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, nextVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    }
                                    success = SetCurrentCellAddressCore(nextVisibleColumnIndex, _ptCurrentCell.Y, !MultiSelect, false, false);
                                    Debug.Assert(success);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (nextVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(nextVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(nextVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedCellCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    success = SetCurrentCellAddressCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                    success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (nextVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(nextVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(nextVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    if (MultiSelect)
                                    {
                                        if (_ptAnchorCell.X == -1)
                                        {
                                            return true;
                                        }
                                        if (Columns.DisplayInOrder(_ptAnchorCell.X, nextVisibleColumnIndex))
                                        {
                                            SelectColumnRange(_ptAnchorCell.X, nextVisibleColumnIndex, true);
                                        }
                                        else
                                        {
                                            SelectColumnRange(nextVisibleColumnIndex, _ptAnchorCell.X, true);
                                        }
                                    }
                                    else
                                    {
                                        SetSelectedColumnCore(nextVisibleColumnIndex, true);
                                    }
                                    success = SetCurrentCellAddressCore(nextVisibleColumnIndex, _ptCurrentCell.Y, !MultiSelect, false, false);
                                    Debug.Assert(success);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                    success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (nextVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(nextVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(nextVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedColumnCore(nextVisibleColumnIndex, true);
                                    success = SetCurrentCellAddressCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (nextVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(nextVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(nextVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        ClearSelection();
                                        if (MultiSelect)
                                        {
                                            if (_ptAnchorCell.X == -1)
                                            {
                                                return true;
                                            }
                                            if (Columns.DisplayInOrder(_ptAnchorCell.X, nextVisibleColumnIndex))
                                            {
                                                SelectColumnRange(_ptAnchorCell.X, nextVisibleColumnIndex, true);
                                            }
                                            else
                                            {
                                                SelectColumnRange(nextVisibleColumnIndex, _ptAnchorCell.X, true);
                                            }
                                        }
                                        else
                                        {
                                            SetSelectedColumnCore(nextVisibleColumnIndex, true);
                                        }
                                    }
                                    else
                                    {
                                        if (MultiSelect)
                                        {
                                            if (_ptAnchorCell.X == -1)
                                            {
                                                return true;
                                            }
                                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, nextVisibleColumnIndex,
                                                _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                        }
                                        else
                                        {
                                            ClearSelection();
                                            SetSelectedCellCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true);
                                        }
                                    }
                                    success = SetCurrentCellAddressCore(nextVisibleColumnIndex, _ptCurrentCell.Y, !MultiSelect, false, false);
                                    Debug.Assert(success);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                    success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                    Debug.Assert(success);
                                    if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (nextVisibleColumnIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(nextVisibleColumnIndex, _ptCurrentCell.Y, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsColumnOutOfBounds(nextVisibleColumnIndex))
                                    {
                                        return true;
                                    }
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        ClearSelection();
                                        SetSelectedColumnCore(nextVisibleColumnIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    }
                                    success = SetCurrentCellAddressCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            return ProcessRightMost((keyData & Keys.Shift) == Keys.Shift, lastVisibleColumnIndex, firstVisibleRowIndex);
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedRowCore(firstVisibleRowIndex, true);
                                success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (nextVisibleColumnIndex == -1)
                                {
                                    return true;
                                }
                                if (!ScrollIntoView(nextVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(nextVisibleColumnIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(nextVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        // Ctrl Right <==> End
        // Shift Ctrl Right <==> Shift End
        private bool ProcessRightMost(bool shift, int lastVisibleColumnIndex, int firstVisibleRowIndex)
        {
            bool success;

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if (shift)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(lastVisibleColumnIndex))
                                {
                                    return true;
                                }
                                if (MultiSelect)
                                {
                                    Debug.Assert(_ptAnchorCell.X >= 0);
                                    if (_ptAnchorCell.X == -1)
                                    {
                                        return true;
                                    }
                                    int oldEdgeColumnIndex = _ptCurrentCell.X;
                                    int oldEdgeRowIndex = _ptCurrentCell.Y;
                                    UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, lastVisibleColumnIndex,
                                        _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, false, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(lastVisibleColumnIndex))
                                {
                                    return true;
                                }
                                ClearSelection();
                                SetSelectedCellCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true);
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if (shift)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(lastVisibleColumnIndex))
                                {
                                    return true;
                                }
                                if (MultiSelect)
                                {
                                    if (_ptAnchorCell.X == -1)
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    Debug.Assert(_ptAnchorCell.X >= 0);
                                    SelectColumnRange(_ptAnchorCell.X, lastVisibleColumnIndex, true);
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, false, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    SetSelectedColumnCore(_ptCurrentCell.X, false);
                                    SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(lastVisibleColumnIndex))
                                {
                                    return true;
                                }
                                ClearSelection();
                                SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if (shift)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(lastVisibleColumnIndex))
                                {
                                    return true;
                                }
                                if (MultiSelect)
                                {
                                    Debug.Assert(_ptAnchorCell.X >= 0);
                                    if (_ptAnchorCell.X == -1)
                                    {
                                        return true;
                                    }
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        ClearSelection();
                                        SelectColumnRange(_ptAnchorCell.X, lastVisibleColumnIndex, true);
                                    }
                                    else
                                    {
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, lastVisibleColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, oldEdgeRowIndex);
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, false, false, false);
                                    Debug.Assert(success);
                                }
                                else
                                {
                                    if (Columns[_ptCurrentCell.X].Selected)
                                    {
                                        SetSelectedColumnCore(_ptCurrentCell.X, false);
                                        SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(_ptCurrentCell.X, _ptCurrentCell.Y, false);
                                        SetSelectedCellCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true);
                                    }
                                    success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                    Debug.Assert(success);
                                }
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedCellCore(lastVisibleColumnIndex, firstVisibleRowIndex, true);
                                success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                                Debug.Assert(success);
                                if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                Debug.Assert(success);
                            }
                            else
                            {
                                if (!ScrollIntoView(lastVisibleColumnIndex, _ptCurrentCell.Y, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(lastVisibleColumnIndex))
                                {
                                    return true;
                                }
                                if (Columns[_ptCurrentCell.X].Selected)
                                {
                                    ClearSelection();
                                    SetSelectedColumnCore(lastVisibleColumnIndex, true);
                                }
                                else
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true);
                                }
                                success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                                Debug.Assert(success);
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            ClearSelection();
                            SetSelectedRowCore(firstVisibleRowIndex, true);
                            success = ScrollIntoView(lastVisibleColumnIndex, firstVisibleRowIndex, false);
                            Debug.Assert(success);
                            if (IsInnerCellOutOfBounds(lastVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            success = SetCurrentCellAddressCore(lastVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            Debug.Assert(success);
                        }
                        else
                        {
                            if (!ScrollIntoView(lastVisibleColumnIndex, _ptCurrentCell.Y, true))
                            {
                                return true;
                            }
                            if (_ptCurrentCell.Y == -1 || IsColumnOutOfBounds(lastVisibleColumnIndex))
                            {
                                return true;
                            }
                            success = SetCurrentCellAddressCore(lastVisibleColumnIndex, _ptCurrentCell.Y, true, false, false);
                            Debug.Assert(success);
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessSpaceKey(Keys keyData)
        {
            if ((keyData & (Keys.Control | Keys.Shift | Keys.Alt)) == Keys.Shift &&
                _ptCurrentCell.X != -1)
            {
                _noSelectionChangeCount++;
                bool switchedToBulkPaint = false;
                if (_selectedBandIndexes.Count > BulkPaintThreshold)
                {
                    _inBulkPaintCount++;
                    switchedToBulkPaint = true;
                }
                try
                {
                    if (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect)
                    {
                        // Same as clicking the column header cell
                        Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                        int bandIndex = 0;
                        while (bandIndex < _selectedBandIndexes.Count)
                        {
                            if (_selectedBandIndexes[bandIndex] != _ptCurrentCell.X)
                            {
                                // deselect currently selected column
                                SetSelectedColumnCore(_selectedBandIndexes[bandIndex], false);
                            }
                            else
                            {
                                bandIndex++;
                            }
                        }
                        RemoveIndividuallySelectedCells();
                        if (!Columns[_ptCurrentCell.X].Selected)
                        {
                            Debug.Assert(!_selectedBandIndexes.Contains(_ptCurrentCell.X));
                            SetSelectedColumnCore(_ptCurrentCell.X, true);
                        }
                        return true;
                    }
                    else if (SelectionMode == DataGridViewSelectionMode.RowHeaderSelect)
                    {
                        // Same as clicking the row header cell
                        Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                        int bandIndex = 0;
                        while (bandIndex < _selectedBandIndexes.Count)
                        {
                            if (_selectedBandIndexes[bandIndex] != _ptCurrentCell.Y)
                            {
                                // deselect currently selected row
                                SetSelectedRowCore(_selectedBandIndexes[bandIndex], false);
                            }
                            else
                            {
                                bandIndex++;
                            }
                        }
                        RemoveIndividuallySelectedCells();
                        if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) == 0)
                        {
                            Debug.Assert(!_selectedBandIndexes.Contains(_ptCurrentCell.Y));
                            SetSelectedRowCore(_ptCurrentCell.Y, true);
                        }
                        return true;
                    }
                }
                finally
                {
                    NoSelectionChangeCount--;
                    if (switchedToBulkPaint)
                    {
                        ExitBulkPaint(-1, -1);
                    }
                }
            }
            return false;
        }

        /// <summary>
        ///  Gets a value indicating whether the Tab key should be processed.
        /// </summary>
        protected bool ProcessTabKey(Keys keyData)
        {
            if (StandardTab)
            {
                if ((keyData & Keys.Control) == Keys.Control)
                {
                    if ((keyData & Keys.Shift) == Keys.Shift)
                    {
                        if (!VisibleCellExists || CurrentCellIsFirstVisibleCell)
                        {
                            // Goto previous control
                            return false;
                        }
                        else
                        {
                            // Goto previous cell
                            return TabToPreviousCell();
                        }
                    }
                    else
                    {
                        if (!VisibleCellExists || CurrentCellIsLastVisibleCell)
                        {
                            // Goto next control
                            return false;
                        }
                        else
                        {
                            // Goto next cell
                            return TabToNextCell();
                        }
                    }
                }
                else
                {
                    return false;
                }
            }
            else
            {
                if ((keyData & Keys.Control) == Keys.Control)
                {
                    return false;
                }
                else
                {
                    if ((keyData & Keys.Shift) == Keys.Shift)
                    {
                        if (!VisibleCellExists || CurrentCellIsFirstVisibleCell)
                        {
                            // Goto previous control
                            return false;
                        }
                        else
                        {
                            // Goto previous cell
                            return TabToPreviousCell();
                        }
                    }
                    else
                    {
                        if (!VisibleCellExists || CurrentCellIsLastVisibleCell)
                        {
                            // Goto next control
                            return false;
                        }
                        else
                        {
                            // Goto next cell
                            return TabToNextCell();
                        }
                    }
                }
            }
        }

        /// <summary>
        ///  Processes keys for dataGridView navigation.
        /// </summary>
        protected virtual bool ProcessDataGridViewKey(KeyEventArgs e)
        {
            switch (e.KeyCode)
            {
                case Keys.Tab:
                    {
                        return ProcessTabKey(e.KeyData);
                    }
                case Keys.Up:
                    {
                        return ProcessUpKey(e.KeyData);
                    }
                case Keys.Down:
                    {
                        return ProcessDownKey(e.KeyData);
                    }
                case Keys.Next:
                    {
                        return ProcessNextKey(e.KeyData);
                    }
                case Keys.Prior:
                    {
                        return ProcessPriorKey(e.KeyData);
                    }
                case Keys.Left:
                    {
                        return ProcessLeftKey(e.KeyData);
                    }
                case Keys.Right:
                    {
                        return ProcessRightKey(e.KeyData);
                    }
                case Keys.F2:
                    {
                        return ProcessF2Key(e.KeyData);
                    }
                case Keys.F3:
                    {
                        return ProcessF3Key(e.KeyData);
                    }
                case Keys.F10:
                    {
                        if (e.Control && e.Shift)
                        {
                            return ProcessControlShiftF10Keys(e.KeyData);
                        }
                        break;
                    }
                case Keys.Home:
                    {
                        return ProcessHomeKey(e.KeyData);
                    }
                case Keys.D0:
                case Keys.NumPad0:
                    {
                        return ProcessZeroKey(e.KeyData);
                    }
                case Keys.Delete:
                    {
                        return ProcessDeleteKey(e.KeyData);
                    }
                case Keys.End:
                    {
                        return ProcessEndKey(e.KeyData);
                    }
                case Keys.Enter:
                    {
                        return ProcessEnterKey(e.KeyData);
                    }
                case Keys.Escape:
                    {
                        return ProcessEscapeKey(e.KeyData);
                    }
                case Keys.A:
                    {
                        return ProcessAKey(e.KeyData);
                    }
                case Keys.C:
                case Keys.Insert:
                    {
                        return ProcessInsertKey(e.KeyData);
                    }
                case Keys.Space:
                    {
                        return ProcessSpaceKey(e.KeyData);
                    }
            }
            return false;
        }

        protected bool ProcessUpKey(Keys keyData)
        {
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            if (firstVisibleColumnIndex == -1 || firstVisibleRowIndex == -1)
            {
                return false;
            }
            int previousVisibleRowIndex = -1;
            if (_ptCurrentCell.Y != -1)
            {
                previousVisibleRowIndex = Rows.GetPreviousRow(_ptCurrentCell.Y, DataGridViewElementStates.Visible);
            }

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (MultiSelect)
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptAnchorCell.X == -1 || _ptCurrentCell.X == -1 ||
                                            IsRowOutOfBounds(firstVisibleRowIndex))
                                        {
                                            return true;
                                        }
                                        Debug.Assert(_ptAnchorCell.Y >= 0);
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, firstVisibleRowIndex);
                                        SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, false, false, false);
                                    }
                                    else
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(firstVisibleRowIndex))
                                        {
                                            return true;
                                        }
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, firstVisibleRowIndex, true);
                                        SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, true, false, false);
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedCellCore(_ptCurrentCell.X, firstVisibleRowIndex, true);
                                    SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, true, false, false);
                                }
                            }
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (previousVisibleRowIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, previousVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    if (MultiSelect)
                                    {
                                        Debug.Assert(_ptAnchorCell.Y >= 0);
                                        if (_ptAnchorCell.Y == -1)
                                        {
                                            return true;
                                        }
                                        int oldEdgeColumnIndex = _ptCurrentCell.X;
                                        int oldEdgeRowIndex = _ptCurrentCell.Y;
                                        UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                            _ptAnchorCell.Y, ref oldEdgeRowIndex, previousVisibleRowIndex);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, previousVisibleRowIndex, true);
                                    }

                                    SetCurrentCellAddressCore(_ptCurrentCell.X, previousVisibleRowIndex, !MultiSelect, false, false);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (previousVisibleRowIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, previousVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedCellCore(_ptCurrentCell.X, previousVisibleRowIndex, true);
                                    SetCurrentCellAddressCore(_ptCurrentCell.X, previousVisibleRowIndex, true, false, false);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (MultiSelect)
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptAnchorCell.X == -1 || _ptCurrentCell.X == -1 ||
                                            IsRowOutOfBounds(firstVisibleRowIndex))
                                        {
                                            return true;
                                        }
                                        ClearSelection();
                                        Debug.Assert(_ptAnchorCell.Y >= 0);
                                        SelectRowRange(firstVisibleRowIndex, _ptAnchorCell.Y, true);
                                        SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, false, false, false);
                                    }
                                    else
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(firstVisibleRowIndex))
                                        {
                                            return true;
                                        }
                                        SetSelectedRowCore(_ptCurrentCell.Y, false);
                                        SetSelectedRowCore(firstVisibleRowIndex, true);
                                        SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, true, false, false);
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedRowCore(firstVisibleRowIndex, true);
                                    SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, true, false, false);
                                }
                            }
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (previousVisibleRowIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, previousVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    if (MultiSelect)
                                    {
                                        if (_ptAnchorCell.Y == -1)
                                        {
                                            return true;
                                        }
                                        if (_ptAnchorCell.Y >= previousVisibleRowIndex)
                                        {
                                            SelectRowRange(previousVisibleRowIndex, _ptAnchorCell.Y, true);
                                        }
                                        else
                                        {
                                            SelectRowRange(_ptAnchorCell.Y, previousVisibleRowIndex, true);
                                        }
                                    }
                                    else
                                    {
                                        SetSelectedRowCore(previousVisibleRowIndex, true);
                                    }

                                    SetCurrentCellAddressCore(_ptCurrentCell.X, previousVisibleRowIndex, !MultiSelect, false, false);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedRowCore(firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (previousVisibleRowIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, previousVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    ClearSelection();
                                    SetSelectedRowCore(previousVisibleRowIndex, true);
                                    SetCurrentCellAddressCore(_ptCurrentCell.X, previousVisibleRowIndex, true, false, false);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (MultiSelect)
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptAnchorCell.X == -1 || _ptCurrentCell.X == -1 ||
                                            IsRowOutOfBounds(firstVisibleRowIndex))
                                        {
                                            return true;
                                        }
                                        Debug.Assert(_ptAnchorCell.Y >= 0);
                                        if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                        {
                                            ClearSelection();
                                            SelectRowRange(firstVisibleRowIndex, _ptAnchorCell.Y, true);
                                        }
                                        else
                                        {
                                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                                _ptAnchorCell.Y, ref oldEdgeRowIndex, firstVisibleRowIndex);
                                        }

                                        SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, false, false, false);
                                    }
                                    else
                                    {
                                        if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                        {
                                            return true;
                                        }
                                        if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(firstVisibleRowIndex))
                                        {
                                            return true;
                                        }
                                        if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                        {
                                            SetSelectedRowCore(_ptCurrentCell.Y, false);
                                            SetSelectedRowCore(firstVisibleRowIndex, true);
                                        }
                                        else
                                        {
                                            SetSelectedCellCore(_ptCurrentCell.X, _ptCurrentCell.Y, false);
                                            SetSelectedCellCore(_ptCurrentCell.X, firstVisibleRowIndex, true);
                                        }

                                        SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, true, false, false);
                                    }
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(firstVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SetSelectedRowCore(firstVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, firstVisibleRowIndex, true);
                                    }

                                    SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, true, false, false);
                                }
                            }
                        }
                        else
                        {
                            if ((keyData & Keys.Shift) == Keys.Shift)
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (previousVisibleRowIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, previousVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        if (MultiSelect)
                                        {
                                            if (_ptAnchorCell.Y == -1)
                                            {
                                                return true;
                                            }
                                            if (_ptAnchorCell.Y >= previousVisibleRowIndex)
                                            {
                                                SelectRowRange(previousVisibleRowIndex, _ptAnchorCell.Y, true);
                                            }
                                            else
                                            {
                                                SelectRowRange(_ptAnchorCell.Y, previousVisibleRowIndex, true);
                                            }
                                        }
                                        SetSelectedRowCore(previousVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        if (MultiSelect)
                                        {
                                            int oldEdgeColumnIndex = _ptCurrentCell.X;
                                            int oldEdgeRowIndex = _ptCurrentCell.Y;
                                            if (_ptAnchorCell.Y == -1)
                                            {
                                                return true;
                                            }
                                            UpdateSelectedCellsBlock(_ptAnchorCell.X, ref oldEdgeColumnIndex, oldEdgeColumnIndex,
                                                _ptAnchorCell.Y, ref oldEdgeRowIndex, previousVisibleRowIndex);
                                        }
                                        else
                                        {
                                            ClearSelection();
                                            SetSelectedCellCore(_ptCurrentCell.X, previousVisibleRowIndex, true);
                                        }
                                    }

                                    SetCurrentCellAddressCore(_ptCurrentCell.X, previousVisibleRowIndex, !MultiSelect, false, false);
                                }
                            }
                            else
                            {
                                if (_ptCurrentCell.X == -1)
                                {
                                    ClearSelection();
                                    SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                                    ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                    if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                    {
                                        return true;
                                    }

                                    SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                                }
                                else
                                {
                                    if (previousVisibleRowIndex == -1)
                                    {
                                        return true;
                                    }
                                    if (!ScrollIntoView(_ptCurrentCell.X, previousVisibleRowIndex, true))
                                    {
                                        return true;
                                    }
                                    if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousVisibleRowIndex))
                                    {
                                        return true;
                                    }
                                    if ((Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Selected) != 0)
                                    {
                                        ClearSelection();
                                        SetSelectedRowCore(previousVisibleRowIndex, true);
                                    }
                                    else
                                    {
                                        ClearSelection();
                                        SetSelectedCellCore(_ptCurrentCell.X, previousVisibleRowIndex, true);
                                    }

                                    SetCurrentCellAddressCore(_ptCurrentCell.X, previousVisibleRowIndex, true, false, false);
                                }
                            }
                        }
                        return true;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if ((keyData & Keys.Control) == Keys.Control)
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }

                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            }
                            else
                            {
                                if (!ScrollIntoView(_ptCurrentCell.X, firstVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(firstVisibleRowIndex))
                                {
                                    return true;
                                }

                                SetCurrentCellAddressCore(_ptCurrentCell.X, firstVisibleRowIndex, true, false, false);
                            }
                        }
                        else
                        {
                            if (_ptCurrentCell.X == -1)
                            {
                                ClearSelection();
                                SetSelectedColumnCore(firstVisibleColumnIndex, true);
                                ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                                {
                                    return true;
                                }

                                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
                            }
                            else
                            {
                                if (previousVisibleRowIndex == -1)
                                {
                                    return true;
                                }
                                if (!ScrollIntoView(_ptCurrentCell.X, previousVisibleRowIndex, true))
                                {
                                    return true;
                                }
                                if (_ptCurrentCell.X == -1 || IsRowOutOfBounds(previousVisibleRowIndex))
                                {
                                    return true;
                                }

                                SetCurrentCellAddressCore(_ptCurrentCell.X, previousVisibleRowIndex, true, false, false);
                            }
                        }
                        return true;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }
            return true;
        }

        protected bool ProcessZeroKey(Keys keyData)
        {
            if (_ptCurrentCell.X != -1 && !IsCurrentCellInEditMode && ColumnEditable(_ptCurrentCell.X))
            {
                DataGridViewCell dataGridViewCell = CurrentCellInternal;
                Debug.Assert(dataGridViewCell != null);

                if (!IsSharedCellReadOnly(dataGridViewCell, _ptCurrentCell.Y) &&
                    (EditMode == DataGridViewEditMode.EditOnKeystroke || EditMode == DataGridViewEditMode.EditOnKeystrokeOrF2) &&
                    dataGridViewCell.EditType != null)
                {
                    bool success = ScrollIntoView(_ptCurrentCell.X, _ptCurrentCell.Y, false);
                    Debug.Assert(success);
                    if (!BeginEditInternal(false /*selectAll*/))
                    {
                        return false;
                    }
                }
            }

            if ((keyData & (Keys.Alt | Keys.Shift | Keys.Control)) == Keys.Control &&
                IsCurrentCellInEditMode)
            {
                DataGridViewCell dataGridViewCurrentCell = CurrentCellInternal;
                Debug.Assert(dataGridViewCurrentCell != null);
                object nullValue = dataGridViewCurrentCell.GetInheritedStyle(null, _ptCurrentCell.Y, false).NullValue;
                if (nullValue is null ||
                    (dataGridViewCurrentCell.FormattedValueType != null && dataGridViewCurrentCell.FormattedValueType.IsAssignableFrom(nullValue.GetType())))
                {
                    if (EditingControl != null)
                    {
                        ((IDataGridViewEditingControl)EditingControl).EditingControlFormattedValue = nullValue;
                        ((IDataGridViewEditingControl)EditingControl).EditingControlValueChanged = true;
                        ((IDataGridViewEditingControl)EditingControl).PrepareEditingControlForEdit(true /*selectAll*/);
                    }
                    else
                    {
                        Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                        IDataGridViewEditingCell dataGridViewEditingCell = dataGridViewCurrentCell as IDataGridViewEditingCell;
                        Debug.Assert(dataGridViewEditingCell != null);
                        dataGridViewEditingCell.EditingCellFormattedValue = nullValue;
                        dataGridViewEditingCell.EditingCellValueChanged = true;
                        dataGridViewEditingCell.PrepareEditingCellForEdit(true /*selectAll*/);
                        InvalidateCellPrivate(_ptCurrentCell.X, _ptCurrentCell.Y);
                    }
                    NotifyCurrentCellDirty(true);
                    return true;
                }
                return false;
            }
            return false;
        }

        private void PushAllowUserToAddRows()
        {
            if (AllowUserToAddRowsInternal)
            {
                if (Columns.Count > 0 && NewRowIndex == -1)
                {
                    AddNewRow(false);
                }
            }
            else if (NewRowIndex != -1)
            {
                // Delete the 'new' row
                Debug.Assert(NewRowIndex == Rows.Count - 1);
                Rows.RemoveAtInternal(NewRowIndex, false /*force*/);
            }
        }

        private bool PushFormattedValue(ref DataGridViewCell dataGridViewCurrentCell, object formattedValue, out Exception exception)
        {
            Debug.Assert(IsCurrentCellInEditMode);

            exception = null;

            DataGridViewCellStyle cellStyle = InheritedEditingCellStyle;

            DataGridViewCellParsingEventArgs dgvcpe = OnCellParsing(_ptCurrentCell.Y,
                                                                    _ptCurrentCell.X,
                                                                    formattedValue,
                                                                    dataGridViewCurrentCell.ValueType,
                                                                    cellStyle);
            if (dgvcpe.ParsingApplied &&
                dgvcpe.Value != null &&
                dataGridViewCurrentCell.ValueType != null &&
                dataGridViewCurrentCell.ValueType.IsAssignableFrom(dgvcpe.Value.GetType()))
            {
                if (dataGridViewCurrentCell.RowIndex == -1)
                {
                    dataGridViewCurrentCell = Rows[_ptCurrentCell.Y].Cells[_ptCurrentCell.X]; // unsharing the row before pushing the new value
                }
                return dataGridViewCurrentCell.SetValueInternal(_ptCurrentCell.Y, dgvcpe.Value);
            }

            object val;
            try
            {
                val = dataGridViewCurrentCell.ParseFormattedValue(formattedValue, dgvcpe.InheritedCellStyle, null, null);
            }
            catch (Exception e)
            {
                if (ClientUtils.IsCriticalException(e))
                {
                    throw;
                }
                exception = e;
                return false;
            }
            if (dataGridViewCurrentCell.RowIndex == -1)
            {
                dataGridViewCurrentCell = Rows[_ptCurrentCell.Y].Cells[_ptCurrentCell.X]; // unsharing the row before pushing the new value
            }
            return dataGridViewCurrentCell.SetValueInternal(_ptCurrentCell.Y, val);
        }

        private void RecordCellMouseClick(DataGridViewCellMouseEventArgs dgvcme)
        {
            Debug.Assert(dgvcme.Clicks == 1);
            _lastMouseClickInfo.Button = dgvcme.Button;
            _lastMouseClickInfo.TimeStamp = DateTime.Now.Ticks;
            _lastMouseClickInfo.X = dgvcme.X;
            _lastMouseClickInfo.Y = dgvcme.Y;
            _lastMouseClickInfo.Col = dgvcme.ColumnIndex;
            _lastMouseClickInfo.Row = dgvcme.RowIndex;
        }

        private void RefreshColumnsAndRows()
        {
            Rows.ClearInternal(false /*recreateNewRow*/);
            RefreshColumns();
            RefreshRows(true /*scrollIntoView*/);
        }

        private void RefreshColumns()
        {
            // if AutoGenerateColumns == true then:
            // 1. remove the columns which were previously bound
            // 2. add new columns based on data source
            //

            bool startUpdateInternal = Visible;
            if (startUpdateInternal)
            {
                BeginUpdateInternal();
            }

            _dataGridViewOper[OperationInRefreshColumns] = true;
            try
            {
                DataGridViewColumnCollection dataGridViewCols = Columns;
                DataGridViewColumn[] boundColumns = null;

                if (DataConnection != null)
                {
                    boundColumns = DataConnection.GetCollectionOfBoundDataGridViewColumns();
                }

                if (AutoGenerateColumns)
                {
                    AutoGenerateDataBoundColumns(boundColumns);
                }
                else
                {
                    for (int j = 0; j < dataGridViewCols.Count; j++)
                    {
                        // when we refresh the columns, always clear whatever binding information we had on the columns
                        dataGridViewCols[j].IsDataBoundInternal = false;
                        dataGridViewCols[j].BoundColumnIndex = -1;
                        dataGridViewCols[j].BoundColumnConverter = null;
                        // set up the columns which have DataPropertyName set to something
                        if (DataSource != null && dataGridViewCols[j].DataPropertyName.Length != 0)
                        {
                            MapDataGridViewColumnToDataBoundField(dataGridViewCols[j]);
                        }
                    }
                }

                if (DataSource != null)
                {
                    DataConnection.ApplySortingInformationFromBackEnd();
                }
            }
            finally
            {
                _dataGridViewOper[OperationInRefreshColumns] = false;

                if (startUpdateInternal)
                {
                    EndUpdateInternal(false);
                    Invalidate(true);
                }
            }
        }

        //  Returns true for success, and false if an OnDataError event was raised and cancelled the operation (e.Cancel = true).
        public bool RefreshEdit()
        {
            if (_ptCurrentCell.X != -1 && IsCurrentCellInEditMode)
            {
                Debug.Assert(_ptCurrentCell.Y != -1);
                DataGridViewCell dataGridViewCurrentCell = CurrentCellInternal;
                DataGridViewCellStyle dataGridViewCellStyle = dataGridViewCurrentCell.GetInheritedStyle(null, _ptCurrentCell.Y, true);
                if (EditingControl != null)
                {
                    if (InitializeEditingControlValue(ref dataGridViewCellStyle, dataGridViewCurrentCell))
                    {
                        if (((IDataGridViewEditingControl)EditingControl).RepositionEditingControlOnValueChange)
                        {
                            PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                        }
                        ((IDataGridViewEditingControl)EditingControl).PrepareEditingControlForEdit(true /*selectAll*/);
                        ((IDataGridViewEditingControl)EditingControl).EditingControlValueChanged = false;
                        IsCurrentCellDirtyInternal = false;
                        return true;
                    }
                    return false;
                }
                else
                {
                    Debug.Assert(_dataGridViewState1[State1_CurrentCellInEditMode]);
                    if (InitializeEditingCellValue(ref dataGridViewCellStyle, ref dataGridViewCurrentCell))
                    {
                        IDataGridViewEditingCell dataGridViewEditingCell = dataGridViewCurrentCell as IDataGridViewEditingCell;
                        Debug.Assert(dataGridViewEditingCell != null);
                        dataGridViewEditingCell.PrepareEditingCellForEdit(true /*selectAll*/);
                        dataGridViewEditingCell.EditingCellValueChanged = false;
                        IsCurrentCellDirtyInternal = false;
                        return true;
                    }
                    return false;
                }
            }
            return true;
        }

        private void RefreshRows(bool scrollIntoView)
        {
            bool startBeginUpdate = Visible;
            if (startBeginUpdate)
            {
                BeginUpdateInternal();
            }

            try
            {
                if (_dataGridViewOper[OperationInCurrentCellChange])
                {
                    _dataGridViewState2[State2_RowsCollectionClearedInSetCell] = true;
                }

                // Clear existing rows
                Rows.ClearInternal(true /*recreateNewRow*/);

                // Add a row for each object in the data source
                if (DataConnection != null && Columns.Count > 0)
                {
                    IList list = DataConnection.List;
                    if (list != null && list.Count > 0)
                    {
                        int rowsCount = list.Count;
                        bool oldDoNotChangePositionInTheCurrencyManager = DataConnection.DoNotChangePositionInTheCurrencyManager;

                        // scroll into view when we have a non-empty list
                        // and the layout is not dirty and we are not in a sort operation.
                        bool matchPositionInCurrencyManagerAfterRecreatingRows = !_layout._dirty && !InSortOperation;

                        if (matchPositionInCurrencyManagerAfterRecreatingRows)
                        {
                            // Prevent the data connection from changing position in the currency manager.
                            // But only if the data grid view will set the position in the currency manager after recreating the rows collection.
                            DataConnection.DoNotChangePositionInTheCurrencyManager = true;
                        }
                        try
                        {
                            Rows.AddInternal(RowTemplateClone);
                            Debug.Assert(list.Count == rowsCount);
                            if (rowsCount > 1)
                            {
                                Rows.AddCopiesInternal(0, rowsCount - 1);
                            }
                            // Add selected Columns back in selectedBandIndexes
                            foreach (DataGridViewColumn column in Columns)
                            {
                                if (column.Selected && (!_selectedBandIndexes.Contains(column.Index)))
                                {
                                    _selectedBandIndexes.Add(column.Index);
                                }
                            }
                        }
                        finally
                        {
                            DataConnection.DoNotChangePositionInTheCurrencyManager = oldDoNotChangePositionInTheCurrencyManager;
                        }

                        if (matchPositionInCurrencyManagerAfterRecreatingRows)
                        {
                            DataConnection.MatchCurrencyManagerPosition(scrollIntoView, true /*clearSelection*/);
                        }
                    }
                }
            }
            finally
            {
                if (startBeginUpdate)
                {
                    EndUpdateInternal(false);
                    Invalidate(true);
                }
            }
        }

        private void RealeaseMouse()
        {
            Cursor.Clip = Rectangle.Empty;
            Capture = false;
        }

        private void RemoveIndividualReadOnlyCellsInColumn(int columnIndex)
        {
            int cellIndex = 0;
            while (cellIndex < _individualReadOnlyCells.Count)
            {
                DataGridViewCell dataGridViewCell = _individualReadOnlyCells[cellIndex];
                if (dataGridViewCell.ColumnIndex == columnIndex)
                {
                    SetReadOnlyCellCore(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex, false);
                }
                else
                {
                    cellIndex++;
                }
            }
        }

        private void RemoveIndividualReadOnlyCellsInRow(int rowIndex)
        {
            int cellIndex = 0;
            while (cellIndex < _individualReadOnlyCells.Count)
            {
                DataGridViewCell dataGridViewCell = _individualReadOnlyCells[cellIndex];
                if (dataGridViewCell.RowIndex == rowIndex)
                {
                    SetReadOnlyCellCore(dataGridViewCell.ColumnIndex, rowIndex, false);
                }
                else
                {
                    cellIndex++;
                }
            }
        }

        private void RemoveIndividuallySelectedCells()
        {
            Debug.Assert(_noSelectionChangeCount > 0);
            bool switchedToBulkPaint = false;
            if (_individualSelectedCells.Count > BulkPaintThreshold)
            {
                _inBulkPaintCount++;
                switchedToBulkPaint = true;
            }
            try
            {
                while (_individualSelectedCells.Count > 0)
                {
                    DataGridViewCell dataGridViewCell = _individualSelectedCells.HeadCell;
                    SetSelectedCellCore(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex, false);
                }
            }
            finally
            {
                if (switchedToBulkPaint)
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        private void RemoveIndividuallySelectedCells(int columnIndexException, int rowIndexException)
        {
            Debug.Assert(_noSelectionChangeCount > 0);
            bool switchedToBulkPaint = false;
            if (_individualSelectedCells.Count > BulkPaintThreshold)
            {
                _inBulkPaintCount++;
                switchedToBulkPaint = true;
            }
            try
            {
                while (_individualSelectedCells.Count > 0)
                {
                    DataGridViewCell dataGridViewCell = _individualSelectedCells.HeadCell;
                    if (dataGridViewCell.ColumnIndex != columnIndexException || dataGridViewCell.RowIndex != rowIndexException)
                    {
                        SetSelectedCellCore(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex, false);
                    }
                    else
                    {
                        while (_individualSelectedCells.Count > 1)
                        {
                            dataGridViewCell = _individualSelectedCells[1];
                            Debug.Assert(dataGridViewCell.ColumnIndex != columnIndexException || dataGridViewCell.RowIndex != rowIndexException);
                            SetSelectedCellCore(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex, false);
                        }
                        break;
                    }
                }
            }
            finally
            {
                if (switchedToBulkPaint)
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        private void RemoveIndividuallySelectedCellsInColumn(int columnIndex)
        {
            Debug.Assert(_noSelectionChangeCount > 0);
            int cellIndex = 0;
            int cellCountInColumn = 0;
            bool switchToBulkOperation = false;
            DataGridViewCell dataGridViewCell;

            while (cellIndex < _individualSelectedCells.Count)
            {
                dataGridViewCell = _individualSelectedCells[cellIndex];
                if (dataGridViewCell.ColumnIndex == columnIndex)
                {
                    SetSelectedCellCore(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex, false);
                    cellCountInColumn++;
                    if (cellCountInColumn > BulkPaintThreshold)
                    {
                        switchToBulkOperation = true;
                        break;
                    }
                }
                else
                {
                    cellIndex++;
                }
            }

            if (switchToBulkOperation)
            {
                _inBulkPaintCount++;
                try
                {
                    while (cellIndex < _individualSelectedCells.Count)
                    {
                        dataGridViewCell = _individualSelectedCells[cellIndex];
                        if (dataGridViewCell.ColumnIndex == columnIndex)
                        {
                            SetSelectedCellCore(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex, false);
                        }
                        else
                        {
                            cellIndex++;
                        }
                    }
                }
                finally
                {
                    ExitBulkPaint(columnIndex, -1);
                }
            }
        }

        private void RemoveIndividuallySelectedCellsInRow(int rowIndex)
        {
            Debug.Assert(_noSelectionChangeCount > 0);
            // Since there are typically not many columns in a row, we don't try to switch into a bulk operation
            // as we do in RemoveIndividuallySelectedCellsInColumn.
            int cellIndex = 0;
            while (cellIndex < _individualSelectedCells.Count)
            {
                DataGridViewCell dataGridViewCell = _individualSelectedCells[cellIndex];
                if (dataGridViewCell.RowIndex == rowIndex)
                {
                    SetSelectedCellCore(dataGridViewCell.ColumnIndex, dataGridViewCell.RowIndex, false);
                }
                else
                {
                    cellIndex++;
                }
            }
        }

        // Required by the Designer
        private void ResetBackgroundColor() => BackgroundColor = s_defaultBackgroundColor;

        // Required by the Designer
        private void ResetGridColor() => GridColor = DefaultGridColor;

        [EditorBrowsable(EditorBrowsableState.Never)]
        public override void ResetText() => base.ResetText();

        /// <summary>
        ///  Re-initializes all tracking related state.
        /// </summary>
        private void ResetTrackingState()
        {
            if (IsKeyboardOperationActive())
            {
                return;
            }
            if (_horizScrollTimer != null && _horizScrollTimer.Enabled)
            {
                _horizScrollTimer.Enabled = false;
            }
            if (_vertScrollTimer != null && _vertScrollTimer.Enabled)
            {
                _vertScrollTimer.Enabled = false;
            }

            _dataGridViewOper[OperationMouseOperationMask] = false;
            _dataGridViewOper[OperationTrackColSelect] = false;
            _dataGridViewOper[OperationTrackRowSelect] = false;
            _dataGridViewOper[OperationTrackCellSelect] = false;
            _trackColumn = -1;
            _trackRow = -1;
            _ptMouseDownCell.X = -2;
            _ptMouseDownCell.Y = -2;

            if (_currentRowSplitBar != -1)
            {
                Invalidate(CalcRowResizeFeedbackRect(_currentRowSplitBar), true);
                _lastRowSplitBar = _currentRowSplitBar = -1;
            }
            if (_currentColSplitBar != -1)
            {
                Invalidate(CalcColResizeFeedbackRect(_currentColSplitBar), true);
                _lastColSplitBar = _currentColSplitBar = -1;
            }
            if (_lastHeaderShadow != -1)
            {
                _dataGridViewState2[State2_ShowColumnRelocationInsertion] = false;
                _trackColumnEdge = -1;
                _lastHeaderShadow = -1;
                Invalidate(Rectangle.Union(_layout.TopLeftHeader, _layout.ColumnHeaders));
            }
            RealeaseMouse();
        }

        // Re-initializes all state that is related to tracking keyboard operations
        private void ResetKeyboardTrackingState()
        {
            if (IsMouseOperationActive())
            {
                return;
            }
            _dataGridViewOper[OperationKeyboardOperationMask] = false;
            _trackColumn = -1;
            if (_currentColSplitBar != -1)
            {
                Invalidate(CalcColResizeFeedbackRect(_currentColSplitBar), true);
                _lastColSplitBar = _currentColSplitBar = -1;
            }
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private bool IsMouseOperationActive()
        {
            return (_dataGridViewOper.Data & OperationMouseOperationMask) != 0;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private bool IsKeyboardOperationActive()
        {
            return (_dataGridViewOper.Data & OperationKeyboardOperationMask) != 0;
        }

        /// <summary>
        ///  Re-initializes all UI related state.
        /// </summary>
        internal void ResetUIState(bool useRowShortcut, bool computeVisibleRows)
        {
            PerformLayoutPrivate(useRowShortcut, computeVisibleRows, true /*invalidInAdjustFillingColumns*/, !useRowShortcut /*repositionEditingControl*/);
            if (!useRowShortcut)
            {
                Invalidate();
                InvalidateScrollBars();
            }
        }

        private void RestoreRowsCachedThickness()
        {
            // Switch to batch operation
            _inBulkPaintCount++;
            _inBulkLayoutCount++;
            try
            {
                // Only height of visible rows are restored since invisible rows are not autosized.
                for (int rowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                    rowIndex != -1;
                    rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible))
                {
                    DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
                    dataGridViewRow.GetHeightInfo(rowIndex, out int height, out int minimumHeight);
                    if (height != dataGridViewRow.CachedThickness &&
                        !OnRowHeightInfoPushed(rowIndex, dataGridViewRow.CachedThickness, minimumHeight))
                    {
                        dataGridViewRow.ThicknessInternal = dataGridViewRow.CachedThickness;
                    }
                }
            }
            finally
            {
                ExitBulkLayout(true /*invalidInAdjustFillingColumns*/);
                ExitBulkPaint(-1, -1);
            }
        }

        // we need to access the GetRowState, otherwise we would unshare the row
        private bool RowIsResizable(int rowIndex)
        {
            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
            if ((rowState & DataGridViewElementStates.ResizableSet) == DataGridViewElementStates.ResizableSet)
            {
                return (rowState & DataGridViewElementStates.Resizable) == DataGridViewElementStates.Resizable;
            }
            else
            {
                return AllowUserToResizeRows;
            }
        }

        private bool RowNeedsDisplayedState(int rowIndex, int lastDisplayedFrozenRowIndex, int lastDisplayedScrollingRowIndex)
        {
            Debug.Assert(rowIndex >= 0);
            Debug.Assert(rowIndex < Rows.Count);

            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);

            if ((rowState & DataGridViewElementStates.Visible) == 0)
            {
                return false;
            }

            if ((rowState & DataGridViewElementStates.Frozen) != 0)
            {
                return rowIndex <= lastDisplayedFrozenRowIndex;
            }
            else if (DisplayedBandsInfo.FirstDisplayedScrollingRow != -1 &&
                     rowIndex >= DisplayedBandsInfo.FirstDisplayedScrollingRow &&
                     rowIndex <= lastDisplayedScrollingRowIndex)
            {
                return true;
            }
            return false;
        }

        private void ScrollBar_MouseEnter(object sender, EventArgs e)
        {
            if (_dataGridViewState2[State2_MouseEnterExpected])
            {
                OnMouseEnter(EventArgs.Empty);
            }
            UpdateMouseEnteredCell(hti: null, e: null);
        }

        private void ScrollBar_MouseLeave(object sender, EventArgs e)
        {
            UpdateMouseEnteredCell(hti: null, e: null);
            Point ptMouse = PointToClient(Control.MousePosition);
            if (!ClientRectangle.Contains(ptMouse))
            {
                OnMouseLeave(EventArgs.Empty);
            }
        }

        private bool ScrollColumnIntoView(int columnIndex, int rowIndex, bool committed, bool forCurrentCellChange)
        {
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count);

            if (DisplayedBandsInfo.FirstDisplayedScrollingCol != -1 &&
                !Columns[columnIndex].Frozen &&
                (columnIndex != DisplayedBandsInfo.FirstDisplayedScrollingCol || FirstDisplayedScrollingColumnHiddenWidth > 0))
            {
                int columnsToScroll;
                if (Columns.DisplayInOrder(columnIndex, DisplayedBandsInfo.FirstDisplayedScrollingCol))
                {
                    if (!committed && _ptCurrentCell.X >= 0 &&
                        !CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                    forCurrentCellChange && (_ptCurrentCell.X != columnIndex || _ptCurrentCell.Y != rowIndex),
                                    _ptCurrentCell.Y != rowIndex /*forCurrentRowChange*/))
                    {
                        return false;
                    }

                    columnsToScroll = Columns.GetColumnCount(DataGridViewElementStates.Visible, columnIndex, DisplayedBandsInfo.FirstDisplayedScrollingCol);
                    if (FirstDisplayedScrollingColumnHiddenWidth > 0)
                    {
                        columnsToScroll++;
                    }
                    ScrollColumns(-columnsToScroll);
                }
                else if (columnIndex == DisplayedBandsInfo.FirstDisplayedScrollingCol && FirstDisplayedScrollingColumnHiddenWidth > 0)
                {
                    if (!committed && _ptCurrentCell.X >= 0 &&
                        !CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                    forCurrentCellChange && (_ptCurrentCell.X != columnIndex || _ptCurrentCell.Y != rowIndex),
                                    _ptCurrentCell.Y != rowIndex /*forCurrentRowChange*/))
                    {
                        return false;
                    }
                    ScrollColumns(-1);
                }
                else if (DisplayedBandsInfo.LastTotallyDisplayedScrollingCol == -1 ||
                         (DisplayedBandsInfo.LastTotallyDisplayedScrollingCol != columnIndex &&
                          Columns.DisplayInOrder(DisplayedBandsInfo.LastTotallyDisplayedScrollingCol, columnIndex)))
                {
                    if (!committed && _ptCurrentCell.X >= 0 &&
                        !CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                    forCurrentCellChange && (_ptCurrentCell.X != columnIndex || _ptCurrentCell.Y != rowIndex),
                                    _ptCurrentCell.Y != rowIndex /*forCurrentRowChange*/))
                    {
                        return false;
                    }

                    columnsToScroll = 0;
                    int firstDisplayedScrollingColumn = DisplayedBandsInfo.FirstDisplayedScrollingCol;
                    int xColumnRightEdge;

                    if (RightToLeftInternal)
                    {
                        xColumnRightEdge = GetColumnXFromIndex(columnIndex) - Columns[columnIndex].Width;
                        while (xColumnRightEdge < _layout.Data.X && Columns.DisplayInOrder(firstDisplayedScrollingColumn, columnIndex))
                        {
                            xColumnRightEdge += Columns[firstDisplayedScrollingColumn].Width;
                            if (firstDisplayedScrollingColumn == DisplayedBandsInfo.FirstDisplayedScrollingCol)
                            {
                                xColumnRightEdge -= FirstDisplayedScrollingColumnHiddenWidth;
                            }
                            columnsToScroll++;
                            if (xColumnRightEdge < _layout.Data.X)
                            {
                                firstDisplayedScrollingColumn = Columns.GetNextColumn(Columns[firstDisplayedScrollingColumn],
                                                                                           DataGridViewElementStates.Visible,
                                                                                           DataGridViewElementStates.None).Index;
                            }
                        }
                    }
                    else
                    {
                        xColumnRightEdge = GetColumnXFromIndex(columnIndex) + Columns[columnIndex].Width;
                        while (xColumnRightEdge > _layout.Data.Right && Columns.DisplayInOrder(firstDisplayedScrollingColumn, columnIndex))
                        {
                            xColumnRightEdge -= Columns[firstDisplayedScrollingColumn].Width;
                            if (firstDisplayedScrollingColumn == DisplayedBandsInfo.FirstDisplayedScrollingCol)
                            {
                                xColumnRightEdge += FirstDisplayedScrollingColumnHiddenWidth;
                            }
                            columnsToScroll++;
                            if (xColumnRightEdge > _layout.Data.Right)
                            {
                                firstDisplayedScrollingColumn = Columns.GetNextColumn(Columns[firstDisplayedScrollingColumn],
                                                                                           DataGridViewElementStates.Visible,
                                                                                           DataGridViewElementStates.None).Index;
                            }
                        }
                    }
                    if (columnsToScroll != 0)
                    {
                        ScrollColumns(columnsToScroll);
                    }
                }
            }
            return true;
        }

        private void ScrollColumns(int columns)
        {
            DataGridViewColumn newFirstVisibleScrollingCol = null;
            DataGridViewColumn dataGridViewColumnTmp;
            int colCount = 0;
            if (columns > 0)
            {
                if (DisplayedBandsInfo.LastTotallyDisplayedScrollingCol >= 0)
                {
                    dataGridViewColumnTmp = Columns[DisplayedBandsInfo.LastTotallyDisplayedScrollingCol];
                    while (colCount < columns && dataGridViewColumnTmp != null)
                    {
                        dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp,
                            DataGridViewElementStates.Visible,
                            DataGridViewElementStates.None);
                        colCount++;
                    }

                    if (dataGridViewColumnTmp is null)
                    {
                        // no more column to display on the right of the last totally seen column
                        return;
                    }
                }
                Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0);
                dataGridViewColumnTmp = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
                colCount = 0;
                while (colCount < columns && dataGridViewColumnTmp != null)
                {
                    dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.None);
                    colCount++;
                }
                newFirstVisibleScrollingCol = dataGridViewColumnTmp;
            }

            if (columns < 0)
            {
                Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingCol >= 0);
                dataGridViewColumnTmp = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
                if (FirstDisplayedScrollingColumnHiddenWidth > 0)
                {
                    colCount++;
                }
                while (colCount < -columns && dataGridViewColumnTmp != null)
                {
                    dataGridViewColumnTmp = Columns.GetPreviousColumn(dataGridViewColumnTmp,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.Frozen);
                    colCount++;
                }
                newFirstVisibleScrollingCol = dataGridViewColumnTmp;
                if (newFirstVisibleScrollingCol is null)
                {
                    if (FirstDisplayedScrollingColumnHiddenWidth == 0)
                    {
                        // no more column to display on the left of the first seen column
                        FlushDisplayedChanged();
                        return;
                    }
                    else
                    {
                        newFirstVisibleScrollingCol = Columns[DisplayedBandsInfo.FirstDisplayedScrollingCol];
                    }
                }
            }

            int newColOffset = 0;
            for (DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible,
                     DataGridViewElementStates.Frozen);
                dataGridViewColumn != newFirstVisibleScrollingCol;
                dataGridViewColumn = Columns.GetNextColumn(dataGridViewColumn,
                DataGridViewElementStates.Visible,
                DataGridViewElementStates.None))
            {
                newColOffset += dataGridViewColumn.Thickness;
            }

            HorizontalOffset = newColOffset;
        }

        private bool ScrollIntoView(int columnIndex, int rowIndex, bool forCurrentCellChange)
        {
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count);
            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingCol >= -1 && DisplayedBandsInfo.FirstDisplayedScrollingCol < Columns.Count);
            Debug.Assert(DisplayedBandsInfo.LastTotallyDisplayedScrollingCol >= -1 && DisplayedBandsInfo.LastTotallyDisplayedScrollingCol < Columns.Count);
            Debug.Assert(rowIndex >= 0 && rowIndex < Rows.Count);
            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= -1 && DisplayedBandsInfo.FirstDisplayedScrollingRow < Rows.Count);
            Debug.Assert(Columns[columnIndex].Visible);
            Debug.Assert((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) != 0);

            bool committed = false;
            if (_ptCurrentCell.X >= 0 &&
                (_ptCurrentCell.X != columnIndex || _ptCurrentCell.Y != rowIndex))
            {
                if (!CommitEditForOperation(columnIndex, rowIndex, forCurrentCellChange))
                {
                    return false;
                }
                committed = true;
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    return false;
                }
            }

            //scroll horizontally
            if (!ScrollColumnIntoView(columnIndex, rowIndex, committed, forCurrentCellChange))
            {
                return false;
            }

            if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
            {
                return false;
            }

            //scroll vertically
            return ScrollRowIntoView(columnIndex, rowIndex, committed, forCurrentCellChange);
        }

        private void ScrollRectangles(RECT[] rects, int change)
        {
            if (rects != null)
            {
                if (MouseButtons != MouseButtons.None)
                {
                    _dataGridViewState1[State1_ScrolledSinceMouseDown] = true;
                }

                RECT scroll;
                for (int r = 0; r < rects.Length; r++)
                {
                    scroll = rects[r];
                    User32.ScrollWindow(
                        this,
                        change,
                        0,
                        ref scroll,
                        ref scroll);
                }
            }
        }

        private bool ScrollRowIntoView(int columnIndex, int rowIndex, bool committed, bool forCurrentCellChange)
        {
            Debug.Assert(rowIndex >= 0 && rowIndex < Rows.Count);

            if ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Frozen) == 0)
            {
                int rowsToScroll;
                if (rowIndex < DisplayedBandsInfo.FirstDisplayedScrollingRow)
                {
                    if (!committed && _ptCurrentCell.X >= 0 &&
                        !CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                    forCurrentCellChange && (_ptCurrentCell.X != columnIndex || _ptCurrentCell.Y != rowIndex),
                                    _ptCurrentCell.Y != rowIndex /*forCurrentRowChange*/))
                    {
                        return false;
                    }

                    rowsToScroll = Rows.GetRowCount(DataGridViewElementStates.Visible, rowIndex, DisplayedBandsInfo.FirstDisplayedScrollingRow);
                    ScrollRowsByCount(-rowsToScroll, rowsToScroll > 1 ? ScrollEventType.LargeDecrement : ScrollEventType.SmallDecrement);
                }
                else if (DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0 &&
                         rowIndex > DisplayedBandsInfo.FirstDisplayedScrollingRow)
                {
                    rowsToScroll = 0;
                    int firstDisplayedScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                    int yRowBottomEdge = GetRowYFromIndex(rowIndex) + Rows.SharedRow(rowIndex).GetHeight(rowIndex);
                    while (yRowBottomEdge > _layout.Data.Bottom && rowIndex > firstDisplayedScrollingRow)
                    {
                        yRowBottomEdge -= Rows.SharedRow(firstDisplayedScrollingRow).GetHeight(firstDisplayedScrollingRow);
                        rowsToScroll++;
                        if (yRowBottomEdge > _layout.Data.Bottom)
                        {
                            firstDisplayedScrollingRow = Rows.GetNextRow(firstDisplayedScrollingRow, DataGridViewElementStates.Visible);
                            Debug.Assert(firstDisplayedScrollingRow != -1);
                        }
                    }
                    if (rowsToScroll != 0)
                    {
                        if (!committed && _ptCurrentCell.X >= 0 &&
                            !CommitEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.Scroll,
                                        forCurrentCellChange && (_ptCurrentCell.X != columnIndex || _ptCurrentCell.Y != rowIndex),
                                        _ptCurrentCell.Y != rowIndex /*forCurrentRowChange*/))
                        {
                            return false;
                        }
                        ScrollRowsByCount(rowsToScroll, rowsToScroll > 1 ? ScrollEventType.LargeIncrement : ScrollEventType.SmallIncrement);
                    }
                }
            }
            return true;
        }

        private void ScrollRows(int rowCount, int deltaY, ScrollEventType scrollEventType)
        {
            bool invalidateTopOfRowHeaders = false;
            Debug.Assert(rowCount != 0);
            Debug.Assert(deltaY != 0);
            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen));
            VerticalScrollingOffset -= deltaY;
            if (_vertScrollBar.Enabled)
            {
                _vertScrollBar.Value = VerticalScrollingOffset;
            }
            ClearRegionCache();
            int frozenRowsThickness = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            Rectangle rowsRect = _layout.Data;
            if (_layout.RowHeadersVisible)
            {
                rowsRect = Rectangle.Union(rowsRect, _layout.RowHeaders);
                if (SingleHorizontalBorderAdded)
                {
                    rowsRect.Y++;
                    rowsRect.Height--;
                    invalidateTopOfRowHeaders = true;
                }
            }
            else if (SingleVerticalBorderAdded)
            {
                Debug.Assert(rowsRect.X > 0);
                rowsRect.X--;
                rowsRect.Width++;
            }
            rowsRect.Y += frozenRowsThickness;
            rowsRect.Height -= frozenRowsThickness;
            Debug.Assert(rowsRect.Height >= 0);

            if (EditingControl != null &&
                (Rows.GetRowState(_ptCurrentCell.Y) & DataGridViewElementStates.Frozen) == 0)
            {
                Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow > -1);
                PositionEditingControl(true /*setLocation*/, false /*setSize*/, false /*setFocus*/);
            }

            if (MouseButtons != MouseButtons.None)
            {
                _dataGridViewState1[State1_ScrolledSinceMouseDown] = true;
            }

            // The mouse probably is not over the same cell after the scroll.
            UpdateMouseEnteredCell(hti: null, e: null);

            RECT scrollArea = rowsRect;
            User32.ScrollWindow(this, 0, deltaY, ref scrollArea, ref scrollArea);
            if (invalidateTopOfRowHeaders)
            {
                rowsRect.X = _layout.Inside.X;
                rowsRect.Y = _layout.Inside.Y;
                rowsRect.Width = _layout.RowHeaders.Width;
                rowsRect.Height = 1;
                Invalidate(rowsRect);
            }
            if (!_dataGridViewState2[State2_StopRaisingVerticalScroll])
            {
                Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                int firstVisibleScrollingRow = Rows.GetFirstRow(DataGridViewElementStates.Visible, DataGridViewElementStates.Frozen);
                Debug.Assert(firstVisibleScrollingRow != -1);
                int newScrolledOffRowCount = Rows.GetRowCount(DataGridViewElementStates.Visible, firstVisibleScrollingRow, DisplayedBandsInfo.FirstDisplayedScrollingRow);
                Debug.Assert(newScrolledOffRowCount >= rowCount);
                OnScroll(scrollEventType, newScrolledOffRowCount - rowCount, newScrolledOffRowCount, ScrollOrientation.VerticalScroll);
            }
        }

        private void ScrollRowsByCount(int rows, ScrollEventType scrollEventType)
        {
            Debug.Assert(rows != 0);
            Debug.Assert((rows > 0 && (scrollEventType == ScrollEventType.SmallIncrement || scrollEventType == ScrollEventType.LargeIncrement)) ||
                         (rows < 0 && (scrollEventType == ScrollEventType.SmallDecrement || scrollEventType == ScrollEventType.LargeDecrement)));

            int deltaY = 0;
            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
            int newFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
            if (rows > 0)
            {
                for (int rowCount = rows; rowCount > 0; rowCount--)
                {
                    deltaY -= Rows.SharedRow(newFirstVisibleScrollingRow).GetHeight(newFirstVisibleScrollingRow);
                    newFirstVisibleScrollingRow = Rows.GetNextRow(newFirstVisibleScrollingRow,
                        DataGridViewElementStates.Visible);

                    Debug.Assert(newFirstVisibleScrollingRow != -1);
                }
                if (newFirstVisibleScrollingRow != -1)
                {
                    int oldFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                    // Tentative target value for this.displayedBandsInfo.FirstDisplayedScrollingRow.
                    DisplayedBandsInfo.FirstDisplayedScrollingRow = newFirstVisibleScrollingRow;
                    // This sets the actual value of this.displayedBandsInfo.FirstDisplayedScrollingRow
                    ComputeVisibleRows();
                    // Compute the actual deltaY given the new this.displayedBandsInfo.FirstDisplayedScrollingRow
                    if (DisplayedBandsInfo.FirstDisplayedScrollingRow > oldFirstVisibleScrollingRow)
                    {
                        deltaY = -Rows.GetRowsHeight(DataGridViewElementStates.Visible, oldFirstVisibleScrollingRow, DisplayedBandsInfo.FirstDisplayedScrollingRow);
                        rows = Rows.GetRowCount(DataGridViewElementStates.Visible, oldFirstVisibleScrollingRow, DisplayedBandsInfo.FirstDisplayedScrollingRow);
                    }
                    else
                    {
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow == oldFirstVisibleScrollingRow);
                        rows = 0;
                    }
                }
            }
            else
            {
                for (int rowCount = rows; rowCount < 0; rowCount++)
                {
                    newFirstVisibleScrollingRow = Rows.GetPreviousRow(newFirstVisibleScrollingRow,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.Frozen);
                    if (newFirstVisibleScrollingRow != -1)
                    {
                        deltaY += Rows.SharedRow(newFirstVisibleScrollingRow).GetHeight(newFirstVisibleScrollingRow);
                    }
                }
                if (newFirstVisibleScrollingRow != -1)
                {
                    DisplayedBandsInfo.FirstDisplayedScrollingRow = newFirstVisibleScrollingRow;
                    ComputeVisibleRows();
                    Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow == newFirstVisibleScrollingRow);
                }
            }

            if (newFirstVisibleScrollingRow != -1 && rows != 0)
            {
                ScrollRows(rows, deltaY, scrollEventType);
            }

            FlushDisplayedChanged();
        }

        private void ScrollRowsByHeight(int height)
        {
            Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
            int deltaY, scrollHeight = 0;
            int oldFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
            int newFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;
            if (height > 0)
            {
                deltaY = Rows.SharedRow(newFirstVisibleScrollingRow).GetHeight(newFirstVisibleScrollingRow);
                while (deltaY <= height)
                {
                    newFirstVisibleScrollingRow = Rows.GetNextRow(newFirstVisibleScrollingRow, DataGridViewElementStates.Visible);
                    if (newFirstVisibleScrollingRow == -1)
                    {
                        throw new InvalidOperationException();
                    }
                    else
                    {
                        deltaY += Rows.SharedRow(newFirstVisibleScrollingRow).GetHeight(newFirstVisibleScrollingRow);
                    }
                }
            }
            else
            {
                newFirstVisibleScrollingRow = Rows.GetPreviousRow(newFirstVisibleScrollingRow,
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.Frozen);
                Debug.Assert(newFirstVisibleScrollingRow != -1);
                deltaY = -Rows.SharedRow(newFirstVisibleScrollingRow).GetHeight(newFirstVisibleScrollingRow);
                while (deltaY >= height)
                {
                    int scrollingRowTmp = Rows.GetPreviousRow(newFirstVisibleScrollingRow,
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.Frozen);
                    if (scrollingRowTmp != -1)
                    {
                        deltaY -= Rows.SharedRow(scrollingRowTmp).GetHeight(scrollingRowTmp);
                        if (deltaY >= height)
                        {
                            newFirstVisibleScrollingRow = scrollingRowTmp;
                        }
                    }
                    else
                    {
                        break;
                    }
                }
            }

            // Tentative target value for this.displayedBandsInfo.FirstDisplayedScrollingRow.
            DisplayedBandsInfo.FirstDisplayedScrollingRow = newFirstVisibleScrollingRow;
            // This sets the actual value of this.displayedBandsInfo.FirstDisplayedScrollingRow
            ComputeVisibleRows();
            ScrollEventType scrollEventType = ScrollEventType.EndScroll;
            int rowCount = 0;
            // Compute the scrollHeight given the new this.displayedBandsInfo.FirstDisplayedScrollingRow
            if (DisplayedBandsInfo.FirstDisplayedScrollingRow > oldFirstVisibleScrollingRow)
            {
                scrollHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible, oldFirstVisibleScrollingRow, DisplayedBandsInfo.FirstDisplayedScrollingRow);
                rowCount = Rows.GetRowCount(DataGridViewElementStates.Visible, oldFirstVisibleScrollingRow, DisplayedBandsInfo.FirstDisplayedScrollingRow);
                scrollEventType = rowCount > 1 ? ScrollEventType.LargeIncrement : ScrollEventType.SmallIncrement;
            }
            else if (DisplayedBandsInfo.FirstDisplayedScrollingRow < oldFirstVisibleScrollingRow)
            {
                scrollHeight = -Rows.GetRowsHeight(DataGridViewElementStates.Visible, DisplayedBandsInfo.FirstDisplayedScrollingRow, oldFirstVisibleScrollingRow);
                rowCount = -Rows.GetRowCount(DataGridViewElementStates.Visible, DisplayedBandsInfo.FirstDisplayedScrollingRow, oldFirstVisibleScrollingRow);
                scrollEventType = rowCount < -1 ? ScrollEventType.LargeDecrement : ScrollEventType.SmallDecrement;
            }
            if (scrollHeight != 0)
            {
                ScrollRows(rowCount, -scrollHeight, scrollEventType);
            }

            FlushDisplayedChanged();
        }

        public void SelectAll()
        {
            if (!MultiSelect)
            {
                return;
            }
            _inBulkPaintCount++;
            _noDimensionChangeCount++;
            _noSelectionChangeCount++;
            try
            {
                DataGridViewRow dataGridViewRow = null;
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        {
                            // Bonjour the scalability issues! We select each cell, one at the time.
                            int maxColumnIndex = Columns.Count;
                            int rowIndex = 0, maxRowIndex = Rows.Count;
                            while (rowIndex < maxRowIndex)
                            {
                                dataGridViewRow = Rows[rowIndex];  //unsharing each row!
                                int columnIndex = 0;
                                while (columnIndex < maxColumnIndex)
                                {
                                    SetSelectedCellCore(columnIndex, rowIndex, true);
                                    columnIndex++;
                                }
                                rowIndex++;
                            }
                            break;
                        }

                    case DataGridViewSelectionMode.FullRowSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                        {
                            int rowIndex = 0, maxRowIndex = Rows.Count;
                            while (rowIndex < maxRowIndex)
                            {
                                DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
                                if ((rowState & DataGridViewElementStates.Selected) == 0)
                                {
                                    SetSelectedRowCore(rowIndex, true);
                                }
                                rowIndex++;
                            }
                            break;
                        }

                    case DataGridViewSelectionMode.FullColumnSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        {
                            int columnIndex = 0, maxColumnIndex = Columns.Count;
                            while (columnIndex < maxColumnIndex)
                            {
                                if (!Columns[columnIndex].Selected)
                                {
                                    SetSelectedColumnCore(columnIndex, true);
                                }
                                columnIndex++;
                            }
                            break;
                        }
                }
            }
            finally
            {
                _noDimensionChangeCount--;
                _noSelectionChangeCount--;
                Debug.Assert(_noDimensionChangeCount >= 0);
                Debug.Assert(_noSelectionChangeCount >= 0);
                ExitBulkPaint(-1, -1);
            }

            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            if (dataGridViewColumn != null && firstVisibleRowIndex != -1)
            {
                // This is the only place in the code outside of SetCurrentCellAddressCore where this.ptAnchorCell gets changed.
                // There is no way in SetCurrentCellAddressCore to just change the anchor cell.
                _ptAnchorCell.X = dataGridViewColumn.Index;
                _ptAnchorCell.Y = firstVisibleRowIndex;
            }
            else
            {
                _ptAnchorCell.X = -1;
                _ptAnchorCell.Y = -1;
            }

            if (_noSelectionChangeCount == 0)
            {
                FlushSelectionChanged();
            }
        }

        private DataGridViewCell SelectedCell(int index)
        {
            Debug.Assert(index >= 0);
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.CellSelect:
                    {
                        if (index < _individualSelectedCells.Count)
                        {
                            return _individualSelectedCells[index];
                        }
                        break;
                    }
                case DataGridViewSelectionMode.FullColumnSelect:
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    {
                        int selectedBand = 0, selectedBands = _selectedBandIndexes.Count;
                        while (selectedBand < selectedBands && index >= 0)
                        {
                            if (index >= Rows.Count)
                            {
                                index -= Rows.Count;
                                selectedBand++;
                            }
                            else
                            {
                                int columnIndex = _selectedBandIndexes[selectedBand];
                                return Rows.SharedRow(index).Cells[columnIndex];
                            }
                        }

                        if (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect &&
                            index < _individualSelectedCells.Count)
                        {
                            return _individualSelectedCells[index];
                        }
                        break;
                    }
                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    {
                        int selectedBand = 0, selectedBands = _selectedBandIndexes.Count;
                        while (selectedBand < selectedBands && index >= 0)
                        {
                            if (index >= Columns.Count)
                            {
                                index -= Columns.Count;
                                selectedBand++;
                            }
                            else
                            {
                                int rowIndex = _selectedBandIndexes[selectedBand];
                                return Rows.SharedRow(rowIndex).Cells[index];
                            }
                        }

                        if (SelectionMode == DataGridViewSelectionMode.RowHeaderSelect &&
                            index < _individualSelectedCells.Count)
                        {
                            return _individualSelectedCells[index];
                        }
                        break;
                    }
            }
            return null;
        }

        private void SetColumnHeadersHeightInternal(int columnHeadersHeight, bool invalidInAdjustFillingColumns)
        {
            using (LayoutTransaction.CreateTransactionIf(AutoSize, ParentInternal, this, PropertyNames.ColumnHeadersHeight))
            {
                Debug.Assert(this._columnHeadersHeight != columnHeadersHeight);
                Debug.Assert(columnHeadersHeight >= MinimumColumnHeadersHeight);
                Debug.Assert(columnHeadersHeight <= MaxHeadersThickness);
                this._columnHeadersHeight = columnHeadersHeight;
                if (AutoSize)
                {
                    InvalidateInside();
                }
                else
                {
                    if (_layout.ColumnHeadersVisible)
                    {
                        PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, invalidInAdjustFillingColumns, true /*repositionEditingControl*/);
                        InvalidateInside();
                    }
                }
                OnColumnHeadersHeightChanged(EventArgs.Empty);
            }
        }

        protected virtual bool SetCurrentCellAddressCore(int columnIndex,
            int rowIndex,
            bool setAnchorCellAddress,
            bool validateCurrentCell,
            bool throughMouseClick)
        {
            if (columnIndex < -1 ||
                (columnIndex >= 0 && rowIndex == -1) ||
                columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }
            if (rowIndex < -1 ||
                (columnIndex == -1 && rowIndex >= 0) ||
                rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }

            if (columnIndex > -1 &&
                rowIndex > -1 &&
                !IsSharedCellVisible(Rows.SharedRow(rowIndex).Cells[columnIndex], rowIndex))
            {
                throw new InvalidOperationException(SR.DataGridView_CurrentCellCannotBeInvisible);
            }

            if (_dataGridViewOper[OperationInCurrentCellChange] &&                      // Allow the code to be re-entrant only as a result of
                (DataConnection is null || !DataConnection.ProcessingListChangedEvent))   // underlying data changing.
            {
                throw new InvalidOperationException(SR.DataGridView_SetCurrentCellAddressCoreNotReentrant);
            }

            _dataGridViewOper[OperationInCurrentCellChange] = true;
            try
            {
                DataGridViewCell dataGridViewCellTmp = null;

                if (columnIndex > -1)
                {
                    Debug.Assert(rowIndex >= 0 &&
                        columnIndex < Columns.Count &&
                        rowIndex < Rows.Count);

                    if (_ptCurrentCell.X != columnIndex || _ptCurrentCell.Y != rowIndex)
                    {
                        if (_dataGridViewState1[State1_TemporarilyResetCurrentCell])
                        {
                            _dataGridViewState1[State1_TemporarilyResetCurrentCell] = false;
                            _ptCurrentCell.X = columnIndex;
                            _ptCurrentCell.Y = rowIndex;
                            if (_cachedEditingControl != null)
                            {
                                EditingControl = _cachedEditingControl;
                                ((IDataGridViewEditingControl)EditingControl).EditingControlRowIndex = rowIndex;
                                _cachedEditingControl = null;
                                PositionEditingControl(true, true, false);
                            }
                            OnCurrentCellChanged(EventArgs.Empty);
                            return true;
                        }

                        DataGridViewCell currentCell;
                        int oldCurrentCellX = _ptCurrentCell.X;
                        int oldCurrentCellY = _ptCurrentCell.Y;
                        if (oldCurrentCellX >= 0)
                        {
                            currentCell = CurrentCellInternal;
                            if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.CurrentCellChange,
                                        validateCurrentCell ? DataGridViewValidateCellInternal.Always : DataGridViewValidateCellInternal.Never /*validateCell*/,
                                        validateCurrentCell /*fireCellLeave*/,
                                        false /*fireCellEnter*/,
                                        validateCurrentCell && oldCurrentCellY != rowIndex /*fireRowLeave*/,
                                        false /*fireRowEnter*/,
                                        false /*fireLeave*/,
                                        EditMode != DataGridViewEditMode.EditOnEnter /*keepFocus*/,
                                        false /*resetCurrentCell*/,
                                        false /*resetAnchorCell unused here*/))
                            {
                                return false;
                            }
                            if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                            {
                                currentCell = Rows.SharedRow(oldCurrentCellY).Cells[oldCurrentCellX];
                                if (currentCell.LeaveUnsharesRowInternal(oldCurrentCellY, throughMouseClick))
                                {
                                    currentCell = Rows[oldCurrentCellY].Cells[oldCurrentCellX]; // unsharing the current row
                                }
                                currentCell.OnLeaveInternal(oldCurrentCellY, throughMouseClick);
                            }
                            if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                            {
                                return false;
                            }
                            if (oldCurrentCellY != rowIndex)
                            {
                                if (validateCurrentCell)
                                {
                                    if (OnRowValidating(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY))
                                    {
                                        if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                        {
                                            // Row validation was cancelled
                                            Debug.Assert(oldCurrentCellX == _ptCurrentCell.X);
                                            Debug.Assert(oldCurrentCellY == _ptCurrentCell.Y);
                                            OnRowEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY, true /*canCreateNewRow*/, true /*validationFailureOccurred*/);
                                            if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                            {
                                                currentCell.OnEnterInternal(oldCurrentCellY, throughMouseClick);
                                                OnCellEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);
                                            }
                                        }
                                        return false;
                                    }
                                    if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                    {
                                        OnRowValidated(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);
                                    }
                                }
                            }
                        }

                        _dataGridViewState2[State2_RowsCollectionClearedInSetCell] = false;

                        try
                        {
                            if (oldCurrentCellY != rowIndex)
                            {
                                if (!IsInnerCellOutOfBounds(columnIndex, rowIndex))
                                {
                                    OnRowEnter(ref dataGridViewCellTmp, columnIndex, rowIndex, true /*canCreateNewRow*/, false /*validationFailureOccurred*/);
                                }
                            }

                            // Force repainting of the current and previous collumns` header cells to update highlighting
                            if (oldCurrentCellX != columnIndex &&
                                SelectionMode == DataGridViewSelectionMode.FullRowSelect)
                            {
                                if (oldCurrentCellX >= 0)
                                {
                                    InvalidateCellPrivate(oldCurrentCellX, -1);
                                }
                                InvalidateCellPrivate(columnIndex, -1);
                            }

                            if (_dataGridViewState2[State2_RowsCollectionClearedInSetCell])
                            {
                                //
                                // The rows collection was cleared while processing OnRowEnter.
                                // If the new list is too small for rowIndex, fail the call to SetCurrentCellAddressCore.
                                //
                                if (rowIndex >= Rows.Count)
                                {
                                    return false;
                                }
                                // rowIndex = Math.Min(rowIndex, this.Rows.GetRowCount(DataGridViewElementStates.Visible) - 1);
                            }

                            if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                            {
                                return false;
                            }

                            _ptCurrentCell.X = columnIndex;
                            _ptCurrentCell.Y = rowIndex;
                            if (EditingControl != null)
                            {
                                ((IDataGridViewEditingControl)EditingControl).EditingControlRowIndex = rowIndex;
                            }
                            OnCurrentCellChanged(EventArgs.Empty);
                            if (setAnchorCellAddress)
                            {
                                _ptAnchorCell.X = columnIndex;
                                _ptAnchorCell.Y = rowIndex;
                            }

                            currentCell = CurrentCellInternal;
                            if (currentCell.EnterUnsharesRowInternal(rowIndex, throughMouseClick))
                            {
                                currentCell = Rows[rowIndex].Cells[columnIndex]; // unsharing the row
                            }
                            currentCell.OnEnterInternal(rowIndex, throughMouseClick);
                            OnCellEnter(ref dataGridViewCellTmp, _ptCurrentCell.X, _ptCurrentCell.Y);
                            if (oldCurrentCellX >= 0)
                            {
                                Debug.Assert(oldCurrentCellY >= 0);
                                if (oldCurrentCellX < Columns.Count && oldCurrentCellY < Rows.Count)
                                {
                                    InvalidateCellPrivate(oldCurrentCellX, oldCurrentCellY);
                                }
                                if (oldCurrentCellY != _ptCurrentCell.Y && RowHeadersVisible && oldCurrentCellY < Rows.Count)
                                {
                                    InvalidateCellPrivate(-1, oldCurrentCellY);
                                }
                            }
                            InvalidateCellPrivate(_ptCurrentCell.X, _ptCurrentCell.Y);
                            if (RowHeadersVisible && oldCurrentCellY != _ptCurrentCell.Y)
                            {
                                InvalidateCellPrivate(-1, _ptCurrentCell.Y);
                            }
                            if (Focused &&
                                _ptCurrentCell.X != -1 &&
                                !IsCurrentCellInEditMode &&
                                !_dataGridViewState1[State1_LeavingWithTabKey] &&                   // don't edit if we're in the process of leaving the grid
                                !_dataGridViewState2[State2_RowsCollectionClearedInSetCell] &&      // don't edit if the rows collection changed
                                (EditMode == DataGridViewEditMode.EditOnEnter ||
                                (EditMode != DataGridViewEditMode.EditProgrammatically && currentCell.EditType is null)))
                            {
                                BeginEditInternal(true /*selectAll*/);
                            }
                        }
                        finally
                        {
                            _dataGridViewState2[State2_RowsCollectionClearedInSetCell] = false;
                        }

                        // Accessibility
                        if (_ptCurrentCell.X != -1)
                        {
                            AccessibilityNotifyCurrentCellChanged(new Point(_ptCurrentCell.X, _ptCurrentCell.Y));
                        }
                    }
                    else
                    {
                        // Not trying to change the current cell, but may need to edit it.
                        if (setAnchorCellAddress)
                        {
                            _ptAnchorCell.X = columnIndex;
                            _ptAnchorCell.Y = rowIndex;
                        }
                        if (Focused &&
                            (!IsCurrentCellInEditMode && (EditMode == DataGridViewEditMode.EditOnEnter ||
                            (EditMode != DataGridViewEditMode.EditProgrammatically && CurrentCellInternal.EditType is null))))
                        {
                            BeginEditInternal(true /*selectAll*/);
                        }
                        else
                        {
                            CorrectFocus(false /*onlyIfGridHasFocus*/);
                        }
                    }
                }
                else
                {
                    int oldCurrentCellX = _ptCurrentCell.X;
                    int oldCurrentCellY = _ptCurrentCell.Y;
                    if (oldCurrentCellX >= 0 &&
                        !_dataGridViewState1[State1_TemporarilyResetCurrentCell] &&
                        !_dataGridViewOper[OperationInDispose])
                    {
                        DataGridViewCell currentCell = CurrentCellInternal;
                        if (!EndEdit(DataGridViewDataErrorContexts.Parsing | DataGridViewDataErrorContexts.Commit | DataGridViewDataErrorContexts.CurrentCellChange,
                                    validateCurrentCell ? DataGridViewValidateCellInternal.Always : DataGridViewValidateCellInternal.Never,
                                    validateCurrentCell /*fireCellLeave*/,
                                    false /*fireCellEnter*/,
                                    validateCurrentCell /*fireRowLeave*/,
                                    false /*fireRowEnter*/,
                                    false /*fireLeave*/,
                                    EditMode != DataGridViewEditMode.EditOnEnter /*keepFocus*/,
                                    false /*resetCurrentCell*/,
                                    false /*resetAnchorCell unused here*/))
                        {
                            return false;
                        }
                        if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                        {
                            currentCell = Rows.SharedRow(oldCurrentCellY).Cells[oldCurrentCellX];
                            if (currentCell.LeaveUnsharesRowInternal(oldCurrentCellY, throughMouseClick))
                            {
                                currentCell = Rows[oldCurrentCellY].Cells[oldCurrentCellX]; // unsharing the current row
                            }
                            currentCell.OnLeaveInternal(oldCurrentCellY, throughMouseClick);
                        }
                        if (validateCurrentCell)
                        {
                            if (OnRowValidating(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY))
                            {
                                if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                {
                                    // Row validation was cancelled
                                    Debug.Assert(oldCurrentCellX == _ptCurrentCell.X);
                                    Debug.Assert(oldCurrentCellY == _ptCurrentCell.Y);
                                    OnRowEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY, true /*canCreateNewRow*/, true /*validationFailureOccurred*/);
                                    if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                                    {
                                        currentCell.OnEnterInternal(oldCurrentCellY, throughMouseClick);
                                        OnCellEnter(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);
                                    }
                                }
                                return false;
                            }
                            if (!IsInnerCellOutOfBounds(oldCurrentCellX, oldCurrentCellY))
                            {
                                OnRowValidated(ref dataGridViewCellTmp, oldCurrentCellX, oldCurrentCellY);
                            }
                        }
                    }
                    if (_ptCurrentCell.X != -1)
                    {
                        _ptCurrentCell.X = -1;
                        _ptCurrentCell.Y = -1;
                        OnCurrentCellChanged(EventArgs.Empty);
                    }
                    if (setAnchorCellAddress)
                    {
                        _ptAnchorCell.X = -1;
                        _ptAnchorCell.Y = -1;
                    }
                    if (_dataGridViewState1[State1_TemporarilyResetCurrentCell])
                    {
                        if (EditingControl != null)
                        {
                            if (_dataGridViewState2[State2_DiscardEditingControl])
                            {
                                _dataGridViewState2[State2_DiscardEditingControl] = false;
                            }
                            else
                            {
                                _cachedEditingControl = EditingControl;
                            }
                            EditingControl = null;
                        }
                    }
                    else if (oldCurrentCellX >= 0 && !_dataGridViewOper[OperationInDispose])
                    {
                        Debug.Assert(oldCurrentCellY >= 0);
                        if (oldCurrentCellX < Columns.Count && oldCurrentCellY < Rows.Count)
                        {
                            InvalidateCellPrivate(oldCurrentCellX, oldCurrentCellY);
                        }
                        if (RowHeadersVisible && oldCurrentCellY < Rows.Count)
                        {
                            InvalidateCellPrivate(-1, oldCurrentCellY);
                        }
                    }
                }
            }
            finally
            {
                _dataGridViewOper[OperationInCurrentCellChange] = false;
            }
            return true;
        }

        internal void SetCurrentCellAddressCoreInternal(int columnIndex,
            int rowIndex,
            bool setAnchorCellAddress,
            bool validateCurrentCell,
            bool throughMouseClick)
        {
            SetCurrentCellAddressCore(columnIndex, rowIndex, setAnchorCellAddress, validateCurrentCell, throughMouseClick);
        }

        private void SelectCellRange(int columnIndexFrom, int rowIndexFrom, int columnIndexTo, int rowIndexTo, bool select)
        {
            Debug.Assert(columnIndexFrom >= 0 && columnIndexTo >= 0);
            Debug.Assert((Columns[columnIndexFrom]).DisplayIndex <= (Columns[columnIndexTo]).DisplayIndex);
            Debug.Assert(rowIndexFrom >= 0 && rowIndexTo >= 0);
            Debug.Assert(rowIndexFrom <= rowIndexTo);
            Debug.Assert(_noSelectionChangeCount > 0);

            bool switchedToBulkPaint = false;
            if (rowIndexTo - rowIndexFrom > BulkPaintThreshold)
            {
                // Switch to batch operation
                _inBulkPaintCount++;
                switchedToBulkPaint = true;
            }
            try
            {
                // Selection and deselection are done in reverse order for perf. reasons.
                if (select)
                {
                    int columnIndex = columnIndexFrom;
                    do
                    {
                        for (int rowIndex = rowIndexFrom; rowIndex <= rowIndexTo; rowIndex++)
                        {
                            SetSelectedCellCore(columnIndex, rowIndex, true);
                        }
                        if (columnIndex != columnIndexTo)
                        {
                            DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[columnIndex],
                                DataGridViewElementStates.Visible,
                                DataGridViewElementStates.None);
                            Debug.Assert(dataGridViewColumn != null);
                            columnIndex = dataGridViewColumn.Index;
                        }
                    }
                    while (columnIndex != columnIndexTo);

                    if (columnIndexFrom != columnIndexTo)
                    {
                        for (int rowIndex = rowIndexFrom; rowIndex <= rowIndexTo; rowIndex++)
                        {
                            SetSelectedCellCore(columnIndex, rowIndex, true);
                        }
                    }
                }
                else
                {
                    int columnIndex = columnIndexTo;
                    do
                    {
                        for (int rowIndex = rowIndexTo; rowIndex >= rowIndexFrom; rowIndex--)
                        {
                            SetSelectedCellCore(columnIndex, rowIndex, false);
                        }
                        if (columnIndex != columnIndexFrom)
                        {
                            DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[columnIndex],
                                DataGridViewElementStates.Visible,
                                DataGridViewElementStates.None);
                            Debug.Assert(dataGridViewColumn != null);
                            columnIndex = dataGridViewColumn.Index;
                        }
                    }
                    while (columnIndex != columnIndexFrom);

                    if (columnIndexFrom != columnIndexTo)
                    {
                        for (int rowIndex = rowIndexTo; rowIndex >= rowIndexFrom; rowIndex--)
                        {
                            SetSelectedCellCore(columnIndex, rowIndex, false);
                        }
                    }
                }
            }
            finally
            {
                if (switchedToBulkPaint)
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        private void SelectCellUnorderedRange(int columnIndexFrom, int rowIndexFrom, int columnIndexTo, int rowIndexTo, bool select)
        {
            Debug.Assert(_noSelectionChangeCount > 0);
            int columnIndexFromTmp, rowIndexFromTmp, columnIndexToTmp, rowIndexToTmp;

            if (Columns.DisplayInOrder(columnIndexFrom, columnIndexTo))
            {
                columnIndexFromTmp = columnIndexFrom;
                columnIndexToTmp = columnIndexTo;
            }
            else
            {
                columnIndexFromTmp = columnIndexTo;
                columnIndexToTmp = columnIndexFrom;
            }

            if (rowIndexFrom < rowIndexTo)
            {
                rowIndexFromTmp = rowIndexFrom;
                rowIndexToTmp = rowIndexTo;
            }
            else
            {
                rowIndexFromTmp = rowIndexTo;
                rowIndexToTmp = rowIndexFrom;
            }

            SelectCellRange(columnIndexFromTmp, rowIndexFromTmp, columnIndexToTmp, rowIndexToTmp, select);
        }

        private void SelectColumnRange(int columnIndexFrom, int columnIndexTo, bool select)
        {
            Debug.Assert(columnIndexFrom >= 0 && columnIndexTo >= 0);
            Debug.Assert((Columns[columnIndexFrom]).DisplayIndex <= (Columns[columnIndexTo]).DisplayIndex);
            Debug.Assert(_noSelectionChangeCount > 0);

            int columnIndex = columnIndexFrom;
            do
            {
                if (select)
                {
                    if (!_selectedBandIndexes.Contains(columnIndex))
                    {
                        SetSelectedColumnCore(columnIndex, true);
                    }
                }
                else
                {
                    Debug.Assert(_selectedBandIndexes.Contains(columnIndex));
                    SetSelectedColumnCore(columnIndex, false);
                }
                if (columnIndex != columnIndexTo)
                {
                    DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[columnIndex],
                        DataGridViewElementStates.Visible,
                        DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    columnIndex = dataGridViewColumn.Index;
                }
            }
            while (columnIndex != columnIndexTo);

            if (columnIndexFrom != columnIndexTo)
            {
                if (select)
                {
                    if (!_selectedBandIndexes.Contains(columnIndexTo))
                    {
                        SetSelectedColumnCore(columnIndexTo, true);
                    }
                }
                else
                {
                    Debug.Assert(_selectedBandIndexes.Contains(columnIndexTo));
                    SetSelectedColumnCore(columnIndexTo, false);
                }
            }
        }

        private void SelectRowRange(int rowIndexFrom, int rowIndexTo, bool select)
        {
            Debug.Assert(rowIndexFrom >= 0 && rowIndexTo >= 0);
            Debug.Assert(rowIndexFrom <= rowIndexTo);
            Debug.Assert(_noSelectionChangeCount > 0);

            bool switchedToBulkPaint = false;
            if (rowIndexTo - rowIndexFrom > BulkPaintThreshold)
            {
                // Switch to batch operation
                _inBulkPaintCount++;
                switchedToBulkPaint = true;
            }
            try
            {
                // Selecting and deselecting rows in reverse order for perf. reasons
                if (select)
                {
                    for (int rowIndex = rowIndexFrom; rowIndex <= rowIndexTo; rowIndex++)
                    {
                        if ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Selected) == 0)
                        {
                            Debug.Assert(!_selectedBandIndexes.Contains(rowIndex));
                            SetSelectedRowCore(rowIndex, true);
                        }
                    }
                }
                else
                {
                    for (int rowIndex = rowIndexTo; rowIndex >= rowIndexFrom; rowIndex--)
                    {
                        Debug.Assert(_selectedBandIndexes.Contains(rowIndex));
                        SetSelectedRowCore(rowIndex, false);
                    }
                }
            }
            finally
            {
                if (switchedToBulkPaint)
                {
                    ExitBulkPaint(-1, -1);
                }
            }
        }

        internal void SetAccessibleObjectParent(AccessibleObject editingControlAccessibleObject)
        {
            if (CurrentCell is null)
            {
                return;
            }

            editingControlAccessibleObject.SetParent(CurrentCell.AccessibilityObject);

            CurrentCell.AccessibilityObject.SetDetachableChild(editingControlAccessibleObject);
            CurrentCell.AccessibilityObject.RaiseStructureChangedEvent(UiaCore.StructureChangeType.ChildAdded, editingControlAccessibleObject.RuntimeId);
        }

        private bool SetAndSelectCurrentCellAddress(int columnIndex,
            int rowIndex,
            bool setAnchorCellAddress,
            bool validateCurrentCell,
            bool throughMouseClick,
            bool clearSelection,
            bool forceCurrentCellSelection)
        {
            if (!SetCurrentCellAddressCore(columnIndex, rowIndex, setAnchorCellAddress, validateCurrentCell, throughMouseClick))
            {
                return false;
            }
            if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
            {
                return false;
            }
            if (clearSelection)
            {
                ClearSelection(columnIndex, rowIndex, true /*selectException*/);    // we always select the new current cell when clearSelection is true
            }
            else
            {
                if (forceCurrentCellSelection)
                {
                    SetSelectedElementCore(columnIndex, rowIndex, true);
                }
                else
                {
                    if (MultiSelect && (_individualSelectedCells.Count + _selectedBandIndexes.Count) > 1)
                    {
                        return true;   // Do not discard the multi-selection
                    }
                    if (_individualSelectedCells.Count == 1)
                    {
                        DataGridViewCell dataGridViewCell = _individualSelectedCells.HeadCell;
                        if (dataGridViewCell.ColumnIndex != columnIndex || dataGridViewCell.RowIndex != rowIndex)
                        {
                            return true;
                        }
                    }
                    else if (_selectedBandIndexes.Count == 1)
                    {
                        switch (SelectionMode)
                        {
                            case DataGridViewSelectionMode.FullColumnSelect:
                            case DataGridViewSelectionMode.ColumnHeaderSelect:
                                {
                                    if (_selectedBandIndexes.HeadInt != columnIndex)
                                    {
                                        return true;  // Do not change a single selection that does not match the new current cell
                                    }
                                    break;
                                }
                            case DataGridViewSelectionMode.FullRowSelect:
                            case DataGridViewSelectionMode.RowHeaderSelect:
                                {
                                    if (_selectedBandIndexes.HeadInt != rowIndex)
                                    {
                                        return true;  // Do not change a single selection that does not match the new current cell
                                    }
                                    break;
                                }
                        }
                    }
                    SetSelectedElementCore(columnIndex, rowIndex, true);
                }
            }
            return true;
        }

        protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified)
        {
            if ((specified & BoundsSpecified.Width) == BoundsSpecified.Width && width > UpperSize)
            {
                throw new ArgumentOutOfRangeException(nameof(width), width, string.Format(SR.DataGridView_SizeTooLarge, (UpperSize).ToString(CultureInfo.CurrentCulture)));
            }
            if ((specified & BoundsSpecified.Height) == BoundsSpecified.Height && height > UpperSize)
            {
                throw new ArgumentOutOfRangeException(nameof(height), height, string.Format(SR.DataGridView_SizeTooLarge, (UpperSize).ToString(CultureInfo.CurrentCulture)));
            }
            base.SetBoundsCore(x, y, width, height, specified);
        }

        internal void SetReadOnlyCellCore(int columnIndex, int rowIndex, bool readOnly)
        {
            Debug.Assert(columnIndex >= 0 && rowIndex >= 0 &&
                columnIndex < Columns.Count &&
                rowIndex < Rows.Count);

            // cell's readonly state changes
            DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
            if (IsSharedCellReadOnly(dataGridViewRow.Cells[columnIndex], rowIndex) != readOnly)
            {
                DataGridViewCell dataGridViewCell = Rows[rowIndex].Cells[columnIndex];
                if (readOnly)
                {
                    if ((rowState & DataGridViewElementStates.ReadOnly) == 0 &&
                        !Columns[columnIndex].ReadOnly)
                    {
                        _individualReadOnlyCells.Add(dataGridViewCell);
                        dataGridViewCell.ReadOnlyInternal = true;
                    }
                }
                else
                {
                    if (_individualReadOnlyCells.Contains(dataGridViewCell))
                    {
                        _individualReadOnlyCells.Remove(dataGridViewCell);
                    }
                    else
                    {
                        DataGridViewCell dataGridViewCellTmp;
                        if (Columns[columnIndex].ReadOnly)
                        {
                            Columns[columnIndex].ReadOnlyInternal = false;
                            // Perf Issue: this unshares all rows!
                            for (int row = 0; row < rowIndex; row++)
                            {
                                dataGridViewCellTmp = Rows[row].Cells[columnIndex];
                                dataGridViewCellTmp.ReadOnlyInternal = true;
                                _individualReadOnlyCells.Add(dataGridViewCellTmp);
                            }
                            for (int row = rowIndex + 1; row < Rows.Count; row++)
                            {
                                dataGridViewCellTmp = Rows[row].Cells[columnIndex];
                                dataGridViewCellTmp.ReadOnlyInternal = true;
                                _individualReadOnlyCells.Add(dataGridViewCellTmp);
                            }
                        }
                        if ((rowState & DataGridViewElementStates.ReadOnly) != 0)
                        {
                            Rows.SetRowState(rowIndex, DataGridViewElementStates.ReadOnly, false);
                            for (int column = 0; column < columnIndex; column++)
                            {
                                dataGridViewCellTmp = Rows[rowIndex].Cells[column];
                                dataGridViewCellTmp.ReadOnlyInternal = true;
                                _individualReadOnlyCells.Add(dataGridViewCellTmp);
                            }
                            for (int column = columnIndex + 1; column < Columns.Count; column++)
                            {
                                dataGridViewCellTmp = Rows[rowIndex].Cells[column];
                                dataGridViewCellTmp.ReadOnlyInternal = true;
                                _individualReadOnlyCells.Add(dataGridViewCellTmp);
                            }
                        }
                    }
                    if (dataGridViewCell.ReadOnly)
                    {
                        dataGridViewCell.ReadOnlyInternal = false;
                    }
                }
            }
        }

        internal void SetReadOnlyColumnCore(int columnIndex, bool readOnly)
        {
            Debug.Assert(columnIndex >= 0 && columnIndex < Columns.Count);

            if (Columns[columnIndex].ReadOnly != readOnly)
            {
                // ReadOnly state of entire column changes
                if (readOnly)
                {
                    // column is made read-only
                    // remove individual read-only cells of this column
                    try
                    {
                        _dataGridViewOper[OperationInReadOnlyChange] = true;
                        RemoveIndividualReadOnlyCellsInColumn(columnIndex);
                    }
                    finally
                    {
                        _dataGridViewOper[OperationInReadOnlyChange] = false;
                    }
                    Columns[columnIndex].ReadOnlyInternal = true;
                }
                else
                {
                    // column is made read-write
                    Columns[columnIndex].ReadOnlyInternal = false;
                }
            }
            else if (!readOnly)
            {
                // remove any potentially individual read-only cells in the column
                RemoveIndividualReadOnlyCellsInColumn(columnIndex);
            }
        }

        internal void SetReadOnlyRowCore(int rowIndex, bool readOnly)
        {
            Debug.Assert(rowIndex >= 0 && rowIndex < Rows.Count);

            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
            if (((rowState & DataGridViewElementStates.ReadOnly) != 0) != readOnly)
            {
                // ReadOnly state of entire row changes
                if (readOnly)
                {
                    // row is made read-only
                    // first remove individual read-only cells of this row
                    try
                    {
                        _dataGridViewOper[OperationInReadOnlyChange] = true;
                        RemoveIndividualReadOnlyCellsInRow(rowIndex);
                    }
                    finally
                    {
                        _dataGridViewOper[OperationInReadOnlyChange] = false;
                    }
                    Rows.SetRowState(rowIndex, DataGridViewElementStates.ReadOnly, true);
                }
                else
                {
                    // row is made read-write
                    Rows.SetRowState(rowIndex, DataGridViewElementStates.ReadOnly, false);
                }
            }
            else if (!readOnly)
            {
                // remove any potentially individual read-only cells in the row
                RemoveIndividualReadOnlyCellsInRow(rowIndex);
            }
        }

        protected virtual void SetSelectedCellCore(int columnIndex, int rowIndex, bool selected)
        {
            if (columnIndex < 0 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }

            if (rowIndex < 0 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }

            // cell selection changes
            DataGridViewRow dataGridViewRow = Rows.SharedRow(rowIndex);
            DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
            if (IsSharedCellSelected(dataGridViewRow.Cells[columnIndex], rowIndex) != selected)
            {
                DataGridViewCell dataGridViewCell = Rows[rowIndex].Cells[columnIndex];
                if (selected)
                {
                    if ((rowState & DataGridViewElementStates.Selected) == 0 &&
                        !Columns[columnIndex].Selected)
                    {
                        _individualSelectedCells.Add(dataGridViewCell);
                        dataGridViewCell.SelectedInternal = true;
                    }
                }
                else
                {
                    if ((dataGridViewCell.State & DataGridViewElementStates.Selected) != 0)
                    {
                        Debug.Assert(_individualSelectedCells.Contains(dataGridViewCell));
                        _individualSelectedCells.Remove(dataGridViewCell);
                        KeyboardToolTipStateMachine.Instance.NotifyAboutLostFocus(dataGridViewCell);
                    }
                    else
                    {
                        DataGridViewCell dataGridViewCellTmp;
                        bool switchedToBulkPaint = false;
                        if (SelectionMode == DataGridViewSelectionMode.ColumnHeaderSelect)
                        {
                            if (Rows.Count > BulkPaintThreshold)
                            {
                                _inBulkPaintCount++;
                                switchedToBulkPaint = true;
                            }
                            try
                            {
                                Debug.Assert(_selectedBandIndexes.Contains(columnIndex));
                                _selectedBandIndexes.Remove(columnIndex);
                                Columns[columnIndex].SelectedInternal = false;
                                // Perf Issue: this unshares all rows!
                                for (int row = 0; row < rowIndex; row++)
                                {
                                    dataGridViewCellTmp = Rows[row].Cells[columnIndex];
                                    dataGridViewCellTmp.SelectedInternal = true;
                                    _individualSelectedCells.Add(dataGridViewCellTmp);
                                }
                                for (int row = rowIndex + 1; row < Rows.Count; row++)
                                {
                                    dataGridViewCellTmp = Rows[row].Cells[columnIndex];
                                    dataGridViewCellTmp.SelectedInternal = true;
                                    _individualSelectedCells.Add(dataGridViewCellTmp);
                                }
                            }
                            finally
                            {
                                if (switchedToBulkPaint)
                                {
                                    ExitBulkPaint(columnIndex, -1);
                                }
                            }
                        }
                        else if (SelectionMode == DataGridViewSelectionMode.RowHeaderSelect)
                        {
                            if (Columns.Count > BulkPaintThreshold)
                            {
                                _inBulkPaintCount++;
                                switchedToBulkPaint = true;
                            }
                            try
                            {
                                Debug.Assert(_selectedBandIndexes.Contains(rowIndex));
                                _selectedBandIndexes.Remove(rowIndex);
                                Rows.SetRowState(rowIndex, DataGridViewElementStates.Selected, false);
                                for (int column = 0; column < columnIndex; column++)
                                {
                                    dataGridViewCellTmp = Rows[rowIndex].Cells[column];
                                    dataGridViewCellTmp.SelectedInternal = true;
                                    _individualSelectedCells.Add(dataGridViewCellTmp);
                                }
                                for (int column = columnIndex + 1; column < Columns.Count; column++)
                                {
                                    dataGridViewCellTmp = Rows[rowIndex].Cells[column];
                                    dataGridViewCellTmp.SelectedInternal = true;
                                    _individualSelectedCells.Add(dataGridViewCellTmp);
                                }
                            }
                            finally
                            {
                                if (switchedToBulkPaint)
                                {
                                    ExitBulkPaint(-1, rowIndex);
                                }
                            }
                        }
                    }
                    if (dataGridViewCell.Selected)
                    {
                        dataGridViewCell.SelectedInternal = false;
                        KeyboardToolTipStateMachine.Instance.NotifyAboutLostFocus(dataGridViewCell);
                    }
                }
            }
        }

        internal void SetSelectedCellCoreInternal(int columnIndex, int rowIndex, bool selected)
        {
            if (selected && !MultiSelect)
            {
                if (!Columns[columnIndex].Visible ||
                    (Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) == 0)
                {
                    throw new InvalidOperationException(SR.DataGridView_CurrentCellCannotBeInvisible);
                }

                if (!ScrollIntoView(columnIndex, rowIndex, true))
                {
                    return;
                }
                if (IsInnerCellOutOfBounds(columnIndex, rowIndex))
                {
                    return;
                }
            }

            _noSelectionChangeCount++;
            try
            {
                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                        {
                            if (selected && !MultiSelect)
                            {
                                Debug.Assert(_individualSelectedCells.Count <= 1);
                                RemoveIndividuallySelectedCells();
                            }
                            SetSelectedCellCore(columnIndex, rowIndex, selected);
                            break;
                        }

                    case DataGridViewSelectionMode.FullColumnSelect:
                        {
                            if (selected)
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    int bandIndex = 0;
                                    while (bandIndex < _selectedBandIndexes.Count)
                                    {
                                        if (_selectedBandIndexes[bandIndex] != columnIndex)
                                        {
                                            // deselect currently selected column
                                            SetSelectedColumnCore(_selectedBandIndexes[bandIndex], false);
                                        }
                                        else
                                        {
                                            bandIndex++;
                                        }
                                    }
                                }
                                if (!_selectedBandIndexes.Contains(columnIndex))
                                {
                                    SetSelectedColumnCore(columnIndex, true);
                                }
                            }
                            else
                            {
                                if (_selectedBandIndexes.Contains(columnIndex))
                                {
                                    SetSelectedColumnCore(columnIndex, false);
                                }
                            }
                            break;
                        }

                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        {
                            if (selected)
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedColumnCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        RemoveIndividuallySelectedCells();
                                    }
                                }
                                SetSelectedCellCore(columnIndex, rowIndex, true);
                            }
                            else
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedColumnCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(columnIndex, rowIndex, false);
                                    }
                                }
                                else
                                {
                                    SetSelectedCellCore(columnIndex, rowIndex, false);
                                }
                            }
                            break;
                        }

                    case DataGridViewSelectionMode.FullRowSelect:
                        {
                            if (selected)
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    int bandIndex = 0;
                                    while (bandIndex < _selectedBandIndexes.Count)
                                    {
                                        if (_selectedBandIndexes[bandIndex] != rowIndex)
                                        {
                                            // deselect currently selected row
                                            SetSelectedRowCore(_selectedBandIndexes[bandIndex], false);
                                        }
                                        else
                                        {
                                            bandIndex++;
                                        }
                                    }
                                }
                                if ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Selected) == 0)
                                {
                                    Debug.Assert(_selectedBandIndexes.Contains(rowIndex) ==
                                                 ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Selected) != 0));
                                    SetSelectedRowCore(rowIndex, true);
                                }
                            }
                            else
                            {
                                if ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Selected) != 0)
                                {
                                    Debug.Assert(_selectedBandIndexes.Contains(rowIndex) ==
                                                 ((Rows.GetRowState(rowIndex) & DataGridViewElementStates.Selected) != 0));
                                    SetSelectedRowCore(rowIndex, false);
                                }
                            }
                            break;
                        }

                    case DataGridViewSelectionMode.RowHeaderSelect:
                        {
                            if (selected)
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedRowCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        RemoveIndividuallySelectedCells();
                                    }
                                }
                                SetSelectedCellCore(columnIndex, rowIndex, true);
                            }
                            else
                            {
                                if (!MultiSelect)
                                {
                                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                                    if (_selectedBandIndexes.Count > 0)
                                    {
                                        SetSelectedRowCore(_selectedBandIndexes.HeadInt, false);
                                    }
                                    else
                                    {
                                        SetSelectedCellCore(columnIndex, rowIndex, false);
                                    }
                                }
                                else
                                {
                                    SetSelectedCellCore(columnIndex, rowIndex, false);
                                }
                            }
                            break;
                        }
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }

            if (selected && !MultiSelect)
            {
                bool success = SetCurrentCellAddressCore(columnIndex, rowIndex, true, false, true);
                Debug.Assert(success);
            }
        }

        protected virtual void SetSelectedColumnCore(int columnIndex, bool selected)
        {
            if (columnIndex < 0 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }

            _noSelectionChangeCount++;
            try
            {
                if (Columns[columnIndex].Selected != selected)
                {
                    // selection of entire column changes
                    if (selected)
                    {
                        // column is selected
                        // remove individually selected cells of this column
                        RemoveIndividuallySelectedCellsInColumn(columnIndex);
                        Columns[columnIndex].SelectedInternal = true;
                        Debug.Assert(!_selectedBandIndexes.Contains(columnIndex));
                        _selectedBandIndexes.Add(columnIndex);
                    }
                    else
                    {
                        // column is deselected
                        Debug.Assert(_selectedBandIndexes.Contains(columnIndex));
                        Columns[columnIndex].SelectedInternal = false;
                        _selectedBandIndexes.Remove(columnIndex);
                    }
                }
                else if (!selected)
                {
                    // remove any potentially individually selected cells in the column
                    RemoveIndividuallySelectedCellsInColumn(columnIndex);
                }
            }
            finally
            {
                Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                NoSelectionChangeCount--;
            }
        }

        internal void SetSelectedColumnCoreInternal(int columnIndex, bool selected)
        {
            _noSelectionChangeCount++;
            try
            {
                if (!MultiSelect)
                {
                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                    if (_selectedBandIndexes.Count > 0)
                    {
                        int columnIndexSelected = _selectedBandIndexes.HeadInt;
                        if (columnIndexSelected != columnIndex)
                        {
                            SetSelectedColumnCore(columnIndexSelected, false);
                        }
                    }
                }
                SetSelectedColumnCore(columnIndex, selected);
            }
            finally
            {
                NoSelectionChangeCount--;
            }
        }

        private void SetSelectedElementCore(int columnIndex, int rowIndex, bool selected)
        {
            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.CellSelect:
                    {
                        SetSelectedCellCore(columnIndex, rowIndex, selected);
                        break;
                    }
                case DataGridViewSelectionMode.RowHeaderSelect:
                    {
                        if (columnIndex == -1)
                        {
                            SetSelectedRowCore(rowIndex, selected);
                        }
                        else
                        {
                            SetSelectedCellCore(columnIndex, rowIndex, selected);
                        }
                        break;
                    }
                case DataGridViewSelectionMode.ColumnHeaderSelect:
                    {
                        if (rowIndex == -1)
                        {
                            SetSelectedColumnCore(columnIndex, selected);
                        }
                        else
                        {
                            SetSelectedCellCore(columnIndex, rowIndex, selected);
                        }
                        break;
                    }
                case DataGridViewSelectionMode.FullRowSelect:
                    {
                        SetSelectedRowCore(rowIndex, selected);
                        break;
                    }
                case DataGridViewSelectionMode.FullColumnSelect:
                    {
                        SetSelectedColumnCore(columnIndex, selected);
                        break;
                    }
            }
        }

        protected virtual void SetSelectedRowCore(int rowIndex, bool selected)
        {
            if (rowIndex < 0 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }

            _noSelectionChangeCount++;
            try
            {
                DataGridViewElementStates rowState = Rows.GetRowState(rowIndex);
                if (((rowState & DataGridViewElementStates.Selected) != 0) != selected)
                {
                    // selection of entire row changes
                    if (selected)
                    {
                        // row is selected
                        // first remove individually selected cells of this row
                        RemoveIndividuallySelectedCellsInRow(rowIndex);
                        Debug.Assert(!_selectedBandIndexes.Contains(rowIndex));
                        _selectedBandIndexes.Add(rowIndex);
                        Rows.SetRowState(rowIndex, DataGridViewElementStates.Selected, true);
                    }
                    else
                    {
                        // row is deselected
                        Debug.Assert(_selectedBandIndexes.Contains(rowIndex));
                        _selectedBandIndexes.Remove(rowIndex);
                        Rows.SetRowState(rowIndex, DataGridViewElementStates.Selected, false);
                    }
                }
                else if (!selected)
                {
                    // remove any potentially individually selected cells in the row
                    RemoveIndividuallySelectedCellsInRow(rowIndex);
                }
            }
            finally
            {
                Debug.Assert(MultiSelect || _selectedBandIndexes.Count <= 1);
                NoSelectionChangeCount--;
            }
        }

        internal void SetSelectedRowCoreInternal(int rowIndex, bool selected)
        {
            _noSelectionChangeCount++;
            try
            {
                if (!MultiSelect)
                {
                    Debug.Assert(_selectedBandIndexes.Count <= 1);
                    if (_selectedBandIndexes.Count > 0)
                    {
                        int rowIndexSelected = _selectedBandIndexes.HeadInt;
                        if (rowIndexSelected != rowIndex)
                        {
                            SetSelectedRowCore(rowIndexSelected, false);
                        }
                    }
                }
                SetSelectedRowCore(rowIndex, selected);
            }
            finally
            {
                NoSelectionChangeCount--;
            }
        }

        private bool ShouldSerializeAlternatingRowsDefaultCellStyle()
        {
            DataGridViewCellStyle defaultStyle = new DataGridViewCellStyle();
            return !AlternatingRowsDefaultCellStyle.Equals(defaultStyle);
        }

        private bool ShouldSerializeColumnHeadersDefaultCellStyle()
        {
            return !ColumnHeadersDefaultCellStyle.Equals(DefaultColumnHeadersDefaultCellStyle);
        }

        private bool ShouldSerializeDefaultCellStyle()
        {
            return !DefaultCellStyle.Equals(DefaultDefaultCellStyle);
        }

        private bool ShouldSerializeRowHeadersDefaultCellStyle()
        {
            return !RowHeadersDefaultCellStyle.Equals(DefaultRowHeadersDefaultCellStyle);
        }

        private bool ShouldSerializeRowsDefaultCellStyle()
        {
            DataGridViewCellStyle defaultStyle = new DataGridViewCellStyle();
            return !RowsDefaultCellStyle.Equals(defaultStyle);
        }

        public virtual void Sort(DataGridViewColumn dataGridViewColumn, ListSortDirection direction)
        {
            if (dataGridViewColumn is null)
            {
                throw new ArgumentNullException(nameof(dataGridViewColumn));
            }

            if (direction != ListSortDirection.Ascending && direction != ListSortDirection.Descending)
            {
                throw new InvalidEnumArgumentException(nameof(direction), (int)direction, typeof(ListSortDirection));
            }

            if (dataGridViewColumn.DataGridView != this)
            {
                throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView);
            }

            if (VirtualMode && !dataGridViewColumn.IsDataBound)
            {
                throw new InvalidOperationException(SR.DataGridView_OperationDisabledInVirtualMode);
            }

            SortInternal(null, dataGridViewColumn, direction);
        }

        public virtual void Sort(IComparer comparer)
        {
            if (comparer is null)
            {
                throw new ArgumentNullException(nameof(comparer));
            }

            if (VirtualMode)
            {
                throw new InvalidOperationException(SR.DataGridView_OperationDisabledInVirtualMode);
            }

            // can't sort a data bound dataGridView control using a comparer
            if (DataSource != null)
            {
                throw new InvalidOperationException(SR.DataGridView_CannotUseAComparerToSortDataGridViewWhenDataBound);
            }

            SortInternal(comparer, null, ListSortDirection.Ascending);
        }

        private void SortDataBoundDataGridView_PerformCheck(DataGridViewColumn dataGridViewColumn)
        {
            if (!(DataConnection.List is IBindingList ibl))
            {
                throw new InvalidOperationException(SR.DataGridView_CannotSortDataBoundDataGridViewBoundToNonIBindingList);
            }

            if (!ibl.SupportsSorting)
            {
                throw new InvalidOperationException(SR.DataGridView_IBindingListNeedsToSupportSorting);
            }

            if (!dataGridViewColumn.IsDataBound)
            {
                throw new ArgumentException(SR.DataGridView_ColumnNeedsToBeDataBoundWhenSortingDataBoundDataGridView, nameof(dataGridViewColumn));
            }
        }

        private void SortInternal(IComparer comparer, DataGridViewColumn dataGridViewColumn, ListSortDirection direction)
        {
            Debug.Assert(!(comparer != null && DataSource != null));
            Debug.Assert(direction == ListSortDirection.Ascending || direction == ListSortDirection.Descending);

            // Exit editing mode if needed
            _ptCurrentCellCache.X = _ptCurrentCell.X;
            _ptCurrentCellCache.Y = _ptCurrentCell.Y;
            _dataGridViewOper[OperationInSort] = true;
            try
            {
                if (CurrentCell != null)
                {
                    KeyboardToolTipStateMachine.Instance.NotifyAboutLostFocus(CurrentCell);
                }

                if (!SetCurrentCellAddressCore(-1, -1, true, true, false))
                {
                    // Just cancel operation silently instead of throwing InvalidOperationException
                    // 'finally' below resets this.dataGridViewOper[OperationinSort] to false
                    return;
                }

                int firstDisplayedScrollingRowCache = DisplayedBandsInfo.FirstDisplayedScrollingRow;
                int visibleFrozenRows = Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                if (visibleFrozenRows > 0 && DataSource is null)
                {
                    int rowVFIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    Debug.Assert(rowVFIndex != -1);
                    Rows.SetRowState(rowVFIndex, DataGridViewElementStates.Frozen, false);
                    Debug.Assert(0 == Rows.GetRowCount(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen));
                }

                if (SortedColumn != null &&
                    SortedColumn.SortMode == DataGridViewColumnSortMode.Automatic &&
                    SortedColumn.HasHeaderCell)
                {
                    SortedColumn.HeaderCell.SortGlyphDirection = SortOrder.None;
                }

                if (comparer is null)
                {
                    Debug.Assert(dataGridViewColumn != null);
                    SortedColumn = dataGridViewColumn;
                    SortOrder = (direction == ListSortDirection.Ascending) ? SortOrder.Ascending : SortOrder.Descending;
                    if (dataGridViewColumn.SortMode == DataGridViewColumnSortMode.Automatic && dataGridViewColumn.HasHeaderCell)
                    {
                        dataGridViewColumn.HeaderCell.SortGlyphDirection = SortOrder;
                    }
                }
                else
                {
                    SortedColumn = null;
                    SortOrder = SortOrder.None;
                }

                if (DataSource is null)
                {
                    // Displayed rows may end up all spread out in the final layout.
                    // So we simply reset their displayed state before the sort.
                    UpdateRowsDisplayedState(false /*displayed*/);
                    Rows.Sort(comparer, direction == ListSortDirection.Ascending);
                }
                else
                {
                    SortDataBoundDataGridView_PerformCheck(dataGridViewColumn);
                    // the check passed, do the sorting
                    DataConnection.Sort(dataGridViewColumn, direction);
                }

                if (_ptCurrentCellCache.X != -1)
                {
                    if (!IsInnerCellOutOfBounds(_ptCurrentCellCache.X, _ptCurrentCellCache.Y))
                    {
                        SetAndSelectCurrentCellAddress(_ptCurrentCellCache.X,
                                                   _ptCurrentCellCache.Y,
                                                   true,
                                                   false,
                                                   false,
                                                   false /*clearSelection*/,
                                                   false /*forceCurrentCellSelection*/);
                    }
                }
                if (visibleFrozenRows > 0)
                {
                    int rowVIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
                    Debug.Assert(rowVIndex != -1);
                    while (visibleFrozenRows > 1)
                    {
                        rowVIndex = Rows.GetNextRow(rowVIndex, DataGridViewElementStates.Visible);
                        Debug.Assert(rowVIndex != -1);
                        visibleFrozenRows--;
                    }
                    Rows.SetRowState(rowVIndex, DataGridViewElementStates.Frozen, true);
                }
                DisplayedBandsInfo.FirstDisplayedScrollingRow = firstDisplayedScrollingRowCache;
            }
            finally
            {
                Debug.Assert(_dataGridViewOper[OperationInSort]);
                _dataGridViewOper[OperationInSort] = false;
            }
            // Same effect as changing a top level cell style
            OnGlobalAutoSize();
            if (DataSource is null)
            {
                // Ensure that the Displayed states get set properly because they were wiped out by UpdateRowsDisplayedState above.
                DisplayedBandsInfo.EnsureDirtyState();
            }
            ResetUIState(false /*useRowShortcut*/, false /*computeVisibleRows*/);
            OnSorted(EventArgs.Empty);

            // RS4 narrator does not catch this event even though event is indeed raised.
            AccessibilityNotifyClients(AccessibleEvents.Reorder, User32.OBJID.CLIENT, 0);
        }

        internal void SwapSortedRows(int rowIndex1, int rowIndex2)
        {
            Debug.Assert(rowIndex1 != NewRowIndex);
            Debug.Assert(rowIndex2 != NewRowIndex);
            if (rowIndex1 == rowIndex2)
            {
                return;
            }

            // Follow the move of the old current cell
            if (rowIndex1 == _ptCurrentCellCache.Y)
            {
                _ptCurrentCellCache.Y = rowIndex2;
            }
            else if (rowIndex2 == _ptCurrentCellCache.Y)
            {
                _ptCurrentCellCache.Y = rowIndex1;
            }

            switch (SelectionMode)
            {
                case DataGridViewSelectionMode.FullRowSelect:
                case DataGridViewSelectionMode.RowHeaderSelect:
                    int row1Selected = _selectedBandIndexes.IndexOf(rowIndex1);
                    int row2Selected = _selectedBandIndexes.IndexOf(rowIndex2);
                    if (row1Selected != -1 && row2Selected == -1)
                    {
                        _selectedBandIndexes[row1Selected] = rowIndex2;
                    }
                    else if (row1Selected == -1 && row2Selected != -1)
                    {
                        _selectedBandIndexes[row2Selected] = rowIndex1;
                    }
                    if (_selectedBandSnapshotIndexes != null)
                    {
                        row1Selected = _selectedBandSnapshotIndexes.IndexOf(rowIndex1);
                        row2Selected = _selectedBandSnapshotIndexes.IndexOf(rowIndex2);
                        if (row1Selected != -1 && row2Selected == -1)
                        {
                            _selectedBandSnapshotIndexes[row1Selected] = rowIndex2;
                        }
                        else if (row1Selected == -1 && row2Selected != -1)
                        {
                            _selectedBandSnapshotIndexes[row2Selected] = rowIndex1;
                        }
                    }
                    break;
            }
        }

        private void DataGridViewHScrolled(object sender, ScrollEventArgs se)
        {
            if (!Enabled)
            {
                return;
            }

            /* VS Whidbey

*/

            if (se.Type == ScrollEventType.SmallIncrement ||
                se.Type == ScrollEventType.SmallDecrement)
            {
                int dCols = (se.Type == ScrollEventType.SmallIncrement) ? 1 : -1;
                ScrollColumns(dCols);
                se.NewValue = HorizontalOffset;
            }
            else if (se.Type != ScrollEventType.EndScroll)
            {
                HorizontalOffset = se.NewValue;
            }
        }

        private void DataGridViewVScrolled(object sender, ScrollEventArgs se)
        {
            if (!Enabled)
            {
                return;
            }

            /* VS Whidbey

*/

            int totalVisibleFrozenHeight = Rows.GetRowsHeight(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
            switch (se.Type)
            {
                case ScrollEventType.SmallIncrement:
                    {
                        // Making sure that when the last visible scrolling row is taller than the data area, it does not get scrolled off screen
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                        if (_vertScrollBar.Value + Rows.SharedRow(DisplayedBandsInfo.FirstDisplayedScrollingRow).GetHeight(DisplayedBandsInfo.FirstDisplayedScrollingRow) <=
                            _vertScrollBar.Maximum - ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight))
                        {
                            ScrollRowsByCount(1, ScrollEventType.SmallIncrement);
                        }
                        se.NewValue = VerticalOffset;
                        break;
                    }
                case ScrollEventType.SmallDecrement:
                    {
                        if (_vertScrollBar.Value != _vertScrollBar.Minimum)
                        {
                            ScrollRowsByCount(-1, ScrollEventType.SmallDecrement);
                        }
                        se.NewValue = VerticalOffset;
                        break;
                    }
                case ScrollEventType.LargeIncrement:
                    {
                        Debug.Assert(DisplayedBandsInfo.FirstDisplayedScrollingRow >= 0);
                        int firstDisplayedScrollingRowHeight = Rows.SharedRow(DisplayedBandsInfo.FirstDisplayedScrollingRow).GetHeight(DisplayedBandsInfo.FirstDisplayedScrollingRow);
                        VerticalOffset += Math.Max(firstDisplayedScrollingRowHeight, _vertScrollBar.LargeChange);
                        se.NewValue = VerticalOffset;
                        break;
                    }
                case ScrollEventType.LargeDecrement:
                    {
                        VerticalOffset -= _vertScrollBar.LargeChange;
                        se.NewValue = VerticalOffset;
                        break;
                    }
                case ScrollEventType.ThumbTrack:
                case ScrollEventType.First:
                case ScrollEventType.Last:
                    {
                        if (se.NewValue >= _vertScrollBar.Maximum - _vertScrollBar.LargeChange)
                        {
                            // Need to display the last scrolling row
                            VerticalOffset = _vertScrollBar.Maximum - ComputeHeightOfFittingTrailingScrollingRows(totalVisibleFrozenHeight);
                        }
                        else
                        {
                            VerticalOffset = se.NewValue;
                        }
                        break;
                    }
            }
        }

        private bool TabToNextCell()
        {
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            if (firstVisibleColumnIndex == -1 || firstVisibleRowIndex == -1)
            {
                return false;
            }
            int nextVisibleColumnIndex = -1;
            if (_ptCurrentCell.X != -1)
            {
                dataGridViewColumn = Columns.GetNextColumn(Columns[_ptCurrentCell.X],
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
                if (dataGridViewColumn != null)
                {
                    nextVisibleColumnIndex = dataGridViewColumn.Index;
                }
            }
            int nextVisibleRowIndex = -1;
            if (_ptCurrentCell.Y != -1)
            {
                nextVisibleRowIndex = Rows.GetNextRow(_ptCurrentCell.Y, DataGridViewElementStates.Visible);
            }
            int targetRowIndex = -1, targetColumnIndex = -1;

            _noSelectionChangeCount++;
            try
            {
                if (_ptCurrentCell.X == -1)
                {
                    ClearSelection();
                }
                else
                {
                    if (nextVisibleColumnIndex == -1)
                    {
                        targetRowIndex = (nextVisibleRowIndex == -1) ? firstVisibleRowIndex : nextVisibleRowIndex;
                        targetColumnIndex = firstVisibleColumnIndex;
                    }
                    else
                    {
                        targetRowIndex = _ptCurrentCell.Y;
                        targetColumnIndex = nextVisibleColumnIndex;
                    }
                    if (!ScrollIntoView(targetColumnIndex, targetRowIndex, true))
                    {
                        return true;
                    }
                }

                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                        }
                        else
                        {
                            if (IsInnerCellOutOfBounds(targetColumnIndex, targetRowIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            SetSelectedCellCore(targetColumnIndex, targetRowIndex, true);
                        }
                        break;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            if (IsColumnOutOfBounds(firstVisibleColumnIndex))
                            {
                                return true;
                            }
                            SetSelectedColumnCore(firstVisibleColumnIndex, true);
                        }
                        else
                        {
                            if (IsColumnOutOfBounds(targetColumnIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            SetSelectedColumnCore(targetColumnIndex, true);
                        }
                        break;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            if (IsRowOutOfBounds(firstVisibleRowIndex))
                            {
                                return true;
                            }
                            SetSelectedRowCore(firstVisibleRowIndex, true);
                        }
                        else
                        {
                            if (targetRowIndex != _ptCurrentCell.Y || MultiSelect)
                            {
                                if (IsRowOutOfBounds(targetRowIndex))
                                {
                                    return true;
                                }
                                ClearSelection();
                                SetSelectedRowCore(targetRowIndex, true);
                            }
                        }
                        break;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }

            if (_ptCurrentCell.X == -1)
            {
                ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                {
                    return true;
                }

                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
            }
            else
            {
                if (IsInnerCellOutOfBounds(targetColumnIndex, targetRowIndex))
                {
                    return true;
                }

                SetCurrentCellAddressCore(targetColumnIndex, targetRowIndex, true, false, false);
            }
            return true;
        }

        private bool TabToPreviousCell()
        {
            DataGridViewColumn dataGridViewColumn = Columns.GetFirstColumn(DataGridViewElementStates.Visible);
            int firstVisibleColumnIndex = (dataGridViewColumn is null) ? -1 : dataGridViewColumn.Index;
            int firstVisibleRowIndex = Rows.GetFirstRow(DataGridViewElementStates.Visible);
            if (firstVisibleColumnIndex == -1 || firstVisibleRowIndex == -1)
            {
                return false;
            }

            int previousVisibleColumnIndex = -1;
            if (_ptCurrentCell.X != -1)
            {
                dataGridViewColumn = Columns.GetPreviousColumn(Columns[_ptCurrentCell.X],
                    DataGridViewElementStates.Visible,
                    DataGridViewElementStates.None);
                if (dataGridViewColumn != null)
                {
                    previousVisibleColumnIndex = dataGridViewColumn.Index;
                }
            }

            int previousVisibleRowIndex = -1;
            if (_ptCurrentCell.Y != -1)
            {
                previousVisibleRowIndex = Rows.GetPreviousRow(_ptCurrentCell.Y, DataGridViewElementStates.Visible);
            }

            dataGridViewColumn = Columns.GetLastColumn(DataGridViewElementStates.Visible,
                DataGridViewElementStates.None);
            Debug.Assert(dataGridViewColumn != null);
            int lastVisibleColumnIndex = dataGridViewColumn.Index;
            int lastVisibleRowIndex = Rows.GetLastRow(DataGridViewElementStates.Visible);
            Debug.Assert(lastVisibleRowIndex != -1);

            int targetRowIndex = -1, targetColumnIndex = -1;

            _noSelectionChangeCount++;
            try
            {
                if (_ptCurrentCell.X == -1)
                {
                    ClearSelection();
                }
                else
                {
                    if (previousVisibleColumnIndex == -1)
                    {
                        targetRowIndex = (previousVisibleRowIndex == -1) ? lastVisibleRowIndex : previousVisibleRowIndex;
                        targetColumnIndex = lastVisibleColumnIndex;
                    }
                    else
                    {
                        targetRowIndex = _ptCurrentCell.Y;
                        targetColumnIndex = previousVisibleColumnIndex;
                    }
                    if (!ScrollIntoView(targetColumnIndex, targetRowIndex, true))
                    {
                        return true;
                    }
                }

                switch (SelectionMode)
                {
                    case DataGridViewSelectionMode.CellSelect:
                    case DataGridViewSelectionMode.RowHeaderSelect:
                    case DataGridViewSelectionMode.ColumnHeaderSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                            {
                                return true;
                            }
                            SetSelectedCellCore(firstVisibleColumnIndex, firstVisibleRowIndex, true);
                        }
                        else
                        {
                            if (IsInnerCellOutOfBounds(targetColumnIndex, targetRowIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            SetSelectedCellCore(targetColumnIndex, targetRowIndex, true);
                        }
                        break;

                    case DataGridViewSelectionMode.FullColumnSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            if (IsColumnOutOfBounds(firstVisibleColumnIndex))
                            {
                                return true;
                            }
                            SetSelectedColumnCore(firstVisibleColumnIndex, true);
                        }
                        else
                        {
                            if (IsColumnOutOfBounds(targetColumnIndex))
                            {
                                return true;
                            }
                            ClearSelection();
                            SetSelectedColumnCore(targetColumnIndex, true);
                        }
                        break;

                    case DataGridViewSelectionMode.FullRowSelect:
                        if (_ptCurrentCell.X == -1)
                        {
                            if (IsRowOutOfBounds(firstVisibleRowIndex))
                            {
                                return true;
                            }
                            SetSelectedRowCore(firstVisibleRowIndex, true);
                        }
                        else
                        {
                            if (targetRowIndex != _ptCurrentCell.Y || MultiSelect)
                            {
                                if (IsRowOutOfBounds(targetRowIndex))
                                {
                                    return true;
                                }
                                ClearSelection();
                                SetSelectedRowCore(targetRowIndex, true);
                            }
                        }
                        break;
                }
            }
            finally
            {
                NoSelectionChangeCount--;
            }

            if (_ptCurrentCell.X == -1)
            {
                ScrollIntoView(firstVisibleColumnIndex, firstVisibleRowIndex, false);
                if (IsInnerCellOutOfBounds(firstVisibleColumnIndex, firstVisibleRowIndex))
                {
                    return true;
                }

                SetCurrentCellAddressCore(firstVisibleColumnIndex, firstVisibleRowIndex, true, false, false);
            }
            else
            {
                if (IsInnerCellOutOfBounds(targetColumnIndex, targetRowIndex))
                {
                    return true;
                }

                SetCurrentCellAddressCore(targetColumnIndex, targetRowIndex, true, false, false);
            }

            return true;
        }

        private void UnwireEditingControlEvents()
        {
            Debug.Assert(_editingPanel != null);
            _editingPanel.Click -= new EventHandler(EditingControls_Click);
            _editingPanel.DoubleClick -= new EventHandler(EditingControls_DoubleClick);
            _editingPanel.MouseClick -= new MouseEventHandler(EditingControls_MouseClick);
            _editingPanel.MouseDoubleClick -= new MouseEventHandler(EditingControls_MouseDoubleClick);
            _editingPanel.MouseDown -= new MouseEventHandler(EditingControls_MouseDown);
            _editingPanel.MouseEnter -= new EventHandler(EditingControls_MouseEnter);
            _editingPanel.MouseLeave -= new EventHandler(EditingControls_MouseLeave);
            _editingPanel.MouseMove -= new MouseEventHandler(EditingControls_MouseMove);
            _editingPanel.MouseUp -= new MouseEventHandler(EditingControls_MouseUp);

            Debug.Assert(EditingControl != null);
            EditingControl.Click -= new EventHandler(EditingControls_Click);
            EditingControl.DoubleClick -= new EventHandler(EditingControls_DoubleClick);
            EditingControl.MouseClick -= new MouseEventHandler(EditingControls_MouseClick);
            EditingControl.MouseDoubleClick -= new MouseEventHandler(EditingControls_MouseDoubleClick);
            EditingControl.MouseDown -= new MouseEventHandler(EditingControls_MouseDown);
            EditingControl.MouseEnter -= new EventHandler(EditingControls_MouseEnter);
            EditingControl.MouseLeave -= new EventHandler(EditingControls_MouseLeave);
            EditingControl.MouseMove -= new MouseEventHandler(EditingControls_MouseMove);
            EditingControl.MouseUp -= new MouseEventHandler(EditingControls_MouseUp);
        }

        private void UnwireScrollBarsEvents()
        {
            if (_horizScrollBar != null)
            {
                _horizScrollBar.MouseEnter -= new EventHandler(ScrollBar_MouseEnter);
                _horizScrollBar.MouseLeave -= new EventHandler(ScrollBar_MouseLeave);
            }
            if (_vertScrollBar != null)
            {
                _vertScrollBar.MouseEnter -= new EventHandler(ScrollBar_MouseEnter);
                _vertScrollBar.MouseLeave -= new EventHandler(ScrollBar_MouseLeave);
            }
        }

        public void UpdateCellErrorText(int columnIndex, int rowIndex)
        {
            if (columnIndex < -1 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }
            if (rowIndex < -1 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            if (IsHandleCreated)
            {
                InvalidateCellPrivate(columnIndex, rowIndex);
            }
        }

        public void UpdateCellValue(int columnIndex, int rowIndex)
        {
            if (columnIndex < 0 || columnIndex >= Columns.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(columnIndex));
            }
            if (rowIndex < 0 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            if (IsHandleCreated)
            {
                OnCellCommonChange(columnIndex, rowIndex);
            }
        }

        private void UpdateColumnsDisplayedState(bool displayed)
        {
            // Make sure all displayed frozen columns have their Displayed state set to this.Visible
            DataGridViewColumn dataGridViewColumnTmp;
            int numDisplayedFrozenCols = DisplayedBandsInfo.NumDisplayedFrozenCols;
            if (numDisplayedFrozenCols > 0)
            {
                dataGridViewColumnTmp = Columns.GetFirstColumn(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                while (numDisplayedFrozenCols > 0)
                {
                    Debug.Assert(dataGridViewColumnTmp != null);
                    if (dataGridViewColumnTmp.Displayed != displayed)
                    {
                        dataGridViewColumnTmp.Displayed = displayed;
                        Debug.Assert(ColumnNeedsDisplayedState(dataGridViewColumnTmp));
                    }
                    dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen, DataGridViewElementStates.None);
                    numDisplayedFrozenCols--;
                }
            }

            // Make sure all displayed scrolling columns have the Displayed state set to this.Visible
            int columnIndexTmp = DisplayedBandsInfo.FirstDisplayedScrollingCol;
            if (columnIndexTmp != -1)
            {
                int numDisplayedScrollingCols = DisplayedBandsInfo.NumDisplayedScrollingCols;
                Debug.Assert(numDisplayedScrollingCols > 0);
                dataGridViewColumnTmp = Columns[columnIndexTmp];
                while (numDisplayedScrollingCols > 0)
                {
                    Debug.Assert(dataGridViewColumnTmp != null);
                    if (dataGridViewColumnTmp.Displayed != displayed)
                    {
                        dataGridViewColumnTmp.Displayed = displayed;
                        Debug.Assert(ColumnNeedsDisplayedState(dataGridViewColumnTmp));
                    }
                    dataGridViewColumnTmp = Columns.GetNextColumn(dataGridViewColumnTmp, DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    numDisplayedScrollingCols--;
                }
            }
        }

        public void UpdateRowErrorText(int rowIndex)
        {
            if (rowIndex < 0 || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }
            if (IsHandleCreated && _layout.RowHeadersVisible)
            {
                InvalidateCellPrivate(-1, rowIndex);
            }
        }

        public void UpdateRowErrorText(int rowIndexStart, int rowIndexEnd)
        {
            if (rowIndexStart < 0 || rowIndexStart >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndexStart));
            }
            if (rowIndexEnd < 0 || rowIndexEnd >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndexEnd));
            }
            if (rowIndexEnd < rowIndexStart)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndexEnd));
            }
            if (IsHandleCreated && _layout.RowHeadersVisible)
            {
                Rectangle rectUpper = GetCellAdjustedDisplayRectangle(-1, rowIndexStart, true);
                Rectangle rectLower = GetCellAdjustedDisplayRectangle(-1, rowIndexEnd, true);
                if (rectUpper.IsEmpty || rectLower.IsEmpty)
                {
                    if (!rectUpper.IsEmpty || !rectLower.IsEmpty)
                    {
                        Invalidate(_layout.RowHeaders);
                    }
                }
                else
                {
                    Invalidate(Rectangle.Union(rectUpper, rectLower));
                }
            }
        }

        public void UpdateRowHeightInfo(int rowIndex, bool updateToEnd)
        {
            UpdateRowHeightInfoPrivate(rowIndex, updateToEnd, true /*invalidInAdjustFillingColumns*/);
        }

        private void UpdateRowHeightInfoPrivate(int rowIndex, bool updateToEnd, bool invalidInAdjustFillingColumns)
        {
            if ((updateToEnd && rowIndex < 0) || (!updateToEnd && rowIndex < -1) || rowIndex >= Rows.Count)
            {
                throw new ArgumentOutOfRangeException(nameof(rowIndex));
            }

            Rows.InvalidateCachedRowsHeights();

            bool rowVisible = (rowIndex >= 0 && (Rows.GetRowState(rowIndex) & DataGridViewElementStates.Visible) != 0);

            // don't do any layout logic if the handled was not created already
            if (IsHandleCreated && (rowIndex == -1 || rowVisible))
            {
                if (updateToEnd)
                {
                    int oldFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;

                    if (AutoSize)
                    {
                        LayoutTransaction.DoLayout(ParentInternal, this, PropertyNames.Rows);
                    }
                    else
                    {
                        PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, invalidInAdjustFillingColumns, false /*repositionEditingControl*/);
                    }

                    Rectangle bottomArea = _layout.Data;
                    if (_layout.RowHeadersVisible)
                    {
                        bottomArea = Rectangle.Union(bottomArea, _layout.RowHeaders);
                    }
                    else if (SingleVerticalBorderAdded)
                    {
                        if (!RightToLeftInternal)
                        {
                            bottomArea.X--;
                        }
                        bottomArea.Width++;
                    }

                    if (!rowVisible)
                    {
                        rowIndex = Rows.GetNextRow(rowIndex, DataGridViewElementStates.Visible);
                    }
                    if (rowIndex != -1)
                    {
                        int topEdge = GetRowYFromIndex(oldFirstVisibleScrollingRow == DisplayedBandsInfo.FirstDisplayedScrollingRow ? rowIndex : DisplayedBandsInfo.FirstDisplayedScrollingRow);
                        bottomArea.Height -= bottomArea.Y - topEdge;
                        bottomArea.Y = topEdge;
                        Invalidate(bottomArea);
                    }

                    if (EditingControl != null)
                    {
                        PositionEditingControl(true /*setLocation*/, true /*setSize*/, false /*setFocus*/);
                    }
                }
                else
                {
                    if (rowIndex == -1)
                    {
                        if (AutoSize)
                        {
                            LayoutTransaction.DoLayout(ParentInternal, this, PropertyNames.Rows);
                        }
                        else
                        {
                            PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, invalidInAdjustFillingColumns, false /*repositionEditingControl*/);
                        }
                        Invalidate();
                    }
                    else
                    {
                        Debug.Assert(rowVisible);
                        int oldFirstVisibleScrollingRow = DisplayedBandsInfo.FirstDisplayedScrollingRow;

                        if (_inBulkLayoutCount == 0)
                        {
                            if (AutoSize)
                            {
                                LayoutTransaction.DoLayout(ParentInternal, this, PropertyNames.Rows);
                            }
                            else
                            {
                                PerformLayoutPrivate(false /*useRowShortcut*/, false /*computeVisibleRows*/, invalidInAdjustFillingColumns, false /*repositionEditingControl*/);
                            }
                        }

                        if (_inBulkPaintCount == 0)
                        {
                            Rectangle bottomArea = _layout.Data;
                            if (_layout.RowHeadersVisible)
                            {
                                bottomArea = Rectangle.Union(bottomArea, _layout.RowHeaders);
                            }
                            else if (SingleVerticalBorderAdded)
                            {
                                if (!RightToLeftInternal)
                                {
                                    bottomArea.X--;
                                }
                                bottomArea.Width++;
                            }
                            int topEdge = GetRowYFromIndex(oldFirstVisibleScrollingRow == DisplayedBandsInfo.FirstDisplayedScrollingRow ? rowIndex : DisplayedBandsInfo.FirstDisplayedScrollingRow);
                            bottomArea.Height -= bottomArea.Y - topEdge;
                            bottomArea.Y = topEdge;
                            Invalidate(bottomArea);
                        }
                    }

                    if (EditingControl != null)
                    {
                        PositionEditingControl(rowIndex == -1 || _ptCurrentCell.Y != rowIndex, true, false);
                    }
                }

                UpdateMouseEnteredCell(hti: null, e: null);
            }
        }

        private void UpdateRowsDisplayedState(bool displayed)
        {
            // Make sure all displayed frozen rows have their Displayed state set to 'displayed'
            int rowIndexTmp, numDisplayedFrozenRows = DisplayedBandsInfo.NumDisplayedFrozenRows;
            if (numDisplayedFrozenRows > 0)
            {
                rowIndexTmp = Rows.GetFirstRow(DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                while (numDisplayedFrozenRows > 0)
                {
                    Debug.Assert(rowIndexTmp != -1);
                    if (((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) == 0) == displayed)
                    {
                        Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, displayed);
                    }
                    rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen);
                    numDisplayedFrozenRows--;
                }
            }

            // Make sure all displayed scrolling rows have their Displayed state set to 'displayed'
            rowIndexTmp = DisplayedBandsInfo.FirstDisplayedScrollingRow;
            if (rowIndexTmp > -1)
            {
                int numDisplayedScrollingRows = DisplayedBandsInfo.NumDisplayedScrollingRows;
                Debug.Assert(numDisplayedScrollingRows > 0);
                while (numDisplayedScrollingRows > 0)
                {
                    Debug.Assert(rowIndexTmp != -1);
                    if (((Rows.GetRowState(rowIndexTmp) & DataGridViewElementStates.Displayed) == 0) == displayed)
                    {
                        Rows.SetRowState(rowIndexTmp, DataGridViewElementStates.Displayed, displayed);
                    }
                    rowIndexTmp = Rows.GetNextRow(rowIndexTmp, DataGridViewElementStates.Visible);
                    numDisplayedScrollingRows--;
                }
            }
        }

        private void UpdateMouseEnteredCell(HitTestInfo hti, MouseEventArgs e)
        {
            // Don't force handle creation.
            if (!IsHandleCreated)
            {
                return;
            }

            Point ptMouse = PointToClient(Control.MousePosition);
            HitTestInfo htiToUse;
            if (hti != null)
            {
                htiToUse = hti;
            }
            else
            {
                htiToUse = HitTest(ptMouse.X, ptMouse.Y);
            }

            if (htiToUse.Type != DataGridViewHitTestType.None &&
                htiToUse.Type != DataGridViewHitTestType.HorizontalScrollBar &&
                htiToUse.Type != DataGridViewHitTestType.VerticalScrollBar)
            {
                if (_ptMouseEnteredCell.X != htiToUse._col || _ptMouseEnteredCell.Y != htiToUse._row)
                {
                    DataGridViewCellEventArgs dgvce;
                    if (_ptMouseEnteredCell.X >= -1 &&
                        _ptMouseEnteredCell.X < Columns.Count &&
                        _ptMouseEnteredCell.Y >= -1 &&
                        _ptMouseEnteredCell.Y < Rows.Count)
                    {
                        dgvce = new DataGridViewCellEventArgs(_ptMouseEnteredCell.X, _ptMouseEnteredCell.Y);
                        OnCellMouseLeave(dgvce);
                    }
                    dgvce = new DataGridViewCellEventArgs(htiToUse._col, htiToUse._row);
                    OnCellMouseEnter(dgvce);
                }
                if (e != null)
                {
                    int mouseX = e.X - htiToUse.ColumnX;
                    if (RightToLeftInternal)
                    {
                        mouseX += ((htiToUse._col == -1) ? RowHeadersWidth : Columns[htiToUse._col].Thickness);
                    }
                    DataGridViewCellMouseEventArgs dgvcme = new DataGridViewCellMouseEventArgs(htiToUse._col, htiToUse._row, mouseX, e.Y - htiToUse.RowY, e);
                    OnCellMouseMove(dgvcme);
                }
            }
            else if (_ptMouseEnteredCell.X != -2)
            {
                if (_ptMouseEnteredCell.X >= -1 &&
                    _ptMouseEnteredCell.X < Columns.Count &&
                    _ptMouseEnteredCell.Y >= -1 &&
                    _ptMouseEnteredCell.Y < Rows.Count)
                {
                    DataGridViewCellEventArgs dgvce = new DataGridViewCellEventArgs(_ptMouseEnteredCell.X, _ptMouseEnteredCell.Y);
                    OnCellMouseLeave(dgvce);
                }
                else
                {
                    _ptMouseEnteredCell.X = _ptMouseEnteredCell.Y = -2;
                }
            }
        }

        private void UpdateSelectedCellsBlock(int anchorColumnIndex, ref int oldEdgeColumnIndex, int newEdgeColumnIndex,
            int anchorRowIndex, ref int oldEdgeRowIndex, int newEdgeRowIndex)
        {
            Debug.Assert(anchorColumnIndex >= 0);
            Debug.Assert(anchorRowIndex >= 0);
            Debug.Assert(newEdgeColumnIndex >= 0);
            Debug.Assert(newEdgeRowIndex >= 0);
            Debug.Assert(_noSelectionChangeCount > 0);
            if ((Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex) &&
                Columns.DisplayInOrder(newEdgeColumnIndex, anchorColumnIndex)) ||
                (Columns.DisplayInOrder(oldEdgeColumnIndex, anchorColumnIndex) &&
                Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex)) ||
                (anchorRowIndex < oldEdgeRowIndex && newEdgeRowIndex < anchorRowIndex) ||
                (oldEdgeRowIndex < anchorRowIndex && anchorRowIndex < newEdgeRowIndex))
            {
                // deselecting all selected block
                SelectCellUnorderedRange(anchorColumnIndex, anchorRowIndex, oldEdgeColumnIndex, oldEdgeRowIndex, false);
                // and reselecting new block
                SelectCellUnorderedRange(anchorColumnIndex, anchorRowIndex, newEdgeColumnIndex, newEdgeRowIndex, true);
                oldEdgeColumnIndex = newEdgeColumnIndex;
                oldEdgeRowIndex = newEdgeRowIndex;
                return;
            }

            if (Columns.DisplayInOrder(oldEdgeColumnIndex, newEdgeColumnIndex) &&
                (Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex) || anchorColumnIndex == oldEdgeColumnIndex) &&
                oldEdgeRowIndex == newEdgeRowIndex)
            {
                // h1
                DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                Debug.Assert(dataGridViewColumn != null);
                if (anchorRowIndex <= newEdgeRowIndex)
                {
                    SelectCellRange(dataGridViewColumn.Index, anchorRowIndex, newEdgeColumnIndex, newEdgeRowIndex, true);
                }
                else
                {
                    // newEdgeRowIndex < anchorRowIndex
                    SelectCellRange(dataGridViewColumn.Index, newEdgeRowIndex, newEdgeColumnIndex, anchorRowIndex, true);
                }
            }
            else if (Columns.DisplayInOrder(newEdgeColumnIndex, oldEdgeColumnIndex) &&
                (Columns.DisplayInOrder(oldEdgeColumnIndex, anchorColumnIndex) || oldEdgeColumnIndex == anchorColumnIndex) &&
                oldEdgeRowIndex == newEdgeRowIndex)
            {
                // h2
                DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                Debug.Assert(dataGridViewColumn != null);
                if (anchorRowIndex <= newEdgeRowIndex)
                {
                    SelectCellRange(newEdgeColumnIndex, anchorRowIndex, dataGridViewColumn.Index, newEdgeRowIndex, true);
                }
                else
                {
                    // newEdgeRowIndex < anchorRowIndex
                    SelectCellRange(newEdgeColumnIndex, newEdgeRowIndex, dataGridViewColumn.Index, anchorRowIndex, true);
                }
            }
            else if (newEdgeRowIndex > oldEdgeRowIndex &&
                anchorRowIndex <= oldEdgeRowIndex &&
                newEdgeColumnIndex == oldEdgeColumnIndex)
            {
                // h3
                if (Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex) || anchorColumnIndex == newEdgeColumnIndex)
                {
                    SelectCellRange(anchorColumnIndex,
                        Rows.GetNextRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                        newEdgeColumnIndex,
                        newEdgeRowIndex,
                        true);
                }
                else
                {
                    // newEdgeColumnIndex before anchorColumnIndex
                    SelectCellRange(newEdgeColumnIndex,
                        Rows.GetNextRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                        anchorColumnIndex,
                        newEdgeRowIndex,
                        true);
                }
            }
            else if (newEdgeRowIndex < oldEdgeRowIndex &&
                oldEdgeRowIndex <= anchorRowIndex &&
                newEdgeColumnIndex == oldEdgeColumnIndex)
            {
                // h4
                if (Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex) || anchorColumnIndex == newEdgeColumnIndex)
                {
                    SelectCellRange(anchorColumnIndex,
                        newEdgeRowIndex,
                        newEdgeColumnIndex,
                        Rows.GetPreviousRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                        true);
                }
                else
                {
                    // newEdgeColumnIndex before anchorColumnIndex
                    SelectCellRange(newEdgeColumnIndex,
                        newEdgeRowIndex,
                        anchorColumnIndex,
                        Rows.GetPreviousRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                        true);
                }
            }
            else if (Columns.DisplayInOrder(oldEdgeColumnIndex, newEdgeColumnIndex) &&
                !Columns.DisplayInOrder(oldEdgeColumnIndex, anchorColumnIndex) &&
                newEdgeRowIndex > oldEdgeRowIndex && anchorRowIndex <= oldEdgeRowIndex)
            {
                // h5
                DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                Debug.Assert(dataGridViewColumn != null);
                SelectCellRange(dataGridViewColumn.Index, anchorRowIndex, newEdgeColumnIndex, oldEdgeRowIndex, true);
                SelectCellRange(anchorColumnIndex,
                    Rows.GetNextRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                    newEdgeColumnIndex,
                    newEdgeRowIndex,
                    true);
            }
            else if (Columns.DisplayInOrder(oldEdgeColumnIndex, newEdgeColumnIndex) &&
                newEdgeRowIndex < oldEdgeRowIndex && oldEdgeRowIndex <= anchorRowIndex)
            {
                if (!Columns.DisplayInOrder(oldEdgeColumnIndex, anchorColumnIndex))
                {
                    // h6
                    DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectCellRange(dataGridViewColumn.Index, oldEdgeRowIndex, newEdgeColumnIndex, anchorRowIndex, true);
                    SelectCellRange(anchorColumnIndex,
                        newEdgeRowIndex,
                        newEdgeColumnIndex,
                        Rows.GetPreviousRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                        true);
                }
                else
                {
                    if (!Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex))
                    {
                        if (anchorRowIndex == oldEdgeRowIndex)
                        {
                            // g2
                            SelectCellRange(oldEdgeColumnIndex, anchorRowIndex, anchorColumnIndex, oldEdgeRowIndex, false);
                            SelectCellRange(newEdgeColumnIndex, newEdgeRowIndex, anchorColumnIndex, anchorRowIndex, true);
                        }
                        else
                        {
                            // b4
                            DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[newEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                            Debug.Assert(dataGridViewColumn != null);
                            Debug.Assert(oldEdgeRowIndex < anchorRowIndex);
                            SelectCellRange(oldEdgeColumnIndex, oldEdgeRowIndex, dataGridViewColumn.Index, anchorRowIndex, false);
                            SelectCellRange(newEdgeColumnIndex,
                                newEdgeRowIndex,
                                anchorColumnIndex,
                                Rows.GetPreviousRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                                true);
                        }
                    }
                }
            }
            else if (Columns.DisplayInOrder(newEdgeColumnIndex, oldEdgeColumnIndex) &&
                newEdgeRowIndex < oldEdgeRowIndex && anchorRowIndex >= oldEdgeRowIndex)
            {
                if (!Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex))
                {
                    // h7
                    DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                    Debug.Assert(dataGridViewColumn != null);
                    SelectCellRange(newEdgeColumnIndex, oldEdgeRowIndex, dataGridViewColumn.Index, anchorRowIndex, true);
                    SelectCellRange(newEdgeColumnIndex,
                        newEdgeRowIndex,
                        anchorColumnIndex,
                        Rows.GetPreviousRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                        true);
                }
                else
                {
                    if (Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex))
                    {
                        // a4
                        DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[newEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                        Debug.Assert(dataGridViewColumn != null);
                        Debug.Assert(oldEdgeRowIndex <= anchorRowIndex);
                        SelectCellRange(dataGridViewColumn.Index, oldEdgeRowIndex, oldEdgeColumnIndex, anchorRowIndex, false);
                        SelectCellRange(anchorColumnIndex,
                            newEdgeRowIndex,
                            newEdgeColumnIndex,
                            Rows.GetPreviousRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                            true);
                    }
                    else
                    {
                        // g8
                        SelectCellRange(anchorColumnIndex, oldEdgeRowIndex, oldEdgeColumnIndex, anchorRowIndex, false);
                        SelectCellRange(newEdgeColumnIndex, newEdgeRowIndex, anchorColumnIndex, anchorRowIndex, true);
                    }
                }
            }
            else if (Columns.DisplayInOrder(newEdgeColumnIndex, oldEdgeColumnIndex) &&
                !Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex) &&
                newEdgeRowIndex > oldEdgeRowIndex && anchorRowIndex <= oldEdgeRowIndex)
            {
                // h8
                DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                Debug.Assert(dataGridViewColumn != null);
                SelectCellRange(newEdgeColumnIndex, anchorRowIndex, dataGridViewColumn.Index, oldEdgeRowIndex, true);
                SelectCellRange(newEdgeColumnIndex,
                    Rows.GetNextRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                    anchorColumnIndex,
                    newEdgeRowIndex,
                    true);
            }
            else if (Columns.DisplayInOrder(newEdgeColumnIndex, oldEdgeColumnIndex))
            {
                DataGridViewColumn dataGridViewColumn = Columns.GetNextColumn(Columns[newEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                if (newEdgeRowIndex == oldEdgeRowIndex)
                {
                    if (Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex) || (anchorColumnIndex == newEdgeColumnIndex))
                    {
                        // a1
                        Debug.Assert(dataGridViewColumn != null);
                        if (oldEdgeRowIndex > anchorRowIndex)
                        {
                            SelectCellRange(dataGridViewColumn.Index, anchorRowIndex, oldEdgeColumnIndex, oldEdgeRowIndex, false);
                        }
                        else
                        {
                            SelectCellRange(dataGridViewColumn.Index, oldEdgeRowIndex, oldEdgeColumnIndex, anchorRowIndex, false);
                        }
                    }
                }
                else if (newEdgeRowIndex < oldEdgeRowIndex)
                {
                    if (oldEdgeRowIndex > anchorRowIndex)
                    {
                        if (Columns.DisplayInOrder(newEdgeColumnIndex, oldEdgeColumnIndex))
                        {
                            if (anchorRowIndex <= newEdgeRowIndex)
                            {
                                if (Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex))
                                {
                                    if (!Columns.DisplayInOrder(newEdgeColumnIndex, anchorColumnIndex))
                                    {
                                        // a2
                                        Debug.Assert(dataGridViewColumn != null);
                                        SelectCellRange(dataGridViewColumn.Index, anchorRowIndex, oldEdgeColumnIndex, oldEdgeRowIndex, false);
                                        SelectCellRange(anchorColumnIndex,
                                            Rows.GetNextRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                            newEdgeColumnIndex,
                                            oldEdgeRowIndex,
                                            false);
                                    }
                                }
                                else
                                {
                                    // d3
                                    dataGridViewColumn = Columns.GetPreviousColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    Debug.Assert(dataGridViewColumn != null);
                                    SelectCellRange(oldEdgeColumnIndex,
                                        Rows.GetNextRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                        anchorColumnIndex,
                                        oldEdgeRowIndex,
                                        false);
                                    SelectCellRange(newEdgeColumnIndex,
                                        anchorRowIndex,
                                        dataGridViewColumn.Index,
                                        newEdgeRowIndex,
                                        true);
                                }
                            }
                        }
                    }
                }
                else if (newEdgeRowIndex > oldEdgeRowIndex)
                {
                    if (oldEdgeRowIndex < anchorRowIndex)
                    {
                        if ((Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex) || (anchorColumnIndex == newEdgeColumnIndex)) &&
                            newEdgeRowIndex <= anchorRowIndex)
                        {
                            // a3
                            Debug.Assert(dataGridViewColumn != null);
                            SelectCellRange(dataGridViewColumn.Index, oldEdgeRowIndex, oldEdgeColumnIndex, anchorRowIndex, false);
                            SelectCellRange(anchorColumnIndex,
                                oldEdgeRowIndex,
                                newEdgeColumnIndex,
                                Rows.GetPreviousRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                false);
                        }
                        else
                        {
                            if (!Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex))
                            {
                                if (newEdgeRowIndex <= anchorRowIndex)
                                {
                                    // c3
                                    dataGridViewColumn = Columns.GetPreviousColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    Debug.Assert(dataGridViewColumn != null);
                                    SelectCellRange(oldEdgeColumnIndex,
                                        oldEdgeRowIndex,
                                        anchorColumnIndex,
                                        Rows.GetPreviousRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                        false);
                                    SelectCellRange(newEdgeColumnIndex,
                                        newEdgeRowIndex,
                                        dataGridViewColumn.Index,
                                        anchorRowIndex,
                                        true);
                                }
                            }
                        }
                    }
                    else
                    {
                        if (Columns.DisplayInOrder(anchorColumnIndex, newEdgeColumnIndex) || (anchorColumnIndex == newEdgeColumnIndex))
                        {
                            // a5
                            Debug.Assert(oldEdgeRowIndex >= anchorRowIndex);
                            Debug.Assert(dataGridViewColumn != null);
                            SelectCellRange(dataGridViewColumn.Index, anchorRowIndex, oldEdgeColumnIndex, oldEdgeRowIndex, false);
                            SelectCellRange(anchorColumnIndex,
                                Rows.GetNextRow(anchorRowIndex, DataGridViewElementStates.Visible),
                                newEdgeColumnIndex,
                                newEdgeRowIndex,
                                true);
                        }
                    }
                }
            }
            else if (Columns.DisplayInOrder(oldEdgeColumnIndex, newEdgeColumnIndex))
            {
                DataGridViewColumn dataGridViewColumn = Columns.GetPreviousColumn(Columns[newEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                if (newEdgeRowIndex == oldEdgeRowIndex)
                {
                    if (Columns.DisplayInOrder(newEdgeColumnIndex, anchorColumnIndex) || (newEdgeColumnIndex == anchorColumnIndex))
                    {
                        // b1
                        Debug.Assert(dataGridViewColumn != null);
                        if (oldEdgeRowIndex > anchorRowIndex)
                        {
                            SelectCellRange(oldEdgeColumnIndex, anchorRowIndex, dataGridViewColumn.Index, oldEdgeRowIndex, false);
                        }
                        else
                        {
                            SelectCellRange(oldEdgeColumnIndex, oldEdgeRowIndex, dataGridViewColumn.Index, anchorRowIndex, false);
                        }
                    }
                }
                else if (newEdgeRowIndex < oldEdgeRowIndex)
                {
                    if (oldEdgeRowIndex > anchorRowIndex)
                    {
                        if ((Columns.DisplayInOrder(newEdgeColumnIndex, anchorColumnIndex) || (newEdgeColumnIndex == anchorColumnIndex)) &&
                            newEdgeRowIndex >= anchorRowIndex)
                        {
                            // b2
                            SelectCellRange(oldEdgeColumnIndex, anchorRowIndex, dataGridViewColumn.Index, oldEdgeRowIndex, false);
                            SelectCellRange(newEdgeColumnIndex,
                                Rows.GetNextRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                anchorColumnIndex,
                                oldEdgeRowIndex,
                                false);
                        }
                        else
                        {
                            if (!Columns.DisplayInOrder(oldEdgeColumnIndex, anchorColumnIndex))
                            {
                                if (newEdgeRowIndex >= anchorRowIndex)
                                {
                                    // d2
                                    dataGridViewColumn = Columns.GetNextColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    Debug.Assert(dataGridViewColumn != null);
                                    SelectCellRange(anchorColumnIndex,
                                        Rows.GetNextRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                        oldEdgeColumnIndex,
                                        oldEdgeRowIndex,
                                        false);
                                    SelectCellRange(dataGridViewColumn.Index,
                                        anchorRowIndex,
                                        newEdgeColumnIndex,
                                        newEdgeRowIndex,
                                        true);
                                }
                            }
                        }
                    }
                }
                else if (newEdgeRowIndex > oldEdgeRowIndex)
                {
                    if (oldEdgeRowIndex < anchorRowIndex)
                    {
                        if ((Columns.DisplayInOrder(newEdgeColumnIndex, anchorColumnIndex) || (anchorColumnIndex == newEdgeColumnIndex)) &&
                            newEdgeRowIndex <= anchorRowIndex)
                        {
                            // b3
                            SelectCellRange(oldEdgeColumnIndex, oldEdgeRowIndex, dataGridViewColumn.Index, anchorRowIndex, false);
                            SelectCellRange(newEdgeColumnIndex,
                                oldEdgeRowIndex,
                                anchorColumnIndex,
                                Rows.GetPreviousRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                false);
                        }
                        else
                        {
                            if (!Columns.DisplayInOrder(oldEdgeColumnIndex, anchorColumnIndex))
                            {
                                if (newEdgeRowIndex <= anchorRowIndex)
                                {
                                    // c2
                                    dataGridViewColumn = Columns.GetNextColumn(Columns[oldEdgeColumnIndex], DataGridViewElementStates.Visible, DataGridViewElementStates.None);
                                    Debug.Assert(dataGridViewColumn != null);
                                    SelectCellRange(anchorColumnIndex,
                                        oldEdgeRowIndex,
                                        oldEdgeColumnIndex,
                                        Rows.GetPreviousRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                        false);
                                    SelectCellRange(dataGridViewColumn.Index,
                                        newEdgeRowIndex,
                                        newEdgeColumnIndex,
                                        anchorRowIndex,
                                        true);
                                }
                            }
                        }
                    }
                    else
                    {
                        if (Columns.DisplayInOrder(newEdgeColumnIndex, anchorColumnIndex) || (anchorColumnIndex == newEdgeColumnIndex))
                        {
                            // b5
                            Debug.Assert(oldEdgeRowIndex >= anchorRowIndex);
                            SelectCellRange(oldEdgeColumnIndex, anchorRowIndex, dataGridViewColumn.Index, oldEdgeRowIndex, false);
                            SelectCellRange(newEdgeColumnIndex,
                                Rows.GetNextRow(oldEdgeRowIndex, DataGridViewElementStates.Visible),
                                anchorColumnIndex,
                                newEdgeRowIndex,
                                true);
                        }
                    }
                }
            }
            else if (newEdgeRowIndex > oldEdgeRowIndex)
            {
                if (newEdgeColumnIndex == oldEdgeColumnIndex)
                {
                    if (newEdgeRowIndex <= anchorRowIndex)
                    {
                        // c1
                        if (Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex))
                        {
                            SelectCellRange(anchorColumnIndex,
                                oldEdgeRowIndex,
                                oldEdgeColumnIndex,
                                Rows.GetPreviousRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                false);
                        }
                        else
                        {
                            SelectCellRange(oldEdgeColumnIndex,
                                oldEdgeRowIndex,
                                anchorColumnIndex,
                                Rows.GetPreviousRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                false);
                        }
                    }
                }
            }
            else if (newEdgeRowIndex < oldEdgeRowIndex)
            {
                if (newEdgeColumnIndex == oldEdgeColumnIndex)
                {
                    if (newEdgeRowIndex >= anchorRowIndex)
                    {
                        // d1
                        if (Columns.DisplayInOrder(anchorColumnIndex, oldEdgeColumnIndex))
                        {
                            SelectCellRange(anchorColumnIndex,
                                Rows.GetNextRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                oldEdgeColumnIndex,
                                oldEdgeRowIndex,
                                false);
                        }
                        else
                        {
                            SelectCellRange(oldEdgeColumnIndex,
                                Rows.GetNextRow(newEdgeRowIndex, DataGridViewElementStates.Visible),
                                anchorColumnIndex,
                                oldEdgeRowIndex,
                                false);
                        }
                    }
                }
            }
            oldEdgeColumnIndex = newEdgeColumnIndex;
            oldEdgeRowIndex = newEdgeRowIndex;
        }

        private void VertScrollTimer_Tick(object sender, EventArgs e)
        {
            BeginInvoke(new MethodInvoker(VertScrollTimerHandler));
        }

        private void VertScrollTimerHandler()
        {
            // Why would the vertical scroll timer be enabled when vertical selection is not occurring
            Debug.Assert(_dataGridViewOper[OperationTrackRowSelect] || _dataGridViewOper[OperationTrackCellSelect]);

            Point ptMouse = PointToClient(Control.MousePosition);
            HitTestInfo hti = HitTest(ptMouse.X, ptMouse.Y);
            int mouseX = ptMouse.X, mouseY = ptMouse.Y;

            if (GetOutOfBoundCorrectedHitTestInfo(ref hti, ref mouseX, ref mouseY, out int xOffset, out int yOffset))
            {
                if (yOffset != 0)
                {
                    int absYOffset = Math.Abs(yOffset), normOffset = yOffset / absYOffset;
                    ScrollRowsByCount(normOffset, normOffset < 0 ? ScrollEventType.SmallDecrement : ScrollEventType.SmallIncrement);
                    _vertScrollTimer.Interval = GetRowScrollRate(absYOffset);
                    if (_dataGridViewOper[OperationTrackRowSelect])
                    {
                        hti = HitTest(mouseX, ptMouse.Y - yOffset - normOffset);
                        if (hti._row >= 0)
                        {
                            OnRowSelectMouseMove(hti);
                        }
                    }
                    else if (_dataGridViewOper[OperationTrackCellSelect])
                    {
                        if (xOffset != 0)
                        {
                            hti = HitTest(ptMouse.X - xOffset - (xOffset / Math.Abs(xOffset)), ptMouse.Y - yOffset - normOffset);
                        }
                        else
                        {
                            hti = HitTest(mouseX, ptMouse.Y - yOffset - normOffset);
                        }
                        if (hti._col >= 0 && hti._row >= 0)
                        {
                            OnCellSelectMouseMove(hti);
                        }
                    }
                }
                else
                {
                    if (_dataGridViewOper[OperationTrackRowSelect] && hti._row >= 0)
                    {
                        OnRowSelectMouseMove(hti);
                    }
                    else if (_dataGridViewOper[OperationTrackCellSelect] && hti._col >= 0 && hti._row >= 0)
                    {
                        OnCellSelectMouseMove(hti);
                    }
                    VertScrollTimer.Enabled = false;
                }
            }
        }

        private void WireEditingControlEvents()
        {
            Debug.Assert(_editingPanel != null);
            _editingPanel.Click += new EventHandler(EditingControls_Click);
            _editingPanel.DoubleClick += new EventHandler(EditingControls_DoubleClick);
            _editingPanel.MouseClick += new MouseEventHandler(EditingControls_MouseClick);
            _editingPanel.MouseDoubleClick += new MouseEventHandler(EditingControls_MouseDoubleClick);
            _editingPanel.MouseDown += new MouseEventHandler(EditingControls_MouseDown);
            _editingPanel.MouseEnter += new EventHandler(EditingControls_MouseEnter);
            _editingPanel.MouseLeave += new EventHandler(EditingControls_MouseLeave);
            _editingPanel.MouseMove += new MouseEventHandler(EditingControls_MouseMove);
            _editingPanel.MouseUp += new MouseEventHandler(EditingControls_MouseUp);

            Debug.Assert(EditingControl != null);
            EditingControl.Click += new EventHandler(EditingControls_Click);
            EditingControl.DoubleClick += new EventHandler(EditingControls_DoubleClick);
            EditingControl.MouseClick += new MouseEventHandler(EditingControls_MouseClick);
            EditingControl.MouseDoubleClick += new MouseEventHandler(EditingControls_MouseDoubleClick);
            EditingControl.MouseDown += new MouseEventHandler(EditingControls_MouseDown);
            EditingControl.MouseEnter += new EventHandler(EditingControls_MouseEnter);
            EditingControl.MouseLeave += new EventHandler(EditingControls_MouseLeave);
            EditingControl.MouseMove += new MouseEventHandler(EditingControls_MouseMove);
            EditingControl.MouseUp += new MouseEventHandler(EditingControls_MouseUp);
        }

        private void WireScrollBarsEvents()
        {
            if (_horizScrollBar != null)
            {
                _horizScrollBar.MouseEnter += new EventHandler(ScrollBar_MouseEnter);
                _horizScrollBar.MouseLeave += new EventHandler(ScrollBar_MouseLeave);
            }
            if (_vertScrollBar != null)
            {
                _vertScrollBar.MouseEnter += new EventHandler(ScrollBar_MouseEnter);
                _vertScrollBar.MouseLeave += new EventHandler(ScrollBar_MouseLeave);
            }
        }

        /// <summary>
        ///  Handles the WM_CONTEXTMENU message
        /// </summary>
        internal override void WmContextMenu(ref Message m)
        {
            ContextMenuStrip contextMenuStrip;
            int x = unchecked((int)(short)(long)m.LParam);
            int y = unchecked((int)(long)m.LParam) >> 16;
            Point client;
            bool keyboardActivated = false;
            // lparam will be exactly -1 when the user invokes the context menu
            // with the keyboard.
            //
            if (unchecked((int)(long)m.LParam) == -1)
            {
                keyboardActivated = true;
                client = new Point(Width / 2, Height / 2);
                contextMenuStrip = (ContextMenuStrip)ContextMenuStrip;
            }
            else
            {
                client = PointToClient(new Point(x, y));
                HitTestInfo hti = HitTest(client.X, client.Y);
                DataGridViewCell dataGridViewCell = null;
                switch (hti.Type)
                {
                    case DataGridViewHitTestType.Cell:
                        dataGridViewCell = Rows.SharedRow(hti._row).Cells[hti._col];
                        break;
                    case DataGridViewHitTestType.ColumnHeader:
                        Debug.Assert(hti._row == -1);
                        dataGridViewCell = Columns[hti._col].HeaderCell;
                        break;
                    case DataGridViewHitTestType.RowHeader:
                        Debug.Assert(hti._col == -1);
                        dataGridViewCell = Rows.SharedRow(hti._row).HeaderCell;
                        break;
                    case DataGridViewHitTestType.TopLeftHeader:
                        Debug.Assert(hti._row == -1);
                        Debug.Assert(hti._col == -1);
                        dataGridViewCell = TopLeftHeaderCell;
                        break;
                }
                if (dataGridViewCell != null)
                {
                    contextMenuStrip = dataGridViewCell.GetInheritedContextMenuStrip(hti._row);
                }
                else
                {
                    contextMenuStrip = (ContextMenuStrip)ContextMenuStrip;
                }
            }

            // VisualStudio7 # 156, only show the context menu when clicked in the client area
            if (contextMenuStrip != null && ClientRectangle.Contains(client))
            {
                contextMenuStrip.ShowInternal(this, client, keyboardActivated);
            }
            else
            {
                DefWndProc(ref m);
            }
        }

        /// <summary>
        ///  Handles the WM_GETDLGCODE message
        /// </summary>
        private void WmGetDlgCode(ref Message m)
        {
            m.Result = (IntPtr)((long)m.Result | (int)User32.DLGC.WANTARROWS | (int)User32.DLGC.WANTCHARS);

            Keys modifierKeys = ModifierKeys;
            if (GetTabKeyEffective((modifierKeys & Keys.Shift) == Keys.Shift, (modifierKeys & Keys.Control) == Keys.Control))
            {
                m.Result = (IntPtr)((long)m.Result | (int)User32.DLGC.WANTTAB);
            }
        }

        private unsafe bool WmNotify(ref Message m)
        {
            if (m.LParam == IntPtr.Zero)
            {
                return false;
            }

            User32.NMHDR* nmhdr = (User32.NMHDR*)m.LParam;
            if (nmhdr->code == (int)ComCtl32.TTN.GETDISPINFOW && !DesignMode)
            {
                string toolTip = ToolTipPrivate;

                if (!string.IsNullOrEmpty(toolTip))
                {
                    // Setting the max width has the added benefit of enabling multiline tool tips
                    User32.SendMessageW(nmhdr->hwndFrom, (User32.WM)ComCtl32.TTM.SETMAXTIPWIDTH, IntPtr.Zero, (IntPtr)SystemInformation.MaxWindowTrackSize.Width);

                    ComCtl32.NMTTDISPINFOW* ttt = (ComCtl32.NMTTDISPINFOW*)m.LParam;
                    _toolTipBuffer.SetText(toolTip);
                    ttt->lpszText = _toolTipBuffer.Buffer;
                    ttt->hinst = IntPtr.Zero;

                    if (RightToLeft == RightToLeft.Yes)
                    {
                        ttt->uFlags |= ComCtl32.TTF.RTLREADING;
                    }

                    return true;
                }
            }

            return false;
        }

        protected override void WndProc(ref Message m)
        {
            switch ((User32.WM)m.Msg)
            {
                case User32.WM.GETDLGCODE:
                    WmGetDlgCode(ref m);
                    return;
                case User32.WM.LBUTTONDBLCLK:
                case User32.WM.LBUTTONDOWN:
                    // If the OnEnter procedure is called, it's because of a mouse down event, and not a TAB key.
                    _dataGridViewOper[OperationInMouseDown] = true;
                    try
                    {
                        base.WndProc(ref m);
                    }
                    finally
                    {
                        _dataGridViewOper[OperationInMouseDown] = false;
                    }
                    return;
                case User32.WM.NOTIFY:
                    if (WmNotify(ref m))
                    {
                        // we are done - skip default handling
                        return;
                    }
                    break;

                case User32.WM.IME_STARTCOMPOSITION:
                case User32.WM.IME_COMPOSITION:
                    if (EditingControl != null)
                    {
                        // Make sure that the first character is forwarded to the editing control.
                        User32.SendMessageW(EditingControl, (User32.WM)m.Msg, m.WParam, m.LParam);
                    }
                    break;
            }

            base.WndProc(ref m);
        }
    }
}
