FYI @richlander

Do we have a runtime pack for this yet?

Ideally I'd like to also add a basic test that this works.

There are at least three pieces we need:

• Ref pack for Windows Desktop. This is required to build, and should be in-box.
• Runtime for Windows desktop @ C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App. This is required for fx-dependent apps to run and should be in-box.
• Runtime pack for Windows desktop. This is required for self-contained publishing and should be referenced as a URL (not in box).

Will we have all of these after this PR merges?

Do we have a runtime pack for this yet?

https://dnceng.visualstudio.com/public/_packaging?_a=package&feed=dotnet5&package=Microsoft.WindowsDesktop.App.Runtime.win-arm64&protocolType=NuGet&version=5.0.0-preview.6.20261.2

Ideally I'd like to also add a basic test that this works.

Yes, this I have to look how to do. Tom and I confirmed manually it worked but it would be good to actually confirm it works as expected. I'll take a look at the tree tomorrow to see where they are.

Ideally I could test these two:

• Winforms works on arm64
• Wpf errors as expected

Should I also open an issue to track the cleanup?

Are you blocked by this change? If not, I think we should checkin until the feature can work.

Yes, you should open an issue to track everything that is required for this feature to function.

There's some loose ends here:

• Cleanup WindowsDesktop KnownFrameworkReferences once WPF adds ARM64 support #7466 tracking the cleanup for KnownFrameworkReference consolidation once WPF bits are in.
• Error out properly when building WPF on ARM64 app until support is added. #7467 tracking runtime failures with less than helpful messages for RID agnostic WPF builds running on an ARM64 machine.
• ARM64 WindowsDesktop Runtime pack's PlatformManifest is a superset of shipped assets windowsdesktop#770 tracking the incoherent manifests in the runtime pack.

• Ref pack for Windows Desktop. This is required to build, and should be in-box.
• Runtime for Windows desktop @ C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App. This is required for fx-dependent apps to run and should be in-box.
• Runtime pack for Windows desktop. This is required for self-contained publishing and should be referenced as a URL (not in box).
  Will we have all of these after this PR merges?

All three are done to some extent:

• The ARM64 zipped SDK has the WD ref pack under DOTNET_ROOT\packs\Microsoft.WindowsDesktop.App.Ref\<VERSION>\ref. @dsplaisted, is there a way to solve or warn about Error out properly when building WPF on ARM64 app until support is added. #7467 is targeting refs in the Wpf profile?
• The ARM64 zipped SDK has DOTNET_ROOT\shared\Microsoft.WindowsDesktop.App\<VERSION> after this. The assets contained are only the winforms ones. This causes one of the issues above.
• The runtime pack, albeit with the issues mentioned, is up in the dotnet5 feed. A win-arm64 publish on x64 pulls that package and I can marshal the self contained app and use it on a cobalt device and it runs as an ARM64 app and not under emulation.

I would like to see a simple test case that we can build a self-contained Windows Forms app for ARM64 before merging this.

I don't think we need to address #7467 before merging this though.