TextBoxExtensions sample in gallery crashes under Windows App SDK

[Arlodotexe]

Describe the bug

Under the latest main commit, opening the TextBoxExtensions sample will cause the gallery app to crash.

   at WinRT.ExceptionHelpers.<ThrowExceptionForHR>g__Throw|38_0(Int32 hr)
   at ABI.Windows.UI.Input.IRadialControllerStaticsMethods.CreateForCurrentView(IObjectReference _obj)
   at Windows.UI.Input.RadialController.CreateForCurrentView()
   at CommunityToolkit.WinUI.TextBoxExtensions.OnSurfaceDialOptionsPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) in /_/components/Extensions/src/Text/TextBoxExtensions.SurfaceDial.cs:line 138
   at ABI.Microsoft.UI.Xaml.PropertyChangedCallback.Do_Abi_Invoke(IntPtr thisPtr, IntPtr d, IntPtr e)

This behavior is not present when running the gallery under UWP.

Steps to reproduce

1. Clone the repo
2. Generate the gallery solution, include the Extensions component and the wasdk multitarget/head.
3. Build and deploy the wasdk gallery 
4. Navigate to the TextBoxExtensions sample page and observe crash.

Expected behavior

No crash

Screenshots

No response

Code Platform

• [ ] UWP
• [X] WinAppSDK / WinUI 3
• [ ] Web Assembly (WASM)
• [ ] Android
• [ ] iOS
• [ ] MacOS
• [ ] Linux / GTK

Windows Build Number

• [ ] Windows 10 1809 (Build 17763)
• [ ] Windows 10 1903 (Build 18362)
• [ ] Windows 10 1909 (Build 18363)
• [ ] Windows 10 2004 (Build 19041)
• [ ] Windows 10 20H2 (Build 19042)
• [ ] Windows 10 21H1 (Build 19043)
• [ ] Windows 10 21H2 (Build 19044)
• [ ] Windows 10 22H2 (Build 19045)
• [ ] Windows 11 21H2 (Build 22000)
• [ ] Other (specify)

Other Windows Build number

No response

App minimum and target SDK version

• [ ] Windows 10, version 1809 (Build 17763)
• [ ] Windows 10, version 1903 (Build 18362)
• [ ] Windows 10, version 1909 (Build 18363)
• [ ] Windows 10, version 2004 (Build 19041)
• [ ] Windows 10, version 2104 (Build 20348)
• [ ] Windows 11, version 22H2 (Build 22000)
• [ ] Other (specify)

Other SDK version

No response

Visual Studio Version

No response

Visual Studio Build Number

No response

Device form factor

No response

Additional context

No response

Help us help you

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[Arlodotexe]

This error will throw even after disabling AoT, suggesting it might be a regression that happened between Microsoft.WindowsAppSdk 1.5 and 1.6.

[Arlodotexe]

The source of the issue here seems to be that RadialController.CreateForCurrentView is being called from a non-UI thread, despite being invoked by a dependency property as a PropertyChangedCallback delegate.

https://github.com/CommunityToolkit/Windows/blob/7ab8a422eb20b8829091808e192a389087195f00/components/Extensions/src/Text/TextBoxExtensions.SurfaceDial.cs?plain=1#L125-L148

This behavior isn't present in UWP or WindowsAppSdk 1.5 and doesn't seem to be related to the recent AoT changes in 1.6.

This definitely seems like a regression that occurred between 1.5 and 1.6, will need to gather more information to decide whether to file an issue with the platform.

[Sergio0694]

"Windows.UI.Input.RadialController.CreateForCurrentView()"

That doesn't sound like it should work on WASDK at all. WinUI 3 apps have no "current view" (that's a UWP concept). Are you sure that same code was actually running and working before, on WASDK?