.NET MAUI Throws Exception w/ Lib C#/WinRT

Description

TL;DR Project to reproduce: https://github.com/jingkecn/Microsoft.WinRT.Starter/tree/app/main-maui A .NET 6 console app Main.Console works fine w/ the C#/WinRT lib Lib.CsWinRT. However, when comes to the .NET 6 MAUI app Main.MAUI, it throws an exception:

System.Reflection.TargetInvocationException
  HResult=0x80131604
  Message=Exception has been thrown by the target of an invocation.
  Source=System.Private.CoreLib
  StackTrace:
   at System.RuntimeType.CreateInstanceOfT()
   at System.Activator.CreateInstance[T]()
   at WinRT.WeakLazy`1.get_Value()
   at WinRT.ActivationFactory`1.ActivateInstance[I]()
   at Lib.CppWinRT.MyStruct..ctor()
   at Main.MAUI.MainPage.OnCounterClicked(Object sender, EventArgs e) in C:\Users\...\source\repos\microsoft\winrt\starter\src\Main.MAUI\MainPage.xaml.cs:line 16
   at Microsoft.Maui.Controls.Button.Microsoft.Maui.Controls.Internals.IButtonElement.PropagateUpClicked()
   at Microsoft.Maui.Controls.ButtonElement.ElementClicked(VisualElement visualElement, IButtonElement ButtonElementManager)
   at Microsoft.Maui.Controls.Button.SendClicked()
   at Microsoft.Maui.Controls.Button.Microsoft.Maui.IButton.Clicked()
   at Microsoft.Maui.Handlers.ButtonHandler.OnClick(Object sender, RoutedEventArgs e)
   at WinRT._EventSource_global__Microsoft_UI_Xaml_RoutedEventHandler.EventState.<GetEventInvoke>b__1_0(Object sender, RoutedEventArgs e)
   at ABI.Microsoft.UI.Xaml.RoutedEventHandler.<>c__DisplayClass10_0.<Do_Abi_Invoke>b__0(RoutedEventHandler invoke)
   at ABI.Microsoft.UI.Xaml.RoutedEventHandler.Do_Abi_Invoke(IntPtr thisPtr, IntPtr sender, IntPtr e)

  This exception was originally thrown at this call stack:
    [External Code]

Inner Exception 1:
COMException: Class not registered (0x80040154 (REGDB_E_CLASSNOTREG))

PS: I follow the walkthrough guide of C#/WinRT: https://docs.microsoft.com/en-us/windows/uwp/csharp-winrt/net-projection-from-cppwinrt-component PPS: Remember to build at first the project Lib.CsWinRT to generate the NuGet package.

Any ideas?

Steps to Reproduce

1. Clone my sample project: https://github.com/jingkecn/Microsoft.WinRT.Starter/tree/app/main-maui
2. Launch Main.MAUI (on Windows Machine) and click the button

PS:

• Main.UWP works => Lib.CppWinRT works
• Main.Console works => Lib.CsWinRT works

Version with bug

Preview 10 (current)

Last version that worked well

Unknown/Other

Affected platforms

Windows, I was not able test on other platforms

Affected platform versions

Windows SDK 10.0.19041

Did you find any workaround?

Nope

Relevant log output

System.Reflection.TargetInvocationException
  HResult=0x80131604
  Message=Exception has been thrown by the target of an invocation.
  Source=System.Private.CoreLib
  StackTrace:
   at System.RuntimeType.CreateInstanceOfT()
   at System.Activator.CreateInstance[T]()
   at WinRT.WeakLazy`1.get_Value()
   at WinRT.ActivationFactory`1.ActivateInstance[I]()
   at Lib.CppWinRT.MyStruct..ctor()
   at Main.MAUI.MainPage.OnCounterClicked(Object sender, EventArgs e) in C:\Users\...\source\repos\microsoft\winrt\starter\src\Main.MAUI\MainPage.xaml.cs:line 16
   at Microsoft.Maui.Controls.Button.Microsoft.Maui.Controls.Internals.IButtonElement.PropagateUpClicked()
   at Microsoft.Maui.Controls.ButtonElement.ElementClicked(VisualElement visualElement, IButtonElement ButtonElementManager)
   at Microsoft.Maui.Controls.Button.SendClicked()
   at Microsoft.Maui.Controls.Button.Microsoft.Maui.IButton.Clicked()
   at Microsoft.Maui.Handlers.ButtonHandler.OnClick(Object sender, RoutedEventArgs e)
   at WinRT._EventSource_global__Microsoft_UI_Xaml_RoutedEventHandler.EventState.<GetEventInvoke>b__1_0(Object sender, RoutedEventArgs e)
   at ABI.Microsoft.UI.Xaml.RoutedEventHandler.<>c__DisplayClass10_0.<Do_Abi_Invoke>b__0(RoutedEventHandler invoke)
   at ABI.Microsoft.UI.Xaml.RoutedEventHandler.Do_Abi_Invoke(IntPtr thisPtr, IntPtr sender, IntPtr e)

  This exception was originally thrown at this call stack:
    [External Code]

Inner Exception 1:
COMException: Class not registered (0x80040154 (REGDB_E_CLASSNOTREG))

[jingkecn]

Hello @jfversluis, sorry for late reply. I just tried the latest versions of VS + MAUI Workload, the issue seems to be fixed. You can refer to the repo I mentioned before, I just updated it: https://github.com/jingkecn/Microsoft.WinRT.Starter/tree/app/main-maui

[msftbot[bot]]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment. If it is closed, feel free to comment when you are able to provide the additional information and we will re-investigate.