Bug: COMException (0x80040154 - REGDB_E_CLASSNOTREG) after migrating NetProjectionSample to .NET 8.0

[Nicococoooo]

Description

When I update the NetProjectionSample project from net6.0-windows10.0.19041.0 to net8.0-windows10.0.19041.0, a System.Runtime.InteropServices.COMException is thrown at runtime. The error message is Class not registered (0x80040154 (REGDB_E_CLASSNOTREG)).

This error occurs in the ConsoleAppSample when trying to create an instance of the SimpleMathComponent.

Steps To Reproduce

1. In the ConsoleAppSample project, change the Target Framework in the project file (.csproj) from:<TargetFramework>net6.0-windows10.0.19041.0</TargetFramework> to <TargetFramework>net8.0-windows10.0.19041.0</TargetFramework>
2. Also, update the Target Framework for the SimpleMathProjection to net8.0-windows10.0.19041.0.
3. Update the Nuget package for the SimpleMathProjection from:<PackageReference Include="Microsoft.Windows.CsWinRT" VersionOverride="1.3.5" /> to <PackageReference Include="Microsoft.Windows.CsWinRT" VersionOverride="2.2.0" />
4. Rebuild both solution.
5. Run the ConsoleAppSample.

Expected Behavior

The ConsoleAppSample should run successfully without any exceptions, just as it does when targeting net6.0. The application should be able to activate and use the SimpleMath component.

Version Info

CsWinRT Version: 2.2.0
Target Framework: net8.0-windows10.0.19041.0
Windows SDK Version: 10.0.19041.0
Visual Studio Version: 17.14.8

Additional Context

This issue seems to be related to the .NET 8.0 upgrade. The COM activation of the projected component fails, suggesting a potential issue with how the component is registered or activated in the context of a .NET 8.0 application. The project works perfectly fine on net6.0.

[dongle-the-gadget]

This issue is because there's no app.manifest or AppxManifest.xml, WinRT could not look up the class (hence the CLASSNOTREG error). Old versions of CsWinRT tried to work around this by attempting a DLL probe, but newer versions of CsWinRT don't by default.

TL;DR: this is expected behavior.

[manodasanW]

To confirm, were you building x64 release?

[Nicococoooo]

To confirm, were you building x64 release?

yes

[Nicococoooo]

This issue is because there's no app.manifest or AppxManifest.xml, WinRT could not look up the class (hence the CLASSNOTREG error). Old versions of CsWinRT tried to work around this by attempting a DLL probe, but newer versions of CsWinRT don't by default.

TL;DR: this is expected behavior.

In the NetProjectionSample example project, the behavior of CsWinRT does not match your description. When I make no modifications, i.e., using net6.0, if I do not modify the version of CsWinRT, there will be a type mismatch error. When I upgrade the version of CsWinRT to 2.2.0 and do not make any other modifications, the example project runs successfully. without needing to configure the app.manifest. However, after updating the version to net8.0, the aforementioned error occurred.

I want to know if this is really expected behavior.

[Nicococoooo]

@Gaoyifei1011 Can you give me some help?

[Gaoyifei1011]

@Gaoyifei1011 Can you give me some help?

It seems that the WinRT class being called has not yet been registered.
I have two questions here.
Does the WinRT class you call only use the classes under the Windows namespace or are there other custom classes? For instance, the content generated by creating a winmd through projection from a cpp project under the Windows App SDK or written by oneself.
Second: Could you provide a small sample call or attach a screenshot of the error?
To facilitate better inspection of the source of the anomaly?

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看起来是调用的 WinRT 类尚未注册。
我这边有两个问题。
您调用的 WinRT 类是仅使用 Windows 命名空间下的类还是有其他自定义的类？比如 Windows App SDK 下的或者是自己写的 cpp 项目生成 winmd 然后通过投影生成的内容。
第二：您能否提供一个小的示例调用，或附一张错误截图？
以方便更好检查异常来源？