Doesn't work with C# System.Uri

[andrewleader]

Describe the bug When trying to build a C# class library that uses System.Uri in methods, like the one seen below, I get an "Incorrect function" error. And then trying to consume the library from a C++ app fails at runtime with a class not registered exception. If I omit using System.Uri, it works fine. The Windows Community Toolkit Notifications library is littered with System.Uri and this blocks attempting to make a CsWinRT version of the library for C++ apps.

To Reproduce

Have a C# class library that uses CsWinRT and has a public method that uses C# System.Uri as seen below...

        public ToastContentBuilder AddAudio(System.Uri uri)
        {
            return this;
        }

Build the project. Notice a warning appears while building...

1>CSC : warning CS8785: Generator 'SourceGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'Win32Exception' with message 'Incorrect function'

Attempt to consume the library (as a NuGet in my case) from a C++ app. Notice you get a class not registered exception when trying to access anything from the library in that class.

Expected behavior It should work? 😊 If you change System.Uri to string, it builds without a warning and is consumable.

Version Info

CsWinRT NuGet: 1.3.3 .NET 5

[j0shuams]

@andrewleader Is this a C#/WinRT component? As in, <CsWinRTComponent>true</CsWinRTComponent> in the project file?

[andrewleader]

@j0shuams correct, <CsWinRTComponent>true</CsWinRTComponent> in the C# class library that's exposing a method that uses System.Uri.

[angelazhangmsft]

It seems that setting <CsWinRTWindowsMetadata>10.0.19041.0</CsWinRTWindowsMetadata> might be a workaround for this, but not sure why yet.