Unable to add C++/WinRT Runtime Component to UWP C# Application

[Code-ScottLe]

Just want to make sure that I'm not doing something wrong here. I have created a Runtime Component project , implemented a bare minimum of a single Runtime class (following the example here: https://docs.microsoft.com/en-us/windows/uwp/cpp-and-winrt-apis/author-events), but i could not reference this project from a C# UWP Application within the same solution. Trying to add a reference to the project would just end up with the message of The method or opration is not implemented . Is this a known issue with Visual Studio or C++/WinRT? Project referencing from a C++/WinRT Blank application doesn't have this issue.

Directly referencing the winmd files under Debug\Merged\ will just result in a runtime exception of something not activated class.

Also, if i tried to manually reference the project by editing the csproj file manually, I have 2 cases happening. One project works just fine and the other one is complaining about not having the DLL of the Runtime Time component under its Debug folder.

I can try to upload both projects here (the one that kinda-works and the one that doesn't) later but if anybody have any pointers, that would be great.

[kennykerr]

The method or operation is not implemented

Did you provide an implementation? The default for a component project is to generate stubs that throw an exception.

[Code-ScottLe]

TestWinRT.zip

Here is the example. The Runtime Component project is the BankAccountWRC. It can be added to the BlankApp1 (a C++/WinRT UWP app), but when trying to add to App1 (C# UWP) VS won't allow to do such things.

However, if you modify the csproj of App1 to have a project reference manually, you can get it to build. However, this is not guaranteed as i was not able to get it to build on others projects that might complain about missing DLLs.

This works:

This does not:

Did you provide an implementation? The default for a component project is to generate stubs that throw an exception.

Yes, i followed the Docs example and was able to get it to build and referenced from a C++/WinRT UWP app just fine (run and verified). Just C# app giving me problem.

[Code-ScottLe]

Is there an example somewhere that have the C# UWP and C++/WinRT Runtime component working together? I couldn't find any example to follow on rather than the MS Docs link above on how to implement a Runtime Component.

[kennykerr]

Cross language support in Visual Studio is not very robust. I believe you can get it to work if you reference the winmd directly and then also make sure that the necessary build artifacts (including .winmd files and .dll files) are copied to a shared build directory so that the loader can find them all. This is admittedly non-trivial, but not something I really have any say over. My suggestion is to bring up the issue here:

https://developercommunity.visualstudio.com/spaces/62/index.html

The benefit of doing so is that it will immediately create an issue (a bug report) with the Visual Studio team. If you then link back to the issue here, we can bump the issue internally to make sure it gets attention.

[Code-ScottLe]

i did submit a feedback on this on the inability to add the project reference:

https://developercommunity.visualstudio.com/content/problem/820413/unable-to-add-cwinrt-runtime-component-as-a-projec.html

@kennykerr Just want to be sure, the only winmd file that i need to manually reference is in the {project_root}/Debug/Merged folder? I don't think i see any other dlls. And when i try to manually reference the winmd files, this happens:

[kennykerr]

Yes, that looks right. Also, "Class not registered" typically means the loader doesn't know how to find the type. This is distinct from whether or not you have the dll/winmd present. Typically that is done via a manifest of some kind.

[Code-ScottLe]

Then how would a normal user would reference a runtime class from a C# UWP app then? All i did was to add a reference to the winmd file that was built from the C++/WinRT project. I don't think i have ever have to touch a manifest file to get a class loaded in.

PS: There is no distinct guide on how to do this. All MSDocs has was "reference the winmd file" and that's it.

[kennykerr]

Are you referring to this problem when adding a project reference? I just tried this now and this is what I get when trying to add a project reference from a C# UWP app to a C++/WinRT component project. @jlaanstra this was working before. Any ideas?

[Code-ScottLe]

Yes, so there are total of 2 problems here:

1. The screenshot above. Unable to add the C++/WinRT Project reference to a C# UWP app with VS.

2. Adding the Winmd file to the C# UWP app will result in runtime exception of TypeLoadException.

[kennykerr]

Assigning to @Scottj1s - thanks for reporting this issue.

[Scottj1s]

@Code-ScottLe - note that this scenario requires reg-free winrt activation from the C# app. I don't see that in you package.appmanifest. For details, see:
https://github.com/microsoft/xlang/wiki/Referencing-a-Windows-Runtime-component-from-a-Desktop-app

I was able to get the attached sample working with the two edits mentioned in the wiki page above:

App1.csproj:

  <ItemGroup>
    <ProjectReference Include="..\BankAccountWRC\BankAccountWRC.vcxproj" />
  </ItemGroup>

Package.appxmanifest:

  <Extensions>
    <Extension Category="windows.activatableClass.inProcessServer">
      <InProcessServer>
        <Path>BankAccountWRC.dll</Path>
        <ActivatableClass ActivatableClassId="BankAccountWRC.BankAccount" ThreadingModel="both"/>
      </InProcessServer>
    </Extension>
  </Extensions>