[C++/WinRT][WPF] Unable to use Windows Runtime Component from WPF app (CO_E_ERRORINDLL).

Question

Hi!

I made a Windows Runtime Component which I want to use in a WPF application. I created the WinRT component using C++/WinRT, and I am able to use it from a C# UWP application (it loads and I can call methods).

Now I try to add it as a reference to a NetCore 3.1 WPF project, but as soon as I try to create an instance of the component (it has a constructor), I get the following error:

System.Runtime.InteropServices.COMException: 'Error in the DLL (0x800401F9 (CO_E_ERRORINDLL))'

I added a manifest with the following section:

      <file name="RuntimeComponent2.winmd" xmlns:winrt="urn:schemas-microsoft-com:winrt.v1">
          <winrt:activatableClass name="RuntimeComponent2.Class1" threadingModel="both" />
      </file>

I also tried creating a runtime component in C#, which does work (using the section above), but I need it to be a C++/WinRT component.

My guess is it has something to do with the VC Redistributables, I also followed the steps in Enhancing Non-packaged Desktop Apps using Windows Runtime Components and I added the Microsoft.VCRTForwarders.140 package.

Do you have any suggestions?

Kind regards,

Maarten van Sambeek

Answer 1

hi Maarten,

Could you try to use this manifest code:

  <file name="WinRTComponent.dll">
    <activatableClass
        name="WinRTComponent.Class"
        threadingModel="both"
        xmlns="urn:schemas-microsoft-com:winrt.v1" />
  </file>

Any updates, please let me know.
BR,
Will