Failed to resolve WinRT.Runtime.dll?

[imba-tjd]

Firstly I didn't install WinSDK or UWP workload.

I dotnet add package Microsoft.Windows.CsWinRT, and set TargetFramework=net7.0-windows10.0.22000.0 and CsWinRTMessageImportance=high

dotnet build says:

MSBuild version 17.5.0-preview-23061-01+040e2a90e for .NET
  Determining projects to restore...
  All projects are up-to-date for restore.
  "C:\Users\xxx\.nuget\packages\microsoft.windows.cswinrt\2.0.1\build\tools\IIDOptimizer\IIDOptimizer.exe" @"C:\dotnet\obj\Debug\n
  et7.0-windows10.0.22000.0\IIDOptimizer\cswinrt_iidoptimizer.rsp"
  Failed to resolve WinRT.Runtime.dll.
  dotnet -> C:\dotnet\bin\Debug\net7.0-windows10.0.22000.0\dotnet.dll

Build succeeded.
    0 Warning(s)
    0 Error(s)

Is this expected? I googled it but get nothing. Thanks

[manodasanW]

In your scenario where you are seeing this, are you generating a C#/WinRT projection? We have recently seen this where the project has a CsWinRT package reference, but it isn't generating any C#/WinRT projection so the DLL being built has no reference to WinRT.Runtime. This causes the IID Optimizer tool that this error is coming from to fail to find WinRT.Runtime. We do need to improve our message such that it doesn't output in these cases, but the optimizer will just silently not continue, and everything should still build fine.

[imba-tjd]

Thanks. I just do some test as a beginner, not for real work.
I have another issue. How do I consume Windows.Win32.winmd? In .NET Framework, I can use <Reference HintPath>.
I know CsWin32 but I want to use api via the namespaces defined in winmd, rather than using NativeMethods.txt and Windows.Win32.PInvoke.XXX().

I tried

  <PropertyGroup>
    <CsWinRTIncludes>Windows.Win32</CsWinRTIncludes>
    <CsWinRTWindowsMetadata>local</CsWinRTWindowsMetadata>
    <CsWinRTMessageImportance>high</CsWinRTMessageImportance>
  </PropertyGroup>

  <ItemGroup>
    <ReferencePath Include="Windows.Win32.winmd" />
    <PackageReference Include="Microsoft.Windows.CsWinRT" Version="2.0.1" />
  </ItemGroup>

But it doesn't work.