Weird WebAssembly error - regarding 'ManagedToNativeGenerator'

[TangibleDave]

I have a new WebAssembly test project which I've added to a copy of an existing working Avalonia UI solution (desktop up to this point).
I've stripped out most of the UI code and am still getting this compile error:

Parameter types of pinvoke callback method 'System.Int32 DragEnter(System.Void*, System.Void*, System.Int32, Avalonia.Win32.Interop.UnmanagedMethods+POINT, Avalonia.Win32.Win32Com.DropEffect*)' needs to be blittable.
Visual Studio sends me to the WasmApp.Native.targets file at the 'ManagedToNativeGenerator' section when I double-click on the error:

    <ManagedToNativeGenerator
      Assemblies="@(_WasmAssembliesInternal);$(_MscorlibPath)"
      RuntimeIcallTableFile="$(_WasmRuntimeICallTablePath)"
      IcallOutputPath="$(_WasmICallTablePath)"
      PInvokeModules="@(_WasmPInvokeModules)"
      PInvokeOutputPath="$(_WasmPInvokeTablePath)"
      InterpToNativeOutputPath="$(_WasmInterpToNativeTablePath)"
      CacheFilePath="$(_WasmM2NCachePath)">
      <Output TaskParameter="FileWrites" ItemName="FileWrites" />
    </ManagedToNativeGenerator>

[TangibleDave]

Found the problem: the UI project referenced by the WebAssembly has a reference to 'Avalonia.Desktop'.
The solution is to move nearly all the existing desktop UI code to a new library project shared by both the desktop project and the WebAssembly project. The shared UI project will not have the Avalonia.Desktop reference.

If I had followed the existing documentation more carefully I would have seen this earlier, but impatience got the better of me.

[timunie]

Happens all of us from time to time.

Thanks for sharing your experience with us, so others may find the solution quicker 🤗