Method '[Avalonia.Win32]Avalonia.Win32.Interop.UnmanagedMethods.CoCreateInstance(Guid&,native int,int32,Guid&,object&)' requires marshalling that is not yet supported by this compiler

[FoggyFinder]

OpenFileDialog/SaveFileDialog/OpenFolderDialog throws exception on CoreRt build

MCVE

  <StackPanel>
    <Button x:Name="selectPathBtn" HorizontalAlignment="Center" 
            Content="Select Path" />
    <TextBox x:Name="pathTxb" />
  </StackPanel>

public class MainWindow : Window
{
    readonly Button selectPathBtn;
    readonly TextBox pathTxb;
    public MainWindow()
    {
        AvaloniaXamlLoader.Load(this);

        selectPathBtn = this.Find<Button>(nameof(selectPathBtn));
        selectPathBtn.Click += SelectPathBtn_Click;
        pathTxb = this.Find<TextBox>(nameof(pathTxb));
    }

    private async void SelectPathBtn_Click(object sender, Avalonia.Interactivity.RoutedEventArgs e)
    {
        var folders = await new OpenFolderDialog()
        {
            Title = "Select folder",
        }.ShowAsync((Window)this.VisualRoot);
        pathTxb.Text = folders;
    }
}

Exception

Unhandled Exception: System.Exception: Method '[Avalonia.Win32]Avalonia.Win32.Interop.UnmanagedMethods.CoCreateInstance(Guid&,native int,int32,Guid&,object&)' requires marshalling that is not yet supported by this compiler.
   at Avalonia.Win32.Interop.UnmanagedMethods.CoCreateInstance(Guid&, IntPtr, Int32, Guid&, Object&) + 0x34
   at Avalonia.Win32.SystemDialogImpl.<>c__DisplayClass2_0.<ShowFolderDialogAsync>b__0() + 0xca
   at System.Threading.Tasks.Task`1.InnerInvoke() + 0x37
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread, ExecutionContext, ContextCallback, Object) + 0x47
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x20
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task&, Thread) + 0x161
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x20
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task) + 0xba
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task) + 0x44
   at AvaloniaApplicationSample.MainWindow.<SelectPathBtn_Click>d__3.MoveNext() + 0x111
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x20
   at Avalonia.Threading.JobRunner.RunJobs(Nullable`1) + 0x45
   at Avalonia.Win32.Win32Platform.WndProc(IntPtr, UInt32, IntPtr, IntPtr) + 0x79
   at AvaloniaApplicationSample!<BaseAddress>+0xc926da

Works with .UseManagedSystemDialogs()

[FrankenApps]

I think that kind of Marshalling simply is not supported yet in CoreRT see here.

What version of Avalonia did you use?

[FoggyFinder]

What version of Avalonia did you use?

0.9.x (various)

[FoggyFinder]

This is current limitation of Avalonia that related to COM indeed. See no reason to keep it open. Closing.