Open filepicker/folderpicker crashing the app

[WenHong-Lau]

I am currently developing a Windows desktop application using Uno. When I attempt to open either the FilePicker or FolderPicker, the application crashes.

Below is my code snippet for opening the folder picker:

    private async void PickFolderButton_Click(object sender, RoutedEventArgs e)
    {
        var folderPicker = new FolderPicker();
        folderPicker.FileTypeFilter.Add("*");
        IntPtr handdle = WinRT.Interop.WindowNative.GetWindowHandle(App.MainWindow);
        WinRT.Interop.InitializeWithWindow.Initialize(folderPicker, handdle);
        var storageFolder = await folderPicker.PickSingleFolderAsync();
        if (storageFolder != null)
        {
            var fileList = await storageFolder.GetFilesAsync();
            var folderList = await storageFolder.GetFoldersAsync();

            // Do something with the contents...
        }
        else
        {
            // Did not pick any folder.
        }
    }

This is the exception:

System.Runtime.InteropServices.COMException (0x80004005)
   at UnoDesktopApp.Presentation.ExportPage.PickFolderButton_Click(Object sender, RoutedEventArgs e) in C:\Users\wenhong.lau\source\repos\UnoDesktopApp\UnoDesktopApp\Presentation\ExportPage.xaml.cs:line 60
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
   at Microsoft.UI.Dispatching.DispatcherQueueSynchronizationContext.<>c__DisplayClass2_0.<Post>b__0()

[MartinZikmund]

@WenHong-Lau please try specifying the start location and filter before PickSingleFolderAsync call:

folderPicker.SuggestedStartLocation = PickerLocationId.Desktop;
folderPicker.FileTypeFilter.Add("*");

If this does not help, please provide us with a simple repro project and we will investigate further.