System.Runtime.InteropServices.COMException: 'Invalid window handle. (0x80070578)

[yegorisB]

Which version of the app?

WinUI 3 Gallery

Description

Source:
StorageFile file = await savePicker.PickSaveFileAsync();
VS 2022: System.Runtime.InteropServices.COMException: 'Invalid window handle. (0x80070578)
Consider WindowNative, InitializeWithWindow
See https://aka.ms/cswinrt/interop#windows-sdk'

Screenshots

Windows version

No response

Additional context

Edition Windows 11 Home
Version 23H2
Installed on ‎9/‎11/‎2023
OS build 22631.2861
Experience Windows Feature Experience Pack 1000.22681.1000.0

Processor 13th Gen Intel(R) Core(TM) i9-13900H 2.60 GHz
Installed RAM 16.0 GB (15.6 GB usable)

System type 64-bit operating system, x64-based processor
Pen and touch No pen or touch input is available for this display

[yegorisB]

everything is all right if you use this:
private async void SaveButton_Click(object sender, RoutedEventArgs e)
{
FileSavePicker picker = new();
picker.SuggestedStartLocation = PickerLocationId.Downloads;

 picker.FileTypeChoices.Add("Rich Text", new List<string>() { ".rtf" });
 

 var hwnd = WindowNative.GetWindowHandle(this);  // App.m_window?
 InitializeWithWindow.Initialize(picker, hwnd);

 StorageFile file = await picker.PickSaveFileAsync();


 if (file != null)
 {
     // Prevent updates to the remote version of the file until we
     // finish making changes and call CompleteUpdatesAsync.
     CachedFileManager.DeferUpdates(file);
     // write to file
     using (Windows.Storage.Streams.IRandomAccessStream randAccStream =
         await file.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite))
     {
         editor.Document.SaveToStream(Microsoft.UI.Text.TextGetOptions.FormatRtf, randAccStream);
     }

     // Let Windows know that we're finished changing the file so the
     // other app can update the remote version of the file.
     FileUpdateStatus status = await CachedFileManager.CompleteUpdatesAsync(file);
     if (status != FileUpdateStatus.Complete)
     {
         Windows.UI.Popups.MessageDialog errorBox =
             new Windows.UI.Popups.MessageDialog("File " + file.Name + " couldn't be saved.");
         await errorBox.ShowAsync();
     }
 }

}

instead of this:

private async void SaveButton_Click(object sender, RoutedEventArgs e)
{
FileSavePicker savePicker = new FileSavePicker();
savePicker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary;

// Dropdown of file types the user can save the file as
savePicker.FileTypeChoices.Add("Rich Text", new List<string>() { ".rtf" });

// Default file name if the user does not type one in or select a file to replace
savePicker.SuggestedFileName = "New Document";

StorageFile file = await savePicker.PickSaveFileAsync();
if (file != null)
{
    // Prevent updates to the remote version of the file until we
    // finish making changes and call CompleteUpdatesAsync.
    CachedFileManager.DeferUpdates(file);
    // write to file
    using (Windows.Storage.Streams.IRandomAccessStream randAccStream =
        await file.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite))
    {
        editor.Document.SaveToStream(Microsoft.UI.Text.TextGetOptions.FormatRtf, randAccStream);
    }

    // Let Windows know that we're finished changing the file so the
    // other app can update the remote version of the file.
    FileUpdateStatus status = await CachedFileManager.CompleteUpdatesAsync(file);
    if (status != FileUpdateStatus.Complete)
    {
        Windows.UI.Popups.MessageDialog errorBox =
            new Windows.UI.Popups.MessageDialog("File " + file.Name + " couldn't be saved.");
        await errorBox.ShowAsync();
    }
}

}