WPF render thread failure exception

Question

In my application, I have a task which runs in the background to perform a long-running job. The user can cancel the job anytime by clicking Stop button. The implementation is as belows:

private CancellationTokenSource m_tokenSource;


private void onStop()
{
    m_tokenSource.Cancel();
}

private void onStart()
{
    m_tokenSource = new CancellationTokenSource();
    AsyncDoingJob();
}

private async void AsyncDoingJob()
{
     await Task.Run(() =>
     {
          for (int imgIdx = 0; imgIdx < m_ListImageFiles.Count; imgIdx++)
          {
                if (m_tokenSource.IsCancellationRequested) // Check if the user clicks Stop button
                {
                    return;
                }

                byte[] imageData = File.ReadAllBytes(m_ListImageFiles[imgIdx]); // Load image in background

                Application.Current.Dispatcher.Invoke(() =>
                {
                        m_model.Image = CreateImage(imageData);
                        m_model.Image.Freeze();                      
                        MyImage = m_model.Image;   // This calls NotifyPropertyChanged() to update the image on GUI                     
                }

                // Access to m_model.Image for some reason

          }
     }, m_tokenSource.Token);
}

The problem: Sometimes, while the job is being performed, GUI stop updating (hanging). And if I try to manipulate the GUI, an exception happens: System.Runtime.InteropServices.COMException: UCEERR_RENDERTHREADFAILURE (Exception from HRESULT: 0x88980406)

I found a similar problem reported here: WPF render thread failures

Do you know what it is and how to fix this? Is there anything wrong with my source code?

Answer 1

After migrating a large WPF application from the .NET Framework to .NET 7, for some users the application began to crash with this exception.

System.Runtime.InteropServices.COMException UCEERR_RENDERTHREADFAILURE (0x88980406)

The reason for the exception is not clear, but disabling hardware graphics acceleration worked for me.

using System.Windows.Media;

RenderOptions.ProcessRenderMode = System.Windows.Interop.RenderMode.SoftwareOnly;

P.S. See the document from Microsoft for a discussion of this exception.

Answer 2

I can't tell why you get that error. You may however try an implementation like this:

private bool continueLoading;

private void OnStop()
{
    continueLoading = false;
}

private async Task OnStart()
{
    continueLoading = true;
    await LoadImagesAsync(m_ListImageFiles);
}

private async Task LoadImagesAsync(IEnumerable<string> imageFiles)
{
    foreach (var imageFile in imageFiles)
    {
        if (!continueLoading)
        {
            break;
        }

        Image = await LoadImageAsync(imageFile); // assignment in UI thread

        // do more async calls here if necessary
    }
}

private static Task<ImageSource> LoadImageAsync(string fileName)
{
    return Task.Run(() =>
    {
        using (var stream = File.OpenRead(fileName))
        {
            return LoadImage(stream);
        }
    });
}

private static ImageSource LoadImage(Stream stream)
{
    return BitmapFrame.Create(
        stream, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);

    // Alternative:
    //
    // var bitmapImage = new BitmapImage();
    // bitmapImage.BeginInit();
    // bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
    // bitmapImage.StreamSource = stream;
    // bitmapImage.EndInit();
    // bitmapImage.Freeze();
    // return bitmapImage;
}