private async Task ConvertCallBack(BackgroundTaskControl bgtc)
 {
     Dispatcher.Invoke(() =>
     {
         WaitingLabel.Content = "Conversion Done";
         WaitingProgressBar.IsIndeterminate = false;
         WaitingProgressBar.Value           = WaitingProgressBar.Maximum;
         Exportbutton.IsEnabled             = true;
         if (parentWindow != null)
         {
             bgtc?.Dispose();
         }
     });
 }
 public async Task BackgroundCallback(BackgroundTaskControl bgtc)
 {
     bgtc?.Dispose();
 }