Microsoft.win32.SaveFileDialog interferes with memory usage WPF (.Net5)-CodePudding

I have a private method in my MVVM view model that is called when the user presses a button on the view. In this method I want to ask the user to specify a file to save, and then call a static class library to perform some image processing (reading files from disc, doing some minor processing and writting them to an mp4 file using ffmediaToolkit.

private void makeMP4()
{
    Microsoft.Win32.SaveFileDialog saveFileDialog = new Microsoft.Win32.SaveFileDialog();
    saveFileDialog.Filter = "Media File (*.mp4)|*.mp4";
    saveFileDialog.InitialDirectory = @"D:\temp\mp4output\";
    saveFileDialog.FileName = myImageHandler.SuggestedFileName   ".mp4";

    // If I remove the following line, memory usage is stable at 1GB. If I keep this line
    // memory grows linearly until program terminates.
    _ = saveFileDialog.ShowDialog();

    // I also tried passing current window handle to ShowDialog (with same outcome):
    //_ = saveFileDialog.ShowDialog(Application.Current.Windows.OfType<MainWindow>().FirstOrDefault());

    MP4Maker mp4Maker = new(myImageHandler);
    mp4Maker.GenerateMP4(@"D:\temp\mp4maker\hardcodedFileName.mp4");
}

As explained by the comments in the code above, if I call the ShowDialog method my applicaiton consumes too much memory while processing the mp4 file. But if I omit the call to ShowDialog, the memory usage is stable at about 1GB.

Two suggested solutions I've seen (and reasons they have not worked for me) are:

Passing the current window (parent/owner) handle to the ShowDialog method (see my attempt to do this commented out in code above: This didn't change the memory usage.
Using system.windows.forms.savefiledialog as an alternative to Microsoft.Win32.SaveFileDialog: I wasn't able to do this because I am using .Net5 (my understanding is that you can't refernce System.windows.forms from a .net5 application?)

Can anybody see why calls to ShowDialog are causing memory leakage and how to prevent it? Thank you.

CodePudding user response：

After running the SaveFileDialog.ShowDialog you should try running

GC.Collect(); GC.WaitForPendingFinalizers();

Which should force .Net to clean up any memory relating to the previous calls before then calling the next routines.