private void bgWorker_Play_DoWork(object sender, DoWorkEventArgs e) { BackgroundWorker bw = sender as BackgroundWorker; PlayOpts opts = (PlayOpts)e.Argument; MusicNoteLib.PlayMusicStringWithOptsCB(opts.strNotes, opts.nMidiOutPort, opts.nTimerRes, new MusicNoteLib.ParserTraceDelegate(OnParseTrace), new MusicNoteLib.ParserErrorDelegate(OnParseError), IntPtr.Zero); }