WPF mp3

private MediaPlayer mediaPlayer = new MediaPlayer();

public MyMediaPlayer()
{
  InitializeComponent();

  OpenFileDialog openFileDialog = new OpenFileDialog();
  openFileDialog.Filter = "MP3 files (*.mp3)|*.mp3|All files (*.*)|*.*";
  if(openFileDialog.ShowDialog() == true){
    mediaPlayer.Open(new Uri(openFileDialog.FileName));
  }

  DispatcherTimer timer = new DispatcherTimer();
  timer.Interval = TimeSpan.FromSeconds(1);
  timer.Tick += timer_Tick;
  timer.Start();
}

void timer_Tick(object sender, EventArgs e)
{
  if(mediaPlayer.Source != null) {
    lblStatus.Content = String.Format(mediaPlayer.Position.ToString(@"mm\:ss") + 
                        " / " + mediaPlayer.NaturalDuration.TimeSpan.ToString(@"mm\:ss"));
  }
  else {
    lblStatus.Content = "No file selected...";
  }
}

private void btnPlay_Click(object sender, RoutedEventArgs e)
{
  mediaPlayer.Play();
}

private void btnPause_Click(object sender, RoutedEventArgs e)
{
  mediaPlayer.Pause();
}

private void btnStop_Click(object sender, RoutedEventArgs e)
{
  mediaPlayer.Stop();
}