/// <summary>
 /// Plays next track in the list
 /// </summary>
 private void Next_Click(object sender, RoutedEventArgs e)
 {
     if (_tracks != null)
     {
         IAudio audio = _tracks.GetNext(_currentAudio);
         if (audio != null)
         {
             int index = _tracks.GetIndex(audio);
             if (_tracks == Library.Files)
             {
                 MusicLibrary.GetInstance().SetSelection(index);
             }
             else
             {
                 PlaylistPage.GetInstance().SetSelection(index);
             }
             SetAudio(audio, _tracks);
         }
     }
 }