/// <summary>
 /// Play slideshow
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 private void ButtonPlay_Click(object sender, RoutedEventArgs e)
 {
     // Check that slideshow is not empty
     if (selectedSlideShow != null)
     {
         if (selectedSlideShow.Count > 0)
         {
             // Check that all files exist
             bool filesExist = true;
             for (int i = 0; i < selectedSlideShow.Count; i++)
             {
                 MediaData mediaData = selectedSlideShow.GetAt(i);
                 if (mediaData != null)
                 {
                     if (!File.Exists(mediaData.FilePathName))
                     {
                         filesExist = false;
                     }
                 }
             }
             // If files exist, play slide show
             if (filesExist)
             {
                 List <MediaData> imageCards = selectedSlideShow.GetMediaDataInOrder();
                 FullScreen       fullScreen = new FullScreen(imageCards);
                 fullScreen.Show();
             }
             else
             {
                 MessageBox.Show("All files does no longer exist", "Error");
             }
         }
         else
         {
             MessageBox.Show("Slideshow is empty", "Error");
         }
     }
     else
     {
         MessageBox.Show("Slideshow does not exist", "Error");
     }
 }