private void classTypePictureBox_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
 {
     if (item != null)
     {
         CpMediaItem[] items = new CpMediaItem[1];
         items[0] = item;
         classTypePictureBox.DoDragDrop(items, DragDropEffects.Copy | DragDropEffects.Move);
     }
 }