public virtual string[] ExtractFilePaths(DragEventArgs dragEventArgs)
  {
     string[] droppedPaths = null;

     if (dragEventArgs.Data.GetDataPresent(DataFormats.FileDrop))
     {
        droppedPaths = dragEventArgs.Data.GetData(DataFormats.FileDrop, true) as string[];
     }

     return droppedPaths;
  }