void _asyncLoadFunction_Completed(object sender, PictureBoxLoadCompletedEventArgs e)
 {
     if (LoadCompleted != null)
     {
         LoadCompleted(this, e);
     }
 }
 static void pic_LoadCompleted(object sender, PictureBoxLoadCompletedEventArgs e)
 {
     Console.WriteLine("Picture Load Completed:{0}", e.ImagePath);
     waitHandle.Set();
 }