void es_GetPricesCompleted(object sender, GetPricesCompletedEventArgs e)
 {
     if (e.Error == null)
     {
         for (int i = 0; i < e.Result.Length; i++)
         {
             PriceControl ev = new PriceControl(ppd);
             this.panel1.Controls.Add(ev);
             ev.Location = new Point(0, 48 * i);
             ev.Display(e.Result[i]);
             priceControlList.Add(ev);
         }
     }
 }