/// <summary>
 /// Handles the Click event of the btnSave control.
 /// </summary>
 /// <param name="sender">The source of the event.</param>
 /// <param name="e">The <see cref="T:System.EventArgs"/> instance containing the event data.</param>
 protected void btnSave_Click(object sender, EventArgs e)
 {
     if(!string.IsNullOrEmpty(txtShippingTrackingNumber.Text)) {
     try {
       Order order = new Order(orderId);
       order.ShippingTrackingNumber = txtShippingTrackingNumber.Text;
       order.Save(WebUtility.GetUserName());
       MessageService messageService = new MessageService();
       messageService.SendShippingNotificationToCustomer(order);
       base.MasterPage.MessageCenter.DisplaySuccessMessage(LocalizationUtility.GetText("lblShippingSaved"));
     }
     catch(Exception ex) {
       Logger.Error(typeof(shipping).Name + ".btnSave_Click", ex);
       base.MasterPage.MessageCenter.DisplayCriticalMessage(ex.Message);
     }
       }
 }