private void BtnDelete_Click(object sender, System.EventArgs e)
 {
     if (selectedCust == null)
     {
         MessageBox.Show("Please select from customer list first.", "Information",
             MessageBoxButtons.OK, MessageBoxIcon.Information);
         return;
     }
     CustomerService.CustomerService service = new CustomerService.CustomerService();
     string result = service.DeleteCustomer(selectedCust.CustID);
     if (result != null)
     {
         MessageBox.Show(result);
         return;
     }
     ClearCustomer();
     BtnCustList_Click(null, null);
 }