protected void btnSubmit_Click(object sender, EventArgs e) { //Check if null if (tbxNewDestinationPostcode.Text == "") { lblError.Text = "Please enter a Postcode"; } else { //create an object clsOrder AnOrder = new clsOrder(); //Update AnOrder.UpdateDestinationPostcode(Sec.OrderNo, tbxNewDestinationPostcode.Text); lblError.Text = "The Postcode have been change"; } }