//Update PromoGridView with exception handling protected void UpGV1(object sender, GridViewUpdateEventArgs e) { try { GridViewRow row = PromoGridView.Rows[e.RowIndex]; string promoCode = (row.FindControl("Label1") as Label).Text; short discount = short.Parse((row.FindControl("TextBox2") as TextBox).Text); DateTime validStart = (row.FindControl("Calendar3") as Calendar).SelectedDate; int promoDuration = Convert.ToInt32((row.FindControl("TextBox4") as TextBox).Text); BusinessLogic.UpdatePromoCode(promoCode, discount, validStart, promoDuration); PromoGridView.EditIndex = -1; PromoGridView.DataSource = BusinessLogic.Promos(); PromoGridView.DataBind(); Label7.Text = "Update success!"; } catch (Exception) { Label7.Text = "Please input a valid discount amount and duration."; } }