// Delect Button Click private void customerDeleteButton_Click(object sender, EventArgs e) { // If selected ID is valid if (selectedCustomerID != -1) { // Delete customer DataInterface.deleteCustomer(selectedCustomerID); } else { // If not valid, display message MessageBox.Show("Please select a customer to delete and try again."); } // Re-display data customersDGV.Refresh(); displayCustomers(); }