private void btnCheck_Click(object sender, EventArgs e) { activeCustomer = GetData.GetCustomer(txtPhone.Text); if (activeCustomer == null) { MessageBox.Show("Could not find a customer with that phone number!\nPlease insert first/lastname."); txtFirst.Enabled = true; txtLast.Enabled = true; txtPhone.Enabled = false; btnCheck.Enabled = false; txtFirst.Text = ""; txtLast.Text = ""; } else { txtPhone.Enabled = false; btnCheck.Enabled = false; txtFirst.Text = activeCustomer.FirstName; txtLast.Text = activeCustomer.LastName; btnSubmit.Enabled = false; BtnCheckout.Enabled = true; } }