private void OkButton_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { byte rentDays = 0; if (byte.TryParse(RentDaysBox.Text, out rentDays)) { CarRentalDbWorker.EditRent(_connection, _orderId, rentDays); DialogResult = true; Close(); } else { MessageBox.Show("Неверно введены данные"); } }