private void btUpdate_Click(object sender, EventArgs e) { if (selectedAirplane != null) { selectedAirplane.ChangeFuel(Convert.ToInt32(nUDChangeFuel.Value)); selectedAirplane.ChangeSpeed(Convert.ToInt32(nUDChangeSpeed.Value)); string destination = cbChangeDestination.Text; if (!destination.ToUpper().Equals(selectedAirplane.Flight.DestinationAirport.Name.ToUpper())) { bool found = false; foreach (Airport a in airNetwork.Airports) { if (a.Name.ToUpper() == destination.ToUpper()) { selectedAirplane.ChangeRoute(selectedAirplane.CurrentLocation, a); found = true; } } if (!found) { MessageBox.Show("No such airport was found. Please enter another one"); } } } }