private void Fixupaircraft(aircraft previousValue) { if (previousValue != null && previousValue.aircraftimages.Contains(this)) { previousValue.aircraftimages.Remove(this); } if (aircraft != null) { if (!aircraft.aircraftimages.Contains(this)) { aircraft.aircraftimages.Add(this); } if (AircraftId != aircraft.Id) { AircraftId = aircraft.Id; } } }