public void AddAccomodation() { if (_accomodationRepository.HasAccomodationWithId(_accomodation.Id) == false) { _accomodationRepository.Add(_accomodation); _locationRepository.Add(_accomodation.Location); DataManagementService.Instance.SaveData(); ClearAccomodationFields(); ClearRoomFields(); } else { MessageBox.Show("This id already exists"); } }