public override void OnNavigatedTo(NavigationContext navigationContext) { IsEditMode = navigationContext.Parameters.Count() != 0; if (IsEditMode) { Guid patietnId = Guid.Parse((string)navigationContext.Parameters[NavigationParams.PATIENT_ID_PARAM]); SetPatientModel(_patientService.GetPatientById(patietnId)); } else { SetPatientModel(new Patient()); } OnPropertyChanged(() => IsEditMode); PatientModel.ForceValidation(); AddAppointmentCommand.RaiseCanExecuteChanged(); SavePatientDataCommand.RaiseCanExecuteChanged(); AttachEvents(); }