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();
        }