private void DoShowTariffCmd()
        {
            TariffView tariffView = new TariffView();
            TariffViewModel TariffVM = new TariffViewModel(_UnitOfWork, tariffView);
            tariffView.DataContext = TariffVM;

            tariffView.ShowDialog();

            if (tariffView.DialogResult.HasValue && tariffView.DialogResult.Value)
            {
                RefreshList(_selectedMonthId);
            }

        }
 public TariffViewModel(UnitOfWork UnitOfWork, TariffView view)
 {
     _UnitOfWork = UnitOfWork;
     _instanceWindow = view;
     _Tarriff = _UnitOfWork.TariffDAO.getAll().FirstOrDefault();
 }