private static void onChangedSelObiekKom(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            UserControl_CelNabycia u = d as UserControl_CelNabycia;

            u.istObName     = string.Empty;
            u.zadInwestName = string.Empty;

            u.selectedName = u.obiektKomName;
            u.selectedId   = u.obiektKomSelId;
        }
        private static void onChangedSelectedId(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            UserControl_CelNabycia u = d as UserControl_CelNabycia;
            var v = u.celNabyciaList.list.FirstOrDefault(row => row.Id == u.selectedId);

            if (v != null)
            {
                u.selectedName = v.Nazwa;
            }
            else
            {
                u.selectedName = string.Empty;
            }
        }