private void SortirajDodatnuUslugu()
        {
            string orderHack = cbOrderHack.SelectedValue.ToString();

            view = CollectionViewSource.GetDefaultView(DodatnaUsluga.Sort(cbSortiranje.SelectedItem.ToString(), orderHack));
            dgNamestaj.ItemsSource = DodatnaUsluga.Sort((cbSortiranje.SelectedItem.ToString()), orderHack);
            dgNamestaj.IsSynchronizedWithCurrentItem = true;
        }