public void RefreshDataGrid()
        {
            AllGadgets = service.GetAllGadgets();
            GadgetList.Clear();
            if (AllGadgets != null)
            {
                AllGadgets.ForEach(GadgetList.Add);

                AllLoans = service.GetAllLoans();
                LoanList.Clear();
                AllLoans.ForEach(LoanList.Add);
            }
            else
            {
                MessageBox.Show("Keine Verbindung zum Server gefunden!", "Fehler", MessageBoxButton.OK, MessageBoxImage.Error);
                Application.Current.Shutdown();
            }
        }
 public void filterGadgets(String filter)
 {
     GadgetList.Clear();
     if (filter.Length > 0)
     {
         filter = filter.ToUpper();
         AllGadgets.Where(gadget => {
             return(gadget.Name.ToUpper().Contains(filter) ||
                    gadget.Manufacturer.ToUpper().Contains(filter) ||
                    gadget.Price.ToString().ToUpper().Contains(filter) ||
                    gadget.InventoryNumber.ToUpper().Contains(filter) ||
                    gadget.Condition.ToString().ToUpper().Contains(filter));
         }).ToList().ForEach(GadgetList.Add);
     }
     else
     {
         AllGadgets.ForEach(GadgetList.Add);
     }
 }