public override void Search() { Proxy proxy = new Proxy(); Result = proxy.SearchInvoice(DateFrom, DateTo, AmountFrom,AmountTo,SearchContact); Items.Clear(); if (Result.Invoice != null) { foreach (var obj in Result.Invoice) { Items.Add(new InvoiceViewModel(obj)); } } else { Invoice obj = new Invoice(); obj.Nummer = "Keinen Eintrag gefunden!"; obj.ID = "x"; Items.Add(new InvoiceViewModel(obj)); } }