public override void Search()
 {
     Proxy proxy = new Proxy();
     if (Selected == "Kontakte")
     {
         ResultContact = proxy.Search(SearchText);
         Items.Clear();
         if (ResultContact.contact != null)
         {
             foreach (var obj in ResultContact.contact)
             {
                 Items.Add(new ContactViewModel(obj));
             }
         }
         else
         {
             Contact obj = new Contact();
             obj.Vorname = "Keinen Eintrag gefunden!";
             obj.Id = "x";
             Items.Add(new ContactViewModel(obj));
         }
     }
     else
     {
         ResultFirm = proxy.SearchFirm(SearchText);
         Items.Clear();
         if (ResultFirm.Firma != null)
         {
             foreach (var obj in ResultFirm.Firma)
             {
                 Items.Add(new FirmViewModel(obj));
             }
         }
         else
         {
             Firma obj = new Firma();
             obj.Name = "Keinen Eintrag gefunden!";
             obj.Id = "x";
             Items.Add(new FirmViewModel(obj));
         }
     }
 }