//get all parking places from webservice public void getAllParkingPlacesFromWebservice() { //clear list if (ParkingPlace == null) { ParkingPlace = new ObservableCollection <ParkingPlaceData>(); } else { ParkingPlace.Clear(); } Webservice Service = new Webservice(); Service.getAllParkingPlaces(); for (int i = 0; i < Service.ParkingPlaceList.Count; i++) { ParkingPlace.Add(Service.ParkingPlaceList.ElementAt(i)); } }