private void FillArrivalCity() { DropDownListArrival.Items.Clear(); FlightsService service = Service.getInstanse().flightService; string DepartureCity = DropDownListDeparture.SelectedValue; DataTable table; if (!service.GetArrivalCitiesByDeparture(DepartureCity, out table)) { return; } foreach (DataRow row in table.Rows) { DropDownListArrival.Items.Add((string)row[0]); } }