private void UpdateAllTable()
        {
            FlightsService service = Service.getInstanse().flightService;
            DataTable      FlightPriceTable;

            if (service.GetFlightsPrice(out FlightPriceTable))
            {
                GridView.DataSource = FlightPriceTable;
                GridView.DataBind();
            }

            DataTable FlightCitiesTable;

            if (service.GetFlightsCities(out FlightCitiesTable))
            {
                DropDownListDeparture.Items.Clear();
                DropDownListArrival.Items.Clear();

                foreach (DataRow row in FlightCitiesTable.Rows)
                {
                    DropDownListDeparture.Items.Add((string)row[0]);
                    DropDownListArrival.Items.Add((string)row[0]);
                }
            }
        }