protected void OnButtonPressedAddFlight(object sender, EventArgs e) { string arrival = DropDownListArrival.SelectedValue; string departure = DropDownListDeparture.SelectedValue; string priceStr = TextBoxPrice.Text; if (arrival == "" || departure == "" || priceStr == "") { return; } if (arrival == departure) { return; } int price = Convert.ToInt32(priceStr); FlightsService service = Service.getInstanse().flightService; service.AddFlightPrice(departure, arrival, price); UpdateAllTable(); }