private void btnEditTerminal_Click(object sender, RoutedEventArgs e)
        {
            Terminal terminal = (Terminal)((Button)sender).Tag;

            if (!terminal.IsBuilt)
            {
                WPFMessageBox.Show(Translator.GetInstance().GetString("MessageBox", "2210"), Translator.GetInstance().GetString("MessageBox", "2210", "message"), WPFMessageBoxButtons.Ok);
            }
            else
            {
                object o = PopUpTerminal.ShowPopUp(terminal);
                if (o != null)
                {
                    int gates = (int)o;

                    long price = gates * this.Airport.getTerminalGatePrice();

                    terminal.extendTerminal(gates);

                    showTerminals();
                    showContracts();
                    showGatesInformation();

                    AirlineHelpers.AddAirlineInvoice(GameObject.GetInstance().HumanAirline, GameObject.GetInstance().GameTime, Invoice.InvoiceType.Purchases, -price);
                }
            }
        }
        private void btnTerminal_Click(object sender, RoutedEventArgs e)
        {
            Terminal terminal = PopUpTerminal.ShowPopUp(this.Airport) as Terminal;

            if (terminal != null)
            {
                // chs, 2011-01-11 changed so a message for confirmation are shown9han
                long price = terminal.Gates.NumberOfGates * this.Airport.getTerminalGatePrice() + this.Airport.getTerminalPrice();

                if (price > GameObject.GetInstance().HumanAirline.Money)
                {
                    WPFMessageBox.Show(Translator.GetInstance().GetString("MessageBox", "2205"), Translator.GetInstance().GetString("MessageBox", "2205", "message"), WPFMessageBoxButtons.Ok);
                }
                else
                {
                    WPFMessageBoxResult result = WPFMessageBox.Show(Translator.GetInstance().GetString("MessageBox", "2206"), string.Format(Translator.GetInstance().GetString("MessageBox", "2206", "message"), terminal.Gates.NumberOfGates, price), WPFMessageBoxButtons.YesNo);

                    if (result == WPFMessageBoxResult.Yes)
                    {
                        this.Airport.addTerminal(terminal);
                        showGatesInformation();
                        showContracts();
                        showTerminals();

                        AirlineHelpers.AddAirlineInvoice(GameObject.GetInstance().HumanAirline, GameObject.GetInstance().GameTime, Invoice.InvoiceType.Purchases, -price);
                    }
                }
            }
        }