C# Code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;


namespace CSFramework.Tech2011.PosTerminal
{
   public partial class frmPosMain : Form
   {
      private PosTerminal _terminal = null; //收银管理器实例
      
      public frmPosMain()
      {
         InitializeComponent();
      }
      
      private void frmPosMain_Load(object sender, EventArgs e)
      {
         //IPrinter printer = new Printer_Epson600();
         //IMonitor monitor = new Monitor_Samsung200();
         
         ICashier cashier = new StandardCashier();
         IPrinter printer = new Printer_HP5000();
         IMonitor monitor = new Monitor_BENQ500();
         
         IStockDataView view = new ListBoxStockDataView(lbStocks);
         ITraceLog log = new TraceLogListBox(lbTrace);
         
         printer.Init(lbPrinter, log);
         cashier.Init(label9, label10, log);
         monitor.Init(lbCurStock, lblRec, log);
         
         //创建收银管理器实例
         _terminal = new PosTerminal(cashier, monitor, printer, view);
         
         //检查系统
         _terminal.CheckSystem();
         
         //加载完毕...可以收银
      }
      
      private void txtStock_KeyDown(object sender, KeyEventArgs e)
      {
         if ((e.KeyCode == Keys.Enter) &&&& (txtStock.Text != null))
         {
            string code = txtStock.Text.Trim();
            Stock stock = StockData.GetStock(code); //跟据输入的货品编号创建Stock对象
            if (stock != null)//数据库存在货品编号
            _terminal.AddStock(stock, int.Parse(txtQty.Text));
            else
            lbTrace.Items.Add("Stock " txtStock.Text " doesn't exists!");
            txtStock.Clear();
            txtStock.Focus();
         }
      }
      
      private void txtPay_KeyDown(object sender, KeyEventArgs e)
      {
         if ((e.KeyCode == Keys.Enter) & (txtPay.Text != null))
         {
            decimal amt = 0;
            bool ok = decimal.TryParse(txtPay.Text, out amt);
            if (ok & amt > 0)
            {
               bool pay = _terminal.Pay(amt); // Pay by the customer
               if (pay) //收款成功将焦点移入货品输入框
               {
                  txtPay.Clear();
                  txtStock.Clear();
                  txtStock.Focus();
               }
            }
            else
            {
               lbTrace.Items.Add("不是数字!");
            }
         }
      }
      
      private void btnReset_Click(object sender, EventArgs e)
      {
         decimal rcv = _terminal.PosStockDataView.GetReceivableAmount();
         if (rcv > 0)
         {
            DialogResult ret = MessageBox.Show("正在收银，要取消么?", "正在收银", MessageBoxButtons.YesNo);
            if (ret == DialogResult.No) return;
         }
         lbTrace.Items.Clear();
         _terminal.Reset();
      }
   }
}



//来源:C/S框架网(www.csframework.com) QQ:1980854898