C# 扫条形码

　//需要有调用窗体注册：KeyDown事件且属性：KeyPreview=true
  #region 条件处理
        BarCodeHook barCodeHook = null;
        private void MIE_MainFrom_KeyDown(object sender, KeyEventArgs e)
        { 
            if (barCodeHook == null)
            {
                barCodeHook = new BarCodeHook();
                barCodeHook.ResolveBarCodeCompletedEvent += new BarCodeHook.ResolveBarCodeCompleted(barCodeHook_ResolveBarCodeCompletedEvent);
            }
            barCodeHook.AppendBarCode = e.KeyValue;
        } 

        void barCodeHook_ResolveBarCodeCompletedEvent(BarCodeHook barCodeHook)
        {  
　　　　　　　　//自己的条码处理方法
        }
   #endregion 条件处理

 public class BarCodeHook
    {
        /// <summary>
        /// 条形码实例
        /// </summary>
        BarCodes barCode;  
        /// <summary>
        /// 单据编号
        /// </summary> 
        public delegate void ResolveBarCodeCompleted(BarCodeHook barCodeHook);
        public event ResolveBarCodeCompleted ResolveBarCodeCompletedEvent;
        /// <summary>
        /// 构造函数
        /// </summary>
        public BarCodeHook()
        {
            //初始化条码事件
            this.barCode = new BarCodes();
            // 添加条码扫描完成事件
            this.barCode.BarCodeCompletedEvent += new BarCodes.BarCodeCompleted(barCode_BarCodeCompletedEvent);
        }
        /// <summary>
        /// 添加条码扫描完成触发事件
        /// </summary>
        /// <param name="barCode"></param>
        private void barCode_BarCodeCompletedEvent(string barCode)
        {
            if (barCode == null || barCode == "")
                return;
            ResolveBarCode(barCode.ToLower());
        }

        /// <summary>
        ///  条码编号处理
        /// </summary>
        private void ResolveBarCode(string barCode)
        {
            this.ResolveBarCodeCompletedEvent(this);
        }   

        /// <summary>
        /// 逐个添加字符
        /// </summary>
        public int AppendBarCode
        {
            set
            {
                barCode.AppendBarCode(value);
            }
        }
         
        /// <summary>
        /// 条形码
        /// </summary>
        private struct BarCodes
        {
            public int VirtKey;      //虚拟码   
            public int ScanCode;     //扫描码   
            public int KeyValue;   //键名   
            public uint AscII;       //AscII   
            public char Chr;         //字符  

            public string BarCode;   //条码信息   
            public bool IsValid;     //条码是否有效   
            public DateTime Time;    //扫描时间   
            /// <summary>
            /// 条件读取完毕触发的事件
            /// </summary>
            /// <param name="barCode"></param>
            public delegate void BarCodeCompleted(string barCode);
            public event BarCodeCompleted BarCodeCompletedEvent;

            /// <summary>
            /// 逐个添加字符
            /// </summary>
            /// <param name="keyValue">当前字符</param>
            public void AppendBarCode(int keyValue)
            {
                if (keyValue == 16)
                    return;
                if ((DateTime.Now.Ticks - this.Time.Ticks) > 800000)
                {
                    this.BarCode = "";
                }
                this.KeyValue = keyValue;
                this.BarCode += (char)keyValue;
                this.Time = DateTime.Now;
                if (KeyValue == 13 && this.BarCode.Length > 3)//回车键&&条件长度大于3
                {
                    this.IsValid = true;
                    if (this.BarCodeCompletedEvent != null)
                        BarCodeCompletedEvent(this.BarCode);
                }
            }
        }
    }