public   class  PortData
    {
         public   event  PortDataReceivedEventHandle Received;
         public   event  SerialErrorReceivedEventHandler Error; 
         public  SerialPort port;
         public   bool  ReceiveEventFlag  =   false ;   // 接收事件是否有效 false表示有效

         public  PortData( string  sPortName,  int  baudrate,Parity parity,SerialInterface.SerialMode mode)
        {
            port  =   new  SerialPort(sPortName, baudrate, parity,  8 , StopBits.One);
            port.RtsEnable  =   true ;
            port.ReadTimeout  =   3000 ;
            port.DataReceived  +=   new  SerialDataReceivedEventHandler(DataReceived);
            port.ErrorReceived  +=   new  SerialErrorReceivedEventHandler(ErrorEvent);
        }

         ~ PortData()
        {
            Close();
        }
         public   void  Open()
        {
             if  ( ! port.IsOpen)
            {           
                port.Open();
            }
        }

         public   void  Close()
        {
             if  (port.IsOpen)
            {
                port.Close();
            }
        }
         // 数据发送
         public   void  SendData( byte [] data)
        {
             if  (port.IsOpen)
            {
                port.Write(data,  0 , data.Length);
            }
        }
         public   void  SendData( byte [] data, int  offset, int  count)
        {
             if  (port.IsOpen)
            {
                port.Write(data, offset, count);
            }
        }
         // 发送命令
         public   int  SendCommand( byte [] SendData,  ref    byte [] ReceiveData, int  Overtime)
        {

             if (port.IsOpen)
            {
                ReceiveEventFlag  =   true ;         // 关闭接收事件
                port.DiscardInBuffer();          // 清空接收缓冲区                 
                port.Write(SendData,  0 , SendData.Length);
                 int  num = 0 ,ret = 0 ;
                 while  (num ++   <  Overtime)
                {
                     if  (port.BytesToRead  >=  ReceiveData.Length)  break ;
                    System.Threading.Thread.Sleep( 1 ); 
                }
                 if  (port.BytesToRead  >=  ReceiveData.Length) 
                    ret  =  port.Read(ReceiveData,  0 , ReceiveData.Length);
                ReceiveEventFlag  =   false ;        // 打开事件
                 return  ret;
            }
             return   - 1 ;
        }

         public   void  ErrorEvent( object  sender, SerialErrorReceivedEventArgs e)
        {
             if  (Error  !=   null ) Error(sender, e);
        }
         // 数据接收
         public   void  DataReceived( object  sender, SerialDataReceivedEventArgs e)
        {
             // 禁止接收事件时直接退出
             if  (ReceiveEventFlag)  return ;

             byte [] data  =   new   byte [port.BytesToRead];
            port.Read(data,  0 , data.Length);
             if  (Received  !=   null ) Received(sender,  new  PortDataReciveEventArgs(data));
        }

         public   bool  IsOpen()
        {
             return  port.IsOpen;
        }
    }
     public   delegate   void  PortDataReceivedEventHandle( object  sender, PortDataReciveEventArgs e);
     public   class  PortDataReciveEventArgs : EventArgs
    {
         public  PortDataReciveEventArgs()
        {
             this .data  =   null ;
        }

         public  PortDataReciveEventArgs( byte [] data)
        {
             this .data  =  data;
        }

         private   byte [] data;

         public   byte [] Data
        {
             get  {  return  data; }
             set  { data  =  value; }
        }
    }