关于SerialPort类的读取问题

[linxiamaomao]

//////////////以上是COM类
protected int BytesToRead = 0;
protected int ReadStart = 0;
protected char[] ReadBuffer = new char[500];

public void Open
{
SerialPort COMPort = new SerialPort()
COMPort.PortName = "COM3"
COMPort.BaudRate = 19200
COMPort.DataBits = 7
COMPort.Parity = "偶"
COMPort.StopBits = one
if (!COMPort.IsOpen)
{
   COMPort.Open();
   COMPort.RtsEnable = true;
   "连接成功"
}
else
{
   "连接失败"   
}
COMPort.DataReceived += new SerialDataReceivedEventHandler(COMPort_DataReceived);
}
protected virtual void COMPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{

       SendCommand();                       
            //RetryCount = 0;                          
       ReadBuffer = new char[500];   
 }
public void SendCommand()
{
    COMPort.Write(LastCommad.GetCommand(), 0, LastCommad.GetCommand().Length);
}
//////////////PLC类
PLC类 :COM类
protected override void COMPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
      ByteToRead = COMPort.BytesToRead;
      COMPort.Read(ReadBuffer, ReadStart, BytesToRead);
      ReadStart = ReadStart + BytesToRead;
}

请各位大师不要纠结参数的问题，
现在我可以写入值，但是ReadBuffer一起取不到值，一直报错ArgumentException 有大师能帮我解决下吗？在线等！谢谢

[linxiamaomao]

COMPort.BytesToRead 这个字节在读第二次的时候 为什么会继续累加上去呢？

[xiacheng1984]

ReadBuffer数组的大小可能不足以容纳待读取的内容，读取前先判断BytesToRead的大小

[xiacheng1984]

如果读取没有成功的话，BytesToRead自然会一直累加。或者可用DiscardInBuffer();