vs 2005 serialport 问题

Question

帮我解决下串口的问题
 public Form1()
        {            InitializeComponent();
            serialport1.DataReceived += new SerialDataReceivedEventHandler(serialport1_DataReceived);        }  private void serialport1_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {            System.Threading.Thread.Sleep(100);
            string s100 = "";            if (radioButton1.Checked)
            {
                string data = serialport1.ReadExisting();
                // Log(data, 2);
            }
            else
            {
                    int bytes = serialport1.BytesToRead;
                    MessageBox.Show("数量为:" + bytes.ToString());
                    byte[] buffer = new byte[bytes];
                    if (bytes == 0)
                    { return; }
                    serialport1.Read(buffer, 0, bytes);                    s100 = ByteArrayToHexString(buffer);                    s200 = del(s100);           }
        }接收的时候8个只收6个，有时候接收函数不响应，什么原因，帮下忙？谢了