private void post_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            //发送数据
            if (serialPort.IsOpen)
            {                                           //如果串口开启
                string str = serialPort.ReadExisting(); //字符串方式读

                if (ReceiveTbox.Text.Length > 600)
                {
                    ReceiveTbox.Text = ReceiveTbox.Text.Remove(0, 300);
                }

                ReceiveTbox.AppendText(str);
                ReceiveTbox.Focus();

                Packet_Analysis(str);
            }
            else
            {
                MessageBox.Show("通讯端口由于其他异常被迫关闭!");
            }
        }
 private void ReceiveTbox_TextChanged(object sender, EventArgs e)//保持侧测试窗口
 {
     ReceiveTbox.ScrollToCaret();
 }