这是程序

using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using

namespace 串口调试助手
{
    public partial class 串口调试助手 : Form
    {
        SerialPort sp = null;
        bool isOpen = false;
        bool isSetProperty = false;
        bool isHex = false;

        public 串口调试助手()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.MaximumSize = this.Size;
            this.MinimumSize = this.Size;
            this.MaximizeBox = false;
            for (int i = 0; i < 10; i++)
            {
                cbxCOMPort.Items.Add("COM" + (i + 1).ToString());
            }
            cbxCOMPort.SelectedIndex = 0;
            cbxBaudRate.Items.Add("1200");
            cbxBaudRate.Items.Add("2400");
            cbxBaudRate.Items.Add("4800");
            cbxBaudRate.Items.Add("9600");
            cbxBaudRate.Items.Add("19200");
            cbxBaudRate.Items.Add("38400");
            cbxBaudRate.Items.Add("43000");
            cbxBaudRate.Items.Add("56000");
            cbxBaudRate.Items.Add("57600");
            cbxBaudRate.Items.Add("115200");
            cbxBaudRate.SelectedIndex = 5;
            cbxStopBits.Items.Add("0");
            cbxStopBits.Items.Add("1");
            cbxStopBits.Items.Add("1.5");
            cbxStopBits.Items.Add("2");
            cbxStopBits.SelectedIndex = 1;
            cbxDataBits.Items.Add("8");
            cbxDataBits.Items.Add("7");
            cbxDataBits.Items.Add("6");
            cbxDataBits.Items.Add("5");
            cbxDataBits.SelectedIndex = 0;
            cbxParity.Items.Add("无");
            cbxParity.Items.Add("奇校验");
            cbxParity.Items.Add("偶校验");
            cbxParity.SelectedIndex = 0;
            rbnChar.Checked = true;
        }

        private void btnCheckCOM_Click(object sender, EventArgs e)
        {
            bool comExistence = false;
            cbxCOMPort.Items.Clear();
            for (int i = 0; i < 10; i++)
            {
                try
                {
                    SerialPort sp = new SerialPort("COM" + (i + 1).ToString());
                    sp.Open();
                    sp.Close();
                    cbxCOMPort.Items.Add("COM" + (i + 1).ToString());
                    comExistence = true;
                }
                catch (Exception)
                {
                    continue;
                }
            }
            if (comExistence)
            {
                cbxCOMPort.SelectedIndex = 0;
            }
            else
            {
                MessageBox.Show("没有找到可用的端口!", "错误提示");
            }
        }

        private bool CheckPortSetting()
        {
            if (cbxCOMPort.Text.Trim() == "") return false;
            if (cbxBaudRate.Text.Trim() == "") return false;
            if (cbxDataBits.Text.Trim() == "") return false;
            if (cbxParity.Text.Trim() == "") return false;
            if (cbxStopBits.Text.Trim() == "") return false;
            return true;
        }

        private bool CheckSendData()
        {
            if (tbxSendData.Text.Trim() == "") return false;
            return true;
        }

        private void SetPortProperty()
        {
            sp = new SerialPort();
            sp.PortName = cbxCOMPort.Text.Trim();
            sp.BaudRate = Convert.ToInt32(cbxBaudRate.Text.Trim());

            float f = Convert.ToSingle(cbxStopBits.Text.Trim());
            if (f == 0)
            {
                sp.StopBits = StopBits.None;
            }
            else if (f == 1.5)
            {
                sp.StopBits = StopBits.OnePointFive;
            }
            else if (f == 1)
            {
                sp.StopBits = StopBits.One;
            }
            else if (f == 2)
            {
                sp.StopBits = StopBits.Two;
            }
            else
            {
                sp.StopBits = StopBits.One;
            }
            sp.DataBits = Convert.ToInt16(cbxDataBits.Text.Trim());

            string s = cbxParity.Text.Trim();
            if (("无") == 0)
            {
                sp.Parity = Parity.None;
            }
            else if (("奇校验") == 0)
            {
                sp.Parity = Parity.Odd;
            }
            else if (("偶校验") == 0)
            {
                sp.Parity = Parity.Even;
            }
            else
            {
                sp.Parity = Parity.None;
            }
            sp.ReadTimeout = -1;
            sp.RtsEnable = true;
            sp.DataReceived += new SerialDataReceivedEventHandler(sp_DataReceived);
            if (rbnHex.Checked)
            {
                isHex = true;
            }
            else
            {
                isHex = false;
            }
        }

        private void btnSend_Click(object sender, EventArgs e)
        {
            if (isOpen)
            {
                try
                {
                    sp.WriteLine(tbxSendData.Text);
                }
                catch (Exception)
                {
                    MessageBox.Show("发送数据时发生错误!", "错误提示");
                    return;
                }
            }
            else
            {
                MessageBox.Show("串口未打开!", "错误提示");
                return;
            }
        }
            

        private void btnOpenCom_Click(object sender, EventArgs e)
        {
            if (isOpen == false)
            {
                if (!CheckPortSetting())
                {
                    MessageBox.Show("串口未设置!", "错误提示");
                    return;
                }
                if (!isSetProperty)
                {
                    SetPortProperty();
                    isSetProperty = true;
                }
                try
                {
                    sp.Open();
                    isOpen = true;
                    btnOpenCom.Text = "关闭串口";
                    cbxCOMPort.Enabled = false;
                    cbxBaudRate.Enabled = false;
                    cbxDataBits.Enabled = false;
                    cbxParity.Enabled = false;
                    cbxStopBits.Enabled = false;
                    rbnChar.Enabled = false;
                    rbnHex.Enabled = false;
                }
                catch (Exception)
                {
                    isSetProperty = false;
                    isOpen = false;
                    MessageBox.Show("串口无效或被占用!", "错误提示");
                }
            }


            else
            {
                try
                {
                    sp.Close();
                    isOpen = false;
                    isSetProperty = false;
                    btnOpenCom.Text = "打开串口";
                    cbxCOMPort.Enabled = true;
                    cbxBaudRate.Enabled = true;
                    cbxDataBits.Enabled = true;
                    cbxParity.Enabled = true;
                    cbxStopBits.Enabled = true;
                    rbnChar.Enabled = true;
                    rbnHex.Enabled = true;
                }
                catch (Exception)
                {
                    btnOpenCom.Text = "关闭串口时出现错误";
                }
            }
        }

        private void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            System.Threading.Thread.Sleep(100);
            this.Invoke((EventHandler)(delegate
            {
                if (isHex == false)
                {
                    tbxRecvData.Text += sp.ReadLine();
                }
                else
                {
                    Byte[] ReceivedData = new Byte[sp.BytesToRead];
                    sp.Read(ReceivedData, 0, ReceivedData.Length);
                    String RecvDataText = null;
                    for (int i = 0; i < ReceivedData.Length - 1; i++)
                    {
                        RecvDataText += ("0x" + ReceivedData[i].ToString("X2") + "");
                    }
                    tbxRecvData.Text += RecvDataText;
                }
                sp.DiscardInBuffer();
            }));
        }
        private void btnCleanData_DataClick(object sender, EventArgs e)
        {
            tbxRecvData.Text = "";
            tbxSendData.Text = "";
        }
    }
}