C#实现串口监听 | 易学教程

Visual Stdio 2005中,对于串口操作Framework提供了一个很好的类接口-SerialPort,在这当中,串口数据的读取与写入有较大的不同。由于串口不知道数据何时到达，因此有两种方法可以实现串口数据的读取。
1.用线程实时读串口
2.用事件触发方式实现。
但由于线程实时读串口的效率不是十分高效，因此比较好的方法是事件触发的方式。在SerialPort类中有DataReceived事件，当串口的读缓存有数据到达时则触发DataReceived事件，其中SerialPort.ReceivedBytesThreshold属性决定了当串口读缓存中数据多少个时才触发DataReceived事件，默认为1。
此外，SerialPort.DataReceived事件运行比较特殊，其运行在辅线程，不能与主线程中的显示数据控件直接进行数据传输，必须用间接的方式实现。
一.创建WIndow项目,设计界面
二,编写实现代码
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;
using Microsoft.Win32;
namespace ComMonitor
{
    public partial class Form1 : Form
     {
        public Form1()
         {
             InitializeComponent();
         }
        private SerialPort Sp = new SerialPort();
        public delegate void HandleInterfaceUpdataDelegate(string text); //委托，此为重点 
        private HandleInterfaceUpdataDelegate interfaceUpdataHandle;
        private bool qiii = false;
        private void btENT_Click(object sender, EventArgs e)
         {
            if ((cmID.Text.Trim() != "") && (cmRate.Text != ""))
             {
                 interfaceUpdataHandle = new HandleInterfaceUpdataDelegate(UpdateTextBox);//实例化委托对象 
                 Sp.PortName = cmID.Text.Trim();
                 Sp.BaudRate = Convert.ToInt32(cmRate.Text.Trim());
                 Sp.Parity = Parity.None;
                 Sp.StopBits = StopBits.One;
                 Sp.DataReceived += new SerialDataReceivedEventHandler(Sp_DataReceived);
                 Sp.ReceivedBytesThreshold = 1;
                try
                 {
                     Sp.Open();
                     ATCommand3("AT+CLIP=1\r", "OK");
                     btPause.Enabled = true;
                     btENT.Enabled = false;
                 }
                catch
                 {
                     MessageBox.Show("端口" + cmID.Text.Trim() + "打开失败！");
                 }
             }
            else
             {
                 MessageBox.Show("请输入正确的端口号和波特率！");
                 cmID.Focus();
             }
         }
        private void btPause_Click(object sender, EventArgs e)
         {
             Sp.Close();
             btENT.Enabled = true;
             btPause.Enabled = false;
         }
        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
         {
             Sp.Close();
         }
        private void Form1_Load(object sender, EventArgs e)
         {
             GetComList();
             btPause.Enabled = false;
         }
        public void Sp_DataReceived(object sender,System.IO.Ports.SerialDataReceivedEventArgs e)
         {
            string strTemp = "";
            double iSecond = 0.5;
             DateTime dtOld = System.DateTime.Now;
             DateTime dtNow = System.DateTime.Now;
             TimeSpan dtInter;
             dtInter = dtNow - dtOld;
            int i = Sp.BytesToRead;
            if (i > 0)
             {
                try
                 {
                     strTemp = Sp.ReadExisting();
                 }
                catch
                 { }
                if (strTemp.ToLower().IndexOf("\r") < 0)
                 {
                     i = 0;
                 }
                else
                 {
                    this.Invoke(interfaceUpdataHandle, strTemp);
                 }
             }
            while (dtInter.TotalSeconds < iSecond && i <= 0)
             {
                 dtNow = System.DateTime.Now;
                 dtInter = dtNow - dtOld;
                 i = Sp.BytesToRead;
                if (i > 0)
                 {
                    try
                     {
                         strTemp += Sp.ReadExisting();
                     }
                    catch
                     { }
                    if (strTemp.ToLower().IndexOf("\r") < 0)
                     {
                         i = 0;
                     }
                    else
                     {
                        this.Invoke(interfaceUpdataHandle, strTemp);
                     }
                 }
             }
            // do null 
         }
        private void UpdateTextBox(string text)
         {
             tbData.Text = text;
         }
        /// <summary> 
        /// 执行AT指令并返回 成功失败 
        /// </summary> 
        /// <param name="ATCmd">AT指令</param> 
        /// <param name="StCmd">AT指令标准结束标识</param> 
        /// <returns></returns> 
        private void ATCommand3(string ATCmd, string StCmd)
         {
            string response = "";
             response = ATCommand(ATCmd, StCmd);
         }
        /// <summary> 
        /// 执行AT指令并返回结果字符 
        /// </summary> 
        /// <param name="ATCmd">AT指令</param> 
        /// <param name="StCmd">AT指令标准结束标识</param> 
        /// <returns></returns> 
        private string ATCommand(string ATCmd, string StCmd)
         {
            string response = "";
            int i;
            if (!ATCmd.EndsWith("\x01a"))
             {
                if (!(ATCmd.EndsWith("\r") || ATCmd.EndsWith("\r\n")))
                 {
                     ATCmd = ATCmd + "\r";
                 }
             }
             Sp.WriteLine(ATCmd);
            //第一次读响应数据 
            if (Sp.BytesToRead > 0)
             {
                 response = Sp.ReadExisting();
                //去除前端多可能多读取的字符 
                if (response.IndexOf(ATCmd) > 0)
                 {
                     response = response.Substring(response.IndexOf(ATCmd));
                 }
                else
                 {
                 }
                if (response == "" || response.IndexOf(StCmd) < 0)
                 {
                    if (response != "")
                     {
                        if (response.Trim() == "ERROR")
                         {
                            //throw vError = new UnknowException("Unknown exception in sending command:" + ATCmd); 
                         }
                        if (response.IndexOf("+CMS ERROR") >= 0)
                         {
                            string[] cols = new string[100];
                             cols = response.Split(';');
                            if (cols.Length > 1)
                             {
                                string errorCode = cols[1];
                             }
                         }
                     }
                 }
             }
            //读第一次没有读完的响应数据，直到读到特征数据或超时 
            for (i = 0; i < 3; i++)
             {
                 Thread.Sleep(1000);
                 response = response + Sp.ReadExisting();
                if (response.IndexOf(StCmd) >= 0)
                 {
                    break;
                 }
             }
            return response;
         }
        /// <summary> 
        /// 从注册表获取系统串口列表 
        /// </summary> 
        private void GetComList()
         {
             RegistryKey keyCom = Registry.LocalMachine.OpenSubKey("Hardware\\DeviceMap\\SerialComm");
            if (keyCom != null)
             {
                string[] sSubKeys = keyCom.GetValueNames();
                this.cmID.Items.Clear();
                foreach (string sName in sSubKeys)
                 {
                    string sValue = (string)keyCom.GetValue(sName);
                    this.cmID.Items.Add(sValue);
                 }
             }
         }
        private void cmID_DropDown(object sender, EventArgs e)
         {
             GetComList();
         }
     }
} 
来源：https://www.cnblogs.com/sunxiaonan/archive/2009/11/24/1609449.html
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