using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using System.IO.Ports;

namespace com测试
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }
        
        Mutex m_Mutex = null;//锁

        private void Form1_Load(object sender, EventArgs e)
        {
            serialPort1 = new SerialPort("com1", 2400, Parity.Even, 7, StopBits.One);
            m_Mutex = new Mutex();
            flag = false;
        }
        
        delegate void setTextCallback(string msg);
        
        bool flag;

        SerialPort serialPort1; 
        private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
        {
           
                    if (flag==true)
                    {
                        return;
                    }
                    m_Mutex.WaitOne();//这个地方加一个互斥
                        
                if (serialPort1.IsOpen)
                {
                    setTextCallback d = new setTextCallback(addText);
                    string temp = serialPort1.ReadTo("49").ToString();
                    this.BeginInvoke(d, new object[] { temp });
                }
                m_Mutex.ReleaseMutex();
              
                       
        }
        void addText(string msg)
        {
                richTextBox1.AppendText(msg);
         
        }

        private void btnOpen_Click(object sender, EventArgs e)
        {
            this.serialPort1.DataReceived += new System.IO.Ports.SerialDataReceivedEventHandler(this.serialPort1_DataReceived);
            serialPort1.Open();
            this.btnOpen.Enabled = false;
            this.btnClose.Enabled = true;
            this.flag = false;
        }

        private void btnClose_Click(object sender, EventArgs e)
        {
               m_Mutex.WaitOne();
            {
                this.serialPort1.DataReceived -= new System.IO.Ports.SerialDataReceivedEventHandler(this.serialPort1_DataReceived);//先关掉对应的事件
            }
            serialPort1.Close();//然后关掉程序
            flag = true;
            m_Mutex.ReleaseMutex();

            this.btnOpen.Enabled = true;
            this.btnClose.Enabled = false;
           
        }
    }
}

}