线程的同步和线程间的协调笔记

  线程的同步和线程间的协调

通常非同步线程的运行时间不可予知；

保护数据，当多个线程访问数据时，避免出现不可知的结果；

协调线程使线程在到达某个状态是可以改变其状态。

线程同步，线程安全

线程通常不能协调，需要开发者处理

可使用的同步对象：Interlocked、AutoResetEvant、ManualResetEvent、Monitor、Mutex

多线程访问对象可能会引发异常；

读取到不一致数据；

两个线程可能会同时更新数据导致错误结果

使用同步对象创建线程安全类；

只有需要并发的类才需要线程安全。
代码：

#define RUN_IN_SYNC  //予定义运行时同步 不同步时该为#define NOT_RUN_IN_SYNC 

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

using System.Threading;

namespace WindowsApplication2
{
    public  class Form1 : Form
    {
        //定义label显示字符
        private string text;
        private bool thread1Running;
        private bool thread2Running;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Label label1;

#if RUN_IN_SYNC
        private Mutex myMutex;//用于进程间同步
#endif

        public Form1()
        {
            InitializeComponent();
        }

        //程序住入口
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.Run(new Form1());
        }

        //按钮
        private void button1_Click(object sender, EventArgs e)
        {
            label1.Text = "";
            text = "";
            button1.Enabled = false;
#if RUN_IN_SYNC
            myMutex = new Mutex();
#endif
            Thread workerThread1 = new Thread(new ThreadStart(Thread1Function));
            Thread workerThread2 = new Thread(new ThreadStart(Thread2Function));
            thread1Running = true;
            thread2Running = true;
            workerThread1.Start();
            workerThread2.Start();

        }

        //线程执行函数1
        private void Thread1Function()
        {
#if RUN_IN_SYNC

            myMutex.WaitOne();

#endif
            for (int i = 0; i < 5; i++)
            {
                text += i.ToString();
                Thread.Sleep(0);
            }

#if RUN_IN_SYNC
            myMutex.ReleaseMutex();
#endif
            thread1Running = false;
            this.Invoke(new EventHandler(WorkerThreadsFinished));
        }

        //线程执行函数2
        private void Thread2Function()
        {
#if RUN_IN_SYNC

            myMutex.WaitOne();

#endif

            for (int i = 0; i < 5; i++)
            {
                text += i.ToString();
                Thread.Sleep(0);
            }

#if RUN_IN_SYNC

            myMutex.ReleaseMutex();

#endif

            thread2Running = false;
            this.Invoke(new EventHandler(WorkerThreadsFinished));
        }

        public delegate void EventHandler();
        private void WorkerThreadsFinished()
        {
            label1.Text = text;
            button1.Enabled = true;

        }

        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.label1 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(96, 176);
            this.button1.Name = "button1";
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // label1
            // 
            this.label1.Location = new System.Drawing.Point(72, 72);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(160, 23);
            this.label1.TabIndex = 1;
            this.label1.Text = "label1";
            // 
            // Form1
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
            this.ClientSize = new System.Drawing.Size(292, 273);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);

        }

        private void Form1_Load(object sender, System.EventArgs e)
        {

        }
    }
}