C# ManualResetEvent用法详解

145 阅读 0 评论 96 点赞

我是靠谱客的博主大力小熊猫，最近开发中收集的这篇文章主要介绍C# ManualResetEvent用法详解，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

ManualResetEvent表示线程同步事件，可以对所有进行等待的线程进行统一管理（收到信号时必须手动重置该事件）

其构造函数为：

public ManualResetEvent (bool initialState);

参数 initialState 表示是否初始化，如果为 true，则将初始状态设置为终止（不阻塞）；如果为 false，则将初始状态设置为非终止（阻塞）。

注意：如果其参数设置为true，则ManualResetEvent等待的线程不会阻塞。如果初始状态为false, 则在Set调用方法之前, 将阻止线程。

它只有两个方法

//将事件状态设置为终止状态，从而允许继续执行一个或多个等待线程。
public bool Set ();

//将事件状态设置为非终止，从而导致线程受阻。
public bool Reset ();

//返回值：操作成功返回true，否则false

讲了这么多，看个例子理解一下

using System;
using System.Threading;

public class Example
{
  // mre is used to block and release threads manually. It is
  // created in the unsignaled state.
  private static ManualResetEvent mre = new ManualResetEvent(false);

  static void Main()
  {
    Console.WriteLine("nStart 3 named threads that block on a ManualResetEvent:n");

    for (int i = 0; i <= 2; i++)
    {
      Thread t = new Thread(ThreadProc);
      t.Name = "Thread_" + i;
      t.Start(); //开始线程
    }

    Thread.Sleep(500);
    Console.WriteLine("nWhen all three threads have started, press Enter to call Set()" +
             "nto release all the threads.n");
    Console.ReadLine();

    mre.Set();

    Thread.Sleep(500);
    Console.WriteLine("nWhen a ManualResetEvent is signaled, threads that call WaitOne()" +
             "ndo not block. Press Enter to show this.n");
    Console.ReadLine();

    for (int i = 3; i <= 4; i++)
    {
      Thread t = new Thread(ThreadProc);
      t.Name = "Thread_" + i;
      t.Start();
    }

    Thread.Sleep(500);
    Console.WriteLine("nPress Enter to call Reset(), so that threads once again block" +
             "nwhen they call WaitOne().n");
    Console.ReadLine();

    mre.Reset();

    // Start a thread that waits on the ManualResetEvent.
    Thread t5 = new Thread(ThreadProc);
    t5.Name = "Thread_5";
    t5.Start();

    Thread.Sleep(500);
    Console.WriteLine("nPress Enter to call Set() and conclude the demo.");
    Console.ReadLine();

    mre.Set();

    // If you run this example in Visual Studio, uncomment the following line:
    //Console.ReadLine();
  }


  private static void ThreadProc()
  {
    string name = Thread.CurrentThread.Name;

    Console.WriteLine(name + " starts and calls mre.WaitOne()");

    mre.WaitOne(); //阻塞线程，直到调用Set方法才能继续执行

    Console.WriteLine(name + " ends.");
  }
}

结果如下