C# ManualResetEvent用法

時間 2019-11-07

原文原文鏈接

ManualResetEvent表示線程同步事件，能夠對全部進行等待的線程進行統一管理（收到信號時必須手動重置該事件）api

　　其構造函數爲：函數

public ManualResetEvent (bool initialState);

　　參數 initialState 表示是否初始化，若是爲 true，則將初始狀態設置爲終止（不阻塞）；若是爲 false，則將初始狀態設置爲非終止（阻塞）。this

注意：若是其參數設置爲true，則ManualResetEvent等待的線程不會阻塞。若是初始狀態爲false, 則在Set調用方法以前, 將阻止線程。
spa

　　它只有兩個方法線程

//將事件狀態設置爲終止狀態，從而容許繼續執行一個或多個等待線程。
public bool Set ();

//將事件狀態設置爲非終止，從而致使線程受阻。
public bool Reset ();

//返回值：操做成功返回true，不然false

　　講了這麼多，看個例子理解一下3d

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();  //開始線程
        }

        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();  //阻塞線程，直到調用Set方法才能繼續執行

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