ASP.NET / C＃事件的區別

Question

可能重復： .net中的ManualResetEvent和AutoResetEvent有什么區別？

ManualResetEvent和AutoResetEvent有什么區別？ （示例可能會有所幫助）。

Answer 1

ManualResetEvent就像一個字段中的門 - 一旦打開它，它就會讓人們通過直到有人關閉它。

AutoResetEvent就像火車站的旋轉門 - 一旦你把車票放進去， 一個人可以通過，但只有一個。

這是一個例子 - 5個線程都在等待同一事件，每秒設置一次。 通過手動復位事件， 所有線程一旦設置一次就“通過門”。 使用自動重置事件時，一次只能執行一次。

using System;
using System.Threading;

class Test
{
    static void Main()
    {
        // Change to AutoResetEvent to see different behaviour
        EventWaitHandle waitHandle = new ManualResetEvent(false);

        for (int i = 0; i < 5; i++)
        {
            int threadNumber = i;
            new Thread(() => WaitFor(threadNumber, waitHandle)).Start();
        }
        // Wait for all the threads to have started
        Thread.Sleep(500);

        // Now release the handle three times, waiting a
        // second between each time
        for (int i = 0; i < 3; i++)
        {
            Console.WriteLine("Main thread setting");
            waitHandle.Set();
            Thread.Sleep(1000);
        }
    }

    static void WaitFor(int threadNumber, EventWaitHandle waitHandle)
    {
        Console.WriteLine("Thread {0} waiting", threadNumber);
        waitHandle.WaitOne();
        Console.WriteLine("Thread {0} finished", threadNumber);        
    }
}

ManualResetEvent示例輸出：

Thread 0 waiting
Thread 4 waiting
Thread 1 waiting
Thread 2 waiting
Thread 3 waiting
Main thread setting
Thread 2 finished
Thread 1 finished
Thread 0 finished
Thread 4 finished
Thread 3 finished
Main thread setting
Main thread setting

AutoResetEvent示例輸出：

Thread 0 waiting
Thread 1 waiting
Thread 2 waiting
Thread 3 waiting
Thread 4 waiting
Main thread setting
Thread 3 finished
Main thread setting
Thread 2 finished
Main thread setting
Thread 1 finished

（程序然后只是掛起，因為有兩個線程仍在等待設置事件，並且沒有任何設置它。）