C#多线程编程笔记(2.4)-使用ManualResetEventSlim类

近来在学习Eugene Agafonov编写的《C#多线程编程实战》（译），做些笔记也顺便分享一下^-^

using System;
using System.Threading;

namespace ManualResetEventSlim_Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var t1 = new Thread(() => TravelThroughGates("Thread1", 5));
            var t2 = new Thread(() => TravelThroughGates("Thread2", 6));
            var t3 = new Thread(() => TravelThroughGates("Thread3", 12));
            t1.Start();
            t2.Start();
            t3.Start();
            Thread.Sleep(TimeSpan.FromSeconds(6));
            Console.WriteLine("The gates are now open!");
            _mainEvent.Set();
            Thread.Sleep(TimeSpan.FromSeconds(2));
            _mainEvent.Reset();
            Console.WriteLine("The gates have been closed!");
            Thread.Sleep(TimeSpan.FromSeconds(10));
            Console.WriteLine("The gates are now open for the second time!");
            _mainEvent.Set();
            Thread.Sleep(TimeSpan.FromSeconds(2));
            Console.WriteLine("The gates have been closed!");
            _mainEvent.Reset();

            Console.ReadKey();
        }

        static ManualResetEventSlim _mainEvent = new ManualResetEventSlim(false);

        static void TravelThroughGates(string threadName,int seconds)
        {
            Console.WriteLine("{0} false to sleep", threadName);
            Thread.Sleep(TimeSpan.FromSeconds(seconds));
            Console.WriteLine("{0} waits for the gates to open!", threadName);
            _mainEvent.Wait();
            Console.WriteLine("{0} enters the gates!", threadName);
        }
    }
}

程序运行结果如下

当主程序启动时，首先创建了ManualResetEventSlim类的一个实例。然后启动了三个线程，等待事件信号通知它们继续执行。

ManualResetEventSlim的整个工作方法有点像人群通过大门，AutoResetEvent事件像一个旋转门，一次只允许一人通过。ManualResetEventSlim是ManualResetEvent的混合版本，一直保持大门敞开直到手动调用Reset方法。当调用_mainEvent.Set时，相当于打开了大门从而允许准备好的线程接收信号并继续工作。然而线程3还处于睡眠状态，没有赶上时间。当调用_mainEvent.Reset相当于关闭了大门。最后一个线程已经准备好要执行，但是不得不等待下一个信号。