C# .NET Framework 3.5 下 Task 与 EventWaitHandle 的简单例子

只是把 Semaphore 换成了 EventWaitHandle。请与这个贴子中的例子进行比较：https://www.cnblogs.com/pencilstart/p/15865478.html

注意，由于 .NET 3.5下并没有官方实现的 Task 库，所以，是通过 VS 中 NuGet 取得的 非官方 实现的 Task 库，调用接口与官方.NET 4.0 后的应该是差不多的。

EventWaitHandle 初始化时，初始值为 signaled 的状态。

using System;
using System.Threading;
using System.Threading.Tasks;

namespace testEventWaitHandle
{
    class Program
    {
        EventWaitHandle ewh = new EventWaitHandle(true, EventResetMode.AutoReset);

        static int count = 0;

        void test()
        {
            object param1 = new object[] { "Thread A", 0 };
            object param2 = new object[] { "Thread B", 500 };

            Action<object> a1 = new Action<object>(TaskProc);
            Action<object> a2 = new Action<object>(TaskProc);

            Task task1 = new TaskFactory().StartNew(a1, param1);
            Task task2 = new TaskFactory().StartNew(a1, param2);

            Task.WaitAll(task1, task2);
        }

        static void Main(string[] args)
        {
            Program p = new Program();

            p.test();

            Console.WriteLine("main end, mainthreadid = {0}", System.Threading.Thread.CurrentThread.ManagedThreadId);
        }

        void TaskProc(object args)
        {
            string name = (string)((object[])args)[0];
            int startdelay = (int)((object[])args)[1];

            Console.WriteLine("{0}: COME IN, threadid = {1}", name, System.Threading.Thread.CurrentThread.ManagedThreadId);

            System.Threading.Thread.Sleep(startdelay);

            Console.WriteLine("{0}: START, threadid = {1}", name, System.Threading.Thread.CurrentThread.ManagedThreadId);

            for (int i = 0; i < 10; ++i)
            {
                ewh.WaitOne();

                Random r = new Random();

                int s = r.Next(50, 1000);

                count = count + 1;
                Console.WriteLine("{0}: i = {1}, sleep({2}), threadid = {3}, count = {4}", name, i, s, System.Threading.Thread.CurrentThread.ManagedThreadId, count);

                System.Threading.Thread.Sleep(s);

                ewh.Set();
            }

            Console.WriteLine("{0}: END, threadid = {1}", name, System.Threading.Thread.CurrentThread.ManagedThreadId);
        }
    }
}

//Thread A: COME IN, threadid = 3
//Thread A: START, threadid = 3
//Thread A: i = 0, sleep(566), threadid = 3, count = 1
//Thread B: COME IN, threadid = 4
//Thread B: START, threadid = 4
//Thread B: i = 0, sleep(530), threadid = 4, count = 2
//Thread A: i = 1, sleep(918), threadid = 3, count = 3
//Thread B: i = 1, sleep(610), threadid = 4, count = 4
//Thread A: i = 2, sleep(759), threadid = 3, count = 5
//Thread B: i = 2, sleep(928), threadid = 4, count = 6
//Thread A: i = 3, sleep(961), threadid = 3, count = 7
//Thread B: i = 3, sleep(684), threadid = 4, count = 8
//Thread A: i = 4, sleep(935), threadid = 3, count = 9
//Thread B: i = 4, sleep(359), threadid = 4, count = 10
//Thread A: i = 5, sleep(883), threadid = 3, count = 11
//Thread B: i = 5, sleep(389), threadid = 4, count = 12
//Thread A: i = 6, sleep(148), threadid = 3, count = 13
//Thread B: i = 6, sleep(621), threadid = 4, count = 14
//Thread A: i = 7, sleep(161), threadid = 3, count = 15
//Thread B: i = 7, sleep(976), threadid = 4, count = 16
//Thread A: i = 8, sleep(430), threadid = 3, count = 17
//Thread B: i = 8, sleep(261), threadid = 4, count = 18
//Thread A: i = 9, sleep(682), threadid = 3, count = 19
//Thread A: END, threadid = 3
//Thread B: i = 9, sleep(139), threadid = 4, count = 20
//Thread B: END, threadid = 4
//main end, mainthreadid = 1
//请按任意键继续. . .