multithreading - ThreadPool.QueueUserWorkItem和异步编程

Question

我在下面编写了一个示例程序。

class Program
    {
        static int x = 2;

        static void Main(string[] args)
        {
            Console.WriteLine("Thread ID {0} and Main Called!", Thread.CurrentThread.ManagedThreadId);

            ThreadPool.QueueUserWorkItem(Count, args);
            ThreadPool.QueueUserWorkItem(Count2, args);

            Console.WriteLine("Thread ID {0} and Main Done!", Thread.CurrentThread.ManagedThreadId);
            Console.ReadLine();
        }
        static void Count(object args)
        { 
            for (int i = 0; i < 10; i++)
            {
                x = x + 2;
                Console.WriteLine("Thread ID {0} AND Count 1: " + x, Thread.CurrentThread.ManagedThreadId);
            }
        }
        static void Count2(object args)
        {
            for (int i = 0; i < 10; i++)
            {
                x = x + 2;
                Console.WriteLine("Thread ID {0} AND Count 2: " + x, Thread.CurrentThread.ManagedThreadId);
            }
        }
    }

当使用ThreadPool.QueueUserWorkItem调用Count方法时，我注意到Main在Count方法完成之前已经完成，并且Count2方法与Count方法纠缠在一起。

无论如何，Main(和Count2)是否可以等待Count方法完成？我不想使用锁或Thread.Sleep(因为我不知道Count操作将花费多长时间)。我读过某个地方的异步调用或WAIT用于这种情况。

有任何想法吗？

Answer 1

我认为AutoResetEvent是您所追求的

**编辑: **
这是修改后的代码(未经测试)。在此示例中，我使用了AutoResetEvent而不是Manual

class Program
{
    static int x = 2;
    // Define an array with two AutoResetEvent WaitHandles.
    static WaitHandle[] waitHandles = new WaitHandle[] 
    {
        new AutoResetEvent(false),
        new AutoResetEvent(false)
    };



    static void Main(string[] args)
    {
        Console.WriteLine("Thread ID {0} and Main Called!", Thread.CurrentThread.ManagedThreadId);

        ThreadPool.QueueUserWorkItem(new WaitCallback(Count), waitHandles[0]);
        ThreadPool.QueueUserWorkItem(new WaitCallback(Count2), waitHandles[1]);
        WaitHandle.WaitAll(waitHandles);


        Console.WriteLine("Thread ID {0} and Main Done!", Thread.CurrentThread.ManagedThreadId);
        Console.ReadLine();
    }
    static void Count(object args)
    {
        AutoResetEvent are = (AutoResetEvent)args;

        for (int i = 0; i < 10; i++)
        {
            x = x + 2;
            Console.WriteLine("Thread ID {0} AND Count 1: " + x, Thread.CurrentThread.ManagedThreadId);
        }
        are.Set();

    }
    static void Count2(object args)
    {
        AutoResetEvent are = (AutoResetEvent)args;

        for (int i = 0; i < 10; i++)
        {
            x = x + 2;
            Console.WriteLine("Thread ID {0} AND Count 2: " + x, Thread.CurrentThread.ManagedThreadId);
        }
        are.Set();
    }
}