c# - 是否有可能知道哪个线程先完成？

Question

如果我有 3 个线程。是否有可能知道哪个线程先完成。

一些示例代码

    Thread thread1 = new Thread(() => MyFunc());
    Thread thread2 = new Thread(() => MyFunc());
    Thread thread3 = new Thread(() => MyFunc());

   thread1.Start();
   thread2.Start();
   thread3.Start();

   while (thread1.IsAlive || thread2.IsAlive || thread3.IsAlive)
   {
        //I need condition to which thread dead first.
    }

Answer 1

您可以使用Interlocked.CompareExchange设置获胜线程:

static Thread winner = null;

private static void MyFunc()
{
    Thread.Sleep((int)(new Random().NextDouble() * 1000));
    Interlocked.CompareExchange(ref winner, Thread.CurrentThread, null);
}

public static void Main()
{
    Thread thread1 = new Thread(() => MyFunc());
    Thread thread2 = new Thread(() => MyFunc());
    Thread thread3 = new Thread(() => MyFunc());

    thread1.Name = "thread1";
    thread2.Name = "thread2";
    thread3.Name = "thread3";

    thread1.Start();
    thread2.Start();
    thread3.Start();

    thread1.Join();
    thread2.Join();
    thread3.Join();

    Console.WriteLine("The winner is {0}", winner.Name);
}

Live Demo

更新:如果您不希望所有线程在您检查之前完成，可以使用 AutoResetEvent 和 WaitHandle.WaitAny() 更简单的方法:

private static void MyFunc(AutoResetEvent ev)
{
    Thread.Sleep((int)(new Random().NextDouble() * 1000));
    ev.Set();
}

public static void Main()
{
    AutoResetEvent[] evs = {new AutoResetEvent(false), new AutoResetEvent(false), new AutoResetEvent(false)};
    Thread thread1 = new Thread(() => MyFunc(evs[0]));
    Thread thread2 = new Thread(() => MyFunc(evs[1]));
    Thread thread3 = new Thread(() => MyFunc(evs[2]));

    thread1.Start();
    thread2.Start();
    thread3.Start();

    int winner = WaitHandle.WaitAny(evs);

    Console.WriteLine("The winner is thread{0}", winner + 1);
}

Live Demo