//在使用多線程過程中，可能會遇到在一些情況下必須等待子線程全部執(zhí)行結束后主線程才進行下一步，做法如下
      List<ManualResetEvent> manualEvents = new List<ManualResetEvent>();//創(chuàng)建線程等待集合
      for (int i = 0; i < 64; i++) //WaitHandles 的數(shù)目必須少于或等于 64 個,所以最大線程數(shù)為64
      {
        MB m = new MB();//自定義類，用于傳參
        m.mre= new ManualResetEvent(false);
        m.ID = i;

        manualEvents.Add(m.mre);
        ThreadPool.QueueUserWorkItem(ThreadMethod, m);
      }
      WaitHandle.WaitAll(manualEvents.ToArray());//等待所有線程結束
      Console.WriteLine("Thread Finished!");

private static void ThreadMethod(object obj)
    {
      MB m = (MB)obj;
      Thread.Sleep(1000);//等待1秒，用于模擬系統(tǒng)在處理事情
      m.mre.Set();//將事件設置為終止狀態(tài)
      Console.WriteLine("Thread execute:" + m.ID);
    }

        using (var countdown = new MutipleThreadResetEvent(list.Count))
        {
          for (int i = 0; i < list.Count; i++)
          {
            //開啟N個線程，傳遞MutipleThreadResetEvent對象給子線程
            Param p = new Param();
            p.countdown = countdown;
            p.Path = pa[i];
            ThreadPool.QueueUserWorkItem(MyHttpRequest, p);
          }

          //等待所有線程執(zhí)行完畢
          countdown.WaitAll();
        }

public class MutipleThreadResetEvent: IDisposable
  {
    private readonly ManualResetEvent done;
    private readonly int total;
    private long current;

    /// <summary>
    /// 構造函數(shù)
    /// </summary>
    /// <param name="total">需要等待執(zhí)行的線程總數(shù)</param>
    public MutipleThreadResetEvent(int total)
    {
      this.total = total;
      current = total;
      done = new ManualResetEvent(false);
    }

    /// <summary>
    /// 喚醒一個等待的線程
    /// </summary>
    public void SetOne()
    {
      // Interlocked 原子操作類 ,此處將計數(shù)器減1
      if (Interlocked.Decrement(ref current) == 0)
      {
        //當所以等待線程執(zhí)行完畢時，喚醒等待的線程
        done.Set();
      }
    }

    /// <summary>
    /// 等待所以線程執(zhí)行完畢
    /// </summary>
    public void WaitAll()
    {
      done.WaitOne();
    }

    /// <summary>
    /// 釋放對象占用的空間
    /// </summary>
    public void Dispose()
    {
      ((IDisposable)done).Dispose();
    }
  }