using System;
using System.Collections;
using System.Threading;

namespace ThreadExample {
   //这是用来保存信息的数据结构，将作为参数被传递
   public class SomeState {
      public int Cookie;
      public SomeState(int iCookie) {
         Cookie = iCookie;
      }
   }

   public class Alpha {
      public Hashtable HashCount;
      public ManualResetEvent eventX;
      public static int iCount = 0;
      public static int iMaxCount = 0;

      public Alpha(int MaxCount) {
         HashCount = new Hashtable(MaxCount);
         iMaxCount = MaxCount;
      }

      //线程池里的线程将调用Beta()方法
      public void Beta(Object state) {
         //输出当前线程的hash编码值和Cookie的值
         Console.WriteLine(" {0} {1} :", Thread.CurrentThread.GetHashCode(), ((SomeState)state).Cookie);
         Console.WriteLine("HashCount.Count=={0}, Thread.CurrentThread.GetHashCode()=={1}", HashCount.Count, Thread.CurrentThread.GetHashCode());
         lock (HashCount) {
            //如果当前的Hash表中没有当前线程的Hash值，则添加之
            if (!HashCount.ContainsKey(Thread.CurrentThread.GetHashCode()))
               HashCount.Add(Thread.CurrentThread.GetHashCode(), 0);
            HashCount[Thread.CurrentThread.GetHashCode()] =
               ((int)HashCount[Thread.CurrentThread.GetHashCode()]) + 1;
         }
         int iX = 2000;
         Thread.Sleep(iX);
         //Interlocked.Increment()操作是一个原子操作，具体请看下面说明
         Interlocked.Increment(ref iCount);

         if (iCount == iMaxCount) {
            Console.WriteLine();
            Console.WriteLine("Setting eventX ");
            eventX.Set();
         }
      }
   }

   public class SimplePool {
      public static int Main(string[] args) {
         Console.WriteLine("Thread Pool Sample:");
         bool W2K = false;
         int MaxCount = 10;//允许线程池中运行最多10个线程
         //新建ManualResetEvent对象并且初始化为无信号状态
         ManualResetEvent eventX = new ManualResetEvent(false);
         Console.WriteLine("Queuing {0} items to Thread Pool", MaxCount);
         Alpha oAlpha = new Alpha(MaxCount);
         //创建工作项
         //注意初始化oAlpha对象的eventX属性
         oAlpha.eventX = eventX;
         Console.WriteLine("Queue to Thread Pool 0");
         try {
            //将工作项装入线程池 
            //这里要用到Windows 2000以上版本才有的API，所以可能出现NotSupportException异常
            ThreadPool.QueueUserWorkItem(new WaitCallback(oAlpha.Beta), new SomeState(0));
            W2K = true;
         } catch (NotSupportedException) {
            Console.WriteLine("These API's may fail when called on a non-Windows 2000 system.");
            W2K = false;
         }
         if (W2K)//如果当前系统支持ThreadPool的方法.
         {
            for (int iItem = 1; iItem < MaxCount; iItem++) {
               //插入队列元素
               Console.WriteLine("Queue to Thread Pool {0}", iItem);
               ThreadPool.QueueUserWorkItem(new WaitCallback(oAlpha.Beta), new SomeState(iItem));
            }
            Console.WriteLine("Waiting for Thread Pool to drain");
            //等待事件的完成，即线程调用ManualResetEvent.Set()方法
            eventX.WaitOne(Timeout.Infinite, true);
            //WaitOne()方法使调用它的线程等待直到eventX.Set()方法被调用
            Console.WriteLine("Thread Pool has been drained (Event fired)");
            Console.WriteLine();
            Console.WriteLine("Load across threads");
            foreach (object o in oAlpha.HashCount.Keys)
               Console.WriteLine("{0} {1}", o, oAlpha.HashCount[o]);
         }
         Console.ReadLine();
         return 0;
      }
   }
}