class Program  
{  
  static TimeSpan Boil()  
  {  
    Console.WriteLine("水壶：开始烧水...");  
    Thread.Sleep(6000);  
    Console.WriteLine("水壶：水已经烧开了！");  
    return TimeSpan.MinValue;  
  }  
 
  delegate TimeSpan BoilingDelegate();  
 
  static void Main(string[] args)  
  {  
    Console.WriteLine("小文：将水壶放在炉子上");  
    BoilingDelegate d = new BoilingDelegate(Boil);  
    IAsyncResult result = d.BeginInvoke(BoilingFinishedCallback, null);  
    Console.WriteLine("小文：开始整理家务...");  
    for (int i = 0; i < 20; i++)  
    {  
      Console.WriteLine("小文：整理第{0}项家务...", i + 1);  
      Thread.Sleep(1000);  
    }  
  }  
 
  static void BoilingFinishedCallback(IAsyncResult result)  
  {  
    AsyncResult asyncResult = (AsyncResult)result;  
    BoilingDelegate del = (BoilingDelegate)asyncResult.AsyncDelegate;
    del.EndInvoke(result);
    Console.WriteLine("小文：将热水灌到热水瓶");  
    Console.WriteLine("小文：继续整理家务");   
  }  
}

static TimeSpan Boil()  
{  
  DateTime begin = DateTime.Now;  
  Console.WriteLine("水壶：开始烧水...");  
  Thread.Sleep(6000);  
  Console.WriteLine("水壶：水已经烧开了！");  
  return DateTime.Now - begin;  
}  

static void BoilingFinishedCallback(IAsyncResult result)  
{  
  AsyncResult asyncResult = (AsyncResult)result;  
  BoilingDelegate del = (BoilingDelegate)asyncResult.AsyncDelegate;  
  Console.WriteLine("（烧水一共用去{0}时间）", del.EndInvoke(result));  
  Console.WriteLine("小文：将热水灌到热水瓶");  
  Console.WriteLine("小文：继续整理家务");  
}  

AsyncResult asyncResult = (AsyncResult)result;  
BoilingDelegate del = (BoilingDelegate)asyncResult.AsyncDelegate;  

class Program  
{  
  delegate void MethodInvoker();  
  static void Foo()  
  {  
    int intAvailableThreads, intAvailableIoAsynThreds;  
    ThreadPool.GetAvailableThreads(out intAvailableThreads, out intAvailableIoAsynThreds);  
    string strMessage = String.Format(@"Is Thread Pool: {0},  
    Thread Id: {1} Free Threads {2}",  
        Thread.CurrentThread.IsThreadPoolThread.ToString(),  
        Thread.CurrentThread.GetHashCode(),  
        intAvailableThreads);  
    Console.WriteLine(strMessage);  
    Thread.Sleep(10000);  
    return;  
  }  
 
  static void CallFoo()  
  {  
    MethodInvoker simpleDelegate = new MethodInvoker(Foo);  
    for (int i = 0; i < 15; i++)  
    {  
      simpleDelegate.BeginInvoke(null, null);  
    }  
  }  
  static void Main(string[] args)  
  {  
    ThreadPool.SetMaxThreads(10, 10);  
    CallFoo();  
    Console.ReadLine();  
  }  
}