weiconfig:

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一般处理程序Handler1：

1  public class Handler1 : IHttpHandler 2     { 3  4         public void ProcessRequest(HttpContext context) 5         { 6             context.Response.ContentType = "text/plain"; 7             context.Response.Write("Hello World:" + DateTime.Now.ToString("HH:mm:ss"));//需要输出特定的信息的,可以在这里处理,例如读取数据库的最新参数啊,获取memcached的值之类的都行. 8         } 9 10         public bool IsReusable11         {12             get13             {14                 return false;15             }16         }17     }

 

页面：

1  2  3     
       4      5     15     16     46 47 48     
      
       49         
       
        50             后台推送最新消息：51         
        
         52         
        
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54     
      
55 56 

 

AsnyHandler类与 myAsynResult类：

1 public class AsnyHandler:IHttpAsyncHandler 2 { 3     public AsnyHandler() 4     { 5     } 6  7     public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData) 8     { 9         //myAsynResult为实现了IAsyncResult接口的类，当不调用cb的回调函数时，该请求不会返回到给客户端，会一直处于连接状态10         myAsynResult asyncResult = new myAsynResult(context, cb, extraData);11         String content = context.Request.Params["content"];12 13         //向Message类中添加该消息14         Messages.Instance().AddMessage(content, asyncResult);15         return asyncResult;16     }17 18     #region 不必理会19     20     public void EndProcessRequest(IAsyncResult result)21     {22       23     }24 25     public bool IsReusable26     {27         get { return false; ; }28     }29 30     public void ProcessRequest(HttpContext context)31     {32     }33     #endregion34 }35 public class myAsynResult : IAsyncResult36 {37     bool _IsCompleted = false;38     private HttpContext context;39     private AsyncCallback cb;40     private object extraData;41     public myAsynResult(HttpContext context, AsyncCallback cb, object extraData)42     {43         this.context = context;44         this.cb = cb;45         this.extraData = extraData;46     }47     private string _content;48     public string Content { 49         get {
    return _content;}50         set{_content=value;} 51     }52 53     #region IAsyncResult接口54     public object AsyncState55     {56         get { return null; }57     }58 59     public System.Threading.WaitHandle AsyncWaitHandle60     {61         get { return null; }62     }63 64     public bool CompletedSynchronously65     {66         get { return false; }67     }68     public bool IsCompleted69     {70         get { return _IsCompleted; }71     }72     #endregion73 74     //在Message类中的添加消息方法中，调用该方法，将消息输入到客户端，从而实现广播的功能75     public void Send(object data)76     {77             context.Response.Write(this.Content);78             if (cb!=null)79             {80                 cb(this);81             }82             _IsCompleted = true; ;83     }84 }

 

Messages类：

1 public class Messages 2 { 3     //记录所有请求的客户端 4     List
      
        clients = new List
       
        (); 5  6     #region 实现该类的单例 7     private static readonly Messages _Instance = new Messages(); 8     private Messages() 9     {10     }11     public static Messages Instance()12     {13         return _Instance;14     }15     #endregion16 17     public void AddMessage(string content,myAsynResult asyncResult)18     {19         //当传入的内容为"-1"时，表示为建立连接请求，即为了维持一个从客户端到服务器的连接而建立的连接20         //此时将该连接保存到 List
        
          clients中，待再有消息发送过来时，该连接将会被遍历，并且会将该连接输出内容后，结束该连接21         if (content=="-1")22         {23             clients.Add(asyncResult);24         }25         else26         {27             //将当前请求的内容输出到客户端28             asyncResult.Content = content;29             asyncResult.Send(null);30 31             //否则将遍历所有已缓存的client,并将当前内容输出到客户端32             foreach (myAsynResult result in clients)33             {34                 result.Content = content;35                 result.Send(null);36             }37 38             //清空所有缓存39             clients.Clear();40         }41     }42 }