如何创建在Windows Phone的UDP广播监听套接字

Question

我试图开发了Windows Phone 7.5应用程序，我想创建一个监听套接字听UDP广播消息在端口8001

我已经修改示例How to: Create and Use a UDP Socket Client Application for Windows Phone但我得到“无效的参数异常”，但我修复了该错误。

现在这是我的代码：

public String SecureRecive(int portNumber, bool isBroadcast) 
    { 
     SocketAsyncEventArgs socketEventArg; 

     Send("melnibone", portNumber, " ", isBroadcast, out socketEventArg); 
     Thread.Sleep(1000); 

     if (!isHasSent) ; 
     return Receive(portNumber, isBroadcast, socketEventArg); 
    } 

    private string Send(string serverName, int portNumber, string data, bool isBroadcast, out SocketAsyncEventArgs socketEventArg) 
    { 
     string response = "Operation Timeout"; 

     // We are re-using the _socket object that was initialized in the Connect method 
     if (_socket != null) 
     { 
      socketEventArg = new SocketAsyncEventArgs(); 
      // Set properties on context object 
      if (isBroadcast) 
       socketEventArg.RemoteEndPoint = new IPEndPoint(IPAddress.Broadcast, portNumber); 
      else 
       socketEventArg.RemoteEndPoint = new DnsEndPoint(serverName, portNumber); 

      // Inline event handler for the Completed event. 
      // Note: This event handler was implemented inline in order to make this method self-contained. 
      socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(delegate(object s, SocketAsyncEventArgs e) 
      { 
       response = e.SocketError.ToString(); 

       // Unblock the UI thread 
       _clientDone.Set(); 
       isHasSent = true; 
      }); 
      // Add the data to be sent into the buffer 
      byte[] payload = Encoding.UTF8.GetBytes(data); 
      socketEventArg.SetBuffer(payload, 0, payload.Length); 

      // Sets the state of the event to nonsignaled, causing threads to block 
      _clientDone.Reset(); 

      // Make an asynchronous Send request over the socket 
      _socket.SendToAsync(socketEventArg); 

      // Block the UI thread for a maximum of TIMEOUT_MILLISECONDS milliseconds. 
      // If no response comes back within this time then proceed 
      //_clientDone.WaitOne(TIMEOUT_MILLISECONDS); 
     } 
     else 
     { 
      socketEventArg = null; 
      response = "Socket is not initialized"; 
     } 

     return response; 
    } 

    /// <summary> 
    /// Receive data from the server 
    /// </summary> 
    /// <param name="portNumber">The port on which to receive data</param> 
    /// <returns>The data received from the server</returns> 
    private string Receive(int portNumber, bool isBroadcast, SocketAsyncEventArgs socketEventArg) 
    { 
     string response = "Operation Timeout"; 

     // We are receiving over an established socket connection 
     if (_socket != null) 
     { 
      if (isBroadcast) 
       socketEventArg.RemoteEndPoint = new IPEndPoint(IPAddress.Broadcast, portNumber); 
      else 
       socketEventArg.RemoteEndPoint = new IPEndPoint(IPAddress.Any, portNumber); 

      // Setup the buffer to receive the data 
      socketEventArg.SetBuffer(new Byte[MAX_BUFFER_SIZE], 0, MAX_BUFFER_SIZE); 

      // Inline event handler for the Completed event. 
      // Note: This even handler was implemented inline in order to make this method self-contained. 
      socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(delegate(object s, SocketAsyncEventArgs e) 
      { 
       if (e.SocketError == SocketError.Success) 
       { 
        // Retrieve the data from the buffer 
        response = Encoding.UTF8.GetString(e.Buffer, e.Offset, e.BytesTransferred); 
        response = response.Trim('\0'); 
       } 
       else 
       { 
        response = e.SocketError.ToString(); 
       } 

       _clientDone.Set(); 
      }); 
      // Sets the state of the event to nonsignaled, causing threads to block 
      _clientDone.Reset(); 

      // Make an asynchronous Receive request over the socket 
      _socket.ReceiveFromAsync(socketEventArg); 

      // Block the UI thread for a maximum of TIMEOUT_MILLISECONDS milliseconds. 
      // If no response comes back within this time then proceed 
      //_clientDone.WaitOne(TIMEOUT_MILLISECONDS); 
     } 
     else 
     { 
      response = "Socket is not initialized"; 
     } 

     return response; 
    } 

但我不知道如何设置套接字超时为无限。

是否有可能在Windows Phone上创建这种套接字？

Answer 1

让我们依次是：

1. 请问上面的代码工作？你说你修复了“无效参数异常”的问题，但我的猜测是它仍然无法按预期工作，这是由于下面几点的原因：
2. 你不能在Windows Phone 7的套接字上“侦听”您只能从与您发起通信的IP接收安全原因，因此先发送一个空包，然后再听一段有限的时间。
3. 不支持UDP广播，只有TCP，UDP单播和UDP多播。

我希望以上三点总结出您的代码的主要问题。