UDP发包收包

异步发包：

public void SendData(string ip,int port,object data)
{   
    IPEndPoint ipep = new IPEndPoint(IPAdress.Parse(ip), port);  
    UdpClient udpClient=new UdpClient(); 
    udpClient.BeginSend(data,data.Length,ipep,SendComplete,new AsyncCallbackArg(ip,udpClient));
}

///<summary>

///发送完成后的回调函数

///</summary>

///<param name="param"></param>
private void sendComplete(IAsyncResult param)
{ 
    AsyncCallbackArg arg=param.AsyncState as AsyncCallbackArg;//param.AsyncState 对应的就是BeginSend的最后一个参数state  
    using(UdpClient client=(UdpClient)param.AsyncState) 
   ｛  

      try

      ｛
             client.EndSend(param);//这句话必须得写，BeginSend（）和EndSend（）是成对出现的 

       ｝

        catch(Exception ex)

       {

         ....

       }

   ｝

//自己定义的返回状态参数类型
private struct AsyncCallbackArg
{ 
   private UdpClient udpClient;  
   private string ipAddress;  
   public AsyncCallbackArg(string ip,string client)    
   {        
    udpClient=client;     
    ipAddress=ip;   
   }
}

为防止丢包，收包时一个线程接收数据放到队列，而多个线程处理队列

或异步接收，代码如下：

private int m_Port;

private bool m_IsReceive;

private UdpClient m_ReceiveUdpClient;

private Thread m_ReceiveThread;

public void StartReceiveData(int port)
{ 

  m_IsReceive=true;
  m_Port=port; 
  m_ReceiveThread=new Thread();
  m_ReceiveThread.IsBackground=true;
  m_ReceiveThreads.start();
}

private void Receive()
{  
  m_ReceiveUdpClient=new UdpClient(m_Port); 
  byte[] data; 
   while(m_IsReceive) 
   {  
      if(m_ReceiveUdpClient.Client==null)  
       {         
            break;    
       }   
      if(m_ReceiveUdpClient.Client.Poll(-1,SelectMode.Selectread))  
       {            
           break;   
       }      

      try{   
          m_ReceiveUdpClient.BeginReceive(new AsyncCallBack(ReceiveComplete),m_ReceiveUdpClient);
         }catch(Exception ex){ .....} 
    } 
  }

private void ReceiveComplete(IAsyncResult param)
{
     UDPClient client=param.AsyncState as UDPClient ;//对应的就是BeginSend的最后一个参数state    
     try    
     ｛     
        IPEndPoint ipep = new IPEndPoint(IPAdress.Any,m_Port);               
          byte[] datas=client.EndReceive(param,ref ipep);//接受到的数据     
      ｝    
      catch(Exception ex)  { ....  }
}