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详解C# Socket异步通信实例

2020-01-24 00:53:34
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TCPServer 

1、使用的通讯通道:socket

2、用到的基本功能:

①Bind,

②Listen,

③BeginAccept

④EndAccept

⑤BeginReceive 

⑥EndReceive

3、函数参数说明

 Socket listener = new Socket(AddressFamily.InterNetwork,      SocketType.Stream, ProtocolType.Tcp);

新建socket所使用的参数均为系统预定义的量,直接选取使用。

listener.Bind(localEndPoint);

localEndPoint 表示一个定义完整的终端,包括IP和端口信息。

//new IPEndPoint(IPAddress,port)//IPAdress.Parse("192.168.1.3")listener.Listen(100);

监听

  listener.BeginAccept(          new AsyncCallback(AcceptCallback),          listener);

AsyncCallback(AcceptCallback),一旦连接上后的回调函数为AcceptCallback。当系统调用这个函数时,自动赋予的输入参数为IAsyncResoult类型变量ar。

 listener,连接行为的容器。

Socket handler = listener.EndAccept(ar);

完成连接,返回此时的socket通道。

handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,      new AsyncCallback(ReadCallback), state);

接收的字节,0,字节长度,0,接收时调用的回调函数,接收行为的容器。

========

容器的结构类型为:

public class StateObject{  // Client socket.  public Socket workSocket = null;  // Size of receive buffer.  public const int BufferSize = 1024;  // Receive buffer.  public byte[] buffer = new byte[BufferSize];  // Received data string.  public StringBuilder sb = new StringBuilder();}

容器至少为一个socket类型。

===============

 // Read data from the client socket.     int bytesRead = handler.EndReceive(ar);

完成一次连接。数据存储在state.buffer里,bytesRead为读取的长度。

handler.BeginSend(byteData, 0, byteData.Length, 0,      new AsyncCallback(SendCallback), handler);

发送数据byteData,回调函数SendCallback。容器handler

int bytesSent = handler.EndSend(ar);

发送完毕,bytesSent发送字节数。

4 程序结构

主程序:

    byte[] bytes = new Byte[1024];    IPAddress ipAddress = IPAddress.Parse("192.168.1.104");    IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);    // 生成一个TCP的socket    Socket listener = new Socket(AddressFamily.InterNetwork,      SocketType.Stream, ProtocolType.Tcp);    listener.Bind(localEndPoint);    listener.Listen(100);    while (true)    {      // Set the event to nonsignaled state.      allDone.Reset();      //开启异步监听socket      Console.WriteLine("Waiting for a connection");      listener.BeginAccept(           new AsyncCallback(AcceptCallback),           listener);      // 让程序等待,直到连接任务完成。在AcceptCallback里的适当位置放置allDone.Set()语句.      allDone.WaitOne();      }  Console.WriteLine("/nPress ENTER to continue");  Console.Read();

连接行为回调函数AcceptCallback:

  public static void AcceptCallback(IAsyncResult ar)  {    //添加此命令,让主线程继续.    allDone.Set();    // 获取客户请求的socket    Socket listener = (Socket)ar.AsyncState;    Socket handler = listener.EndAccept(ar);    // 造一个容器,并用于接收命令.    StateObject state = new StateObject();    state.workSocket = handler;    handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,      new AsyncCallback(ReadCallback), state);  }

读取行为的回调函数ReadCallback:

  public static void ReadCallback(IAsyncResult ar)  {    String content = String.Empty;    // 从异步state对象中获取state和socket对象.    StateObject state = (StateObject)ar.AsyncState;    Socket handler = state.workSocket;    // 从客户socket读取数据.     int bytesRead = handler.EndReceive(ar);    if (bytesRead > 0)    {      // 如果接收到数据,则存起来      state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));      // 检查是否有结束标记,如果没有则继续读取      content = state.sb.ToString();      if (content.IndexOf("<EOF>") > -1)      {        //所有数据读取完毕.        Console.WriteLine("Read {0} bytes from socket. /n Data : {1}",          content.Length, content);        // 给客户端响应.        Send(handler, content);      }      else      {        // 接收未完成,继续接收.        handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,        new AsyncCallback(ReadCallback), state);      }    }  }

发送消息给客户端:

private static void Send(Socket handler, String data)  {    // 消息格式转换.    byte[] byteData = Encoding.ASCII.GetBytes(data);    // 开始发送数据给远程目标.    handler.BeginSend(byteData, 0, byteData.Length, 0,      new AsyncCallback(SendCallback), handler);  }private static void SendCallback(IAsyncResult ar)  {         // 从state对象获取socket.      Socket handler = (Socket)ar.AsyncState;      //完成数据发送      int bytesSent = handler.EndSend(ar);      Console.WriteLine("Sent {0} bytes to client.", bytesSent);      handler.Shutdown(SocketShutdown.Both);      handler.Close();  }

在各种行为的回调函数中,所对应的socket都从输入参数的AsyncState属性获得。使用(Socket)或者(StateObject)进行强制转换。BeginReceive函数使用的容器为state,因为它需要存放传送的数据。

而其余接收或发送函数的容器为socket也可。

完整代码

  using System;  using System.Net;  using System.Net.Sockets;  using System.Text;  using System.Threading;    // State object for reading client data asynchronously  public class StateObject  {   // Client socket.   public Socket workSocket = null;   // Size of receive buffer.   public const int BufferSize = ;   // Receive buffer.   public byte[] buffer = new byte[BufferSize];   // Received data string.   public StringBuilder sb = new StringBuilder(); }  public class AsynchronousSocketListener {   // Thread signal.   public static ManualResetEvent allDone = new ManualResetEvent(false);    public AsynchronousSocketListener()   {   }    public static void StartListening()   {     // Data buffer for incoming data.     byte[] bytes = new Byte[];      // Establish the local endpoint for the socket.     // The DNS name of the computer     // running the listener is "host.contoso.com".     //IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());     IPAddress ipAddress = IPAddress.Parse("...");      IPEndPoint localEndPoint = new IPEndPoint(ipAddress, );      // Create a TCP/IP socket.     Socket listener = new Socket(AddressFamily.InterNetwork,       SocketType.Stream, ProtocolType.Tcp);      // Bind the socket to the local endpoint and listen for incoming connections.     try     {       listener.Bind(localEndPoint);       listener.Listen();       while (true)       {         // Set the event to nonsignaled state.         allDone.Reset();          // Start an asynchronous socket to listen for connections.         Console.WriteLine("Waiting for a connection");         listener.BeginAccept(           new AsyncCallback(AcceptCallback),           listener);          // Wait until a connection is made before continuing.         allDone.WaitOne();       }     }     catch (Exception e)     {       Console.WriteLine(e.ToString());     }      Console.WriteLine("/nPress ENTER to continue");     Console.Read();   }    public static void AcceptCallback(IAsyncResult ar)   {     // Signal the main thread to continue.     allDone.Set();      // Get the socket that handles the client request.     Socket listener = (Socket)ar.AsyncState;     Socket handler = listener.EndAccept(ar);       // Create the state object.     StateObject state = new StateObject();     state.workSocket = handler;     handler.BeginReceive(state.buffer, , StateObject.BufferSize, , new AsyncCallback(ReadCallback), state);   }    public static void ReadCallback(IAsyncResult ar)   {     String content = String.Empty;         // Retrieve the state object and the handler socket     // from the asynchronous state object.     StateObject state = (StateObject)ar.AsyncState;     Socket handler = state.workSocket;      // Read data from the client socket.      int bytesRead = handler.EndReceive(ar);      if (bytesRead > )     {       // There might be more data, so store the data received so far.       state.sb.Append(Encoding.ASCII.GetString(         state.buffer, , bytesRead));        // Check for end-of-file tag. If it is not there, read        // more data.       content = state.sb.ToString();       if (content.IndexOf("<EOF>") > -)       {         // All the data has been read from the          // client. Display it on the console.         Console.WriteLine("Read {} bytes from socket. /n Data : {}",content.Length, content);          // Echo the data back to the client.         Send(handler, content);       }       else       {         // Not all data received. Get more.         handler.BeginReceive(state.buffer, , StateObject.BufferSize, , new AsyncCallback(ReadCallback), state);       }     }   }    private static void Send(Socket handler, String data)   {     // Convert the string data to byte data using ASCII encoding.     byte[] byteData = Encoding.ASCII.GetBytes(data);      // Begin sending the data to the remote device.     handler.BeginSend(byteData, , byteData.Length, ,       new AsyncCallback(SendCallback), handler);   }      private static void SendCallback(IAsyncResult ar)    {     try     {       // Retrieve the socket from the state object.       Socket handler = (Socket)ar.AsyncState;        // Complete sending the data to the remote device.       int bytesSent = handler.EndSend(ar);       Console.WriteLine("Sent {} bytes to client.", bytesSent);       handler.Shutdown(SocketShutdown.Both);       handler.Close();     }      catch (Exception e)      {       Console.WriteLine(e.ToString());     }   }    public static int Main(String[] args)    {     StartListening();     return ;   }  }

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