异步服务器套接字示例

下面的示例程序创建一个接收来自客户端的连接请求的服务器。该服务器是用异步套接字生成的，因此在等待来自客户端的连接时不挂起服务器应用程序的执行。该应用程序接收来自客户端的字符串，在控制台显示该字符串，然后将该字符串回显到客户端。来自客户端的字符串必须包含字符串“<EOF>”，以发出表示消息结尾的信号。

 [C#]

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 {

   public Socket workSocket = null;       // Client  socket.

   public const int BufferSize = 1024;       // Size of receive buffer.

   public byte[] buffer = new byte[BufferSize]; // Receive buffer.

   public StringBuilder sb = new StringBuilder();  // Received data string.

}

public class AsynchronousSocketListener {

   // Incoming data from client.

   public static string data = null;

   // Thread signal.

   public static ManualResetEvent allDone = new ManualResetEvent(false);

   public AsynchronousSocketListener() {

   }

   public static void StartListening() {

      // Data buffer for incoming data.

      byte[] bytes = new Byte[1024];

      // 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 = ipHostInfo.AddressList[0];

      IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);

      // 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(100);

         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 );