C#网络编程---(2) 经过验证并调试后适合自身环境的客户端socket通信

本文参考了http://www.codeproject.com/KB/IP/socketasynceventargssampl.aspx

作了一些修改

在.NET 2.0 SP1上可以使用SocketAsyncEventArgs类，本文的代码就是用Microsoft Visual Studio .NET 2005编写的。

Code
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

namespace SocketAsyncClient
{
    /**//// <summary>
    /// socket客户端
    /// 异步实现
    /// </summary>
    public sealed class SocketClient : IDisposable
    {
        /**//// <summary>
        /// Constants for socket operations.
        /// </summary>
        private const Int32 ReceiveOperation = 1, SendOperation = 0;

        /**//// <summary>
        /// The socket used to send/receive messages.
        /// </summary>
        private Socket clientSocket;

        /**//// <summary>
        /// Flag for connected socket.
        /// </summary>
        private Boolean connected = false;
      
        public Boolean Connected
        {
            get { return connected; }
        }


        /**//// <summary>
        /// Listener endpoint.
        /// </summary>
        private IPEndPoint hostEndPoint;

        /**//// <summary>
        /// Signals a connection.
        /// </summary>
        private AutoResetEvent autoConnectEvent = new AutoResetEvent(false);
       // private static AutoResetEvent autoConnectEvent = new AutoResetEvent(false); 

        /**//// <summary>
        /// Signals the send/receive operation.
        /// </summary>
       // private static AutoResetEvent[] autoSendReceiveEvents = new AutoResetEvent[]
             private  AutoResetEvent[] autoSendReceiveEvents = new AutoResetEvent[]
        {
            new AutoResetEvent(false),
            new AutoResetEvent(false)
        };

        /**//// <summary>
        /// Create an uninitialized client instance.  
        /// To start the send/receive processing
        /// call the Connect method followed by SendReceive method.
        /// </summary>
        /// <param name="hostName">Name of the host where the listener is running.</param>
        /// <param name="port">Number of the TCP port from the listener.</param>
        public SocketClient(String hostName, Int32 port)
        {
            // Get host related information.
            IPHostEntry host = Dns.GetHostEntry(hostName);

            // Addres of the host.
            IPAddress[] addressList = host.AddressList;

            // Instantiates the endpoint and socket.
            this.hostEndPoint = new IPEndPoint(addressList[addressList.Length - 1], port);
            this.clientSocket = new Socket(this.hostEndPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);

        }

        /**//// <summary>
        /// Connect to the host.
        /// </summary>
        /// <returns>True if connection has succeded, else false.</returns>
        public void Connect()
        {
            
            SocketAsyncEventArgs connectArgs = new SocketAsyncEventArgs();

            connectArgs.UserToken = this.clientSocket;
            connectArgs.RemoteEndPoint = this.hostEndPoint;
            connectArgs.Completed += new EventHandler<SocketAsyncEventArgs>(OnConnect);
            
            clientSocket.ConnectAsync(connectArgs);            
            autoConnectEvent.WaitOne();        
            

            SocketError errorCode = connectArgs.SocketError;
            
            if (errorCode != SocketError.Success)
            {
                throw new SocketException((Int32)errorCode);
            }
           

        }

        /**//// <summary>
        /// Disconnect from the host.
        /// </summary>
        public void Disconnect()
        {
            clientSocket.Disconnect(false);
        }

        private void OnConnect(object sender, SocketAsyncEventArgs e)
        {
            // Signals the end of connection.
            autoConnectEvent.Set();

            // Set the flag for socket connected.
            this.connected = (e.SocketError == SocketError.Success);
        }

        private void OnReceive(object sender, SocketAsyncEventArgs e)
        { 
            // Signals the end of receive.
            autoSendReceiveEvents[SendOperation].Set();         
        }

        private void OnSend(object sender, SocketAsyncEventArgs e)
        {
            // Signals the end of send.
            autoSendReceiveEvents[ReceiveOperation].Set();
           

            if (e.SocketError == SocketError.Success)
            {
                if (e.LastOperation == SocketAsyncOperation.Send)
                {                   
                    // Prepare receiving.
                    Socket s = e.UserToken as Socket;

                    byte[] receiveBuffer = new byte[255];
                    e.SetBuffer(receiveBuffer, 0, receiveBuffer.Length);
                    e.Completed += new EventHandler<SocketAsyncEventArgs>(OnReceive);                  

                 
                    s.ReceiveAsync(e);


                    //  Encoding.ASCII.GetString(s..Buffer, completeArgs.Offset, completeArgs.BytesTransferred);

                }
            }
            else
            {
                this.ProcessError(e);
            }
        }

       

        /**//// <summary>
        /// Close socket in case of failure and throws a SockeException according to the SocketError.
        /// </summary>
        /// <param name="e">SocketAsyncEventArg associated with the failed operation.</param>
        private void ProcessError(SocketAsyncEventArgs e)
        {
            Socket s = e.UserToken as Socket;
            if (s.Connected)
            {
                // close the socket associated with the client
                try
                {
                    s.Shutdown(SocketShutdown.Both);
                }
                catch (Exception)
                {
                    // throws if client process has already closed
                }
                finally
                {
                    if (s.Connected)
                    {
                        s.Close();
                    }
                }
            }

            // Throw the SocketException
            throw new SocketException((Int32)e.SocketError);
        }

        /**//// <summary>
        /// Exchange a message with the host.
        /// </summary>
        /// <param name="message">Message to send.</param>
        /// <returns>Message sent by the host.</returns>
        public String SendReceive(String message)
        {
            //指示应挂起此线程以使其他等待线程能够执行
            System.Threading.Thread.Sleep(0);            
            
            if (this.connected)
            {
                // Create a buffer to send.
                Byte[] sendBuffer = Encoding.Default.GetBytes(message);
                //StrHelper.Str2AscArr(message);

                // Prepare arguments for send/receive operation.
                SocketAsyncEventArgs completeArgs = new SocketAsyncEventArgs();
                completeArgs.SetBuffer(sendBuffer, 0, sendBuffer.Length);
                completeArgs.UserToken = this.clientSocket;
                completeArgs.RemoteEndPoint = this.hostEndPoint;
                completeArgs.Completed += new EventHandler<SocketAsyncEventArgs>(OnSend);

                // Start sending asyncronally.
                clientSocket.SendAsync(completeArgs);

                // Wait for the send/receive completed.
                AutoResetEvent.WaitAll(autoSendReceiveEvents);
              
                StringBuilder resultMsg = new StringBuilder();
                resultMsg.Append(Encoding.Default.GetString(completeArgs.Buffer, completeArgs.Offset, completeArgs.BytesTransferred));

                while ((completeArgs.UserToken as Socket).Available > 0)
                {
                    clientSocket.ReceiveAsync(completeArgs);
                    AutoResetEvent.WaitAll(autoSendReceiveEvents);
                    resultMsg.Append(Encoding.Default.GetString(completeArgs.Buffer, completeArgs.Offset, completeArgs.BytesTransferred));
                }

                return resultMsg.ToString();


                // return Encoding.ASCII.GetString(completeArgs.Buffer, completeArgs.Offset, completeArgs.BytesTransferred);


            }
            else
            {
                throw new SocketException((Int32)SocketError.NotConnected);
            }
        }

        IDisposable Members#region IDisposable Members

        /**//// <summary>
        /// Disposes the instance of SocketClient.
        /// </summary>
        public void Dispose()
        {
            autoConnectEvent.Close();
            autoSendReceiveEvents[SendOperation].Close();
            autoSendReceiveEvents[ReceiveOperation].Close();
            if (this.clientSocket.Connected)
            {
                this.clientSocket.Close();
            }
        }

        #endregion
    }
}