C＃异步socket的线程通讯

MSDN里（同）异步socket通信的代码

ms-help://MS.MSDNQTR.v90.en/dv_fxnetwork/html/f3fc7533-6956-42c6-bbc3-73e5a221027d.htm

 

Asynchronous Client Socket Example：

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

// State object for receiving data from remote device.
public class StateObject {
    // Client socket.
    public Socket workSocket = null;
    // Size of receive buffer.
    public const int BufferSize = 256;
    // Receive buffer.
    public byte[] buffer = new byte[BufferSize];
    // Received data string.
    public StringBuilder sb = new StringBuilder();
}

public class AsynchronousClient {
    // The port number for the remote device.
    private const int port = 11000;

    // ManualResetEvent instances signal completion.
    private static ManualResetEvent connectDone =
        new ManualResetEvent(false);
    private static ManualResetEvent sendDone =
        new ManualResetEvent(false);
    private static ManualResetEvent receiveDone =
        new ManualResetEvent(false);

    // The response from the remote device.
    private static String response = String.Empty;

    private static void StartClient() {
        // Connect to a remote device.
        try {
            // Establish the remote endpoint for the socket.
            // The name of the
            // remote device is "host.contoso.com".
            IPHostEntry ipHostInfo = Dns.Resolve("host.contoso.com");
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

            // Create a TCP/IP socket.
            Socket client = new Socket(AddressFamily.InterNetwork,
                SocketType.Stream, ProtocolType.Tcp);

            // Connect to the remote endpoint.
            client.BeginConnect( remoteEP,
                new AsyncCallback(ConnectCallback), client);
            connectDone.WaitOne();

            // Send test data to the remote device.
            Send(client,"This is a test<EOF>");
            sendDone.WaitOne();

            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();

            // Write the response to the console.
            Console.WriteLine("Response received : {0}", response);

            // Release the socket.
            client.Shutdown(SocketShutdown.Both);
            client.Close();
           
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void ConnectCallback(IAsyncResult ar) {
        try {
            // Retrieve the socket from the state object.
            Socket client = (Socket) ar.AsyncState;

            // Complete the connection.
            client.EndConnect(ar);

            Console.WriteLine("Socket connected to {0}",
                client.RemoteEndPoint.ToString());

            // Signal that the connection has been made.
            connectDone.Set();
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void Receive(Socket client) {
        try {
            // Create the state object.
            StateObject state = new StateObject();
            state.workSocket = client;

            // Begin receiving the data from the remote device.
            client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReceiveCallback), state);
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void ReceiveCallback( IAsyncResult ar ) {
        try {
            // Retrieve the state object and the client socket
            // from the asynchronous state object.
            StateObject state = (StateObject) ar.AsyncState;
            Socket client = state.workSocket;

            // Read data from the remote device.
            int bytesRead = client.EndReceive(ar);

            if (bytesRead > 0) {
                // There might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead));

                // Get the rest of the data.
                client.BeginReceive(state.buffer,0,StateObject.BufferSize,0,
                    new AsyncCallback(ReceiveCallback), state);
            } else {
                // All the data has arrived; put it in response.
                if (state.sb.Length > 1) {
                    response = state.sb.ToString();
                }
                // Signal that all bytes have been received.
                receiveDone.Set();
            }
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }

    private static void Send(Socket client, 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.
        client.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), client);
    }

    private static void SendCallback(IAsyncResult ar) {
        try {
            // Retrieve the socket from the state object.
            Socket client = (Socket) ar.AsyncState;

            // Complete sending the data to the remote device.
            int bytesSent = client.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to server.", bytesSent);

            // Signal that all bytes have been sent.
            sendDone.Set();
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }
   
    public static int Main(String[] args) {
        StartClient();
        return 0;
    }
}

 

Asynchronous Server Socket Example：

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 = 1024;
    // 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[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 );

                // 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, 0, StateObject.BufferSize, 0,
            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 > 0) {
            // There  might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(
                state.buffer,0,bytesRead));

            // Check for end-of-file tag. If it is not there, read
            // more data.
            content = state.sb.ToString();
            if (content.IndexOf("<EOF>") > -1) {
                // All the data has been read from the
                // client. Display it on the console.
                Console.WriteLine("Read {0} bytes from socket. /n Data : {1}",
                    content.Length, content );
                // Echo the data back to the client.
                Send(handler, content);
            } else {
                // Not all data received. Get more.
                handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                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, 0, byteData.Length, 0,
            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 {0} 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 0;
    }
}

 

根据MSDN的原话：

“异步套接字使用系统线程池中的线程处理传入的连接。

一个线程负责接受连接，

另一线程用于处理每个传入的连接，

还有一个线程负责接收连接数据。

这些线程可以是同一个线程，具体取决于线程池所分配的线程。”

个人理解：根据MSDN对异步socket连接、接受、发送等线程分配的解释，以及上面代码的注释和演示，我们在做异步socket编程时，不用对socket这组线程做任何处理，只要处理好主线程及其它线程与socket这周线程的关系就可。

转：补充：在main方法和AcceptCallback方法里分别加入
bool threadBool = Thread.CurrentThread.IsBackground;
Console.WriteLine(threadBool.ToString());
这两条语句，则会发现main方法里线程的IsBackground属性为false，AcceptCallback方法里线程的IsBackground属性为True；MSDN里说：“托管线程池中的线程为后台线程，即它们的 IsBackground 属性为 true”；再根据上面引用的MSDN的原文“这些线程可以是同一个线程，具体取决于线程池所分配的线程。”的这一句可知，此线程就是由线程池所分配的，也许有人会认为此补充为多此一举，但是我最初对于这几个线程的出现，以及MSDN的解释没有很好的理解，所以出现了这个补充，现在好了，我知道了这几个隐藏的线程出自那里了，呵呵，你呢？

再次补充：
//如果要查看线程是否属于托管线程池，可使用
   bool poolThread = Thread.CurrentThread.IsThreadPoolThread;//指示线程是否属于托管线程池