C# Socket Programming

public partial class ClientSocket : Form
	private int port = 139;
	// 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;
	public ClientSocket()
		InitializeComponent();
	private void ClientSocket_Load(object sender, EventArgs e)
		this.txtIP.Text = "XXX.XXX.XXX.XXX";
		this.CenterToScreen();
	private void btnStart_Click(object sender, EventArgs e)
			// Establish the remote endpoint for the socket.
			IPHostEntry ipHostInfo = Dns.Resolve(this.txtIP.Text.Trim());
			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 ex)
			Console.WriteLine(ex.ToString());
	private static void ConnectCallback(IAsyncResult ar)
			// 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)
			// 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)
			// 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);
				// 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)
			// 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 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();
}

Select all Open in new window

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);
    private const int port = 139;
    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.
            listener.Bind(localEndPoint);
            listener.Listen(100);
            Console.WriteLine("Starting...");
            while (true)
                Console.WriteLine("Getting Ready to Reset...");
                // 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);
				//GETS STUCK HERE *************************
                Console.WriteLine("Waiting...");
                // Wait until a connection is made before continuing.
                allDone.WaitOne();
        catch (Exception e)
            Console.WriteLine("ERRO HAS OCCURRED...");
            Console.WriteLine(e.ToString());
        Console.WriteLine("\nPress ENTER to continue...");
        Console.Read();
    public static void AcceptCallback(IAsyncResult ar)
        Console.WriteLine("Accept Callback...");
        Console.WriteLine("Tell Thread to Continue...");
        // Signal the main thread to continue.
        allDone.Set();
        Console.WriteLine("Get the socket...");
        // Get the socket that handles the client request.
        Socket listener = (Socket)ar.AsyncState;
        Console.WriteLine("End accept...");
        Socket handler = listener.EndAccept(ar);
        Console.WriteLine("Create State Object...");
        // Create the state object.
        StateObject state = new StateObject();
        state.workSocket = handler;
        Console.WriteLine("Begin Receive...");
        handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallback), state);
    public static void ReadCallback(IAsyncResult ar)
        Console.WriteLine("Read Callback...");
        String content = String.Empty;
        Console.WriteLine("Retrieve State of the object and handler socket...");
        // Retrieve the state object and the handler socket
        // from the asynchronous state object.
        StateObject state = (StateObject)ar.AsyncState;
        Socket handler = state.workSocket;
        Console.WriteLine("End Receive...");
        // Read data from the client socket. 
        int bytesRead = handler.EndReceive(ar);
        Console.WriteLine("Read Bytes...");
        if (bytesRead > 0)
            Console.WriteLine("Appending Bytes...");
            // 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);
                Console.WriteLine("Not all data received, getting more data...");
                // 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)
        Console.WriteLine("Sending data...");
        // Convert the string data to byte data using ASCII encoding.
        byte[] byteData = Encoding.ASCII.GetBytes(data);
        Console.WriteLine("Begin Send...");
        // 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)
            Console.WriteLine("Send Callback...");
            // 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("ERROR in SENDCALLBACK...");
            Console.WriteLine(e.ToString());
    public static int Main(String[] args)
        Console.WriteLine("Start Listening...");
        StartListening();
        return 0;
}

Select all Open in new window