Example.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace SocketsTest
{
    public class Example
    {
        static ManualResetEvent clientDone = new ManualResetEvent(false);

        public static void Demo()
        {
            try
            {
                SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();
                // Don't write http or www before. Don't add '/' after. Else it will fail.
                DnsEndPoint hostEntry = new DnsEndPoint("137.135.176.144", 1337);

                // Create a socket and connect to the server
                Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

                socketEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(SocketEventArg_Completed);

                socketEventArg.RemoteEndPoint = hostEntry;
                Debug.WriteLine("User token used: "+sock.ToString());
                socketEventArg.UserToken = sock;
                sock.ConnectAsync(socketEventArg);
                clientDone.WaitOne();
            }catch(Exception e){
                Debug.WriteLine(e.Message);
            }
        }

        // A single callback is used for all socket operations.
        // This method forwards execution on to the correct handler
        // based on the type of completed operation
        static void SocketEventArg_Completed(object sender, SocketAsyncEventArgs e)
        {
            Debug.WriteLine("Operation processing: " + e.LastOperation.ToString());
            switch (e.LastOperation)
            {
                case SocketAsyncOperation.Connect:
                    ProcessConnect(e);
                    break;
                case SocketAsyncOperation.Receive:
                    ProcessReceive(e);
                    break;
                case SocketAsyncOperation.Send:
                    ProcessSend(e);
                    break;
                default:
                    throw new Exception("Invalid operation completed");
            }
        }

        // Called when a ConnectAsync operation completes
        private static void ProcessConnect(SocketAsyncEventArgs e)
        {
            if (e.SocketError == SocketError.Success)
            {
                // Successfully connected to the server
                Debug.WriteLine("Connect: Successful connection etablished to "+e.RemoteEndPoint.ToString());
                // Send 'Hello World' to the server
                byte[] buffer = Encoding.UTF8.GetBytes("connection");
                e.SetBuffer(buffer, 0, buffer.Length);
                Socket sock = e.UserToken as Socket;
                bool willRaiseEvent = sock.SendAsync(e);
                if (!willRaiseEvent)
                {
                    ProcessSend(e);
                }
            }
            else
            {
                throw new SocketException((int)e.SocketError);
            }
        }


        // Called when a SendAsync operation completes
        private static void ProcessSend(SocketAsyncEventArgs e)
        {
            if (e.SocketError == SocketError.Success)
            {
                // Sent "Hello World" to the server successfully

                //Read data sent from the server
                Socket sock = e.UserToken as Socket;
                bool willRaiseEvent = sock.ReceiveAsync(e);
                if (!willRaiseEvent)
                {
                    ProcessReceive(e);
                }
            }
            else
            {
                throw new SocketException((int)e.SocketError);
            }
        }

        // Called when a ReceiveAsync operation completes
        // </summary>
        private static void ProcessReceive(SocketAsyncEventArgs e)
        {
            if (e.SocketError == SocketError.Success)
            {
                // Received data from server
                Debug.WriteLine("Data received: " + Encoding.UTF8.GetString(e.Buffer, 0, e.Count) + " (" + e.Count + ")");
                // Data has now been sent and received from the server.
                // Disconnect from the server
                Socket sock = e.UserToken as Socket;
                sock.Shutdown(SocketShutdown.Send);
                sock.Close();
                clientDone.Set();
            }
            else
            {
                throw new SocketException((int)e.SocketError);
            }
        }
    }
}