Socket Class

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

  public static void Demo(System.Windows.Controls.TextBlock outputBlock)
  {

      SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();

      // NOTE: This is a fake end point. 
      // You must change this to a valid URL or you will get an exception below.
      DnsEndPoint hostEntry = new DnsEndPoint("http://www.contoso.com", 80);

      // 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;
      socketEventArg.UserToken = sock;
      sock.ConnectAsync(socketEventArg);
      clientDone.WaitOne();
  }

  // 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)
  {
      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

          // Send 'Hello World' to the server
          byte[] buffer = Encoding.UTF8.GetBytes("Hello World");
          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 ReceiveAsync operation completes
      // </summary>
  private static void ProcessReceive(SocketAsyncEventArgs e)
  {
      if (e.SocketError == SocketError.Success)
      {
          // Received data from server

          // 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);
      }
  }


  // 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);
      }
  }
}