C# Server Socket program

The C# Socket Programming has two sections.

1. C# Server Socket Program

2. C# Client Socket Program

Server Socket Program

The Server Socket Program here is a C# Console based Application . This program act as a Server and listening to clients request . Here we assign a Port No. 8888 for the Server Socket , it is an instance of the C# Class TcpListener , and call itsstart() method.

  TcpListener serverSocket = new TcpListener(8888);

serverSocket.Start();

The next step is to create an infinite loop for monitoring the request from Client's side . When the Server Socket accept a request from the Client side, it reads the data from NetworkStream and also it write the response to NetworkStream .

From the following C# program you can understand how to create a Socket Server in C# . Create a new C# Console Application Project and put the following source code into the project.

Next :  C# Client Socket program

 

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {

            TcpListener serverSocket = new TcpListener(8888);
            int requestCount = 0;
            TcpClient clientSocket = default(TcpClient);
            serverSocket.Start();
            Console.WriteLine(" >> Server Started");
            clientSocket = serverSocket.AcceptTcpClient();
            Console.WriteLine(" >> Accept connection from client");
            requestCount = 0;

            while ((true))
            {
                try
                {
                    requestCount = requestCount + 1;
                    NetworkStream networkStream = clientSocket.GetStream();
                    byte[] bytesFrom = new byte[10025];
                    networkStream.Read(bytesFrom, 0, (int)clientSocket.ReceiveBufferSize);
                    string dataFromClient = System.Text.Encoding.ASCII.GetString(bytesFrom);
                    dataFromClient = dataFromClient.Substring(0, dataFromClient.IndexOf("$"));
                    Console.WriteLine(" >> Data from client - " + dataFromClient);
                    string serverResponse = "Last Message from client" + dataFromClient;
                    Byte[] sendBytes = Encoding.ASCII.GetBytes(serverResponse);
                    networkStream.Write(sendBytes, 0, sendBytes.Length);
                    networkStream.Flush();
                    Console.WriteLine(" >> " + serverResponse);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.ToString());
                }
            }

            clientSocket.Close();
            serverSocket.Stop();
            Console.WriteLine(" >> exit");
            Console.ReadLine();
        }

    }
}

How to run this program ?
The C# Socket Programming has two sections.

1. C# Server Socket Program

2. C# Client Socket Program

When you finish coding and build the Server and Client program , First you have to start C# Server Socket Program from DOS prompt , then you will get a message " Server Started " in your DOS screen, where the server program is running .

Next step is to start C# Client Socket Program in the same computer or other computers on the same network . When you start the client program , it will establish a connection to the Server and get a message in client screen " Client Started " , at the same time you can see a message in the Server screen " Accept connection from client " .

Now your C# Server Socket Program and C# Client Socket Program is get connected and communicated . If you want to communicate the Server and Client again , click the button in the client program , then you can see new messages in the Server and Client programs displayed.