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Asynchronous Client/Server Socket Example with C# (from MSDN library)
Sample codes from MSDN library about socket programming, specially the asynchronous approach.
Asynchronous Server Socket Example
http://msdn.microsoft.com/en-us/library/fx6588te.aspx
Asynchronous Client Socket Example
http://msdn.microsoft.com/en-us/library/bew39x2a.aspx
Using an Asynchronous Server Socket
http://msdn.microsoft.com/en-us/library/5w7b7x5f.aspx
// Asynchronous Client Socket Example
// http://msdn.microsoft.com/en-us/library/bew39x2a.aspx
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
// http://msdn.microsoft.com/en-us/library/fx6588te.aspx
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;
}
}
@freestar

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freestar commented May 31, 2013

Hello Dear
I want to have a socket tcp server client with tunell
because i have problem in send and receive data
can u help me?
tnks

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freestar commented May 31, 2013

Hello Dear
I want to have a socket tcp server client with tunell
because i have problem in send and receive data
can u help me?
tnks
hneginkvr@yahoo.com

@markwelhar

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markwelhar commented Jul 19, 2013

This one will help you

http://csharp.net-informations.com/communications/csharp-socket-programming.htm c# socket programming with working examples.

Mark

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summy1 commented Nov 21, 2013

thanks for your solution but for reiceieve data replace this code to work correct
private void ReceiveCallback(IAsyncResult ar)
{
try
{
StateObject state = (StateObject)ar.AsyncState;
Socket client = state.workSocket;
int byteRead = client.EndReceive(ar);

            if (byteRead > 0)
            {
                state.sb.Append(Encoding.UTF8.GetString(state.buffer, 0, byteRead));
                response = state.sb.ToString();
                if (response.IndexOf("<EOF>") != -1)
                {
                    state.sb.Clear();
                    receiveDone.Set();
                }
                else
                {
                    client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                    new AsyncCallback(ReceiveCallback), state);
                }
            }
            else
            {
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designer2100 commented Sep 4, 2015

i need socket for wp (windose phone). help me please

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designer2100 commented Sep 4, 2015

@dvaditya

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dvaditya commented Nov 4, 2015

How to create a RESTful web service for Server.cs
Can you give the source code for that ?

@xuyae573

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xuyae573 commented Aug 25, 2017

How can I received dynamic message from server, I mean the message is not under a fixed size bytes array

@dnyaneshpatil20

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dnyaneshpatil20 commented Nov 27, 2017

hello sir, I have created server program using visual studio 2015 C#, i am connecting to esp2866. it gets connected. and send data to esp8266 but cant receive. when i use socket.receive( ) method , it waits for data to be received. but i dont want to wait for data. ho do i gete data automatically received?. I dont understand async method.
my code is:
`using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Threading;

namespace Wifi_Server_Client_Test
{
public partial class Form1 : Form
{
Socket sck, socket;
byte[] bytes = new byte[1024];

    public Form1()
    {
        InitializeComponent();
    }


    private void Form1_Load(object sender, EventArgs e)
    {
        // Setup Socket 
       
      //  sck.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
        txtHost.Text = GetLocalIP();
        btnStp.Enabled = false;
        btnCon.Enabled = true;
        btnSend.Enabled = false;
        // LISTEN FOR RECEPTION---------

        TcpListener server = new TcpListener(IPAddress.Parse(txtHost.Text), Convert.ToInt32(HostPort.Text));
        socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        //Start the server




    }

    private string GetLocalIP()
    {
        IPHostEntry Host;
        Host = Dns.GetHostEntry(Dns.GetHostName());
        foreach(IPAddress ip in Host.AddressList)
        {if (ip.AddressFamily == AddressFamily.InterNetwork)
                return ip.ToString();
     }
        return ("192.0.0.0");
    }

    private void Close_Click(object sender, EventArgs e)
    {
        Close();
    }

    private void Minimise_Click(object sender, EventArgs e)
    {
        WindowState = FormWindowState.Minimized;
    }


    private void btnCon_Click(object sender, EventArgs e)
    {
        //connecting to client
        
        IPHostEntry Host;
        Host = Dns.GetHostEntry(Dns.GetHostName());
        IPEndPoint remoteEP = new IPEndPoint(IPAddress.Parse(txtClient.Text), Convert.ToInt32(txtPort.Text));
        // Setup Socket
        sck = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        //connecting to client remote
       
        if (!sck.Connected)
        {
            sck.Connect(remoteEP);
            listMessage.Items.Add("Succssfully Connected to: " + remoteEP.ToString());
            btnStp.Enabled = true;
            btnCon.Enabled = false;
            btnSend.Enabled = true;
        }

        // Start listening and accept a client.  

        try { 
        // Setup a callback to be notified of connection requests
        int bytesRec = sck.Receive(bytes);
        listMessage.Items.Add("ESP8266 Said:" + Encoding.ASCII.GetString(bytes, 0, bytesRec));
            //--------------------------------------
        }
        catch(Exception ex) { listMessage.Items.Add(ex); }
    }

    private void btnSend_Click(object sender, EventArgs e)
    {
        //convert string message to  byte[]
        ASCIIEncoding aEncoding = new ASCIIEncoding();
        byte[] sendingMessage = new byte[1500];
        sendingMessage = aEncoding.GetBytes(txtMessage.Text);
        //sending encodded byte
        sck.Send(sendingMessage);
        //sending encodded byte
        listMessage.Items.Add("Me: " + txtMessage.Text);
        txtMessage.Text = "";
    }


    private void btnStp_Click(object sender, EventArgs e)
    {
        sck.Shutdown(SocketShutdown.Both);
        sck.Disconnect(true);
        sck.Close();
        listMessage.Items.Add("Disconnected");
       
        btnStp.Enabled = false;
        btnCon.Enabled = true;
        btnSend.Enabled = false;
        
    }

   
}

}
HELP PLEASE.

THANK YOU.
untitled

@Israa-Eltayeb

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Israa-Eltayeb commented Jan 30, 2018

can i use above code to carry voice information? and i need it to go through the UPD protocol.

@vasu0289

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vasu0289 commented Apr 11, 2018

can i use above code as windows service? i tried but having issues with while loop and allDone.Set() and allDone.WaitOne()

@Elvincth

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Elvincth commented Jun 7, 2019

can i use above code to carry voice information? and i need it to go through the UPD protocol.

Just convert the voice data to base64 and send it as text , then translate back it

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