C# Socket Programming

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C# Socket Programming with SharpDevelop.

Download: http://www.icsharpcode.net/opensource/sd/download/
 
Create Server Socket.

 
1. File -> New -> Solution

Select “Windows Application” template and input project name “ServerSocket”.
Then click “Create” button.
 
2. Select the Design tab and create component from the tools.

 
3. Double click on the button component to accept on click action. All 3 buttons (Start, Stop, Send).
 
4. Switch to the Source tab and code.
 

Code:

/*
* Author: psupawa@gmail.com
* Date: 25-Jun-14
* Time: 11:22 AM
*/

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace ServerSocket
{
 /// <summary>
 /// Demonstrate how to use windows socket in C#
 /// </summary>
 public partial class MainForm
 {
   [STAThread]
   public static void Main(string[] args)
   {
     Application.EnableVisualStyles();
     Application.SetCompatibleTextRenderingDefault(false);
     Application.Run(new MainForm());
   }
   
   public MainForm()
   {
     // Initialize the component created in SharpDevelop form designer.
     InitializeComponent();
     
     // Initialize component value.
     hostText.Text = GetHostIP();
     workerSocket = new Socket[MAX_CLIENTS];
     availableSocket = new bool[MAX_CLIENTS];
     clientIP = new String[MAX_CLIENTS];
     for (int i=0; i<availableSocket.Length; i++) {
       availableSocket[i] = true;
     }
   }
   
   private AsyncCallback workerCallBack ;
   private Socket mainSocket;
   private Socket[] workerSocket;
   private int clientIndex = 0;
   private const int MAX_CLIENTS = 10;
   private bool[] availableSocket;
   private String[] clientIP;
   
   private void OpenButtonClick(object sender, System.EventArgs e)
   {
     try {
       // Check the port value
       if (portText.Text == "") {
         statusText.AppendText("Please enter a Port Number\n");
         return;
       }
       string portStr = portText.Text;
       int port = System.Convert.ToInt32(portStr);
       // Create the listening socket...
       mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
       IPEndPoint ipLocal = new IPEndPoint (IPAddress.Any, port);
       // Bind to local IP Address
       mainSocket.Bind(ipLocal);
       // Start listening
       mainSocket.Listen(4);
       // Create the call back for client connections
       statusText.AppendText("Server is listening on port " + portStr + "\n");
       mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null);
       
       UpdateControls(true);
       closeButton.Focus();
     }
     catch(SocketException ex) {
       statusText.AppendText("Error: " + ex.Message + "\n");
     }
   }
   
   private void CloseButtonClick(object sender, System.EventArgs e)
   {
     if (mainSocket != null) {
       mainSocket.Close();
     }
     for (int i = 0; i < workerSocket.Length; i++) {
       if (workerSocket[i] != null) {
         workerSocket[i].Close();
         workerSocket[i] = null;
       }
     }
     UpdateControls(false);
     inText.Clear();
     outText.Clear();
     statusText.Clear();
     sendButton.Enabled = false;
   }
   
   private void UpdateControls(bool listening)
   {
     openButton.Enabled = !listening;
     closeButton.Enabled = listening;
     portText.Enabled = !listening;
     inText.Enabled = listening;
     outText.Enabled = listening;
   }
   
   // This is the call back function, which will be invoked when a client is connected
   private void OnClientConnect(IAsyncResult asyn)
   {
     try {
       // Find available socket
       for (int i=0; i<availableSocket.Length; i++) {
         if (availableSocket[i]) {
           clientIndex = i;
           availableSocket[i] = false;
         }
       }
       // Accept new client connection and assign to the workerSocket
       workerSocket[clientIndex] = mainSocket.EndAccept(asyn);
       clientIP[clientIndex] = workerSocket[clientIndex].RemoteEndPoint.ToString();
       // Display this client connection
       statusText.AppendText("Client connected, " + clientIP[clientIndex] + "\n");
       // Let the worker Socket do the further processing for the just connected client
       WaitForData(workerSocket[clientIndex]);
       
       sendButton.Enabled = true;
       inText.Focus();
       
       // The main Socket is now free and waiting for new client conection
       mainSocket.BeginAccept(new AsyncCallback (OnClientConnect ),null);
     }
     catch(ObjectDisposedException) {
       // Ignore error, when socket disposed
     }
     catch(SocketException ex) {
       statusText.AppendText(ex.Message + "\n");
     }    
   }
   
   // Waiting for data from client
   private void WaitForData(Socket soc)
   {
     try
     {
       if  ( workerCallBack == null ){
         // Invoke the call back function when client send data
         workerCallBack = new AsyncCallback(OnDataReceived);
       }
       SocketPacket socketPacket = new SocketPacket();
       socketPacket.currentSocket = soc;
       // Start receiving data from client, asynchronously
       soc.BeginReceive (
         socketPacket.dataBuffer,
         0,
         socketPacket.dataBuffer.Length,
         SocketFlags.None,
         workerCallBack,
         socketPacket
       );
     }
     catch(SocketException ex) {
       // Display execption message
       statusText.AppendText("WaitForData, error: " + ex.Message + "\n");
     }
   }
   
   // A call back function invoked when the socket detects incoming data on the stream
   private void OnDataReceived(IAsyncResult asyn)
   {
     EndPoint hostID = null;
     try {
       SocketPacket socketData = (SocketPacket)asyn.AsyncState;
       hostID = socketData.currentSocket.RemoteEndPoint;
       
       int iRx  = 0 ;
       // Receive data
       iRx = socketData.currentSocket.EndReceive(asyn);
       char[] chars = new char[iRx +  1];
       Decoder d = Encoding.UTF8.GetDecoder();
       int charLen = d.GetChars(socketData.dataBuffer, 0, iRx, chars, 0);
       String szData = new String(chars);
       inText.AppendText(szData);
       
       // Continue the waiting for data on the Socket
       WaitForData(socketData.currentSocket);
     }
     catch(ObjectDisposedException) {
       // Ignore error, when socket disposed
     }
     catch(SocketException) {
       // Client disconnect
       sendButton.Enabled = false;
       for (int i=0; i<clientIP.Length; i++) {
         if (clientIP[i] == hostID.ToString()) {
           statusText.AppendText("Client disconnected, " + hostID + "\n");
           availableSocket[i] = true;
           clientIP[i] = "";
         }
       }
     }
   }
   
   private class SocketPacket
   {
     public Socket currentSocket;
     public byte[] dataBuffer = new byte[1];
   }
   
   private void SendButtonClick(object sender, System.EventArgs e)
   {
     try {
       Object objData = outText.Text + "\n";
       byte[] byData = Encoding.ASCII.GetBytes(objData.ToString());
       for (int i = 0; i < workerSocket.Length; i++) {
         if (workerSocket[i] != null) {
           if (workerSocket[i].Connected) {
             workerSocket[i].Send (byData);
           }
         }
       }
     }
     catch(SocketException ex) {
       statusText.AppendText("Error" + ex.Message + "\n");
     }    
   }
   
   private String GetHostIP()
   {  
     String strHostName = Dns.GetHostName();
     
     // Find host by name
     IPHostEntry ipEntry = Dns.GetHostEntry(strHostName);
     IPAddress[] addr = ipEntry.AddressList;
     
     // Grab the first IP addresses
     String IPStr = addr[addr.Length-1].ToString();
     return IPStr;
   }
 }
}


 
Create Client Socket.

 
1. File -> New -> Solution

Select “Windows Application” template and input project name “ServerSocket”.
Then click “Create” button.
 
2. Select the Design tab and create component from the tools.

 
3. Double click on the button component to accept on click action. All 3 buttons (Connect, Disconnect, Send).
 
4. Switch to the Source tab and code.
 

Code:

/*
* Author: psupawa@gmail.com
* Date: 25-Jun-14
* Time: 4:07 PM
*/

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace ClientSocket
{
 /// <summary>
 /// Description of MainForm.
 /// </summary>
 public partial class MainForm
 {
   [STAThread]
   public static void Main(string[] args)
   {
      Application.EnableVisualStyles();
      Application.SetCompatibleTextRenderingDefault(false);
      Application.Run(new MainForm());
   }
   
   public MainForm()
   {
     // Initialize the component created in SharpDevelop form designer.
     InitializeComponent();
     
     // Initialize component value.
     hostText.Text = GetHostIP();
   }
   
   private byte[] dataBuffer = new byte[10];
   private IAsyncResult result;
   private AsyncCallback asyncCallBack ;
   private Socket clientSocket;
   
   private void OpenButtonClick(object sender, EventArgs eventArgs)
   {
     // See if there are text input for the Host and Port text fields
     if (hostText.Text == "" || portText.Text == "") {
      statusText.Text = "Host Address and Port Number are required\n";
      return;
     }
     statusText.Text = "Trying connection, please wait..\n";
     this.Cursor = Cursors.WaitCursor;
     try {
      UpdateControls(false);
      // Create the socket instance
      clientSocket = new Socket (AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
     
      // Cet the remote IP address
      IPAddress ip = IPAddress.Parse(hostText.Text);
      int iPortNo = Convert.ToInt16(portText.Text);
      // Create the end point
      IPEndPoint ipEnd = new IPEndPoint(ip, iPortNo);
      // Connect to the remote host
      clientSocket.Connect(ipEnd);
      if(clientSocket.Connected) {
      UpdateControls(true);
      WaitForData();
      }
      statusText.Text = "Connection success\n";
      inText.Clear();
      outText.Clear();
      outText.Focus();
     }
     catch(SocketException ex) {
      UpdateControls(false);
      statusText.AppendText("Error: " + ex.Message + "\n");
     }
     this.Cursor = Cursors.Default;
   }
   
   private void CloseButtonClick(object sender, EventArgs eventArgs)
   {
      PerformCloseAction("Disconnected");
   }
   
   private void PerformCloseAction(String message)
   {
      if (clientSocket != null) {
      clientSocket.Close();
      clientSocket = null;
      UpdateControls(false);
      }
      statusText.Text = message;
      inText.Clear();
      outText.Clear();
      openButton.Focus();
   }
   
   private void SendButtonClick(object sender, EventArgs eventArgs)
   {
     try {
      Object objData = outText.Text + "\n";
      byte[] byData = Encoding.ASCII.GetBytes(objData.ToString());
      if(clientSocket != null){
      clientSocket.Send (byData);
      }
     }
     catch(SocketException ex) {
      statusText.AppendText("SendButtonClick, error: " + ex.Message + "\n");
     }
   }
   
   public void WaitForData()
   {
     try {
      if (asyncCallBack == null)  {
      asyncCallBack = new AsyncCallback(OnDataReceived);
      }
      SocketPacket socketPacket = new SocketPacket();
      socketPacket.thisSocket = clientSocket;
      // Start listening to the data asynchronously
      result = clientSocket.BeginReceive (
         socketPacket.dataBuffer,
         0,
         socketPacket.dataBuffer.Length,
         SocketFlags.None,
         asyncCallBack,
         socketPacket
      );
     }
     catch(SocketException ex) {
      statusText.AppendText("WaitForData, error: " + ex.Message + "\n");
     }  
   }
   
   private class SocketPacket
   {
     public Socket thisSocket;
     public byte[] dataBuffer = new byte[1];
   }
   
   private void OnDataReceived(IAsyncResult asyn)
   {
      try {
      SocketPacket theSockId = (SocketPacket)asyn.AsyncState ;
      int iRx  = theSockId.thisSocket.EndReceive (asyn);
      char[] chars = new char[iRx + 1];
      Decoder d = Encoding.UTF8.GetDecoder();
      int charLen = d.GetChars(theSockId.dataBuffer, 0, iRx, chars, 0);
      String szData = new String(chars);
      inText.AppendText(szData);
      WaitForData();
      }
      catch (ObjectDisposedException) {
      // The socket has been closed, ignore action
      }
      catch(SocketException ex) {
      http://MessageBox.Show(ex.Message);
      statusText.AppendText("OnDataReceived, error: " + ex.Message + "\n");
      PerformCloseAction(ex.Message);
      }
   }
   
   private void UpdateControls( bool connected )
   {
     openButton.Enabled = !connected;
     closeButton.Enabled = connected;
     sendButton.Enabled = connected;
     hostText.Enabled = !connected;
     portText.Enabled = !connected;
     inText.Enabled = connected;
     outText.Enabled = connected;
   }
   
   private String GetHostIP()
   {  
     String strHostName = Dns.GetHostName();
     
     // Find host by name
     IPHostEntry ipEntry = Dns.GetHostEntry(strHostName);
     IPAddress[] addr = ipEntry.AddressList;
     
     // Grab the first IP addresses
     String IPStr = addr[addr.Length-1].ToString();
     return IPStr;
   }
 }
}