Using C# UDPClient Send and Receive message

Client to receive message sent by server:

   1:  using System;

   2:  using System.Collections.Generic;

   3:  using System.ComponentModel;

   4:  using System.Data;

   5:  using System.Drawing;

   6:  using System.Linq;

   7:  using System.Text;

   8:  using System.Windows.Forms;

   9:  using System.Net.Sockets;

  10:  using System.Threading;

  11:  using System.Net;

  12:   

  13:  namespace NoticeSystemClient

  14:  {

  15:      public partial class MainForm : Form

  16:      {

  17:          public delegate void ShowMessage(string message);

  18:          public ShowMessage myDelegate;

  19:          Int32 port = 11000;

  20:          UdpClient udpClient = new UdpClient(11000);

  21:          Thread thread;

  22:          public MainForm()

  23:          {

  24:              //CheckForIllegalCrossThreadCalls = false;

  25:              InitializeComponent();

  26:          }

  27:   

  28:          private void MainForm_KeyDown(object sender, KeyEventArgs e)

  29:          {

  30:              if (e.KeyCode == Keys.Escape)

  31:              {

  32:                  thread.Abort();

  33:                  udpClient.Close();

  34:                  Close();

  35:              }

  36:          }

  37:   

  38:          private void ReceiveMessage()

  39:          {                      

  40:              while (true)

  41:              {

  42:                  IPEndPoint remoteIPEndPoint = new IPEndPoint(IPAddress.Any, port);

  43:                  byte[] content = udpClient.Receive(ref remoteIPEndPoint);

  44:   

  45:                  if (content.Length > 0)

  46:                  {

  47:                      string message = Encoding.ASCII.GetString(content);

  48:                      

  49:                      this.Invoke(myDelegate, new object[] { message });

  50:                  }

  51:              }

  52:          }

  53:   

  54:   

  55:          private void ShowMessageMethod(string message)

  56:          {

  57:              richText.Text = message;

  58:          }

  59:   

  60:          private void MainForm_Load(object sender, EventArgs e)

  61:          {            

  62:              myDelegate = new ShowMessage(ShowMessageMethod);

  63:              thread = new Thread(new ThreadStart(ReceiveMessage));

  64:              thread.IsBackground = true;

  65:              thread.Start();

  66:          }

  67:      }

  68:  }

Server:

   1:  using System;

   2:  using System.Collections.Generic;

   3:  using System.ComponentModel;

   4:  using System.Data;

   5:  using System.Drawing;

   6:  using System.Linq;

   7:  using System.Text;

   8:  using System.Windows.Forms;

   9:  using System.Net.Sockets;

  10:  using System.Net;

  11:   

  12:  namespace NoticeSystem

  13:  {

  14:      public partial class MainForm : Form

  15:      {

  16:          UdpClient udpClient = new UdpClient();

  17:          public MainForm()

  18:          {

  19:              InitializeComponent();

  20:          }

  21:   

  22:          private void btnClose_Click(object sender, EventArgs e)

  23:          {

  24:              udpClient.Close();

  25:              Close();

  26:          }

  27:   

  28:          private void btnSend_Click(object sender, EventArgs e)

  29:          {

  30:              Int32 port = 11000;

  31:              IPAddress ip = IPAddress.Parse(txtStartIP.Text.Trim());

  32:              IPEndPoint ipEndPoint = new IPEndPoint(ip,port);

  33:              byte[] content = Encoding.ASCII.GetBytes(richText.Text);

  34:              try

  35:              {

  36:                  int count = udpClient.Send(content, content.Length, ipEndPoint);

  37:                  if (count > 0)

  38:                  {

  39:                      MessageBox.Show("Message has been sent.", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);

  40:                  }

  41:              }

  42:              catch

  43:              {

  44:                  MessageBox.Show("Error occurs.", "Exclamation", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);

  45:              }

  46:          }

  47:      }

  48:  }