Csharp/CSharp Tutorial/Network/Socket Udp Server

Simple Udp server

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class MainClass
{
   public static void Main()
   {
      int receivedDataLength;
      byte[] data = new byte[1024];
      IPEndPoint ip = new IPEndPoint(IPAddress.Any, 9999);
      Socket socket = new Socket(AddressFamily.InterNetwork,SocketType.Dgram, ProtocolType.Udp);
      socket.Bind(ip);
      IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
      EndPoint Remote = (EndPoint)(sender);
      while(true)
      {
         data = new byte[1024];
         receivedDataLength = socket.ReceiveFrom(data, ref Remote);
       
         Console.WriteLine(Encoding.ASCII.GetString(data, 0, receivedDataLength));
         socket.SendTo(data, receivedDataLength, SocketFlags.None, Remote);
      }
   }
}

Udp Multi receive

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class MainClass
{
   public static void Main()
   {
      Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
      Console.WriteLine("Ready to receive...");
      IPEndPoint iep = new IPEndPoint(IPAddress.Any, 9999);
      EndPoint ep = (EndPoint)iep;
      sock.Bind(iep);
      sock.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership,new MulticastOption(IPAddress.Parse("127.0.0.1")));
      byte[] data = new byte[1024];
      int recv = sock.ReceiveFrom(data, ref ep);
      string stringData = Encoding.ASCII.GetString(data, 0, recv);
      Console.WriteLine("received: {0}  from: {1}", stringData, ep.ToString());
      sock.Close();
   }
}

Udp server setup

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class MainClass
{
   public static void Main()
   {
      int receivedDataLength;
      byte[] data = new byte[1024];
      IPEndPoint ip = new IPEndPoint(IPAddress.Any, 9999);
      Socket socket = new Socket(AddressFamily.InterNetwork,SocketType.Dgram, ProtocolType.Udp);
      socket.Bind(ip);
      IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
      EndPoint tmpRemote = (EndPoint)(sender);
      receivedDataLength = socket.ReceiveFrom(data, ref tmpRemote);
      Console.WriteLine("Message received from {0}:", tmpRemote.ToString());
      Console.WriteLine(Encoding.ASCII.GetString(data, 0, receivedDataLength));
      string welcome = "Welcome";
      data = Encoding.ASCII.GetBytes(welcome);
      socket.SendTo(data, data.Length, SocketFlags.None, tmpRemote);
      for(int i = 0; i < 5; i++)
      {
         data = new byte[1024];
         receivedDataLength = socket.ReceiveFrom(data, ref tmpRemote);
         Console.WriteLine(Encoding.ASCII.GetString(data, 0, receivedDataLength));
      }
      socket.Close();
   }
}