C# UDP

csharp_client_server_udp_readme.md

https://metanit.com/sharp/net/3.3.php

csharp_udp_client.cs

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace TestClient
{
    internal static class Program
    {
        private const int PortNo = 5000;
        private const string ServerIp = "127.0.0.1";

        private static void Main()
        {
            Console.WriteLine("Create socket");
            var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            var localIp = new IPEndPoint(IPAddress.Parse(ServerIp), PortNo);
            var remotePoint = new IPEndPoint(localIp.Address, localIp.Port);
            try
            {
                var message = "Client time is " + DateTime.Now;
                Console.WriteLine("Sending : " + message);
                socket.SendTo(Encoding.Unicode.GetBytes(message), remotePoint);
                Console.WriteLine("Wait answer");
                var builder = new StringBuilder();
                do
                {
                    var receivedData = new byte[256];
                    var bytes = socket.Receive(receivedData);
                    Console.WriteLine("Get answer");
                    builder.Append(Encoding.Unicode.GetString(receivedData, 0, bytes));
                } while (socket.Available > 0);

                Console.WriteLine("Receive: {0} - {1}", DateTime.Now, builder);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                socket.Close();
            }
            Console.WriteLine("End");
        }
    }
}

csharp_udp_server.cs

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace TestServer
{
    internal static class Program
    {
        private const int PortNo = 5000;
        private const string ServerIp = "127.0.0.1";

        private static void Main()
        {
            Console.WriteLine("Create socket");
            var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            var localIp = new IPEndPoint(IPAddress.Parse(ServerIp), PortNo);
            try
            {
                socket.Bind(localIp);
                while (true)
                {
                    Console.WriteLine("Wait connection");
                    var builder = new StringBuilder();
                    var remoteIp = new IPEndPoint(IPAddress.Any, 0) as EndPoint;
                    do
                    {
                        var receivedData = new byte[256];
                        var bytes = socket.ReceiveFrom(receivedData, ref remoteIp);
                        Console.WriteLine("Connection start");
                        builder.Append(Encoding.Unicode.GetString(receivedData, 0, bytes));
                    } while (socket.Available > 0);

                    var remoteFullIp = remoteIp as IPEndPoint;
                    Console.WriteLine("Receive: {0} - {1}:{2} - {3}",
                        DateTime.Now, remoteFullIp.Address, remoteFullIp.Port, builder);

                    var message = "Server time is " + DateTime.Now;
                    Console.WriteLine("Sending : " + message);
                    socket.SendTo(Encoding.Unicode.GetBytes(message), remoteIp);
                    Console.WriteLine("Connection end");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                socket.Shutdown(SocketShutdown.Both);
                socket.Close();
            }
            Console.WriteLine("End");
        }
    }
}