UDP发送组播消息

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;

namespace Asr.App.O2o.Client.UdpMulticast
{
    public class UdpMulticast
    {
        private static IPAddress mcastAddress;
        private static int mcastPort;
        private static Socket mcastSocket;
        private static MulticastOption mcastOption;

        public static void Start()
        {
            //组播地址和端口
            mcastAddress = IPAddress.Parse("224.0.0.1");
            mcastPort = 6005;
            //组播套接字，绑定本地地址（组播端口）
            mcastSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            IPEndPoint localEP = new IPEndPoint(IPAddress.Parse("127.0.0.1"), mcastPort);
            mcastSocket.Bind(localEP);
            //加入组播
            mcastOption = new MulticastOption(mcastAddress, IPAddress.Parse("127.0.0.1"));
            mcastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, mcastOption);
        }

        public static void Stop()
        {
            mcastSocket.Close();
            mcastSocket.Dispose();
        }

        public static void sendMsg(int msgType, int seqInt, string jsonValue)
        {
            byte[] typebytes = BitConverter.GetBytes(msgType);
            byte[] seqbytes = BitConverter.GetBytes(seqInt);
            byte[] msgbytes = Encoding.UTF8.GetBytes(jsonValue);
            byte[] lenbytes = BitConverter.GetBytes(msgbytes.Length);

            byte[] bytes = typebytes.Concat(seqbytes).Concat(lenbytes).Concat(msgbytes).ToArray();
            mcastSocket.SendTo(bytes, new IPEndPoint(mcastAddress, mcastPort));
        }
    }
}

来源：https://www.cnblogs.com/liwb1987/p/4606661.html