用UDP协议发送广播

服务器端:发送消息

private void button1_Click(object sender, EventArgs e)
        {
            //只能用UDP协议发送广播，所以ProtocolType设置为UDP
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            //让其自动提供子网中的IP地址
            //IPEndPoint iep = new IPEndPoint(IPAddress.Parse("192.168.1.13"), 8090);//IPAddress.Broadcast
            IPEndPoint iep = new IPEndPoint(IPAddress.Broadcast, 8090);//IPAddress.Broadcast
            //设置broadcast值为1，允许套接字发送广播信息
            socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);
            //将发送内容转换为字节数组
            byte[] bytes = System.Text.Encoding.Unicode.GetBytes(this.textBox1.Text);
            //向子网发送信息
            socket.SendTo(bytes, iep);
            socket.Close();
        }

客户端：接收消息

//接收信息
        private void AcceptMessage()
        {
            //d定义socket对象
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            //IPEndPoint iep = new IPEndPoint(IPAddress.Parse("192.168.0.105"), 8090);
            IPEndPoint iep = new IPEndPoint(IPAddress.Any, 8090);
            socket.Bind(iep);
            ep = (EndPoint)iep;
            Console.WriteLine("Ready to receive…");
            byte[] bytes;
            while (true)
            {
                stringData = "";
                int recv = 0;
                bytes = new byte[1024];
                try
                {
                    recv = socket.ReceiveFrom(bytes, ref ep);
                }
                catch (Exception ex)
                {
                    Console.WriteLine("有异常", ex.ToString());
                }

                //string stringData = Encoding.ASCII.GetString(bytes, 0, recv);
                stringData = System.Text.Encoding.Unicode.GetString(bytes).TrimEnd('u0000');
                Console.WriteLine("received: {0} from: {1}", stringData, ep.ToString());

                //socket.ReceiveFrom(bytes, ref ep);
                //receiveData = System.Text.Encoding.Unicode.GetString(bytes);
                //receiveData = receiveData.TrimEnd('u0000');
                //Thread th = new Thread(new ThreadStart(Acc));
                //th.Start();
            }
            socket.Close();
        }