private Socket LocalSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
private int size = 1024*64;
private Thread ListenThread;
private byte[] bytData;
        /// <summary>
        /// 监听方法，用于监听远程发送到本机的信息
        /// </summary>
        public void Listen()
        {
            ListenThread = new Thread(new ThreadStart(VideoListen));
            ListenThread.Start();
        }
        /// <summary>
        /// 监听线程
        /// </summary>
        private void VideoListen()
        {
            bytData = new byte[size]
            while (true)
            {
                LocalSocket.BeginReceiveFrom(bytData, 0, bytData.Length, SocketFlags.None, ref ipeRemote, new AsyncCallback(ReceiveVideo), LocalSocket);
            }
        }
        /// <summary>
        /// 接收数据
        /// </summary>
        /// <param name="iar"></param>
        private void ReceiveVideo(IAsyncResult iar)
        {
            int intRecv = 0;
            try
            {
                intRecv = LocalSocket.EndReceiveFrom(iar, ref ipeRemote);
            }
            catch
            {
                //throw new Exception();
            }

第二次执行到LocalSocket.BeginReceiveFrom(bytData, 0, bytData.Length, SocketFlags.None, ref ipeRemote, new AsyncCallback(ReceiveVideo), LocalSocket);