使用IPHostEntry获取本机局域网地址
            string hostName = Dns.GetHostName();
            IPHostEntry localHost = Dns.GetHostEntry(hostName);
            for (int i=0; i < localHost.AddressList.Length ; ++i)
            {
                if (localHost.AddressList[i].AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
                {
                    Console.WriteLine(localHost.AddressList[i].ToString());
                }
            }