WPF 检测计算机网络连接情况

        private const int INTERNET_CONNECTION_MODEM = 1;

        private const int INTERNET_CONNECTION_LAN = 2;

        private const int INTERNET_CONNECTION_PROXY = 4;

        private const int INTERNET_CONNECTION_MODEM_BUSY = 8;

        [DllImport("wininet.dll")]
        private extern static bool InternetGetConnectedState(out int connectionDescription, int reservedValue);

        /// <summary>
        /// 检测用户计算机是否已连接网络
        /// </summary>
        /// <returns></returns>
        public static bool IsOnLine()
        {
            try
            {
                var netstatus = string.Empty;
                var connection = 0;
                if (!InternetGetConnectedState(out connection, 0)) return false;
                if ((connection & INTERNET_CONNECTION_PROXY) != 0)
                    netstatus += " 采用代理上网  
";
                if ((connection & INTERNET_CONNECTION_MODEM) != 0)
                    netstatus += " 采用调治解调器上网 
";
                if ((connection & INTERNET_CONNECTION_LAN) != 0)
                    netstatus += " 采用网卡上网  
";
                if ((connection & INTERNET_CONNECTION_MODEM_BUSY) != 0)
                    netstatus += " MODEM被其他非INTERNET连接占用  
";
                Console.WriteLine(netstatus);
                return true;
            }
            catch (Exception)
            {
                return false;
            }
        }