[Flags]
    enum ConnectState
    {
        None = 0,
        INTERNET_CONNECTION_MODEM = 0x01,
        INTERNET_CONNECTION_LAN = 0x02,
        INTERNET_CONNECTION_PROXY = 0x04,
        INTERNET_CONNECTION_MODEM_BUSY = 0x08,
        INTERNET_RAS_INSTALLED = 0x10,
        INTERNET_CONNECTION_OFFLINE = 0x20,
        INTERNET_CONNECTION_CONFIGURED = 0x40,
    }
class Program
    {
        [DllImport("wininet.dll")]
        private extern static bool InternetGetConnectedState(out ConnectState connectionDescription, int reservedValue);

        static void Main(string[] args)
        {
            ConnectState state = ConnectState.None;
            Console.WriteLine(InternetGetConnectedState(out state ,0));

            Console.WriteLine(state);
        }
    }