一旦下网登录成功，C#怎么立即检测到这一登录成功状态

一旦上网登录成功，C#如何立即检测到这一登录成功状态
一旦上网登录成功，C#如何立即检测到这一登录成功状态

[解决办法]
后台开一个线程，不停的ping 百度，一旦能ping通就提示连接成功，然后退出程序
[解决办法]
类库中, 网络连接状态改变的那个事件叫啥来着

[解决办法]

C# code

    [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);        }    }