public partial class UserControl1 : UserControl, IObjectSafety    {        //检测网络状态        [DllImport("wininet.dll")]        private extern static bool InternetGetConnectedState(out int connectionDescription, int reservedValue);        /// <summary>        /// 检测网络状态        /// </summary>        private bool isConnected()        {            int I = 0;            bool state = InternetGetConnectedState(out I, 0);            return state;        } 　　　　private void update_Load(object sender, EventArgs e)        {            if (isConnected())            {            //network  is connected.            }            else            {             //network is not connected.             }
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