using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Runtime.InteropServices;namespace LocalApp.ConsoleApp.Core{    public class Net    {         [DllImport("wininet")]        private extern static bool InternetGetConnectedState(out int connectionDescription, int reservedValue);        /// 
        /// 检测本机是否联网        /// 
       /// 
              public static bool IsConnectedInternet()        {            int i = 0;            if (InternetGetConnectedState(out i, 0))            {                //已联网                return true;             }            else            {                //未联网                return false;             }         }     }}