C# 檢查是否聯網

 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);

        /**//// <summary>
        /// 檢測本機是否聯網
        /// </summary>
        /// <returns></returns>
        public static bool IsConnectedInternet()
        {
            int i = 0;
            if (InternetGetConnectedState(out i, 0))
            {
                //已聯網
                return true;
            }
            else
            {
                //未聯網
                return false;
            }

        }

    }
}