判断计算机是否联网

-------第一种方法，这种方法比较常用也很简单

public partial class Form1 : Form
{
        //判断网络连接
        [DllImport("wininet")]
        private extern static bool InternetGetConnectedState(out int connectionDescription, int reservedValue);
        ///<summary>
        /// 检测本机的网络连接
        ///</summary>
 
       private void button1_Click(object sender, EventArgs e)
        {
            //判断是否联网
                int i = 0;
                if (InternetGetConnectedState(out i, 0))
                {
                    //联网
                    MessageBox.Show("Thylx提醒您：你的计算机已连接到网络上！");
                 }
                 else
                  {
                     //断网
                     MessageBox.Show("Thylx提醒您：本地连接已断开！");
                  }
        }
}

-----第二种方式

using System.Net.NetworkInformation;

namespace 判断是否联网{class  program{     static void Main(string[] args){       Ping p = new Ping();       PingReply pr;       pr = p.Send("119.75.218.45");//百度的IP if (pr.Status != IPStatus.Success)//如果连接不成功   {      Console.WriteLine("未联网");   }else{      Console.WriteLine("已联网");   }      Console.Read();   }

 }}