调用系统API判断网络连接状态

判断是否连接到网络
using System.Runtime.InteropServices; //调用API用的命名空间

        private void Page_Load(object sender, System.EventArgs e)
        {
            if(!IsConnected())
            {
                Response.Write("没有连接到网络!");
            }
            else
            {
                Response.Write("已连接到网络!");
            }
        }

        //检测网络连接是否连接到Internet
        [DllImport("wininet.dll")]
        private extern static bool InternetGetConnectedState(out int connectionDescription, int reservedValue);
 
        public bool IsConnected()
        {
            int connectionDescription = 0;
            return InternetGetConnectedState(out connectionDescription, 0);
        }