調用系統API判斷網路連接狀態

判斷是否串連到網路
using System.Runtime.InteropServices; //調用API用的命名空間

        private void Page_Load(object sender, System.EventArgs e)
        {
            if(!IsConnected())
            {
                Response.Write("沒有串連到網路!");
            }
            else
            {
                Response.Write("已串連到網路!");
            }
        }

        //檢測網路連接是否串連到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);
        }