using System;  2 using System.Collections.Generic;  3 using System.Text;  4 //方法一  5 using System.Runtime;  6 using System.Runtime.InteropServices;  7 //方法二 Net2.0新增类库  8 using System.Net.NetworkInformation;  9  10 namespace InternetCheck 11 { 12     public class Internet 13     { 14         [DllImport("wininet.dll")] 15         private extern static bool InternetGetConnectedState(int Description, int ReservedValue); 16  17         #region 方法一 18         ///  19         /// 用于检查网络是否可以连接互联网,true表示连接成功,false表示连接失败  20         ///  21         ///  22         public static bool IsConnectInternet() 23         { 24             int Description = 0; 25             return InternetGetConnectedState(Description, 0); 26         } 27         #endregion 28  29         #region 方法二 30         ///  31         /// 用于检查IP地址或域名是否可以使用TCP/IP协议访问(使用Ping命令),true表示Ping成功,false表示Ping失败  32         ///  33         /// 输入参数,表示IP地址或域名 34         ///  35         public static bool PingIpOrDomainName(string strIpOrDName) 36         { 37             try 38             { 39                 Ping objPingSender = new Ping(); 40                 PingOptions objPinOptions = new PingOptions(); 41                 objPinOptions.DontFragment = true; 42                 string data = ""; 43                 byte[] buffer = Encoding.UTF8.GetBytes(data); 44                 int intTimeout = 120; 45                 PingReply objPinReply = objPingSender.Send(strIpOrDName, intTimeout, buffer, objPinOptions); 46                 string strInfo = objPinReply.Status.ToString(); 47                 if (strInfo == "Success") 48                 { 49                     return true; 50                 } 51                 else 52                 { 53                     return false; 54                 } 55             } 56             catch (Exception) 57             { 58                 return false; 59             } 60         } 61         #endregion 62     } 63 }