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使用InternetGetConnectedState判断本地网络状态(C#举例)

函数原型:函数InternetGetConnectedState返回本地系统的网络连接状态。

语法:

BOOL InternetGetConnectedState(
__out LPDWORD lpdwFlags,
__in DWORD dwReserved
);
参数:
lpdwFlags[out]
指向一个变量,该变量接收连接描述内容。该参数在函数返回FLASE时仍可以返回一个有效的标记。该参数可以为下列值的一个或多个
含义
INTERNET_CONNECTION_CONFIGURED  
0x40(64)
Local system has a valid connection to the Internet, but it might or might not be currently connected.
INTERNET_CONNECTION_LAN                
  0x02(2)
Local system uses a local area network to connect to the Internet.
INTERNET_CONNECTION_MODEM0          
  x01(1)
Local system uses a modem to connect to the Internet.
INTERNET_CONNECTION_MODEM_BUSY0  
x08(8)
No longer used.
INTERNET_CONNECTION_OFFLINE          
  0x20(16)
Local system is in offline mode.
INTERNET_CONNECTION_PROXY            
   0x04(4)
Local system uses a proxy server to connect to the Internet.
INTERNET_RAS_INSTALLED                    
   0x10(8)
Local system has RAS installed.
dwReserved[in]
保留值。必须为0。
当存在一个modem或一个LAN连接时,返回TRUE,当不存在internet连接或所有的连接当前未被激活时,返回false。
当该函数返回false时,程序可以调用GetLastError来接收错误代码。

运行效果:

代码:

using System;using System.Collections.Generic;using System.Text;using System.Net.NetworkInformation;namespace ConsoleApplication1{    class Program    {        public static void Main(string[] args)        {            string url = "www.baidu.com;www.sina.com;www.cnblogs.com;www.google.com;www.163.com;www.csdn.com";            string[] urls = url.Split(new char[] { ‘;‘ });            CheckServeStatus(urls);            Console.ReadKey();        }                /// <summary>        /// 检测网络连接状态        /// </summary>        /// <param name="urls"></param>        public static void CheckServeStatus(string[] urls)        {            int errCount = 0;//ping时连接失败个数            if (!LocalConnectionStatus())            {                Console.WriteLine("网络异常~无连接");            }            else if (!MyPing(urls, out errCount))            {                if ((double)errCount / urls.Length >= 0.3)                {                    Console.WriteLine("网络异常~连接多次无响应");                }                else                {                    Console.WriteLine("网络不稳定");                }            }            else            {                Console.WriteLine("网络正常");            }        }        #region 网络检测         private const int INTERNET_CONNECTION_MODEM = 1;        private const int INTERNET_CONNECTION_LAN = 2;        [System.Runtime.InteropServices.DllImport("winInet.dll")]        private static extern bool InternetGetConnectedState(ref int dwFlag, int dwReserved);        /// <summary>        /// 判断本地的连接状态         /// </summary>        /// <returns></returns>        private static bool LocalConnectionStatus()        {            System.Int32 dwFlag = new Int32();            if (!InternetGetConnectedState(ref dwFlag, 0))            {                Console.WriteLine("LocalConnectionStatus--未连网!");                return false;            }            else            {                if ((dwFlag & INTERNET_CONNECTION_MODEM) != 0)                {                    Console.WriteLine("LocalConnectionStatus--采用调制解调器上网。");                    return true;                }                else if ((dwFlag & INTERNET_CONNECTION_LAN) != 0)                {                    Console.WriteLine("LocalConnectionStatus--采用网卡上网。");                    return true;                }            }            return false;        }        /// <summary>        /// Ping命令检测网络是否畅通        /// </summary>        /// <param name="urls">URL数据</param>        /// <param name="errorCount">ping时连接失败个数</param>        /// <returns></returns>        public static bool MyPing(string[] urls, out int errorCount)        {            bool isconn = true;            Ping ping = new Ping();            errorCount = 0;            try            {                PingReply pr;                for (int i = 0; i < urls.Length; i++)                {                    pr = ping.Send(urls[i]);                    if (pr.Status != IPStatus.Success)                    {                        isconn = false;                        errorCount++;                    }                    Console.WriteLine("Ping " + urls[i] + "    " + pr.Status.ToString());                }            }            catch            {                isconn = false;                errorCount = urls.Length;            }            //if (errorCount > 0 && errorCount < 3)            //  isconn = true;            return isconn;        }        #endregion    }}