在。net中检查Internet连接的最快和最有效的方法是什么?


当前回答

我在我的3g路由器/调制解调器上的那些方法上有问题,因为如果互联网断开连接,路由器将页面重定向到它的响应页面,所以你仍然得到一个蒸汽,你的代码认为有互联网。 苹果(或其他)有一个热点删除页面,总是返回特定的响应。下面的示例返回“Success”响应。所以你会完全确定你可以连接互联网,并得到真实的回应!

public static bool CheckForInternetConnection()
{
    try
    {       
        using (var webClient = new WebClient())
        using (var stream = webClient.OpenRead("http://captive.apple.com/hotspot-detect.html"))
        {
            if (stream != null)
            {
                //return true;
                stream.ReadTimeout = 1000;
                using (var reader = new StreamReader(stream, Encoding.UTF8, false))
                {
                    string line;
                    while ((line = reader.ReadLine()) != null)
                    {
                        if (line == "<HTML><HEAD><TITLE>Success</TITLE></HEAD><BODY>Success</BODY></HTML>")
                        {
                            return true;
                        }
                        Console.WriteLine(line);
                    }
                }

            }
            return false;
        }
    }
    catch
    {

    }
    return false;
}

其他回答

bool bb = System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();

if (bb == true)
    MessageBox.Show("Internet connections are available");
else
    MessageBox.Show("Internet connections are not available");

我个人觉得Anton和moffeltje的答案最好,但我增加了一个检查,排除VMWare和其他公司设置的虚拟网络。

public static bool IsAvailableNetworkActive()
{
    // only recognizes changes related to Internet adapters
    if (!System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable()) return false;

    // however, this will include all adapters -- filter by opstatus and activity
    NetworkInterface[] interfaces = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces();
    return (from face in interfaces
            where face.OperationalStatus == OperationalStatus.Up
            where (face.NetworkInterfaceType != NetworkInterfaceType.Tunnel) && (face.NetworkInterfaceType != NetworkInterfaceType.Loopback)
            where (!(face.Name.ToLower().Contains("virtual") || face.Description.ToLower().Contains("virtual")))
            select face.GetIPv4Statistics()).Any(statistics => (statistics.BytesReceived > 0) && (statistics.BytesSent > 0));
}

另一种选择是网络列表管理器API,它适用于Vista和Windows 7。MSDN文章在这里。在本文中有一个下载代码示例的链接,允许您这样做:

AppNetworkListUser nlmUser = new AppNetworkListUser();
Console.WriteLine("Is the machine connected to internet? " + nlmUser.NLM.IsConnectedToInternet.ToString());

请确保从COM选项卡中添加对网络列表1.0类型库的引用…它将显示为NETWORKLIST。

如果你想在网络/连接发生变化时通知用户/采取行动。 使用NLM API:

https://msdn.microsoft.com/en-us/library/ee264321.aspx http://www.codeproject.com/Articles/34650/How-to-use-the-Windows-NLM-API-to-get-notified-of

使用NetworkMonitor监控网络状态和internet连接。

示例:

namespace AmRoNetworkMonitor.Demo
{
    using System;

    internal class Program
    {
        private static void Main()
        {
            NetworkMonitor.StateChanged += NetworkMonitor_StateChanged;
            NetworkMonitor.StartMonitor();

            Console.WriteLine("Press any key to stop monitoring.");
            Console.ReadKey();
            NetworkMonitor.StopMonitor();

            Console.WriteLine("Press any key to close program.");
            Console.ReadKey();
        }

        private static void NetworkMonitor_StateChanged(object sender, StateChangeEventArgs e)
        {
            Console.WriteLine(e.IsAvailable ? "Is Available" : "Is Not Available");
        }
    }
}