问题描述

以编程方式检查互联网连接是否可用的最简单方法是什么?

What is the easiest way to check whether internet connection is available programatically?

正如建议的那样，我尝试使用以下方法，但它总是返回 true.

As suggested I tried using the following method, but it is always returning true.

[Flags]
enum InternetConnectionState : int
{
    INTERNET_CONNECTION_MODEM = 0x1,
    INTERNET_CONNECTION_LAN = 0x2,
    INTERNET_CONNECTION_PROXY = 0x4,
    INTERNET_RAS_INSTALLED = 0x10,
    INTERNET_CONNECTION_OFFLINE = 0x20,
    INTERNET_CONNECTION_CONFIGURED = 0x40
}

class Program
{
    [DllImport("WININET", CharSet = CharSet.Auto)]
    static extern bool InternetGetConnectedState(ref InternetConnectionState lpdwFlags, int dwReserved);

static void Main(string[] args)
{
    InternetConnectionState flags = 0;
    bool isConnected = InternetGetConnectedState(ref flags, 0);
    Console.WriteLine(isConnected);
    //Console.WriteLine(flags);
    Console.ReadKey();
}
}

附加信息(如果有帮助):我通过共享 wifi 网络访问互联网.

Additional Info (if it helps): I access internet over a shared wifi network.

推荐答案

这里是您可以调用的 Windows API.它位于 wininet.dll 中，名为 InternetGetConnectedState.

Here is the Windows API you can call into. It's in wininet.dll and called InternetGetConnectedState.

using System;
using System.Runtime;
using System.Runtime.InteropServices;

public class InternetCS
{
    //Creating the extern function...
    [DllImport("wininet.dll")]
    private extern static bool InternetGetConnectedState( out int Description, int ReservedValue );

    //Creating a function that uses the API function...
    public static bool IsConnectedToInternet( )
    {
        int Desc ;
        return InternetGetConnectedState( out Desc, 0 ) ;
    }
}

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