你绝对没有办法可靠地检查是否有互联网连接(我想你的意思是访问互联网)。

但是，您可以请求几乎从未离线的资源，例如ping google.com或类似的东西。我认为这是有效的。

try { 
    Ping myPing = new Ping();
    String host = "google.com";
    byte[] buffer = new byte[32];
    int timeout = 1000;
    PingOptions pingOptions = new PingOptions();
    PingReply reply = myPing.Send(host, timeout, buffer, pingOptions);
    return (reply.Status == IPStatus.Success);
}
catch (Exception) {
    return false;
}

对于我的应用程序，我们也通过下载小文件进行测试。

string remoteUri = "https://www.microsoft.com/favicon.ico"

WebClient myWebClient = new WebClient();

try
{
    byte[] myDataBuffer = myWebClient.DownloadData (remoteUri);
    if(myDataBuffer.length > 0) // Or add more validate. eg. checksum
    {
        return true;
    }
}
catch
{
    return false;
}

也。有些ISP可能使用中间服务器缓存文件。添加未使用的随机参数。https://www.microsoft.com/favicon.ico?req=random_number 可以防止缓存。

我已经看到了上面列出的所有选项，唯一可行的选项来检查互联网是否可用是“Ping”选项。 导入[DllImport("Wininet.dll")]和System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()或NetworkInterface类的任何其他变体都不能很好地检测网络的可用性。这些方法只检查网线是否插好。

“Ping选项”

if(Connection is available)返回true

if(连接不可用且网线已插入)返回false

if(网线未插入)抛出异常

的NetworkInterface

if(Internet可用)返回True

if(Internet不可用且网线已插入)返回True

if(Network Cable is Not plug in)返回false

[DllImport杂志》(“Wininet等”)。

if(Internet可用)返回True

if(Internet不可用且网线已插入)返回True

if(Network Cable is Not plug in)返回false

因此，在[DllImport("Wininet.dll")]和NetworkInterface的情况下，没有办法知道互联网连接是否可用。

不能解决在检查和运行代码之间网络中断的问题吗 但是相当可靠

public static bool IsAvailableNetworkActive()
{
    // only recognizes changes related to Internet adapters
    if (System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable())
    {
        // 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)
                select face.GetIPv4Statistics()).Any(statistics => (statistics.BytesReceived > 0) && (statistics.BytesSent > 0));
    }

    return false;
}

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

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

private bool ping()
{
    System.Net.NetworkInformation.Ping pingSender = new System.Net.NetworkInformation.Ping();
    System.Net.NetworkInformation.PingReply reply = pingSender.Send(address);
    if (reply.Status == System.Net.NetworkInformation.IPStatus.Success)
    {                
        return true;
    }
    else
    {                
        return false;
    }
}