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
bool bb = System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();
if (bb == true)
MessageBox.Show("Internet connections are available");
else
MessageBox.Show("Internet connections are not available");
其他回答
public static bool CheckForInternetConnection(int timeoutMs = 10000, string url = null)
{
try
{
url ??= CultureInfo.InstalledUICulture switch
{
{ Name: var n } when n.StartsWith("fa") => // Iran
"http://www.aparat.com",
{ Name: var n } when n.StartsWith("zh") => // China
"http://www.baidu.com",
_ =>
"http://www.gstatic.com/generate_204",
};
var request = (HttpWebRequest)WebRequest.Create(url);
request.KeepAlive = false;
request.Timeout = timeoutMs;
using (var response = (HttpWebResponse)request.GetResponse())
return true;
}
catch
{
return false;
}
}
而不是检查，只需执行操作(web请求，邮件，ftp等)，并为请求失败做好准备，即使检查成功，您也必须这样做。
考虑以下几点:
1 - check, and it is OK
2 - start to perform action
3 - network goes down
4 - action fails
5 - lot of good your check did
如果网络坏了，你的动作就会像ping一样迅速失败。
1 - start to perform action
2 - if the net is down(or goes down) the action will fail
NetworkInterface。GetIsNetworkAvailable非常不可靠。只是有一些VMware或其他局域网连接，它将返回错误的结果。 还有Dns。我只是关心测试URL是否可能在我的应用程序部署的环境中被阻止。
我发现的另一种方法是使用InternetGetConnectedState方法。 我的代码是
[System.Runtime.InteropServices.DllImport("wininet.dll")]
private extern static bool InternetGetConnectedState(out int Description, int ReservedValue);
public static bool CheckNet()
{
int desc;
return InternetGetConnectedState(out desc, 0);
}
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));
}
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;
}
