Yes ... Except that it doesn't always work.
Our WinForms app is heavily dependent on the Internet and our biggest
support problem is people with perfectly valid Internet connections that the
app (using the method below) fails to detect. It appears that .Net has a
great deal of trouble with some proxies that require login (including the MS
one) and, it seems, with VPN connections. We have not been able to resolve
this and it's increasingly frustrating as it's not anything we've been to
repro here although several customers, including IT managers and developers,
have noted this problem. It's very real and very, very frustrating. In all
cases, the customer using IE can access the URL just fine; it only fails
when we do the WebRequest.
Any suggestions would be appreciated.
The code we use is something like (simplified):
Try
wr = CType(WebRequest.Create(UseURL), HttpWebRequest)
Resp = CType(wr.GetResponse(), HttpWebResponse)
Catch we As WebException
'Connection failed
End try
One thing -- we do lock the ProtocolVersion to 1.0 for backwards compat with
some systems. Can that be an issue with some proxies? Is there something
we are specifically supposed to be to ensure that we login to the proxy?
Thanks, Steve
"Matt Hawley" <mhawley@!n!o!s!p!a!m!.integrityts.com> wrote in message
news:%23MwrR16KEHA.620@TK2MSFTNGP10.phx.gbl...[color=blue]
> Good explanation. Thanks!
>
> Matt Hawley, MCAD .NET
>
http://www.eworldui.net
>
>
> "Matt Hawley" <mhawley@!n!o!s!p!a!m!.integrityts.com> wrote in message
> news:eF4Klw5KEHA.1956@TK2MSFTNGP10.phx.gbl...[color=green]
> > I'm facing a problem where I need to verify that my windows forms[/color]
> application has access to the internet before it can do anything.[/color]
Currently,[color=blue]
> the only way I can think of is by creating a HttpWebRequest and point it[/color]
to[color=blue]
> the specified URL I wish to connect to later on, and if that throws an
> error, I know I don't have an internet connection. Is this the best[/color]
method[color=blue]
> for detecting an internet connection, or is there some sort of routine[/color]
that[color=blue]
> I need to follow that is more tuned for performance?
>
> This seems to be the only reliable method to check for an internet
> connection. Google will give you other solutions but they generaly rely[/color]
on[color=blue]
> checking if there's a network device configured which doesn't ensure you
> that the computer has actually access to the internet. And even if it has
> access to the internet, it may be behind a proxy server that restricts[/color]
this[color=blue]
> access to some sites or particular protocols. So the only way to know for
> sure if a computer can access your particular site is to try...
>
>
>[/color]
