re:
!> I always go for the latter...

Indeed, that's my preference, too.

I supplied the alternative only because the OP requested the solution
for accessing a root web.config from an application down the wwwroot hierarchy.

There's an additional caveat about storing all the connection strings in the root.

You can't mix 1.1 and 2.0 apps in your site.
You *must* have either all apps being 2.0, or all apps being 1.1.

Mixing 1.1 and 2.0 apps will bring the inevitable "configuration section not recognized" error.

re:
!> Are you sure about this?

Try it... ;-)
...but only if you don't mix 1.1 and 2.0 apps in your wwwroot hierarchy.

re;
!> You're declaring a configPath variable to point to
!> the root web.config, but then not actually using it anywhere...

Here's what happened...

I tried using :

Dim configPath As String = "/"
Dim config As Configuration = WebConfigurationManager.OpenWebConfiguration(configPath)
Dim config2 As ConnectionStringsSection = WebConfigurationManager.GetWebApplicationSection("connectionStrings")
Dim value as String = "The configured connectionStrings connection is : " & config2.connectionstrings("myDB").ToString()

...but when I removed
Dim config As Configuration = WebConfigurationManager.OpenWebConfiguration(configPath)

...and used :
Dim configPath As String = "/"
Dim config As ConnectionStringsSection = WebConfigurationManager.GetWebApplicationSection("connectionStrings")
Dim value as String = "The configured connectionStrings connection is : " & config.connectionstrings("myDB").ToString()

...it *still* worked.

I did some more digging, after I posted the solution, and the answer is that,
if configPath is a null reference, the root Web.config file is opened!

So, actually, Dim configPath As String = "/" is *not* needed if you want to open the root web.config.

If retrieving a web.config in *any* virtual directory, you'll need to use :

Dim configPath As String = "/someVirtualApp"
Dim config As Configuration = WebConfigurationManager.OpenWebConfiguration(configPath)
Dim config2 As ConnectionStringsSection = WebConfigurationManager.GetWebApplicationSection("connectionStrings")
Dim value as String = "The configured connectionStrings connection is : " & config2.connectionstrings("myDB").ToString()

...that will open the web.config in /someVirtualApp and retrieve the "myDB" connection string.

If you just use :

Dim config As ConnectionStringsSection = WebConfigurationManager.GetWebApplicationSection("connectionStrings")
Dim value as String = "The configured connectionStrings connection is : " & config.connectionstrings("myDB").ToString()

...it will open the root web.config and retrieve the "myDB" connection string.

Finally, if you use :
Dim configPath As String = ""
Dim config As Configuration = WebConfigurationManager.OpenWebConfiguration(configPath)
Dim config2 As ConnectionStringsSection = WebConfigurationManager.GetWebApplicationSection("connectionStrings")
Dim value as String = "The configured connectionStrings connection is : " & config2.connectionstrings("myDB").ToString()

...it will retrieve the current app's web.config and retrieve the "myDB" connection string.

Of course, there's easier ways of accessing the current app's web.config.

These contortions are only needed when accessing
a web.config in a different application, or in the root.

Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
======================================

Good point. Agreed.