Web.config in virtual directory is not overriding parent website's Web.config

Question

I've got a website which has a virtual directory that also includes a website, and when I try to launch a page from the virtual directory, I receive an IIS 7.5 error that the name (from the connection string) is already in the collection. This wasn't a problem before I added a domain user as the Identity in the app pool. Does anyone know why this is happening? I was under the impression that sub level application's web.config overrides the parent's by default. And again, this was once working until I added a custom Identity.

The error on the page is "Parser Error Message: The entry 'dbname' has already been added."

Where the dbname is in both connection strings (i.e. parent and virtual directory). I can't delete one of the connection strings because the virtual directory is only created for test purposes, but in production it runs as its own website.

Answer 1

A sub web.config doesn't override a parent regardless of application. All web.configs will stack up all the way to the root of the primary application. In order for sub-application folder to make use of a connection string key that is already in use it must first be removed or all connection strings must be cleared. If you want this to be a truly stand alone application as a child add this to your connection strings:

<connectionStrings>
    <clear />
    <your connection string>
<connectionStrings>

If you just want to remove the single connection string use this:

<remove key="yourConnectionStringName" />