query string parameters for sitemap

I'm using VWD 2010, ASP.NET with C#. I found a pointer for how to do this in another SO post. Unfortunately, I can't get it working.

The sample code it points to is here: http://weblogs.asp.net/jgaylord/adding-querystring-parameters-to-the-sitemapnode

I have included the C# code for this, but I can't seem to get the program to recognize that the code is actually there. I set break points that never get invoked.
I put this into the web.config:

    <siteMap enabled="true">
      <providers>
        <clear/>
        <add name="ExtendedSiteMapProvider" type="Configuration.ExtendedSiteMapProvider" siteMapFile="web.sitemap" securityTrimmingEnabled="true" />
<!--
        <add siteMapFile="Web.sitemap" name="AspNetXmlSiteMapProvider" type="System.Web.XmlSiteMapProvider" securityTrimmingEnabled="true"/>
    -->    
      </providers>
    </siteMap>

Notice how AspNetXmlSiteMapProvider is commented out. That name appears nowhere else in the file. Nevertheless when I attempt to run my program, I get this error message: The provider 'AspNetXmlSiteMapProvider' specified for the defaultProvider does not exist in the providers collection.

If I uncomment that line, the program runs, but the new code is never invoked. Any ideas?

That's because you are not specifying the defaultProvider which defaults exactly to AspNetXmlSiteMapProvide, like you can see here.

So you just have to specify the defualt provider like this:

<siteMap enabled="true" defaultProvider="ExtendedSiteMapProvider">
  <providers>
    ....
  </providers>
</siteMap>

Or specify the provider in corresponding SiteMpaDataSource property, so that the default isn't used.