The SiteMap class retrieves the CurrentNode property by requesting it from the provider.
If no representative node exists for the page in the site map information, or if security trimming is enabled and the node cannot be returned for the current user, nullNothingnullptra null reference (Nothing in Visual Basic) is returned.
The SiteMapResolve event is raised by the default site map provider if one or more subscriptions exist.
If you implement your own SiteMapProvider object, you might create your own mechanism to find and retrieve the CurrentNode. However, if you extend the StaticSiteMapProvider class and use a URL-based scheme to identify pages, you can override the FindSiteMapNode method.