Assembly: System.Web (in system.web.dll)
A lookup key with which a SiteMapNode is created.
Return ValueA SiteMapNode that represents the page identified by key; otherwise, a null reference (Nothing in Visual Basic), if security trimming is enabled and the site map node cannot be shown to the current user or the site map node is not found in the site map node collection by key.
The FindSiteMapNodeFromKey method retrieves a site map node from an internal Hashtable object based on key.
The XmlSiteMapProvider object, which is derived from the StaticSiteMapProvider class and is the default site map provider for ASP.NET, uses the Url property of a SiteMapNode object as a lookup key in its internal collections, by default. If the Url property of the SiteMapNode is set, it must be unique within the scope of the site map provider. The FindSiteMapNode method attempts to retrieve site map nodes based on their Url. Otherwise, you can use the Key property and the corresponding FindSiteMapNodeFromKey method to retrieve site map nodes.
The StaticSiteMapProvider has a default implementation that looks up instances of the SiteMapNode class based on the key parameter. If a site map provider implementer used the AddNode method, the StaticSiteMapProvider already will have stored a reference to each SiteMapNode based on the value of the SiteMapNode.Key property. By default, the XmlSiteMapProvider generates GUIDs for instances of the SiteMapNode class that do not have a value for the SiteMapNode.Url property. Custom site map provider implementers must provide their own mechanism for generating unique values of the SiteMapNode.Key property in the event that an instance of the SiteMapNode class does not have a value for the SiteMapNode.Url property.
The SiteMapProvider and XmlSiteMapProvider classes, which are the default site map provider implementation for ASP.NET, use the URL of a SiteMapNode object as a key in the various collections that the classes maintain.