Defalut XmlSiteMapProvider implementation cannot use SiteMap.FindSiteMapNode? - mvcsitemapprovider

Question

I just upgrade MvcSiteMapProvider from v3 to v4.6.3.
I see the upgrade note indicate:
In general, any reference to System.Web.SiteMap.Provider will need to be updated to MvcSiteMapProvider.SiteMaps.Current
I am trying to get the sitemap node by using:
SiteMaps.Current.FindSiteMapNode(rawUrl)
But it always return null
I looked into the code. In the sitemap it's actually calling the function:
protected virtual ISiteMapNode FindSiteMapNodeFromUrlMatch(IUrlKey urlToMatch)
{
if (this.urlTable.ContainsKey(urlToMatch))
{
return this.urlTable[urlToMatch];
}
return null;
}
It's trying to find a match in the urlTable.
I am using Default implementation of XmlSiteMapProvider .
It define var url = node.GetAttributeValue("url");
siteMapNode.Url = url;
siteMapNode.UrlResolver = node.GetAttributeValue("urlResolver");
So if I did not define url or urlResolver attribute in the .sitemap file. These variables a set to empty string, when generate the node.
And when this nodes are passed to AddNode function in SiteMap.
When adding the node
bool isMvcUrl = string.IsNullOrEmpty(node.UnresolvedUrl) && this.UsesDefaultUrlResolver(node);
this code will check if there is url or urlResolver
// Only store URLs if they are clickable and are configured using the Url
// property or provided by a custom URL resolver.
if (!isMvcUrl && node.Clickable)
{
url = this.siteMapChildStateFactory.CreateUrlKey(node);
// Check for duplicates (including matching or empty host names).
if (this.urlTable
.Where(k => string.Equals(k.Key.RootRelativeUrl, url.RootRelativeUrl, StringComparison.OrdinalIgnoreCase))
.Where(k => string.IsNullOrEmpty(k.Key.HostName) || string.IsNullOrEmpty(url.HostName) || string.Equals(k.Key.HostName, url.HostName, StringComparison.OrdinalIgnoreCase))
.Count() > 0)
{
var absoluteUrl = this.urlPath.ResolveUrl(node.UnresolvedUrl, string.IsNullOrEmpty(node.Protocol) ? Uri.UriSchemeHttp : node.Protocol, node.HostName);
throw new InvalidOperationException(string.Format(Resources.Messages.MultipleNodesWithIdenticalUrl, absoluteUrl));
}
}
// Add the URL
if (url != null)
{
this.urlTable[url] = node;
}
Finally no url is add to the urlTable, which result in FindSiteMapNode cannot find anything.
I am not sure if there needs to be specific configuration. Or should I implement custom XmlSiteMapProvider just add the url.

Answer 1

ISiteMapNodeProvider instances cannot use the FindSiteMapNode function for 2 reasons. The first you have already discovered is that finding by URL can only be done if you set the url attribute explicitly in the node configuration. The second reason is that the SiteMapBuilder doesn't add any of the nodes to the SiteMap until all of the ISiteMapNodeProvider instances have completed running, so it would be moot to add the URL to the URL table anyway.
It might help if you explain what you are trying to accomplish.
The ISiteMapNodeProvider classes have complete control over the data that is added to the SiteMapNode instances and they also have access to their parent SiteMapNode instance. This is generally all that is needed in order to populate the data. Looking up another SiteMapNode from the SiteMap object while populating the data is not supported. But as long as the node you are interested in is populated in the same ISiteMapNodeProvider instance, you can just get a reference to it later by storing it in a variable.
Update
Okay, I reread your question and your comment and it now just seems like you are looking in the wrong place. MvcSiteMapProvider v4 is no longer based on Microsoft's SiteMap provider model, so using XmlSiteMapProvider doesn't make sense, as it would sidestep the entire implementation. The only case where this might make sense is if you have a hybrid ASP.NET and ASP.NET MVC application that you want to keep a consitant menu structure between. See Upgrading from v3 to v4.
There are 2 stages to working with the data. The first stage (the ISiteMapBuilder and ISiteMapNodeProvider) loads the data from various sources (XML, .NET attributes, DynamicNodeProviders, and custom implementations of ISiteMapNodeProvider) and adds it to an object graph that starts at the SiteMap object. Much like Microsoft's model, this data is stored in a shared cache and only loaded when the cache expires. This is the stage you have been focusing on and it definitely doesn't make sense to lookup nodes here.
The second stage is when an individual request is made to access the data. This is where looking up data based on a URL might make sense, but there is already a built-in CurrentNode property that finds the node matching the current URL (or more likely the current route since we are dealing with MVC) which in most cases is the best approach to finding a node. Each node has a ParentNode and ChildNodes properties that can be used to walk up or down the tree from there.
In this second stage, you can access the SiteMap data at any point after the Application_Start event such as within a controller action, in one of the built in HTML helpers, an HTML helper template in the /Views/Shared/DisplayTemplates/ directory, or a custom HTML helper. This is the point in the application life cycle which you might call the lines SiteMaps.Current.FindSiteMapNode(rawUrl) or (more likely) SiteMaps.Current.CurrentNode to get an instance of the node so you can inspect its Attributes property (the custom attributes).
public ActionResult About()
{
ViewBag.Message = "Your app description page.";
var currentNode = MvcSiteMapProvider.SiteMaps.Current.CurrentNode;
string permission = currentNode.Attributes.ContainsKey("permission") ? currentNode.Attributes["permission"].ToString() : string.Empty;
string programs = currentNode.Attributes.ContainsKey("programs") ? currentNode.Attributes["programs"].ToString() : string.Empty;
string agencies = currentNode.Attributes.ContainsKey("agencies") ? currentNode.Attributes["agencies"].ToString() : string.Empty;
// Do something with the custom attributes of the About page here
return View();
}
The most common usage of custom attributes is to use them from within a custom HTML helper template. Here is a custom version of the /Views/Shared/DisplayTemplates/SiteMapNodeModel.cshtml template that displays the custom attributes. Note that this template is called recursively by the Menu, SiteMapPath, and SiteMap HTML helpers. Have a look at this answer for more help if HTML helper customization is what you intend to do.
#model MvcSiteMapProvider.Web.Html.Models.SiteMapNodeModel
#using System.Web.Mvc.Html
#using MvcSiteMapProvider.Web.Html.Models
#if (Model.IsCurrentNode && Model.SourceMetadata["HtmlHelper"].ToString() != "MvcSiteMapProvider.Web.Html.MenuHelper") {
<text>#Model.Title</text>
} else if (Model.IsClickable) {
if (string.IsNullOrEmpty(Model.Description))
{
#Model.Title
}
else
{
#Model.Title
}
} else {
<text>#Model.Title</text>
}
#string permission = Model.Attributes.ContainsKey("permission") ? Model.Attributes["permission"].ToString() : string.Empty
#string programs = Model.Attributes.ContainsKey("programs") ? Model.Attributes["programs"].ToString() : string.Empty
#string agencies = Model.Attributes.ContainsKey("agencies") ? Model.Attributes["agencies"].ToString() : string.Empty
<div>#permission</div>
<div>#programs</div>
<div>#agencies</div>