MvcSiteMapProvider bug with pagination - asp.net-mvc

Question

It's continue ASP.NET MVC incorect generation url when using pagination, but there I found how fix it. How fix that when using #Html.MvcSiteMap().SiteMapPath() I can't understand.
Problem in that when in actions ShowForum or ShowTopic and when I using pagination some forum or topic. In #Html.MvcSiteMap().SiteMapPath() I get url at parent page with number of page
UPDATE
For route configuration I'm using route attribute
[HttpGet]
[Route("{forumName}", Name = "showForum", Order = 6)]
[Route("{forumName}/Page/{page}", Order = 5)]
[OutputCache(Duration = 30, VaryByParam = "forumName;page", Location = OutputCacheLocation.ServerAndClient)]
public async Task<ActionResult> ShowForum(string forumName, int page = 1)
[HttpGet]
[RefreshDetectFilter]
[Block(VisibleBlock = false)]
[Route("{forum}/{topicName}", Name = "showTopic", Order = 8)]
[Route("{forum}/{topicName}/Page/{page}", Order = 7)]
[OutputCache(Duration = 30, VaryByParam = "topicName;page", Location = OutputCacheLocation.ServerAndClient)]
public async Task<ActionResult> ShowTopic(string forum, string topicName, int page = 1)
My ForumDynamicNodeProvider
public override IEnumerable<DynamicNode> GetDynamicNodeCollection(ISiteMapNode node)
{
var rootTitle = ManagerLocalization.Get("Forums", "FORUMS");
var pageParameter = new List<string> { "page" };
var url = "~/Forums";
var attr = new Dictionary<string, object> { { "Controller", "Forums" } };
var nodes = new List<DynamicNode>
{
new DynamicNode
{
Key = "forum_home",
Title = rootTitle,
Url = url,
Attributes = attr
}
};
var forums = this._forumsService.GetAllForumsForMap();
var topics = this._forumsService.GetAllTopicsForMap();
foreach (var forum in forums)
{
var forumRouteValue = new Dictionary<string, object> { { "forumName", forum.NameTranslit } };
nodes.Add(new DynamicNode
{
ParentKey = forum.ForumId != -1 ? $"forum_{forum.ForumId}" : "forum_home",
Key = $"forum_{forum.Id}",
Title = forum.Name,
PreservedRouteParameters = pageParameter,
Controller = "Forums",
Action = "ShowForum",
RouteValues = forumRouteValue,
});
var forumTopics = topics.Where(item => item.ForumId == forum.Id);
foreach (var topic in forumTopics)
{
var topicRouteValue = new Dictionary<string, object> { { "forum", forum.NameTranslit }, { "topicName", topic.TitleTranslite } };
nodes.Add(new DynamicNode
{
ParentKey = $"forum_{forum.Id}",
Key = $"topic_{topic.Id}",
Title = topic.Title,
PreservedRouteParameters = pageParameter,
Controller = "Forums",
Action = "ShowTopic",
RouteValues = topicRouteValue,
});
}
}
return nodes;
}

Answer 1

The problem is that you are using the same route key name {page} in two different places in the same node ancestry in combination with PreservedRouteParameters. PreservedRouteParameters gets its data from the current request. So, it is important that a route key have the same meaning in each request in the same node ancestry. For it to work correctly with PreservedRouteParamters, you need to do three things:
Use a different route key for each separate page parameter (for example, {forumPage} and {page}).
Ensure the ancestor page parameter is passed to the request of its descendants, so when building the URL to an ancestor node the value is in the current request. The simplest way is to build the URL with the page information of all ancestors ({forumName}/Page/{forumPage}/{topicName}/Page/{page}).
Any route keys that have the same meaning between nodes should stay the same ({forumName} in both routes).
Then you need to add the parameters when building the URL of the child node. You must build the URL manually within your application because the request will not have all of the parameters unless you do.
#Html.ActionLink("TheTopicName", "ShowTopic", "Forums",
new { forumName = 1, forumPage = 2, topicName = "foo", page = 1 }, null)
The reason you must supply all of the data in the child node request is because the ancestor node needs it to build its URL. It pulls this information from the request, so it must be present in the request for it to function. MvcSiteMapProvider has no way of knowing what the current page number of the ancestor node is unless it is provided in the request by a URL that is built outside of your menu.
See the MvcSiteMapProvider-Forcing-A-Match-2-Levels project in the code download for How to Make MvcSiteMapProvider Remember a User's Position for a similar configuration and the solution. In that case, it is using productId instead of forumPage as the parameter that is preserved on the descendant nodes so you can navigate back to the parent product.
Note that you could use a similar configuration (with PreservedRouteParameters and SiteMapTitleAttribute) for your entire forum rather than using a dynamic node provider. However, in that case I would suggest you disable the /sitemap.xml endpoint and roll your own.

Answer 2

I found how this fix, thank you to NightOwl888. I'm not the first time understood what should to do.
First I removed initialization PreservedRouteParameters in ForumDynamicNodeProvider
Second I added in action
if (forumPage > 1)
{
var node = SiteMaps.Current.FindSiteMapNodeFromKey(forumName);
if (node != null)
{
node.RouteValues["forumPage"] = forumPage;
}
}
Also I need change generation tree in ForumDynamicNodeProvider because SiteMaps.Current doesn't work in async