Using MvcSiteMap how do I create links to next and previous nodes? - asp.net

Question

I'd like to implement something like the following HTML helpers in MvcSiteMapProvider:
Html.MvcSiteMap().Previous()
Html.MvcSiteMap().Next()
However, I am quite new to their API, is it possible to do that, and if so, how?

Answer 1

You can accomplish this by building custom HTML helpers. I have answered this question already at GitHub and provided a working demo project, but I am copying here for reference.
The logic to walk up and down the document would look something like this, the rest of the code is for the most part boilerplate templated HTML helper code.
private static ISiteMapNode GetNextNode(ISiteMapNode startingNode, IDictionary<string, object> sourceMetadata)
{
ISiteMapNode nextNode = null;
if (startingNode.HasChildNodes)
{
// Get the first child node
nextNode = startingNode.ChildNodes[0];
}
else if (startingNode.ParentNode != null)
{
// Get the next sibling node
nextNode = startingNode.NextSibling;
if (nextNode == null)
{
// If there are no more siblings, the next position
// should be the parent's next sibling
var parent = startingNode.ParentNode;
if (parent != null)
{
nextNode = parent.NextSibling;
}
}
}
// If the node is not visible or accessible, run the operation recursively until a visible node is found
if (nextNode != null && !(nextNode.IsVisible(sourceMetadata) || nextNode.IsAccessibleToUser()))
{
nextNode = GetNextNode(nextNode, sourceMetadata);
}
return nextNode;
}
private static ISiteMapNode GetPreviousNode(ISiteMapNode startingNode, IDictionary<string, object> sourceMetadata)
{
ISiteMapNode previousNode = null;
// Get the previous sibling
var previousSibling = startingNode.PreviousSibling;
if (previousSibling != null)
{
// If there are any children, go to the last descendant
if (previousSibling.HasChildNodes)
{
previousNode = previousSibling.Descendants.Last();
}
else
{
// If there are no children, return the sibling.
previousNode = previousSibling;
}
}
else
{
// If there are no more siblings before this one, go to the parent node
previousNode = startingNode.ParentNode;
}
// If the node is not visible or accessible, run the operation recursively until a visible node is found
if (previousNode != null && !(previousNode.IsVisible(sourceMetadata) || previousNode.IsAccessibleToUser()))
{
previousNode = GetPreviousNode(previousNode, sourceMetadata);
}
return previousNode;
}