I have a Categories table in which each category has a ParentId that can refer to any other category's CategoryId that I want to display as multi-level HTML list, like so:

<ul class="tree">
    <li>Parent Category
        <ul>
            <li>1st Child Category
                <!-- more sub-categories -->
            </li>
            <li>2nd Child Category
                <!-- more sub-categories -->
            </li>
        </ul>
    </li>
</ul>

Presently I am recursively rendering a partial view and passing down the next category. It works great, but it's wrong because I'm executing queries in a view.

How can I render the list into a tree object and cache it for quick display every time I need a list of all hierarchical categories?