<h1>
    TreeView Accordion
</h1>
<p>
    The control below looks like an Accordion but is really
    a TreeView with some CSS and a <b>formatItem</b>
    event handler.
</p>
<p>
    The tree automatically expands the selected item
    and collapses all others, and ensures only top-level
    nodes can be selected:
</p>
<p>
    Selected item: <b><span id="selected"></span></b>
</p>
@Html.C1().TreeView().Id("theTree")