This is a third party control not shipped from Microsoft and provides
additional functionality. There are many ASP.NET 3rd party suites that
provide additional features not shipped in System.Web.UI.WebControls,
for example of embedding content inside nodes:
http://www.telerik.com/demos/aspnet/...DefaultCS.aspx
In this approach they are using templates per node to define custom
content per node:
<radt:RadTreeNode Text="Inbox">
<NodeTemplate>
<div class="boldNode">
<%# DataBinder.Eval(Container, "Text")
%>
</div>
<div class="blueNode">
<%# DataBinder.Eval(Container,
"Attributes['New']") %>
</div>
</NodeTemplate>
<radt:RadTreeNode />
Very convenient. But then again it is a custom 3rd party solution and
costs money.