Load User Control as a treeview node Ondemand

Hi,

   I am using a RadTreeView for displaying certain data in our application.Lets say I need to display 20 records (5 types and 4 records per type. Example: 20 cities where 4 cities each are grouped to a state). In my application I can have upto 200-300 such records real time.

My Approach:

I am populating all the tree view during page load. So in theory, I am creating 20 instances of a user control and adding them to the treeview which is causing a huge performance issue.

What I need:

I need to populate only the parent nodes (5 states from above) and when expanded on a parent node, dynamically add 4 user controls to that node.

Please suggest if there is an example you have (Request to not share examples that just populates text from a data source. You can hard code the number 4 if that makes it easy) or provide an approach for me to execute.

Thanks in advance.

Regards,

Krishna Chaduvula.