TreeView efficiency

Hi,

I'm currently using a treeview control in ASP.NET to display a list of records hierachically.

Each row has 4 levels, and the customer wants the user to select within a tree hierachically amongst these levels. There are approx 250 rows.

e.g. Top nodes contain all possible values of level 1, expanding these show all the possible values of level 2 (under each level 1) .. etc ..

I'm currently loading the nodes by looping through the rows (which are sorted) and adding nodes as children where appropriate.

The problem being that the final tree has therefore around 800 nodes ... and loading the Microsoft Treeview is very slow.

Is there:

a) A better way of loading nodes in TreeView?
b) A more efficient Tree control to use?


Thanks,
Tim