Hi Darryl,
Thank you for showing interest on Syncfusion products.
Using the IsExpanded property and IsVisibility property the expanded mode and visibility of TreeViewAdv can be set. By binding these property of the TreeViewAdv will simplify the usage of properties inside codebehind. We have prepared a sample based on your requirement and we have attached for your reference.
Sample link:
http://www.syncfusion.com/downloads/Support/DirectTrac/General/TreeViewVisibility1660423607.zipLet us know if you have any other queries.
Thank you,
Karthikeyan.