I tried using a Session variable and put it in page_load doesnt work...am I suposed to use

Treeview1.SelectedNode.NavigateUrl = Session["Category"];

but I still get Object not set to a reference of an object...If I remove this line...I have the treeview visible with all categories collapsed and I print the value of the session variable so those two things work so basically it feels like that the tag Treeview1.SelectedNode.NavigateUrl is not the right attribute to select a node.

is this something you can confirm or am I in the wrong...I really need to fix this...I have built the entire website and have everything working but this minor snag and I cant figure it out...so this is the only thing I have to fix before taking this site live...