Post+Back = Headache, 2 Questions

[LacrosseB0ss]

Hey folks, I have a page from ASP.net and it runs VB code off it. I am having AutoPostBack problems with 2 objects on the form: (1) TreeView and (2) Table.

1. When an item is selected from a dropdown list, items corresponding to the selected item are entered into a TreeView with the selected item as the root node then other nodes split alphabetically (A, B, C would be the nodes, etc) and finally the leaves are the items. Using VB, TreeTopic_SelectedIndexChange I am checking if a leaf is selected and expanding/contracting if not. If it is, then the selected leaf is displayed in a label. The problem is, every time ANY node is clicked (root, branch or leaf), the form posts back. Can this be stopped? I have no problem with the form doing it when the button is clicked or when a leaf is selected, but how can I just expand the form if a branch is clicked?

2. I also have a table object that stores a list of people. Columns: ID#, Fisrt Name, Last Name. The table works fine but when the page postsback, the rows in the table are lost. Is there a way to keep them? Or a work-around? I sort of need the postback to happen here, but I need the data too.

Thanks in advance all, my apologies for the semi-lengthy post.
- LB