<p>In the final implementation of the TreeView control, by default at least, there is no viewstate information being passed along (except when you click the "+" or "-" and have Client Script disabled). When you click on a link, it's just a standard link (usually to a different page altogether).
<p>Given this, when you click a link it's going to reload the page to the default depth specified in ExpandDepth. In your case, the tree shouldn't be COMPLETELY collapsed, but should be open to one level.
<p>My ideal would be for the tree to be collapsed on load wtih the exception of the path to the current node; this approach may be of value to you as well. This way large TOCs aren't fully expanded but the user still has feedback as to where they are at in the navigation. This behavior can be implemented with a simple function similar to:
<p>void RevealDescendents(TreeNode treeNode) {
<br> if (treeNode == null) return;
<br> treeNode.Expand = true;
<br> if (treeNode.Parent != null)
<br> RevealDescendents(treeNode.Parent);
<br> }
<p>Here you would save the SelectedNode to a TreeNode object, call objTreeView.CollapseAll() and pass this function the SelectedNode so you end up with a "viewstate" that is at least relevent to the current page.
<p>Unfortunately, however, this approach doesn't work with databinding, apparently, <a HREF="/1122525/ShowPost.aspx">as reported in my recent post</a>.