[2.0] session problem

i have a problem with a session and i cant figure it out on my own :( so i hope someone can help me. ok,here's the problem: i have a TreeViewState.cs that saves the state of the treeview and expands the nodes and a collapse code, they work fine with except one thing, the state is saved with the node expanded after the node is visited, but in the same time if i go to another node the collapse code goes into action and collapses the previous node. the problem is that when i want to revisit a previous node it wont expand because it's saved expanded, and not collapses as it should be. how can i modify the SaveState class so it will "update" the state of the nodes, or the collapse code.they stay on a master page and the treeview is generated via db, no xml file or SitemapDataSource exist.Other info: the nodes have a url property, and the the redirect is made by a server.transfer code. any help would be great. THX

Code:

---

public class TreeViewState
{

    public static bool IsTreeViewStateSaved(TreeView LinksTreeView, string key)
    {

        bool isSaved = (HttpContext.Current.Session[key + LinksTreeView.ID] != null);
        return isSaved;

    }

    public static void SaveTreeView(TreeView LinksTreeView, string key)
    {
        HttpContext.Current.Session[key + LinksTreeView.ID] = LinksTreeView.Nodes;

    }

    public static void RestoreTreeView(TreeView LinksTreeView, string key)
    {
        if (IsTreeViewStateSaved(LinksTreeView, key))
        {
            LinksTreeView.Nodes.Clear();
            TreeNodeCollection nodes = (TreeNodeCollection)HttpContext.Current.Session[key + LinksTreeView.ID];
            for (int index = nodes.Count - 1; index >= 0; index += -1)
            {
                LinksTreeView.Nodes.AddAt(0, nodes[index]);
            }

            HttpContext.Current.Session[key + LinksTreeView.ID] = null;
        }
    }

}

---

collapse code:

Code:

---

protected void TreeView1_TreeNodeExpanded(object sender, TreeNodeEventArgs e)
{

if (e.Node.Parent == null)
return;

string strNodeValue = e.Node.Value;foreach (TreeNode node in e.Node.Parent.ChildNodes)
{

if (node.Value != strNodeValue)
{

node.Collapse();

HttpContext.Current.Session.Clear();
}

}

}

---