How get the same expanded nodes after refresh the page

[Andres]

hi, is there any easy way to show the expanded nodes so that when you save the data, refresh the page and coming back, you still have the same nodes expanded as when you left?. In more details, I have a radtreeview and the user can add or edit nodes, expanding direferents branches. Then when the user clicks the Save button the data is saved on the database and the radtreeview is shown with all nodes collapsed.
In the code I must do some business cheks so when the user clicks the Save button I save the data, I deletes all nodes in the radtreeview, I create (populate) the radtreeview again bringing the data from the database; then I try to expand those nodes that were expanded but this last thing does not work.
The code I use is the next:

if (!DuplicateExists)
                    {
                        oBF.SaveManageLines(oAIlevel3List);

                        // Delete all nodes in the RadTreeView.

                        for (int a = 0; a < trTaxonomy.Nodes.Count; a++)
                        {
                            RadTreeNode oAICategory = trTaxonomy.Nodes[a];
                            for (int b = 0; b < oAICategory.Nodes.Count; b++)
                            {
                                RadTreeNode level1Node = oAICategory.Nodes[b];
                                if (level1Node.Nodes != null && level1Node.Nodes.Count > 0)
                                {
                                    for (int c = 0; c < level1Node.Nodes.Count; c++)
                                    {
                                        RadTreeNode level2Node = level1Node.Nodes[c];
                                        if (level2Node.Nodes != null && level2Node.Nodes.Count > 0)
                                        {
                                            for (int d = 0; d < level2Node.Nodes.Count; d++)
                                            {
                                                level2Node.Nodes.Clear();
                                            }
                                        }
                                    }
                                    level1Node.Nodes.Clear();
                                }
                            }
                            oAICategory.Nodes.Clear();
                        }
                        trTaxonomy.Nodes.Clear();

                        // Create the RadTreeeView again, bringing the values from the DB.

                        string[] ParamArray = new string[4];
                        int iLevelID = 1;
                        ParamArray[0] = iLevelID.ToString();
                        ParamArray[1] = "0";
                        ParamArray[2] = _PartnershipID.ToString();
                        ParamArray[3] = "1";
                        //BusinessFascade.Taxonomy oBF = new BusinessFascade.Taxonomy();
                        oBF = new BusinessFascade.Taxonomy();
                        dsAICategory = oBF.GetAllCategory(ParamArray);
                        foreach (AICategory ai in dsAICategory)
                        {
                            rootNode = new RadTreeNode(ai.Name);
                            rootNode.Value = ai.ID.ToString();
                            rootNode.Text = ai.Name + " (" + ai.TaxonomyCount + ")";
                            rootNode.Expanded = false;
                            rootNode.Checkable = false;
                            rootNode.AllowEdit = false;
                            rootNode.ExpandMode = TreeNodeExpandMode.ServerSideCallBack;
                            trTaxonomy.Nodes.Add(rootNode);
                        }
                        rootNode = new RadTreeNode("State");
                        rootNode.Value = "-999";
                        rootNode.Text = "State";
                        rootNode.Expanded = false;
                        rootNode.Checkable = false;
                        rootNode.AllowEdit = false;
                        rootNode.ExpandMode = TreeNodeExpandMode.ServerSideCallBack;
                        trTaxonomy.Nodes.Add(rootNode);

                        //Added node to show State Source Income Categories
                        rootNode = new RadTreeNode("State Source Schedule");
                        rootNode.Value = "-2";
                        rootNode.Text = "State Source Schedule";
                        rootNode.Expanded = false;
                        rootNode.Checkable = false;
                        rootNode.AllowEdit = false;
                        rootNode.ExpandMode = TreeNodeExpandMode.ServerSideCallBack;
                        trTaxonomy.Nodes.Add(rootNode);


                        // Expand the nodes. Review why is not working.
                        for (int w = 0; w < oAICategoryList.Count; w++)
                        {
                            ExpandNode(oAICategoryList[w]);
                        }
                        for (int z = 0; z < level1NodeList.Count; z++)
                        {
                            ExpandNode(level1NodeList[z]);
                        }
                        for (int y = 0; y < level2NodeList.Count; y++)
                        {
                            ExpandNode(level2NodeList[y]);
                        }
                        trTaxonomy.ExpandAllNodes();
                    }
                }

[Andres]

I forget, the ExpandNode() method is the method that expand the nodes.