I am just starting to use the treeview and the sitemap together. This is a very simple sitemap and treeview.

the problem is that: according to the sitemap there is a root "home" and then there are 2 nodes "work Visa" and "skilled work visa". each of those nodes have subnodes or child nodes.

the tree view works fine in the fist level of nodes. But if I open 1 of the main nodes to expose the child nodes all is ok but if I click on a child node it navigates to that page just fine but the treeview coplapses itself and returns to the initial state where nothing is selected on it at all.

I hope I make myself clear. When you click on a main node (the 2 top ones below "home") it navigates to that page and that node changes its apearance to show that it is the selected node. If I click on the arrow next to the node then the node opens and exposes its child nodes.... but you go click on one of the child nodes it navigates to that page but the treeview retuirns to the initial not selected state all colapsed and all...

you can witness this at:

http://www.canadawelcome.ca/home.aspx?AspxAutoDetectCookieSupport=1

why?

<asp:SiteMapDataSource ID="SiteMapDataSource3" runat="server"
                        SiteMapProvider="TBH_SiteMapProvider" StartFromCurrentNode="False" />

                <asp:TreeView SkinID="MainLeftTree" ID="TreeView1" cssclass="LeftTreeViewMenu" runat="server" ImageSet="Arrows" Style="vertical-align: top; background-color: #FFE4E1; color: darkred;
        width: 100%; text-align: left; padding: 5px;" DataSourceID="SiteMapDataSource3" MaxDataBindDepth="20">
                    <ParentNodeStyle Font-Bold="False" />
                    <HoverNodeStyle Font-Underline="True" ForeColor="#5555DD" />
                    <SelectedNodeStyle Font-Underline="True" ForeColor="#5555DD"
                        HorizontalPadding="0px" VerticalPadding="0px" />
                    <NodeStyle Font-Names="Verdana" Font-Size="8pt" ForeColor="Black"
                        HorizontalPadding="5px" NodeSpacing="0px" VerticalPadding="0px" />
    </asp:TreeView>

this is my site map:

<?xml version="1.0" encoding="utf-8" ?>
<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" enableLocalization="true" >
   <siteMapNode title="HOME" url="~/home.aspx">
       <siteMapNode title="WORK VISA" url="~/WorkVisas/WorkVisas.aspx">
               <siteMapNode title="JOB DESCRIPTION" url="~/WorkVisas/JobDescription.aspx" />
          </siteMapNode>
       <siteMapNode title="SKILLED WORK VISA" url="~/SkilledWorkVisas/SkileedWorkVisaGC.aspx">
         <siteMapNode title="Who can apply" url="~/SkilledWorkVisas/WhoCanApplyGC.aspx" />
         <siteMapNode title="How to apply" url="~/SkilledWorkVisas/HowToApplyGC.aspx" />
         <siteMapNode title="Simplyfied application process" url="~/SkilledWorkVisas/SimplyfiedAppGC.aspx" />
       
       </siteMapNode>
          </siteMapNode>
</siteMap>

The treeview does not maintain the selected item when you navigate to a new page.

One way to overcome this is to put something in the url that signifies which node was selected and use that to programmatically set the selected node when the new page loads.

What language are you writing in? 

In C#.  Place this code in your master page .cs file

using System;
using System.Web.UI.WebControls;
using System.Collections.Generic;

public partial class Site_master : System.Web.UI.MasterPage
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //
        // Disable ExpandDepth if the TreeView's expand/collapse
        // state is stored in session.
        //
        if (Session["TreeViewState"] != null)
            TreeView1.ExpandDepth = -1;
    }

    protected void TreeView1_DataBound(object sender, EventArgs e)
    {
        if (Session["TreeViewState"] == null)
        {
            //
            // Record the TreeView's current expand/collapse state.
            //
            List<string> list = new List<string>(16);
            SaveTreeViewState(TreeView1.Nodes, list);
            Session["TreeViewState"] = list;
        }
        else
        {
            //
            // Apply the recorded expand/collapse state to the TreeView.
            //
            List<string> list = (List<string>)Session["TreeViewState"];
            RestoreTreeViewState(TreeView1.Nodes, list);
        }
    }

    protected void TreeView1_TreeNodeCollapsed(object sender, TreeNodeEventArgs e)
    {
        if (IsPostBack)
        {
            List<string> list = new List<string>(16);
            SaveTreeViewState(TreeView1.Nodes, list);
            Session["TreeViewState"] = list;
        }
    }

    protected void TreeView1_TreeNodeExpanded(object sender, TreeNodeEventArgs e)
    {
        if (IsPostBack)
        {
            List<string> list = new List<string>(16);
            SaveTreeViewState(TreeView1.Nodes, list);
            Session["TreeViewState"] = list;
        }
    }

    private void SaveTreeViewState(TreeNodeCollection nodes, List<string> list)
    {
        //
        // Recursivley record all expanded nodes in the List.
        //
        foreach (TreeNode node in nodes)
        {
            if (node.ChildNodes != null && node.ChildNodes.Count != 0)
            {
                if (node.Expanded.HasValue && node.Expanded == true && !String.IsNullOrEmpty(node.Text))
                    list.Add(node.Text);
                SaveTreeViewState(node.ChildNodes, list);
            }
        }
    }

    private void RestoreTreeViewState(TreeNodeCollection nodes, List<string> list)
    {
        foreach (TreeNode node in nodes)
        {
            //
            // Restore the state of one node.
            //
            if (list.Contains(node.Text))
            {
                if (node.ChildNodes != null && node.ChildNodes.Count != 0 && node.Expanded.HasValue && node.Expanded == false)
                    node.Expand();
            }
            else
            {
                if (node.ChildNodes != null && node.ChildNodes.Count != 0 && node.Expanded.HasValue && node.Expanded == true)
                    node.Collapse();
            }

            //
            // If the node has child nodes, restore their state, too.
            //
            if (node.ChildNodes != null && node.ChildNodes.Count != 0)
                RestoreTreeViewState(node.ChildNodes, list);
        }
    }
}