asp.net treeview expand only selected parent

Question

Im using Treeview in asp.net if i select any parent node then it should be expand and other parents shoulb be collapsed after page postback(navigation)...im using code below.

 protected void Page_Load(object sender, EventArgs e)
{
 if (!IsPostBack)
        {
            if (Session["TreeViewState"] != null)
            {
                List<string> list = (List<string>)Session["TreeViewState"];
                RestoreTreeViewState(TreeViewApplicationSetup.Nodes, list);
            }
        }
        else
        {
            List<string> list = new List<string>(100);
            SaveTreeViewState(TreeViewApplicationSetup.Nodes, list);
            Session["TreeViewState"] = list;
        }
}



 private void SaveTreeViewState(TreeNodeCollection nodes, List<string> list)
    {
        Session["TreeViewState"] = null;
        foreach (TreeNode node in nodes)
        {
            if (node.ChildNodes != null)
            {
                if (node.Expanded.HasValue && node.Expanded == true && !String.IsNullOrEmpty(node.Text))
                {
                    list.Add(node.Text);
                }
                if (node.ShowCheckBox == true && node.ChildNodes.Count == 0 && node.Parent.Expanded == true)
                {
                    if (node.Checked == true)
                    {
                        list.Add(node.ValuePath + "-T");
                    }
                    else
                    {
                        list.Add(node.ValuePath + "-F");
                    }
                }
                SaveTreeViewState(node.ChildNodes, list);
            }
        }
    }
    private void RestoreTreeViewState(TreeNodeCollection nodes, List<string> list)
    {
        foreach (TreeNode node in nodes)
        {

            if (list.Contains(node.Text) || list.Contains(node.ValuePath + "-T") || list.Contains(node.ValuePath + "-F"))
            {
                if (node.ChildNodes != null && node.ChildNodes.Count != 0 && node.Expanded.HasValue && node.Expanded == false)
                {
                    if (node.Parent != null)
                    {
                        if (list.Contains(node.ChildNodes[0].ValuePath + "T") || list.Contains(node.ChildNodes[0].ValuePath + "-F"))
                        {
                            node.Expand();
                        }
                    }
                    else
                    {
                        node.Expand();
                    }
                }
                else if (node.ChildNodes != null && node.Expanded.HasValue && node.Expanded == false)
                {
                    if (node.ShowCheckBox == true && list.Contains(node.Parent.Text) && list.Contains(node.Parent.Parent.Text))
                    {
                        if (list.IndexOf(node.ValuePath + "-T") != -1)
                        {
                            node.Checked = true;

                        }
                        else if (list.IndexOf(node.ValuePath + "-F") != -1)
                        {
                            node.Checked = false;

                        }
                    }
                }
            }
            else
            {
                if (node.ChildNodes != null && node.ChildNodes.Count != 0 && node.Expanded.HasValue && node.Expanded == true)
                {
                    node.Collapse();
                }
            }
            if (node.ChildNodes != null && node.ChildNodes.Count != 0)
            {
                RestoreTreeViewState(node.ChildNodes, list);
            }
        }
    }

its jsut help me to expand parent nodes in every postback but othere parents node didnt collapsed....

can anybody know solution for this?

user274139
– user274139

2010-02-19 05:50:55 +00:00
Commented Feb 19, 2010 at 5:50 — user274139
– user274139, Commented Feb 19, 2010 at 5:50

v0id · Accepted Answer · 2011-07-27 08:48:03Z

3

In your .aspx file:

...
<asp:TreeView ID="Tree" runat="server" OnSelectedNodeChanged="Tree_SelectNodeChange">
...

Then in codebehind Page_Load you just binding data to the TreeView and in OnSelectedNodeChanged handler you need to collapse all nodes and then expand selected node and all it's parents:

protected void Tree_SelectNodeChange(object sender, EventArgs e)
{
    var tree = (TreeView)sender;
    foreach (TreeNode node in tree.Nodes)
    {
        node.CollapseAll();
    }
    ExpandToRoot(tree.SelectedNode);
}

private void ExpandToRoot(TreeNode node)
{
    node.Expand();
    if (node.Parent != null)
    {
        ExpandToRoot(node.Parent);
    }
}

edited Jul 27, 2011 at 8:48

answered Jul 27, 2011 at 7:40

v0id

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1 Comment

brichins Over a year ago

I was trying to do something similar, mixed with the Expand event, and it was a nightmare - recursion for anything below the root node. I looked at this three times before it clicked that I should handle just the select event. Will probably add some jQuery to keep the other root nodes collapsed.

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