asp.net TreeView Expand question

Question

hope you help me with I think a simple TreeView Expand problem.

I have a TreeView control in my MasterPage and my default depth is 2 and I see that when I click on the deeper node it keeps expanded.. But when I redirected into another page, the node collapsed.

I have a problem with my code which suppose to keep the node expanded.

TreeNode thisNode = tvCategories.FindNode(Session["SelectedCIDValPath"].ToString());
if (thisNode != null)
{
    thisNode.Selected = true;
    thisNode.Expand();
    thisNode.Select();
    thisNode.Expanded = true;
    lbl.Text = "valupath: " + Session["SelectedCIDValPath"].ToString();
}

as you can see, I tried all the possible properties and methods to keep the deeper node expanded.. but it doesn't work.

Please help me? Thank you so much

is there any property like MakeSureItsVisible thing? the node was selected though, but parent nodes are not expanded. — jaysonragasa

kbrimington kbrimington · Accepted Answer · 2010-09-01T03:36:35

It happens to be the case (and I find it just a bit frustrating) that expanding a node does not also cause parent nodes to expand. In order to ensure a node expands, it is necessary to also ensure that the parent nodes expand. I keep an extension method handy for this purpose:

public static void EnsureExpanded(this TreeNode node)
{
    if (node != null)
    {
        EnsureExpanded(node.Parent);
        node.Expand();
    }
}

You can employ the extension like so:

TreeNode thisNode = tvCategories.FindNode(Session["SelectedCIDValPath"].ToString());
thisNode.EnsureExpanded();

asp.net TreeView Expand question

1 Answers