Disabling Collapse event of a root node in Treeview in .NET

I am developing a application in which i need to prevent collap开发者_开发知识库sable behaviour of a root node in tree view. I tried using Before Select event. Is there any alternative for it?

---

You need BeforeCollapse event:

private void OnBeforeCollapse(object sender, TreeViewCancelEventArgs e)
{
    if(!CanCollapse(e.Node)) e.Cancel = true;
}

It assumes you have a CanCollapse function, which determines if node can be collapsed.