How to: Prohibit Collapsing Nodes
The sample code below represents an ASPxTreeView.ExpandedChanging event handler. The event handler prevents collapsing nodes if it has selected children in any generation.
Note
A complete sample project is available at https://github.com/DevExpress-Examples/how-to-prevent-parent-node-collapsing-e2439
using DevExpress.Web.ASPxTreeView;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void ASPxTreeView1_ExpandedChanging(object source, DevExpress.Web.ASPxTreeView.TreeViewNodeCancelEventArgs e) {
if ((e.Node.Expanded) && (ASPxTreeView1.SelectedNode != null)) {
TreeViewNode node = ASPxTreeView1.SelectedNode.Parent;
while (node != null) {
if (e.Node == node) {
e.Cancel = true;
break;
}
node = node.Parent;
}
}
}
}