How to: Use the Nodes Iterator

• Aug 01, 2019

This example shows how to collect the key values of all parent nodes displayed within the ASPxTreeList. The TreeListNodeIterator object is used to traverse through the nodes.

C#

using System.Collections.Generic;
using DevExpress.Web.ASPxTreeList;

List<string> nodeKeys;
void ProcessNodes(TreeListNode startNode) {
    if (startNode == null) return;
    TreeListNodeIterator iterator = new TreeListNodeIterator(startNode);
    nodeKeys = new List<string>();
    while (iterator.Current != null) {
        GetParentNodeKey(iterator.Current);
        iterator.GetNext();
    }
}

private void GetParentNodeKey(TreeListNode node) {
    if (node != treeList.RootNode && node.HasChildren)
        nodeKeys.Add(node.Key);
}

VB.NET

Imports System.Collections.Generic
Imports DevExpress.Web.ASPxTreeList

Private nodeKeys As List(Of String)
Private Sub ProcessNodes(ByVal startNode As TreeListNode)
   If startNode Is Nothing Then
   Return
   End If
   Dim iterator As TreeListNodeIterator = New TreeListNodeIterator(startNode)
   nodeKeys = New List(Of String)()
   Do While Not iterator.Current Is Nothing
      GetParentNodeKey(iterator.Current)
      iterator.GetNext()
   Loop
End Sub

Private Sub GetParentNodeKey(ByVal node As TreeListNode)
   If Not node Is treeList.RootNode AndAlso node.HasChildren Then
      nodeKeys.Add(node.Key)
   End If
End Sub