Unable to delete child nodes of a parent node (Devexpress TreeList)

I am trying to delete focused node along with it's all child nodes (if any) from TreeList. The problem is I am unable to retrieve the child nodes. I tried 2 approaches:

1. I used TreeListNodeIterator which returns a TreeListNodes object containing childs of the focused row:

   Public Class TreeListOperationGetChildNodes
           Inherits TreeListOperation
           Private _child_nodes As TreeListNodes
   
       Public Sub New(tree As TreeList)
           _child_nodes = New TreeListNodes(tree)
       End Sub
   
       Public Overrides Sub Execute(node As DevExpress.XtraTreeList.Nodes.TreeListNode)
           _child_nodes.Add(node)
       End Sub
   
       Public ReadOnly Property ChildNodes() As TreeListNodes
           Get
               Return _child_nodes
           End Get
       End Property
   
   End Class
   

This child_nodes object is then used to delete all nodes from TreeList:

Dim child_nodes As TreeListNodes = New TreeListNodes(DataTreeList)
Dim op As New TreeListOperationGetChildNodes(DataTreeList)
Dim nodes As TreeListNodes = New TreeListNodes(DataTreeList)
DataTreeList.NodesIterator.DoLocalOperation(op, nodes)
child_nodes = op.ChildNodes 

For Each node As TreeListNode In child_nodes
   DataTreeList.DeleteNode(node)
Next

2. Another Approach I tried was to Loop through all the nodes of the treelist and see if their parent_id is equals to focused node id. If yes then put them into a stack. At the end, for each node in stack call delete node.

   Dim nodeStack As New Stack(Of DevExpress.XtraTreeList.Nodes.TreeListNode)
   nodeStack.Push(DataTreeList.FocusedNode)
   FillStack(DataTreeList.FocusedNode, nodeStack)
   For i As Integer = 0 To nodeStack.Count - 1 Step +1
       DataTreeList.DeleteNode(nodeStack.Pop)
   Next
   
   Private Sub FillStack(ByVal node As DevExpress.XtraTreeList.Nodes.TreeListNode, ByVal nodestack As Stack(Of DevExpress.XtraTreeList.Nodes.TreeListNode))
       For Each childnode As DevExpress.XtraTreeList.Nodes.TreeListNode In DataTreeList.Nodes
   
           If DirectCast(DataTreeList.GetDataRecordByNode(childnode), Data).ParentID = _
              DirectCast(DataTreeList.GetDataRecordByNode(node), Data).ID Then
   
               nodestack.Push(childnode)
               FillStack(childnode, nodestack)
   
           End If
       Next
   End Sub
   

The issue with above code snippets:

1. Here the node iterator is returning chlid_nodes empty (no child nodes found)
2. In FillDeleteStack DataTreeList.Nodes contains only 2 nodes that is only parent nodes. So stack is always empty.

I can not understand why I am not able to iterate through child nodes. Why the collection of nodes in TreeList contains only parent nodes and not child nodes?

0. To delete focused node along with it's all child nodes you can simply use TreeList.DeleteNode method:

DataTreeList.DeleteNode(DataTreeList.FocusedNode)

1. You are using TreeListNodes(TreeList) constructor which creates an empty nodes collection. If you want to get the collection of existing nodes than you can use TreeList.Nodes or TreeListNode.Nodes properties:

nodes = DataTreeList.Nodes
' or
nodes = DataTreeList.FocusedNode.Nodes

2. TreeList.Nodes property returns the collection of the TreeList's root nodes. If you want to get all visible nodes in TreeList then you can use TreeList.GetNodeList method.