Public Shared Sub Main_nodes(ByVal aTreeView As TreeView)
        Dim loc_il As ImageList = Hauptform.ImageList1
        Hauptform.TreeView1.ImageList = loc_il
 
        For Each knoten As TreeNode In aTreeView.Nodes
            sub_nodes(knoten, loc_il)
        Next
End Sub
Private Shared Sub Sub_nodes(ByVal loc_knoten As TreeNode, ByVal il As _
  ImageList)
        For Each aNode As TreeNode In loc_knoten.Nodes
            If aNode.IsExpanded = True Then
               aNode.ImageIndex = 1 'ein gewünschtes Bild aus der Imagelist
            Else
               aNode.ImageIndex = 2
            End If
            Sub_nodes(aNode, il)
        Next
    End Sub