Friend Function Treeview_CloneNodes(ByVal SourceTreeview As TreeView) As _
  TreeView
        Dim TargetTreeview As New TreeView
        TargetTreeview = SourceTreeview
 
        Try
            For i As Integer = 0 To SourceTreeview.Nodes.Count - 1
                Dim tnc As TreeNode = CType(SourceTreeview.Nodes(i).Clone, _
                  TreeNode)
                TargetTreeview.Nodes.Add(tnc)
            Next i
 
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
 
        Return TargetTreeview
    End Function

  Me.trvCategory = XMLTreeView.Treeview_CloneNodes( _
    dlDocumentDialog.trvCategoryList)