主题：请教 目录树功能

Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")

trv.CreateTree("表a","物料级别",".")

For i As Integer  = trv.AllNodes.count - 1  To 0 Step -1

    Dim nd As WinForm.TreeNode = trv.Allnodes(i)

   Dim dr As DataRow = DataTables("表a").Find("物料级别 = '" & nd.FullPath.Replace("\",".") & "'")

    If dr IsNot Nothing

        nd.text = dr("成品型号")

    End If

Next

 想在生成的节点前面加上条件，，

根据客户来生成， 请教大家怎么实现？