主题：想要目录树前两级节点双击不加载数据

Dim dr As DataRow = e.Node.DataRow

Dim Filter As String
Dim Year As Integer = dr("年")
Dim Month As Integer = dr("月")
Dim Product As String =Right(dr("号码"),15)

Select Case e.Node.Level
    Case 0
          Filter = "[_Identify] is null"         
    Case 1
          Filter = "[_Identify] is null"

    Case 2
          Filter ="Year(订单日期) = " & Year & " And Month(订单日期) = " & Month & " And 订单号码 = '" & Product & "'"
End Select
DataTables("订单明细").LoadFilter = Filter
DataTables("订单明细").Load()

窗口的目录树双击代码如上，在双击第一级和第二级节点的时候，有报错 Invalid parameters for Select method.  ，  第三级节点正常

该怎么改？ 我的要求是，前面两级节点双击后，不加载数据