Dim nms As String() = {"一级分类","二级分类","产品名称"} \'指定生成目录树的各列

Dim qts As String() = {"\'","\'","\'"} \'指定将各列的值括起来的符号,这里都是字符型,所以都是单引号

Dim trv As WinForm.TreeView = e.Sender

Dim flt As String

Dim nd As WinForm.TreeNode

For Each nd In e.node.allNodes \'清除子节点的选中标记

    nd.Checked = False

Next

nd = e.Node.ParentNode

Do While nd IsNot Nothing \'清除父节点的选中标记

    nd.Checked = False

    nd = nd.ParentNode

Loop

For Each nd In trv.AllNodes

    If nd.Checked  Then

        Dim rts() As String = nd.FullPath.Split("\\")

        Dim val As String = ""

        For i As Integer = 0 To rts.length - 1

            If val > "" Then

                val = val & " And "

            End If

            val = val & nms(i) & " = " & qts(i) & rts(i) & qts(i)

        Next

        If flt > "" Then

            flt = flt & " Or (" & val & ")"

        Else

            flt = val

        End If

    End If

Next

Dim a,b As Double

a = Forms("窗口2").Controls("ComboBox1").text

b = Forms("窗口2").Controls("ComboBox2").text

If flt Is Nothing Then

    DataTables("订单").LoadFilter = "[折扣] > " & a & " And [折扣] < " & b

    DataTables("订单").Load

Else

    DataTables("订单").LoadFilter = flt & " And [折扣] > " & a & " And [折扣] < " & b

    DataTables("订单").Load

End If

问题：

  当选择单个节点时满足复合筛选要求，但选择第二个及以上节点节点，附加条件” [折扣] > " & a & " And [折扣] < " & b

”即不起作用。