[5分]按右键出快捷菜单

Private Sub Form_Load() '加载树内容
    Dim objNode As Node
    Dim rst As DAO.Recordset
    Dim MaxLevel As Integer '最大级别
    Dim I As Integer

    Set objTree = Me.TreeView0.Object
    objTree.Nodes.Clear '这句不可少

    Set objNode = objTree.Nodes.Add(, , "NO.1", "全部材料", "K1", "K2") ' 设置最顶层
        MaxLevel = CurrentDb.OpenRecordset("SELECT 类别等级 FROM CLtype order by 类别等级 desc;")(0).Value

    For I = 1 To MaxLevel

        Set rst = CurrentDb.OpenRecordset("SELECT 类别等级,类别编码,类别名称 FROM CLtype where  类别等级=" & I & ";")

        Do Until rst.EOF

            If rst!类别等级 = 1 Then   '顶层菜单
                Set objNode = objTree.Nodes.Add("NO.1", 4, "NO." & Trim(rst!类别编码), Trim(rst!类别名称), "K1", "K2")
            Else
                Set objNode = objTree.Nodes.Add("NO." & Left(rst!类别编码, (rst!类别等级 - 1) * perSectionLong), 4, "NO." & Trim(rst!类别编码), Trim(rst!类别名称), "K1", "K2")
            End If
            rst.MoveNext
        Loop
    Next
    Me.TreeView0.Nodes(1).Expanded = True
    Call TreeView0_NodeClick(objTree.Nodes(1))

End Sub

想问一下,MaxLevel = CurrentDb.OpenRecordset("SELECT 类别等级 FROM CLtype order by 类别等级 desc;")(0).Value中的0,不知是什么意思?