主题：发现一个奇怪的问题，哪位给解释下。谢谢。

Dim dt As DataTable
Dim b As New SQLGroupTableBuilder("统计表1","企业")
b.Groups.AddDef("所属片区","所属片区")
b.Groups.AddDef("所属分片区","所属分片区")
b.Totals.AddDef("_Identify",AggregateEnum.Count,"企业数") '根据主键列来统计记录数,也就是订单数
dt = b.Build(True) '参数设置为False,生成一个临时表,不在主界面显示
'然后根据统计表生成目录树
Tables("窗口1_table2").DataSource = dt
Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")
trv.BuildTree(dt, "所属片区|所属分片区")
trv.StopRedraw
For Each nd As WinForm.TreeNode In trv.AllNodes
    Dim ph As String  = nd.DataRow("所属片区")
    Dim fph As String = nd.DataRow("所属分片区")
    Dim sl As Integer = nd.DataRow("企业数")
    Select Case nd.Level
        Case 0
            nd.Text = nd.text & "(" & dt.Compute("Sum(企业数)","所属片区 = '"  & ph & "'") & "条)"
       ' Case 1
            'nd.Text = nd.text & "(" & dt.Compute("Sum(企业数)","所属片区 = '" & ph & "' And 所属分片区 = '" & fph & "'") & "条)"
        'Case 2
           ' nd.Text = nd.text & "(" & nd.DataRow("订单数") & ")"
    End Select
Next
trv.Nodes.Insert("加载所有行","加载所有行(" & dt.Compute("Sum(企业数)") & "条)",0)
trv.ResumeRedraw