主题：目录树

Dim dt As DataTable

Dim b As New GroupTableBuilder("统计表1",DataTables("供应商订货总表"))
b.Groups.AddDef("日期",DateGroupEnum.Year,"年")
b.Groups.AddDef("日期",DateGroupEnum.Month,"月")
b.Groups.AddDef("供应商名称","供应商名称")
b.Totals.AddDef("供应商名称",AggregateEnum.Count,"订单数") '根据客户列来统计记录数,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

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

trv.BuildTree(dt, "供应商名称|年|月")

trv.StopRedraw

For Each nd As WinForm.TreeNode In trv.AllNodes

    Dim Year As Integer = nd.DataRow("年")

    Dim Month As Integer = nd.DataRow("月")

    Dim Product As String = "'" & nd.DataRow("供应商名称") & "'"

    Select Case nd.Level

        Case 0

            nd.Text = nd.text & "供应商名称(" & dt.Compute("Sum(订单数)","供应商名称 = " & Product) & "条)"

             Case 1

            nd.Text = nd.text & "年(" & dt.Compute("Sum(订单数)","年 = " & Year & " And 供应商名称 = " & Product) & "条)"

        Case 2

            nd.Text = nd.text & "年(" & dt.Compute("Sum(订单数)","年 = " & Year & " And 供应商名称 = " & Product) & "条)"

    End Select

Next

trv.Nodes.Insert("显示所有行","显示所有行(" & dt.Compute("Sum(订单数)") & "条)",0)

trv.ResumeRedraw