主题：目录树时间

参考代码

'首先生成统计表
Dim dt As DataTable
Dim b As New GroupTableBuilder("统计表1",DataTables("流水表"))
b.Groups.AddDef("日期",DateGroupEnum.Year,"年")
b.Groups.AddDef("日期",DateGroupEnum.Month,"月")
b.Groups.AddDef("材料名称")
b.Totals.AddDef("数量",AggregateEnum.sum,"数量") '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True,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
Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")
trv.BuildTree(dt, "年|月|材料名称")
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("材料名称")
    Select Case nd.Level
        Case 0
            nd.Text = nd.text & "年(" & dt.Compute("Sum(数量)","年 = " & Year) & ")"
        Case 1
            nd.Text = nd.text & "月(" & dt.Compute("Sum(数量)","年 = " & Year & " And 月 = " & Month) & ")"
        Case 2
            nd.Text = nd.text & "(" & nd.DataRow("数量") & ")"
    End Select
Next
trv.Nodes.Insert("显示所有行","显示所有行(" & dt.Compute("Sum(数量)") & ")",0)
trv.ResumeRedraw