Excel数据透视表应用大全 155页的代码问题

evillenlee

这段代码是创建数据透视表的代码，我想问红色的代码是什么作用？为什么要这三行红色代码？？
Dim ws As Worksheet
    Dim ptcache As PivotCache
    Dim pt As PivotTable
    Dim prange As Range
    Set ws = Sheet1
    For Each pt In Sheet2.PivotTables
        pt.TableRange2.Clear
    Next pt
    Set ptcache = ActiveWorkbook.PivotCaches.Add(SourceType:=xlDatabase, SourceData:=Sheet1.Range("a1").CurrentRegion.Address)
    Set pt = ptcache.CreatePivotTable(tabledestination:=Sheet2.Range("a3"), tablename:="透视表1")
    pt.ManualUpdate = True
    pt.AddFields RowFields:="项目", ColumnFields:="Data"
    For Each prange In ws.Range(ws.Cells(1, 2), ws.Cells(1, 256).End(xlToLeft))
        With pt.PivotFields(prange.Value)
            .Orientation = xlDataField
            .Name = " " & prange
            .Function = xlSum
        End With
    Next prange
    pt.ManualUpdate = False
    pt.ManualUpdate = True