主题：连续打印

    Dim Book As New XLS.Book(ProjectPath & "Attachments\作废收购单.xls")
    Dim fl As String = ProjectPath & "Reports\作废收购单.xls"
    Book.Build()
    Book.Save(fl)
    Dim App As New MSExcel.Application
    Dim Wb As MSExcel.WorkBook = App.WorkBooks.Open(fl)
    Dim Ws As MSExcel.WorkSheet = Wb.WorkSheets(1)
    Ws.PrintOut
    App.Quit
上述代码如何做到指定几次连续打印？