TableCalcs method Sum does not work

Question

Hi all.
I am newcomer in the ADOBE forms world and I am facing the following issue (although I 've been reading posts in SDN and respective manuals for over 3 days)
My form's hierarchy is:
(xfa.form.)
-data
  -MasterPageSet1 (Page Set)
    ---Page1  (Master)
       --ContentArea
       --HeaderData (positioned subform with various elements)
       --FooterData (positioned subform with various elements)
    ---MainWindow (Flowed subform)
       --t_subf (Flowed subform)
        --Table (table which will show data from respective interface table)
           --Header
           --RowData (actual line items)
           --PageSum (table footer)
  Both RowData and PageSum have a decimal field named "DMBTR_S"
  At the end of every page, in the PageSum-DMBTR_S field, I want to sum the page's RowData[*]-DMBTR_S data to produce a "carry Fwd" for the next page.
  Looking through SDN and LiveCycle designer help, I have tried both using JavaScript and using the tableCalcs but with no luck
  Given that I am a newbie in both ADOBE forms and JS, I assume that I am missing some details.
  So, I suppose that the tableCalcs (with the parameters for the current page) can help me the most, without needing me writing JS.
  However, I do not understan at which level in the aforementioned hierarchy should I insert the tableCalcs.
  I tried inserting it under MainWindow subform and renamed the unnamed subform to "tcalc"
  Then, I set PageSum-DMBTR_S field to Calculated-ReadOnly, with Normal Bindin, and I write in the calculate event:
if ( xfa.layout.page(this) == xfa.layout.pageCount())
//I copy the header's amount as the final total :P
this.rawValue = t_subf.TOT.rawValue;
else
//calculate the cummulative from age 0 to current
this.rawValue = MainWindow.tcalc.tableCalcs.Sum("Table.RowData[*].DMBTR_S",0, xfa.layout.absPage(this)-1);
When I preview the PDF inside the Form Builder (trans: SFP), PDF is generated successfully, without any warnings/errors at all.
What am I missing here?
Thank you in advance,
George

Answer 1

Hello Otto and thanks for the reply.
a) I could indeed do it in the backend but that means that I have to hardocde the max number of line items per page. I always prefer to decouple application logic (the printing program) from the presentation medium ( the form). However, that would be me utmost way of doing it, as the time is against me...
b) I understand what you mean, but I don't have a single clue how to do it with Javascript Pretty smart, but I would prefer the (a)  approach, as I can code it way much faster with ABAP in the printing program
c) another solution may be the tableCalcs. This "collection" of objects/methods has already implemented a Sum method which seems to do exactly what I need. I have read both the PDF documents you mention but unfortunately I haven't managed yet to make it work in a... stylish (!!!) way.
In page 103, the "lc_designer_scripting_basics.pdf" offers a JS snippet to "calculate the sum of repeating fields". I have alse tried this approach but it seems that the statement  var fields = xfa.resolveNodes("RowData[].DMBTR_S[]"); doesn't work at all. I have included it in a "try-finally" block and it fails...
Anyway, I will keep trying and come back to the post. If you have done anything similar I would appreciate it if you could post any relevant JS code snippet.
Thanks again,
George