Problems with ppRegion using KeepTogether

rbuser

Hi,

I designed a report that it's has a ppRegion with two lines in the
DetailBand and it's KeepTogether property is True. I have too a code in
AfterPrint event that sum the value of a field of the record in a variable.
Otherwise, at the end of some page that it's doesn't fit the ppRegion
completely, not with standing the AfterPrint event of the DetailBand is
fired. Therefore, the value of the sum, at this page, is wrong, because the
ppRegion will be printed on next page. And, in the next page, then event is
fired again. I try the OnPrint event of ppRegion too.

What I can make to resolve this problem??

Thank's,


Weverton Gomes

nicocizik

Hi Weverton,

Try using the OnCalc event of the variable to calculate the sum. This is
the only event in RB that is guaranteed to fire only once per traversal. We
recently made some enhancements to this event in order to handle dynamic
detail bands across pages for RB 9. Take a look at the following article
for more information on making calculations inside a report.

----------------------------------------------------------------------
TECH TIP: Performing Calculations
----------------------------------------------------------------------

Calculations can be done either on the data access side or within
ReportBuilder.

When designing reports there are always decisions to be made as to how much
processing to do on the data side versus the report side. Usually doing
more on one side can greatly simplify the other. So it is often a personal
choice based on the power and flexibility of the data and report tools being
used.


DataAccess
----------

a. Use SQL - using SQL you can perform many common calculations:

example: Select FirstName + ' ' + LastName As FullName,
Quantity * Price AS Cost,


b. Delphi TDataSets enable you to create a calculated TField object and use
the DataSet.OnCalcFields event

c. Perform any amount of data processing, summarizing, massaging etc. to
build a result set (query or temp table) to feed to the report.


ReportBuilder
-------------

Calculations in ReportBuilder are performed primarily using
the TppVariable component.

a. Set the Variable.DataType

b. Code the calculations using the Variable.OnCalc event.

c. Use the Timing dialog to control the timing of the OnCalc event. To
access the Timing dialog, right click over the Variable component and select
the Timing... option from the speed menu.

d. Set the LookAhead property to True, when you need to display summary
calculations in the title, header, group header, etc.

e. To perform calculations based on the results of other calculations use
the Calc Order dialog of the band. To access the Calc Order dialog, right
click over the Band component and select the Calc Order... option from the
speed menu.


By using TppVariable components ReportBuilder will take care of caching
intermediate results of accumlated calcs that cross pages.

There are a number of calculation examples in the main demos.dpr project.

---

Additional Notes:

1. Do NOT use Band.BeforePrint or Band.AfterPrint. These events fire
multiple times and therefore should not be used for calculations.

2. Do NOT store results in variables that exist outside of the reports.
For example - form level variables.


--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com