TppEngine.GetNextPage - LastPageCached always 0 after FirstPassCompleted

rbuser

Hello Folks!

I am struggling with a report I have inherited in Delphi 7 and now
migrated to Delphi XE2 with ReportBuilder 14.06. For most customers the
report works fine but there is one customer where TppEngine.Generate
gets into an infinite loop as it calls GetNextPage. The first pass is
completed (e.g. FirstPassCompleted = True), the AbsolutePageNo = 2 but
the LastPageCached always 0. This causes the AbsolutePageNo to be set
back to 0 too.

You can find a call stack of the situation I am facing here:
http://www.maranatha-consulting.com/Delphi/RB-Infinite-Loop.html

In my case TppReport was asked to print to a PDF file. The report should
have at least 24 pages. The report consists of 59 sub-reports.

What can I do to narrow this down to the data, which is printed into
DBMemo controls that can stretch and why it is only happening for a very
small number of clients?

Salut,
Mathias

nicocizik

Hi Mathias,

Do you see this behavior only with this single report or are there
others that also demonstrate it? Does this occur when viewing the
report on screen, printing to a printer, or only when exporting to PDF?

To narrow down what might be causing the problem, I would suggest trying
to simplify the report as much as possible. Try removing all (or most)
event code and see if that helps. If so, periodically begin adding it
back to isolate the problem. You can also do this with the numerous
subreports you have. Try setting all of them to Visible := False, then
periodically toggle their visibility to see if you can isolate the problem.

rbuser

Hello Nico,

Thanks for you reply.

rbuser

Mathias wrote:
Hello Nico,

I have found the TppDBMemo control that caused the problem. It was
linked to a field called PhoneContactFrequency of the DataPipeline
plParent. If I replace that with a TppMemo and assign the
TField.AsString to the Lines.Text property it is working. Funny enough
if I use TppMemo.Text := TField.AsString I run into the same infinite loop.

I bought ReportBuilder Standard, so I can't check what the setter of
TppMemo.Text does in comparison to TppMemo.Lines.Text. All I know is
that my DB fields contain CRLFs here and there.

To avoid an infinite loop if new text is entered into the DB should I
replace the TppDBMemo controls with TppMemo at least for this sub-report?

Salut,
Mathias

rbuser

Mathias wrote:
Hello Nico,

I am afraid I forgot to set TppMemo.Stretch to True for
PhoneContactFrequency. If I do so I run into the same infinite loop as I
did with the data-aware TppDBMemo. In my event handler for the
particular detail band I now assign a fixed text to the TppMemo.Lines to
see when it fails.

...
meoPhoneContactFrequency.Lines.Clear;
meoPhoneContactFrequency.Lines.Add('1st Line');
meoPhoneContactFrequency.Lines.Add('2nd Line');
...

is fine but

...
meoPhoneContactFrequency.Lines.Clear;
meoPhoneContactFrequency.Lines.Add('1st Line');
meoPhoneContactFrequency.Lines.Add('2nd Line');
meoPhoneContactFrequency.Lines.Add('3rd Line');
...

fails.

I also tried to replace all CRLFs in the PhoneContactFrequency with the
text . If I assign the amended string (e.g. 'Text LineText
Line...') it will work.

So there must be a setting in the sub-report for PhoneContactFrequency
that differs form the other PhoneContact* sub-reports. Yet, I haven't
been able to spot it. I checked for other clients that if their
PhoneContactFrequency had multiple lines it would print/export to PDF
fine. All sub-report detail bands have a PrintHeight of phDynamic and
the chained sub-reports have set their ShiftRelativeTo to the
predecessor (except for the first one). All TppMemo controls are
instructed to stretch.

I really don't know why those PhoneContactFrequency values for this
single customer causes the report to go into an infinite loop?!?

Salut,
Mathias

nicocizik

Hi Mathias,

If you try to simplify the report even further by removing all other
subreports except for the PhoneContactFrequency one, do you still get
the same behavior?

Now that you've narrowed down the problem, would it be possible to send
me a simple example I could run here? Perhaps using TClientDatasets. If
so, please send the example in .zip format to
support@digital-metaphors.com and I'll research a solution for you.