Access violation on designtime (in a BoldDataPipeline) - Delphi 7

rbuser

Hi @ everyone!

My name's Sebastian ( call me "Kringel", if you want ;-), I'm an apprentice
on software development from Germany, and currently I'm working on a new
Pipeline. I've derived it from TppCustomDataPipeline and it connects
BOLD-based databases (via BoldListHandles) with reportBuilder.
I am using Digital Metaphor's default field editor to create new fields on
this pipeline.

Now my problem is that I can't change property "FieldName" of a field on
designtime: When I try to accept changes to FieldName, Delphi stops with an
access violation in module rtl70.bpl.

Tried to debug Delphi itself with another instance of Delphi runnin as host
application to reach call stack, but it is empty and "Debug-Delphi" just
gives the same violation...

Does anyone know this kind of behaviour and/or has any clues?

Thanks in advance and greetings from good ol' Germany,
Sebastian Kranz.

nicocizik

Hi Sebastian,

Design time bugs can be tricky to track down. My first suggestion would be
to see if you are able to successfully change a field at runtime in Delphi
code. If this does not give the same AV, you will need to start placing
messages in your code (either using ShowMessage(), or a debugging
application such as CodeSite) to actually see which event/routine of yours
is executing just before the AV occurs and hopefully track down the issue.

--
Regards,

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

rbuser

Hey again and thanks for your information!

Got my first problem worked out but now i've got a new one :-[

I've made up my own "pop-up menu on component"-menu to enable access to
function "create default fields" (my boss wants it). When I now open the
(default) field editor by double-clicking on my component again I get an
access violation - "in module dclRBE107" Delphi says.

Now how to fix this?

nicocizik

Hi Sebastian,

Again, try this at runtime and see if you can track down where the AV is
occuring. Take a look at the CreateDefaultFields routine in the
TppCustomDataPipeline class and see what could be causing a problem in your
case. If you are unable to create this at runtime you will need to use the
same techniques I described in my previous post to trace the code at
designtime. My first guess would be to check the GetFieldForIndex routine
that you are required to implement.

--
Regards,

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