TList.sort

rbuser

I'm trying to call the "sort" method on a TList object in my RAP code but
the compiler doesn't like it. Is the "sort" member exposed to RAP? If not,
then what TraTppxxxRTTI object do I need to descend from to expose it
myself.

I'm using version 10.04

Paul

rbuser

AFAIK because TList doesn't deend from TPersistent but TObject, you can not
do that. You need to create your own via a pass-through function.

HTH,
Ed Dressel
Team DM

rbuser

Sorry, I don't understand: if TList is exposed to RAP, along with some of
its methods list Add(), why can't I just expose Sort() as well? My Tlist is
created dynamically so I'm not sure what persistance has to do with it. Or
maybe I'm missing something fundamental here?

Thanks, Paul

nardmoseley

- One option is to use a TStringList. TStringList includes support for Sort
and enables you to store a string and associated object.

- RAP RTTI support for TList is defined in raObjectRTTI, the class name is
TraTListRTTI. The TList.Sort method requires that a call back function be
passed as a parameter - the callback function performs the item Comparisons.
You cannot pass a RAP function as a callback - so it is not going to work.
(You could probably descend from TList and create a DoSort method that does
not require the callback function).


--
Nard Moseley
Digital Metaphors
www.digital-metaphors.com

rbuser

Thanks Nard

It has to be a Tlist because I need to sort on any number of fields in then
objects (of the same class) that it is listing. I'll look into descending a
TList with a range of sort methods, but surely I would then need to
re-implement the exposing of this new class to RAP, which is going to
replicate all of what you have already done with TList and RAP? If so then
are there any gotchas or minimum requirements,? I ask because you don't make
raObjectRTTI.pas available for me to consult/copy.


Paul

nardmoseley

I just emailed you the TraTListRTTI source code.

--
Nard Moseley
Digital Metaphors
www.digital-metaphors.com\

rbuser

Nard, top draw support again, many thanks. I'm stretching the envelope a bit
with RB at the moment but I'm regularly astonished by how far I can take it.
I've 10 yrs experience of having to work with Crystal Reports and if I were
forced to do some of the stuff I'm doing in RB at the moment in CR I'd have
to hold me head in my hand and weep! Keep it up

Paul