Skipping records

rbuser

Is it possible to skip special records with RAP?

Thanks,
Juergen.

digitalmetaphors

Yes, but you'll need to create a RAP pass through function. See the main
reports demo project. Report #116 skips records. However, it calls the
SkipBack method on the pipeline and this isn't surfaced in RAP. Probably the
best thing to do is create two RAP pass though functions to SkipForward and
SkipBackward. Pass the datapipeline as a parameter of the function. There
are examples of creating RAP pass thorugh functions in the installation in
the Demos\Rap directory. There are also tutorials in the RAP.hlp file and in
the Developer's Guide PDF on pass through functions.


Cheers,

Jim Bennett
Digital Metaphors

rbuser

I have been trying to find a way to do this, as well, without setting the
Detail Band visible to False. I tried making the passthrough functions for
the SkipForward and SkipBackward. Is there a way to have the evaluation of
whether the record should be skipped in RAP instead of hidden inside the
passthough function? I tried the DetailBeforeGenerate but that only lets you
skip one record at a time. So if there are more that one "skippable" records
in a row, the second one is displayed because the DetailBeforeGenerate is
not fired again.

digitalmetaphors

Ok, what you'll have to do is create a new class. Register this class so
that RAP can use RTTI to use its published properties. This class is going
to be a TppCommunicator descendent. Now, the goal is to listen to event
using the communicator rather than the delphi evnet handlers you are used
to. In the RAP global OnCreate you should create this communicator and free
it in the OnDestroy. You'll make a call to your pass through function in the
global OnCreate event after you create this new object.

In your RAP pass through function, pass this object as a parameter and also
the data pipeline. Now in the RAP pass through code in Delphi, you can hook
up the event notification relationship by calling
DataPipeline.AddEventNotify(MyCommunicatorObject). Then in your communicator
object, override the EventNotify method and create a case statement on the
aEventID parameter. Check for ciPipelineFirst, ciPipelineLast,
ciPipelineNext, ciPipelinePrior. These are the notifications that are sent
at the same time the Delphi event handlers are triggered. ppTypes will need
to be in your uses clause.

So, by using a communicator object, you can perform the 4 calls to the two
skip routines in the class. All that has to be done in RAP is surface your
new class type and to make a new pass through function that uses this class
to initialize it with the pipeline of the report. Then the object just
listens as the report is running and does the work you need it to. Instead
of using the TTable component, simply reference the Pipeline['FieldName'] =
SomeValue technique. You should store a reference to the pipeline from the
initial pass through call. Then you'll need a published property to assign
the string you want to limit the records by in the skip methods.

It is a little complicated, but it should work just fine. Let me know if you
have any questions about this approach.

Cheers,

Jim Bennett
Digital Metaphors

rbuser

Right for the pass through function, but why can I use the Eof function
et can't use the Next ?

Philippe Constant
CTRL Informatique

digitalmetaphors

Next is a procedure and is not made visible in RAP through the RAP RTTI for
TppDataPipeline ancestor. EOF is a property and is made available through
the RAP RTTI for the TppDBPipeline descendent. You'll have to create a RAP
pass through function (pass the datapipeline as a parameter of the function)
in order to call Next on the pipeline.

Cheers,

Jim Bennett
Digital Metaphors