Using Report Explorer and Loading From File

rbuser

Greetings,

I would like to use the ppReportExplorer but load the template from a file
rather than from the RB_ITEM.TEMPLATE field.

Does anyone have an example of how I could do this? Is there already a demo
on how to do this? Any tips appeciated. I'm just a little lost on how to
do this.

--
Michael Tuttle
Software Technologies, Inc.
Topeka, KS

nardmoseley

The ReportExplorer is designed to work with DataPipelines. Therefore the
approach to this solution would be use JITPipelines. However, the
JITPipeline does not currently implement the GetFieldAsStream method that is
used to access the report template data. You would need to create a
JITPipeline descendant and add this support.


--
Nard Moseley
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Greetings Nard,

My component developing skills are somewhat limited. Any chance I could get
your help creating this descendant and adding this GetFieldAsStream method
you talk about. If you could do this I could test it. If not, if you could
provide a little more assistance on how to do this it would be much
appreciated.

Thanks,

Mike

nardmoseley

Below is some sample code (I did not compile or test it) that creates a
descendant of TmyJITPipeline and overrides the GetFieldAsStream method
declared in the ancestor. The method fires a new OnGetFieldAsStream event.
This enables an event-handler to be implemented that could load the .rtm
file into a TFileStream and copy it to the aStream parameter passed to the
event.


uses
ppDB, ppDBJIT, ppTypes;


type

TppGetFieldAsStreamEvent = procedure (aFieldName: String; aStream:
TStream) of object;


TmyJITPipeline = class(TppJITPipeline)
private
FOnGetFieldAsStream: TppGetFieldAsStreamEvent ;
public
procedure GetFieldAsStream(aFieldName: String; aStream: TStream);
override;

property OnGetFieldAsSteam: TppGetFieldAsStreamEvent read
FOnGetFieldAsStream write FOnGetFieldAsStream;
end;


{---------------------------------------------------------------------------
---}
{ TmyJITPipeline .GetFieldAsStream }

procedure TmyJITPipeline.GetFieldAsStream(aFieldName: String; aStream:
TStream);
begin
if Assigned(FOnGetFieldAsStream) then FOnGetFieldAsStream(aFieldName,
aStream);

end;







--
Nard Moseley
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Greetings Nard,

Ok, I created the descendant per your instruction, however I have not used a
JitPipeLine before or the descendant we created for that matter. When I now
drop the descendant on the ReportExplorer form I'm guessing I need to
replace the TppPipeline component for the RB_ITEM table? But I do not see a
datasource on the TmyJitPipeline descendant. I must be missing something or
must be dense. How will using a JitPipeline component help me to achieve
loading a report template form a file instead of from a database as it does
now. Again, I want to use the ReportExplorer interface but load form a file
instead of the RB_ITEM.TEMPLATE field. What am I missing here?

Thanks

Mike

nardmoseley

I may hvae misunderstood your original question. I thought that you did not
want to use the rbItems and rbFolders tables at all. Sounds more like, you
want to use them, but store the reports to .rtm files?

If the above is the case, then another approach might be to create a
calculated field for the TDataSet and using the DataSet.OnCalcFields event
to load the data.You could use the BeforePost or AfterPost event to save the
Report.Template to a file.

The JITPipeline is entirely event-handler based. It is really designed for
read-only access to in-memory data-structures such as an Array or List of
objects, etc. Sorry, but after thinking about further, I do not think the
JITPipeline is appropriate. In addition to the GetfieldAsStream it does not
contain events for saving/updating information.



--
Nard Moseley
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Greetings Nard,
not
the

Yes, I do want to use the rbFolders and rbItems table. But instead of
storing the report template to the TEMPLATE field of the RB_ITEM table, I
was going to add a report template name field a(REPORT_TEMPLATE_FILENAME) to
this table and then simply instruct the internal report component to load
the report template from the report template named in that field.

My question is, how do I instruct the report explorer to NOT load from and
save to the TEMPLATE field, but instead load a template from a file when
using the report explorer. I know how to do it with the ppReport component
outside of this report explorer. Is there some internal way to load this
report template? I hope I'm making myself clear in that I'm asking how to
load an external report template into the internal report component of your
report explorer.

Thanks

Mike

nardmoseley

Try creating a custom report explorer form. See
RBuilder\Tutorials\Complete\Applications.


--
Nard Moseley
Digital Metaphors Corporation
http://www.digital-metaphors.com