Deleting groups from a report during run-time while preview is showing

rbuser

Hi,
I am not able to delete groups from my report using a plug-in in the
standard report preview.
Here's what I've found out. The code below works fine when fired from a
button on a form with a TppViewer object.
ppReport1.Groups[0].Free;
ppViewer1.RegenerateReport;

If I call a similar code from a custom report plug-in in the standard RB
preview, I get an AV:

(Viewer.CurrentPage.Producer as TppReport).Groups[0].free;
Viewer.RegenerateReport;

Here's a different approach in the form with a TppViewer:

ppReport1.RemoveBand(ppReport1.Groups[0].HeaderBand);
ppReport1.RemoveGroup(ppReport1.Groups[0]);
ppViewer1.RegenerateReport;

..works fine.


Similar code for using the plug-in on a standard RB preview window:

with (Viewer.CurrentPage.Producer as TppReport) do
begin
RemoveBand(Groups[0].HeaderBand);
RemoveGroup(Groups[0]);
end;
Viewer.RegenerateReport;

When above code is executed it does not give me an AV, but the group's
header band is still showing once for each page on my report. The RemoveBand
is not working here.

What is the correct way of deleting groups from a report?

I am using D7, RB702 on Win XP.
Morten

nicocizik

Morten,

When using the TppViewer, you can access the report component by using the
Viewer.Report property. Your code should look something like the following:

Viewer.Report.Groups[0].Free;
Viewer.RegenerateReport;

--

rbuser

Nico,
Thanks, but that's the method that only works on a custom viewer, but not
with the standard RB viewer.

Please take a look at this project
http://www22.brinkster.com/obergman/rbProject.zip which shows the standard
preview not working, and a custom TppViewer working - both using the same
method of freeing the group.

Here's the code that is fired by the plugin (button on the left in the
preview window) that generates an AV:
= = = =
var
ActiveReport: TppReport;
begin

activeReport:= (Viewer.Currentpage.Producer as TppReport);
//activeReport.DetailBand.Objects[0].Free; //<-- this works!

if activeReport.GroupCount > 0 then
activeReport.Groups[0].free;

Viewer.RegenerateReport;
end;
= = = =

Thanks,
Morten

nicocizik

Morten,

Freeing components inside the a call to Report.Print is not supported by
ReportBuilder. We will research this further. A better way to handle this
is to set the group bands' visibility to False and disable the NewPage
property. Below is a link to an example that demonstrates hiding the group
bands in a custom preview.

http://www.digital-metaphors.com/tips/ClickToHideGroup.zip

--

rbuser

Nico,
Thanks for looking into this. Changing the visibility won't work that well
since I need to re-generate the report with the new
groups/fields/sorts/calculations etc. It would be really neat to have a form
(own report designer) open on top of the preview form and apply changes to
the report on the fly. For our users (who are not very technical adept) the
designer that comes with RB is too advanced for them, so we simply want to
let them select which fields to display and what to group on etc, and it
would help them a lot if this could be visualized. Maybe support for group
freeing could be added to the wish list.

Thanks,
Morten

nicocizik

Morten,

Thanks for the suggestion. The Preview in ReportBuilder was not intended to
be used as a designer. The archetecture of the entire ReportBuilder
application is set up so most, or all, report design must be done before the
report is generated. You will need to create a form with a TppViewer on it
and make multiple calls to Report.PrintToDevices to achieve the the effect
you are after.

--