ReportDesigner

rbuser

We wrote our own custom events to print reports on Dot Matrix printers.

When the form previewer is presented, we want to call our own print
method when the printer icon is clicked.


How can we accomplish this ???


Thank you.


Neil Huhta

digitalmetaphors

Create a custom previewer. Descend from TppPreview and override this method
to call you own print routine.

procedure PerformPreviewAction(aPreviewAction: TppPreviewActionType);

Register you new preview class and you're good to go.


...


{@TppMyPreview}

TppMyPreview = class(TppPreview)
private
procedure MyPrint;

public
procedure PerformPreviewAction(aPreviewAction: TppPreviewActionType);
override;

end; {class, TppMyPreview}

implementation

uses
ppTypes;

procedure TppMyPreview.MyPrint;
begin
{do your printing code}
beep;
end;

procedure TppMyPreview.PerformPreviewAction(aPreviewAction:
TppPreviewActionType);
begin

if (aPreviewAction = paPrint) then
MyPrint

else
inherited PerformPreviewAction(aPreviewAction);

end; {procedure, PerformPreviewAction}


{***************************************************************************
***
*
** I N I T I A L I Z A T I O N / F I N A L I Z A T I O N
*
{***************************************************************************
***}



initialization
TppPreviewPlugin.UnRegister(TppPreview);
TppPreviewPlugIn.Register(TppMyPreview);

finalization
TppPreviewPlugIn.UnRegister(TppMyPreview);
TppPreviewPlugIn.Register(TppPreview);




Cheers,

Jim Bennett
Digital Metaphors

rbuser

Jim:

Thanks - that makes sense. How does my ppReport component know to use
the descendent previewer ???

Neil Huhta

digitalmetaphors

The magical replacement of the previewer is handled in the registration
calls in the initializatoin/finalization section:)

Cheers,

Jim Bennett
Digital Metaphors

rbuser

Jim:

Is there a way to use the custom previewer ONLY in certain areas of my
program ( for instance in the Reports.Pas unit and the InvReports.Pas unit
only ) ???



Neil

digitalmetaphors

The registration mechanism is called in the intialization finalization
sections of a unit, but you can call these methods anytime you want. Before
you call the Report.Print in one of your pas files, you can unregister the
current previewer, then register a new previewer, call print, then
unregister the new previewer and reregister the old previewer.

Instead of registering the previewer in the intialization/finalization
section, do it only in the few cases where you need a special previewer:

..
TppPreviewPlugin.UnRegister(TppPreview);
TppPreviewPlugIn.Register(TppMyPreview);

ppReport1.Print;

TppPreviewPlugIn.UnRegister(TppMyPreview);
TppPreviewPlugIn.Register(TppPreview);
..

Cheers,

Jim Bennett
Digital Metaphors