Accesing public properties on a custom previewer

rbuser

Hi,

I've created a custom previewer, much along the lines of the demo (i.e,
TMyPreviewPlugin = class(TppPreview)...) and I've added an extra button to
the preview form (which I default to invisible in the CreateToolbarItems
block)...
Private
FCustomButton: TppTBXItem;

I have a corresponding public property....

property CustomButtonVisible: boolean read fCustomButtonVisible write
SetCustomButtonVisible;

where SetCustomButtonVisible procedure sets the visibility of fCustomButton.

procedure TMyPreviewPlugin.SetCustomButtonVisible(value: Boolean);
begin
fCustomButtonVisible := Value;
if Assigned(fCustomButton) then
begin
fCustomButton.Visible := fCustomButtonVisible;
fCustomButton.Invalidate;
end;
end;


How can I, and, when do I access this property from my delphi form
containing a report? I've tried using the report's OnPreviewFormCreate
event but this doesn't seem to trigger for me (break point is never reached)
. I had more luck with the reports OnAssignPreviewFormSettings event

procedure TFormrptrbCRMReports.ppReport1AssignPreviewFormSettings(
Sender: TObject);
begin
TMyPreviewPlugIn(ppReport1.PreviewForm).CustomButtonVisible := True;
end;

when this event fires and I trace into the code for SetCustomButtonVisible
above the Assigned(fCustomButton) returns false?? What am I doing wrong
please?

TIA

nicocizik

Willie,

The Report.PreviewForm property does not represent a TppPreview object.
It is the preview form itself. (see the ppPrvDlg.pas file).

The TppPrintPreview object (or preview form) contains some pass thru
properties for accessing each existing button as well as a pass thru to
the toolbar. You can use the toolbar property to access your custom button.

uses
ppPrvDlg;

TppPrintPreview(ppReport1.PreviewForm).Toolbar[MyButtonIndex].Visble :=
False;

rbuser

Thanks Nico,

Ummm I'm not sure I understand this but anyway I've tried your suggestion
and figured out a work-around, thanks for that.

One question though please, in my Plugin object I have some public
properties/methods declared, is it not actually possible to access these
from a report form?

nicocizik

Hi Willie,

The previewer consists of the following parts:
- TppPrintPreview: The preview form
- TppPreview: The default preview plugin (creates toolbars, viewer,
menus, etc. on the preview form)
- TppPreviewPlugin: Manages and registers preview plugins.


The Report object itself only has access to the preview form, not the
preview plugin. This means that any custom routines/properties created
in the plugin will not be accessible.

rbuser

Thanks Nico.