Events in Delphi

Comments

• gordk St.Catherines On. Canada.

  June 2010 edited 10:16AM

  John Pendule wrote: »

  Hello,
  
  I start programming with FastReport and I have a question about the events.
  
  What is the best way to use the report's events in Delphi? For exemple, how can I launch code in delphi when the BeforePrint event of the report occurs.
  gk the best way is what suits your needs, nothing particular.
  the onbefore print event of the tfrxreport component fires for every object in the reportdesign, each time it is encountered.
  typical sample code
  procedure TForm1.frxReport1BeforePrint(Sender: TfrxReportComponent);
  var
  idx2: integer;
  mymemo2: tfrxmemoview;
  begin
  // does not fire for page so start with titleband
  if sender.name = 'ReportTitle1' then
  begin
  mymemo2 := frxreport1.findobject('Memo3')as tfrxmemoview;\\ use find object method
  idx2 := frxreport1.Script.Variables;
  mymemo2.memo.add(inttostr(idx2)+' **** external obp event fired for titleband');
  mymemo2.memo.add(' NOTE the obp event handler of the tfrxreport component fires for every object in the report');
  mymemo2.memo.add(' did not write code in the event for every object just note external fires before internal');
  inc(idx2);
  frxreport1.Script.Variables:= idx2;
  end;
  if sender.name = 'PageHeader1' then
  begin
  mymemo2 := frxreport1.findobject('Memo3')as tfrxmemoview;
  idx2 := frxreport1.Script.Variables;
  mymemo2.memo.add(inttostr(idx2)+' **** external obp event fired for page header band');
  inc(idx2);
  frxreport1.Script.Variables:= idx2;
  end;
  end;
  
  
  I want to translate my old QuickReport reports to FastReport. I used the OnStartPage et OnEndPage events. How can I translate these events?
  Thank you for your answer.
  gk
  onstart usually translates to onbeforeprint onend usually translates to onafterprint.
  it may have a different context if the report is a multidesignpage report.
  the code above is a sampl bit from a demo for newbies in the frbinaries news group

  
  You can also use the find object method to find an object and modify its properties
  after a report design is loaded and before showreport or prepare report is called.
  
  
• John Pendule

  June 2010 edited 10:16AM

  OK but that's mean that I must have a page header and a page footer band. If I want to write a generic code, I must verify if these two bands exist and create them if not after loading the report.
  If my page header and my page footer band have its height equal 0, is the before print event works?
  
  Best regards
• gordk St.Catherines On. Canada.

  June 2010 edited 10:16AM

  if a band has a 0 height the events still fire, in some very complex reports, this can be utilized
  to have events available for use (ie seed variable values etc).
  
  you dont have to have a page header and a page footer.
  
  A band is just a place holder on the design page, the bands are processed from top down according to their type, basicly they control the report engine's output to the finished page, the band is not output only the objects it contains.
  
  Be very careful when altering design heights of bands from delphi if you make the height to small
  you can widow objects to the page.
  read the programmers manual mostly as working from delphi
  and the users manual mainly as working inside the report.