OnBeforePrint called several times ?!?

Comments

• Slashmaster

  October 2011 edited 1:58PM

  Hello,
  
  maybe u have to disable the two-pass option (Report -> Options -> General)
  
  greetz
• gordk St.Catherines On. Canada.

  October 2011 edited 1:58PM

  i would like to see the code from the reports code page. Also where is the memo located that you are printing the variable value? ie which band?
  Note: there are some cases where it is better to increment a variable in the obp of the memoview rather than the band.
• thefreecat

  October 2011 edited 1:58PM

  Slashmaster wrote: »

  maybe u have to disable the two-pass option (Report -> Options -> General)

  
  1) I didn't say all amounts were doubled, only some of them who are at the limit of 2 pages (so hard to find the culprit, believe me)
  2) I tried calculating the total only when Engine.FinalPass which doesn't help
  
• thefreecat

  October 2011 edited 1:58PM

  gordk wrote: »

  i would like to see the code from the reports code page.

  
  This is the relevant code.
  - totphono is the running total
  - The variable "ligne" helped me see the OBP was called twice for some records.
  - The frxMVEN.idtmpven / lastligne is a serialization (workaround) I added to make sure my total was counted only once
  

  procedure MasterData2OnBeforePrint(Sender: TfrxComponent);
  begin
    ligne:=ligne+1;
    with MasterData2, Engine do
    begin
      if <frxMVEN."idtmpven"> <> lastLigne then begin                                                       
        totphono:=totphono+<frxMVEN."brutad">;
        // other calculations not involving totphono
        lastligne:=<frxMVEN."idtmpven">;
      end;
    end
  end;
  

  gordk wrote: »

  Also where is the memo located that you are printing the variable value? ie which band?

  
  The report is a little complex, I will try to make it clear how it's supposed to work :
  
  Main report contains :
  - MasterBand1
  - DetailBand1 (contains subreport1 and only subreport1)
  - totphono is reset to zero in DetailBand1's OBP
  - Child2 (child of DetailBand1) : this is where the "totphono" value is printed
  
  SubReport1 contains :
  - GroupHeader1 based on DetailBand1's datasource (printed when DB1 changes)
  - GroupHeader3 based on MasterData2's datasource
  - MasterData2 : his OBP is called twice sometimes
  - Child1 linked to MasterData2, only printed when report is in "debug" mode (prints more details). Since this changes the layout, it also changes the total.
  - GroupFooter3 (no totals printed but stretchable because text can be long)
  - Child14 linked to GroupFooter3 : just a horizontalline that must be printed underneath GF3
  - GroupFooter1 (counterpart of GroupHeader1). This prints a sum(<frxMVEN."brutad">) which is correct (and how I found the bug)
  
  If I print "totphono" on the MasterData2 line, I see the running total and on top of "some"pages, I can see that the last value has been added twice
  

  gordk wrote: »

  Note: there are some cases where it is better to increment a variable in the obp of the memoview rather than the band.

  
  Also tried this but didn't help, the memo's OBP is called twice also.
  
  Let me know if you want me to send you the .FR3 or a PDF demonstrating the bug.
  
• gordk St.Catherines On. Canada.

  October 2011 edited 1:58PM

  yes zip up the .fr3 and also a .fp3 of the output.
  the culprit seems to be about here
  - MasterData2 : his OBP is called twice sometimes
  
• thefreecat

  October 2011 edited 1:58PM

  gordk wrote: »

  yes zip up the .fr3 and also a .fp3 of the output.

  Attached.
  

  gordk wrote: »

  the culprit seems to be about here
  - MasterData2 : his OBP is called twice sometimes

  100% agree ;-)
  
  I added yellow-background fields to demonstrate the problem. From left to right :
  - unique identifier (frxMVEN."idtmpven")
  - running total
  - "ligne" (number of times MasterData2's OBP has been called)
  
  I have disabled, of course, the unique identifier check code.
  
  The best place to see the bug is at the top of page 5 :
  - running total = 17,15 on line 148 (end of page 4)
  - the value added (rightmost) should be 0,17 so running total should be 17,15+0,17=17,32 but it's 17,15+(2*0,17)=17,49
  - on page 5 you see 19,64 as subtotal which is correct (calculated by FR's aggregate) and "Total pour l'album = 19,82" : the wrong total
  

  OBPcalledtwicebug.zip 25.7K
• gpi

  October 2011 edited 1:58PM

  Try

  procedure MasterData2OnBeforePrint(Sender: TfrxComponent);
  begin
    if not Engine.SecondScriptCall then ligne:=ligne+1;
    with MasterData2, Engine do
    begin
      if <frxMVEN."idtmpven"> <> lastLigne then begin                                                      
        if not Engine.SecondScriptCall then totphono:=totphono+<frxMVEN."brutad">;
        // other calculations not involving totphono
        lastligne:=<frxMVEN."idtmpven">;
      end;
    end
  end;
  
• thefreecat

  October 2011 edited 1:58PM

  gpi wrote: »

  Try

        if not Engine.SecondScriptCall then totphono:=totphono+<frxMVEN."brutad">;
  

  
  It works but should this be considered "normal behaviour" or workaround ? In the former case, it would be a nice idea to add something like this :
  "in some cases the event can be called repeatedly during grouping. To determine if this is the case, see Engine.SecondScriptCall"
  to the "Events" chapter of the documentation.
  
  Thanks for your help.
  
• gordk St.Catherines On. Canada.

  October 2011 edited 1:58PM

  some times Ie miss the easy things
  on looking at your code i realized this was a report converted from fr2 to fr4.
  try to doing your incrementing in the onafterprint event.
• thefreecat

  October 2011 edited 1:58PM

  gordk wrote: »

  try to doing your incrementing in the onafterprint event.

  I tried that but it was still called twice. And that would mean : impossible to print (script-calculated) running totals (because calculated afterwards)...
  
  It would be nice to have a special event (in "Data"-bands : TfrxMasterData, TfrxDetailData, etc.) called only once per row of data : THE place where to do computations whereas other events are more dedicated to appearance (in my vision).
  
  At least, please add a warning to the documentation of "events" about the possibility of the event to be called twice and the way to workaround it : Engine.SecondScriptCall.
  
  Thanks for your help.