TOPIC:

TDBLookupComboBox access violation 9 years 1 month ago #9242

Luca
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Posts: 33
Thank you received: 2

Hi
Here attached a demo project.
It includes two forms:
- form1 used to refresh data and to showmodal form2,
- form2 containing a memdataset with two fields and a tdblookupcombobox
If you run in CT 5.7 you receive an access violation in TDBLookUp.FetchLookupData second time you push button1 to open form2.

Some informations:
1. if you change form2.showmodal with form2.show all works fine
2. this is just an example to reproduce the error: I found the problem using MSSQL tables-

All works fine in CT 5.4 and Lazarus 1.6.

PS: why breakpoints in lcl unit files is not working in debugging mode?

Regards
Luca

test.zip

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Last edit: by Luca.

TDBLookupComboBox access violation 9 years 1 month ago #9246

Sternas Stefanos Offline Moderator Ex Pilot, M.Sc, Ph.D Posts: 4556 Thank you received: 1121	Thanks Sir we will test and report PilotLogic Architect and Core Programmer
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TDBLookupComboBox access violation 9 years 1 month ago #9248

Luca
Topic Author
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Junior Member
Posts: 33
Thank you received: 2

I found a workround.
It seems the problem is linked to handle changing of form2 (see blogs.embarcadero.com/abauer/2004/02/10/295) when you click second time button1.
If I set (directly in Object Inspector),

form2.popumode=pmauto

the handle didn't change and all is fine.

What's really strange is that if you access the handle before showmodal (for example by showing its value) without changing popupmode to pmauto, the error disappears.

  showmessage(inttostr(form2.Handle)); 
  form2.SQLQuery1.Close;
  form2.SQLQuery1.Open;
  form2.ShowModal

Hope this help
Regards
Luca

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Last edit: by Luca.

TDBLookupComboBox access violation 9 years 1 month ago #9249

Sternas Stefanos Offline Moderator Ex Pilot, M.Sc, Ph.D Posts: 4556 Thank you received: 1121	Or add to Form2 OnShow event: procedure TForm2.FormShow(Sender: TObject); begin MemDataset1.Close; MemDataset1.Open; end; and call from Form1 only procedure TForm1.Button1Click(Sender: TObject); begin form2.ShowModal; end; PS: please don't forget CT-LCL is NOT the same with VCL and never will be... PilotLogic Architect and Core Programmer Attachments: test.zip
	Please Log in or Create an account to join the conversation. Last edit: by Sternas Stefanos.

TDBLookupComboBox access violation 9 years 1 month ago #9250

Luca Topic Author Offline Junior Member Posts: 33 Thank you received: 2	OK. I forgot to say that After MemDataset1.Open and Before Form2.ShowModal, I initialized some controls in Form2. So I need to open MemDataset1 before show the form2. I think to set pmAuto for modal forms. Regards Luca
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TDBLookupComboBox access violation 9 years 1 month ago #9251

Sternas Stefanos Offline Moderator Ex Pilot, M.Sc, Ph.D Posts: 4556 Thank you received: 1121	As you want PilotLogic Architect and Core Programmer
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