Interesting discovery with TListView with OwnerData checked and Adding items.

[jamie]

 If you have OwnerData checked and then use the IDE to add items, upon completion of the editor, you get a nice Index of bounds with the trunk.
 
  Older IDE's, it puts the IDE into a loop and you need to hard exit.

[dsiders]

If you have OwnerData checked and then use the IDE to add items, upon completion of the editor, you get a nice Index of bounds with the trunk.
 
  Older IDE's, it puts the IDE into a loop and you need to hard exit.

Interesting.

So, in essence, the property editor should not be displayed at all when OwnerData is enabled?

[jamie]

I would say so.

Not just that, the items should be deleted if one checks the ownerdata too.

[dsiders]

I would say so.

Not just that, the items should be deleted if one checks the ownerdata too.

SetOwnerData already does that. It frees the Items list are creates the TOwnerDataListItems container used instead.

I made a patch (for 3.99) to catch the circumstance you described, if you'd like to try it out...

Code: Diff  [Select][+][-]

1. diff --git a/components/ideintf/listviewpropedit.pp b/components/ideintf/listviewpropedit.pp
2. index 0fc4ca719d..73ba02c024 100644
3. --- a/components/ideintf/listviewpropedit.pp
4. +++ b/components/ideintf/listviewpropedit.pp
5. @@ -92,6 +92,13 @@ function EditListView(AListView: TListView): Boolean;
6.  var
7.    ListViewEditorDlg: TListViewItemsEditorForm;
8.  begin
9. +  if AListView.OwnerData then
10. +  begin
11. +    Beep;
12. +    Application.MessageBox(PChar(sccsLvEdtMsgOwnerData), PChar(sccsLvEdt));
13. +    Result := False;
14. +    Exit;
15. +  end;
16.    ListViewEditorDlg := TListViewItemsEditorForm.Create(Application);
17.    try
18.      ListViewEditorDlg.LoadFromList(AListView);
19. diff --git a/components/ideintf/objinspstrconsts.pas b/components/ideintf/objinspstrconsts.pas
20. index 27366703fb..17099884ca 100644
21. --- a/components/ideintf/objinspstrconsts.pas
22. +++ b/components/ideintf/objinspstrconsts.pas
23. @@ -134,6 +134,7 @@ resourcestring
24.    sccsLvEdtLabelImageIndex = 'Image Index:';
25.    sccsLvEdtLabelStateIndex = 'State Index:';
26.    sccsLvEdtItem            = 'Item';
27. +  sccsLvEdtMsgOwnerData    = 'Cannot edit list items at design-time when OwnerData is enabled. Use Items.Count and OnData at run-time instead.';
28.  
29.    // Image editor strings
30.    oisImageListComponentEditor = 'I&mageList Editor ...';
31.  
32.  

The Beep and Application.MessageBox calls are debatable, but they did not introduce any new dependencies in the unit.

[wp]

I don't like the Beep. Is a Beep used within the IDE anywhere else? And I'd also replace the Application.MessageBox by MessageDlg even it if makes the unit depend on the Dialogs unit. But Dialogs is used already by PropEdits. So, this should not make a difference. Or am I missing something?

[jamie]

I am not sure if the ondata event is even working?

[dsiders]

I don't like the Beep. Is a Beep used within the IDE anywhere else?

Not in the IDE specifically, but in LCL bring-to-front flash-and-beep behavior.

And I'd also replace the Application.MessageBox by MessageDlg even it if makes the unit depend on the Dialogs unit. But Dialogs is used already by PropEdits. So, this should not make a difference. Or am I missing something?

No, you're not missing anything. I just took the path of least resistance.

[dsiders]

I am not sure if the ondata event is even working?

If it's not, then how are you getting values for from the virtual data container?

[wp]

I am not sure if the ondata event is even working?

Here's a demo with 1,000,000 items in a virtual listview.

[wp]

I don't like the Beep. Is a Beep used within the IDE anywhere else?

Not in the IDE specifically, but in LCL bring-to-front flash-and-beep behavior.

And I'd also replace the Application.MessageBox by MessageDlg even it if makes the unit depend on the Dialogs unit. But Dialogs is used already by PropEdits. So, this should not make a difference. Or am I missing something?

No, you're not missing anything. I just took the path of least resistance.

OK when I commit it?

[dsiders]

I don't like the Beep. Is a Beep used within the IDE anywhere else?

Not in the IDE specifically, but in LCL bring-to-front flash-and-beep behavior.

And I'd also replace the Application.MessageBox by MessageDlg even it if makes the unit depend on the Dialogs unit. But Dialogs is used already by PropEdits. So, this should not make a difference. Or am I missing something?

No, you're not missing anything. I just took the path of least resistance.

OK when I commit it?

Here's the modified version.

[wp]

Committed (https://gitlab.com/freepascal.org/lazarus/lazarus/-/commit/5621ec7af3f8d08bf514edb72defc0045ab3ee26), will be backported to Laz/Fixes and the next bug-fix release v3.4

[n7800]

I would like to propose another solution to this problem. I suggest printing a message when trying to set OwnerData if the items are not empty. The user should be warned about the loss of items and delete them themselves. This is a more correct way.

Maybe I'll make a patch myself, but I don't have time yet. Feel free to do it yourself.