[dominique f pannier]

Hi,

The following program adds in a window a listEdit object with a selectionChangedListener. If we add something into the list of the listEdit object, and select the Index item in the list control, it triggers an event catched by the selectionChangedListener.

In VIP 7.4, the Source given by the listener identifies a list Control object corresponding to the listEdit box (same number) :
If we look at the "Variable of the current clause" window :
Source : listControl = <listEdit xxxxxxxxx>
> listEdit$objectDB

In VIP 7.5, the Source given by the listener is a listButton object with a different number by the two last digits.
If we look at the "Variable of the current clause" window :
Source : listControl = <listEdit xxxxxxxyy>
> listButton@objectDB

If we want to convert the Source in a listEdit domain, it triggers an exception.

What is the reason of the intervention, in VIP 7.5, of a listButton which was never created ? Is possible to get from this number the listEdit affected by the event in VIP 7.5 ?

Code: Select all

implement conteneur
    inherits formWindow
    open core, vpiDomains
 
 
clauses
    display(Parent) = Form :-
        Form = new(Parent),
        Form:show().
 
clauses
    new(Parent):-
        formWindow::new(Parent),
        generatedInitialize(),
        stdIO::write(listEdit_ctl, "\n").
 
 
 
clauses
 
% launched in the taskwindow in the event "file new" after creating the conteneur object
% with  'listEdit_ctl' as CONTROL and "toto" as VALUE
    setValueSelected(Control, Value):-
            stdIO::write(Control, "\n"),
            Control:addList(["lolo", "lulu", "toto"]),
            Control:setText(Value),
            Liste = Control:getAll(),
            Index = list::tryGetIndex(Value, Liste), !,
            Control:selectAt(Index, true()).
    setValueSelected(_, _).
 
predicates
    onListEditSelectionChanged : listControl::selectionChangedListener.
clauses
    onListEditSelectionChanged(Source):-
        stdIO::write(Source, "\n"),
        _ = convert(listEdit, Source),
        Source = listEdit_ctl,
        !.
    onListEditSelectionChanged(_Source).
predicates
    onOkValidate : control::validateResponder.
clauses
    onOkValidate(_Source) = control::contentsOk:-
        close().
 
% This code is maintained automatically, do not update it manually. 16:30:04-3.8.2014
facts
    ok_ctl : button.
    listEdit_ctl : listEdit.
 
predicates
    generatedInitialize : ().
clauses
    generatedInitialize():-
        setFont(vpi::fontCreateByName("Tahoma", 8)),
        setText("Conteneur"),
        setRect(rct(50,40,290,160)),
        setDecoration(titlebar([closeButton,maximizeButton,minimizeButton])),
        setBorder(sizeBorder()),
        setState([wsf_ClipSiblings,wsf_ClipChildren]),
        menuSet(noMenu),
        ok_ctl := button::newOk(This),
        ok_ctl:setText("&OK"),
        ok_ctl:setPosition(180, 102),
        ok_ctl:setSize(56, 16),
        ok_ctl:defaultHeight := false,
        ok_ctl:setAnchors([control::right,control::bottom]),
        ok_ctl:addValidateResponder(onOkValidate),
        listEdit_ctl := listEdit::new(This),
        listEdit_ctl:setText("List Edit"),
        listEdit_ctl:setPosition(136, 12),
        listEdit_ctl:setWidth(84),
        listEdit_ctl:setMaxDropDownRows(1),
        listEdit_ctl:addSelectionChangedListener(onListEditSelectionChanged).
% end of automatic code
end implement conteneur

[Thomas Linder Puls]

The numbers you mention are pointers/addresses, so their value only makes sense internally.

The change is not intentional.

You can however fix the problem in your own code by using the publicSelf property:

Code: Select all

predicates
    onListEditSelectionChanged : listControl::selectionChangedListener.
clauses
    onListEditSelectionChanged(Source):-
        stdIO::write(Source, "\n"),
        _ = convert(listEdit, Source:publicSelf),  % yse publicSelf here
        Source = listEdit_ctl,
        !.
    onListEditSelectionChanged(_Source).

That said, we do however consider to remove the "Source" argument from all listeners:

• They are very seldomly used
• There are all sorts of type problems (like this one) with them

When needed you can use an anonymous predicate to transfer the "Source" yourself, like this:

Code: Select all

clauses
    new(Parent):-
        formWindow::new(Parent),
        generatedInitialize(),
        list_ctl1:addSelectionChangedListener( { :- onSelectionChanged(list_ctl1) } ),
        list_ctl2:addSelectionChangedListener( { :- onSelectionChanged(list_ctl2) } ),
        list_ctl3:addSelectionChangedListener( { :- onSelectionChanged(list_ctl3) } ).
 
predicates
    onSelectionChanged : (listEdit Source).
clauses
    ...

[dominique f pannier]

Thanks for these informations, Thomas.

publicself is perfect for updating an old code, and the second solution for a new one.