[daveplummermd]

Guys

I need help with custom controls and "reusable code".

Example:
1) I have made a custom control "lb" that only contains a listbox.
2) I then make a diaglog box "dlg" and insert my new custom control "lb"
3) Now I want to take action in dlg.pro on any selectionChange made in the custom control "lb". In other words "dlg" need to be notified of a selectioncHANGE In "lb"

In lb.pro

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facts
                senderdlg : containerWindow :=erroneous.
                
clauses
        new(Parent) :-
                new(),
                setContainer(Parent),
                senderContainer:=Parent.
       
        new() :-
                userControlSupport::new(),
                generatedInitialize().
                        
        onListboxSelectionChanged(_Source) :-
                senderdlg:selectionChanged()
                !.
                

in dlg.i

Code: Select all

interface dlg supports dialog
    open core
 
        predicates
                selectionChanged : ().
 
end interface dlg

In dlg.pro

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clauses
        selectionChanged() :-
        stdio:write("Selection changed"),
        !.

And finally, at compile time I get:
e229 Undeclared identifier 'selectionChanged/0' lb.pro ..\myCollection\lb\

Naturally , I would like to use my custom control in many different dogs (different classes)

Can you advise ?

Thanks in advance
Dave Plummer

[Thomas Linder Puls]

Your custom control must provide some selection changed event mechanism, so that you can register a listener in your dialog.

It can be in the "old" (still used) form of add<SomeThing>Listener, or you can use an event:

Code: Select all

interface lb
 
properties
    selectionChangedEvent : event0 (o).
...
end interface lb

In the implementation you will have a corresponding fact, which you will "fire" when the embedded listBox (called embeddedListBox below) selection changes:

Code: Select all

implement lb
    ...
 
facts
    selectionChangedEvent : event0 := event0::new().
 
clauses
    new() :-
        ...
        embeddedListBox:addSelectionChangedListener({ :-
            selectionChangedEvent:notify()
        }).

In you dialog you will add a listerner:

i

Code: Select all

mplement dlg
    ...
 
clauses
    new() :-
        ...
        theLB:onSElectionChangedEvent:addListener( { :- 
            % do something when the lb selection changes
        }).

[daveplummermd]

Thomas
Thanks so much. This is an extremely helpful response and works as advertised. Now, I just have to understand how and why, but that's on me.

Thanks Again

dave