[Lazarus] TControl.Click?

[Mattias Gaertner]

On Sat, 01 Oct 2011 14:03:38 +0100
Martin <lazarus at mfriebe.de> wrote:

> On 01/10/2011 09:05, Mattias Gaertner wrote:
> > On Sat, 01 Oct 2011 08:39:42 +0100
> > Martin<lazarus at mfriebe.de>  wrote:
> >
> >> On 01/10/2011 07:53, Mattias Gaertner wrote:
> >>> On Sat, 01 Oct 2011 03:04:56 +0200
> >>> Hans-Peter Diettrich<DrDiettrich1 at aol.com>   wrote:
> >>>
> >>>> I don't understand the logic behind TControl.Click:
> >>>>
> >>>> procedure TControl.Click;
> >>>> begin
> >>>>      //DebugLn(['TControl.Click ',DbgSName(Self)]);
> >>>>      if (not (csDesigning in ComponentState)) and (ActionLink<>   nil) and
> >>>>         ((Action=nil) or (@FOnClick<>   @Action.OnExecute) or
> >>>> Assigned(FOnClick)) then
> >>>>        ActionLink.Execute(Self)
> >>>>      else
> >>>>      if Assigned(FOnClick) then
> >>>>        FOnClick(Self);
> >>>> end;
> >>>>
> >>>>
> >> Maybe I overlook something, but
> >> @FOnClick is the address of the variable holding the method reference
> >> (or nil)
> >> so is @Action.OnExecute
> >>
> >> So when can they ever be equal?
> > You are right.
> ...
> > I added a CompareMem.
> >> Also is that supposed to be a shortcut, saving the call, or is that
> >> indeed supposed to modify behaviour?
> > Good question.
> > I guess it would be enough to check (not (csDesigning in
> > ComponentState)) and (ActionLink<>  nil).
> >
> > Maybe the Delphi docs have an answer.
> >
> 
> further more:
> 
> ActionLink.Execute is virtual
> 
> So comparing with the OnExecute method pointer is at the very least 
> insufficient.
> 
> If ActionLink.Execute  is overridden, it could call/do anything.

True. But it seems Delphi does the same.

 
> I would suggest to drop that check entirely

Why?
Do you have a real case where it hurts?

 
> SVN Blame shows that it's been there for a long time, and always had the 
> @FOnClick => so it never triggered in the past, and there never was a 
> bug, while it did not trigger.

Well, this allows many conclusions. ;)

Mattias