Mattias Gaertner schrieb:
On Sat, 01 Oct 2011 08:39:42 +0100
Martin <[email protected]> wrote:
On 01/10/2011 07:53, Mattias Gaertner wrote:
On Sat, 01 Oct 2011 03:04:56 +0200
Hans-Peter Diettrich<[email protected]> 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.
Really?
AFAIK method pointers are handled differently in Delphi and FPC, where
FPC requires @FOnClick to get the value stored in FOnClick, where Delphi
guesses whether FOnClick should invoke the method or return the value.
Should that maybe compare FOnClick <> Action.OnExecute ?
That would miss difference in Data.
I added a CompareMem.
IMO the comparison worked as-is, as found in several places in the LCL.
What about:
function TControlActionLink.IsOnExecuteLinked: Boolean;
begin
Result := inherited IsOnExecuteLinked
and (FClient.OnClick = Action.OnExecute);
end;
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.
No :-(
Even if the 2 callbacks are pointing to the same method, calling
Action.OnExecute, will call the callback with Sender=TheAction, while
FOnClick gets the current object.
Looks as if Execute should be overridden in TControlActionLink!
DoDi
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