Zitat von Andrea Mauri <[email protected]>:
Dear Mattias,
thanks, now it works.
May I ask you what was the problem? I would like to contribute as
much as possible in this project, more I understand more I can help.
I will try to explain:
property AfterConnect : TNotifyEvent read FAfterConnect write SetAfterConnect;
The write method is defined as:
procedure TCustomConnection.SetAfterConnect(const AValue: TNotifyEvent);
begin
if FAfterConnect=AValue then exit;
FAfterConnect:=AValue;
end;
The problem is that TNotifyEvent is a special "record" of two
pointers: Data and Code. At runtime Data is the instance (the Self
pointer) and Code is the address of the procedure. At designtime there
is no address. Therefore the IDE creates a special fake event, with
Data an unique ID and Code=nil.
The comparison "FAfterConnect=AValue" only compares code, not data.
Probably it is for Delphi compatibility. Although I wonder, why this
happen under mode objfpc. IMHO this feature is inconsistent and almost
useless.
Because at designtime the code is always nil, FAfterConnect=AValue is
always true. I worked around this by first assigning Code=1 and then
Code=nil.
But there is still a bug in the TCustomConnection, because when you
switch the event to the method of the same class, but another
instance, TCustomConnection will ignore this.
I think, it would be better if FPC changes the comparison in mode objfpc.
Mattias
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