[Lazarus] Control Notification bug?
My new TCoolBar component uses overridden notification: procedure Notification(AComponent: TComponent; Operation: TOperation); override; When Operation is opInsert, it adds a band and associates the new control with it. It works as expected when a control is dropped on a CoolBar. However, CoolBar is notified also when a control is dropped anywhere on the same form. I believe it is a bug, it should not happen. I solved the problem by checking if the control's parent = Self. Juha -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Control Notification bug?
On Sun, 3 Feb 2013 13:32:09 +0200 Juha Manninen juha.mannine...@gmail.com wrote: My new TCoolBar component uses overridden notification: procedure Notification(AComponent: TComponent; Operation: TOperation); override; When Operation is opInsert, it adds a band and associates the new control with it. It works as expected when a control is dropped on a CoolBar. However, CoolBar is notified also when a control is dropped anywhere on the same form. I believe it is a bug, it should not happen. No. The Notification is inherited from TComponent. So, it's about Owner, not about TControl.Parent. Most controls are owned by the form. I solved the problem by checking if the control's parent = Self. Good. Mattias -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Control Notification bug?
On Sun, Feb 3, 2013 at 1:44 PM, Mattias Gaertner nc-gaert...@netcologne.de wrote: On Sun, 3 Feb 2013 13:32:09 +0200 Juha Manninen juha.mannine...@gmail.com wrote: No. The Notification is inherited from TComponent. So, it's about Owner, not about TControl.Parent. Most controls are owned by the form. Ok. I solved the problem by checking if the control's parent = Self. Good. In fact the control does not have parent or even name when Notification is called. Apparently the control is still under construction. If I set its properties there, it leads to a crash. I solved it by using OnIdle handler. Notification sets FNewControl and registers the handler which looks like this : procedure TCustomCoolBar.OnIdle(Sender: TObject; var Done: Boolean); var Band: TCoolBand; begin Assert(Assigned(FNewControl) and Assigned(FNewControl.Parent), 'TCoolBar.OnIdle: FNewControl or FNewControl.Parent not assigned'); DebugLn(['TCoolBar.OnIdle, Control.Name=', FNewControl.Name]); if FNewControl.Parent = Self then begin Band := FBands.Add; Band.Control := FNewControl; FNewControl := Nil; end; Application.RemoveOnIdleHandler(@OnIdle); end; It seems to work but may not be the cleanest way to do it. Comments ? Juha -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Control Notification bug?
On Sun, 3 Feb 2013 13:58:42 +0200 Juha Manninen juha.mannine...@gmail.com wrote: [...] In fact the control does not have parent or even name when Notification is called. Apparently the control is still under construction. If I set its properties there, it leads to a crash. I solved it by using OnIdle handler. Notification sets FNewControl and registers the handler which looks like this : procedure TCustomCoolBar.OnIdle(Sender: TObject; var Done: Boolean); var Band: TCoolBand; begin Assert(Assigned(FNewControl) and Assigned(FNewControl.Parent), 'TCoolBar.OnIdle: FNewControl or FNewControl.Parent not assigned'); DebugLn(['TCoolBar.OnIdle, Control.Name=', FNewControl.Name]); if FNewControl.Parent = Self then begin Band := FBands.Add; Band.Control := FNewControl; FNewControl := Nil; end; Application.RemoveOnIdleHandler(@OnIdle); end; It seems to work but may not be the cleanest way to do it. Not to be the cleanest way lol It's a dirty hack. Even an QueueAsyncCall would be better. Comments ? Why not override InsertControl and RemoveControl? Mattias -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Control Notification bug?
On Sun, Feb 3, 2013 at 2:17 PM, Mattias Gaertner nc-gaert...@netcologne.de wrote: Why not override InsertControl and RemoveControl? Because I didn't realize those methods existed. :) I will try them next ... Juha -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Control Notification bug?
On Sun, Feb 3, 2013 at 2:52 PM, Juha Manninen juha.mannine...@gmail.com wrote: On Sun, Feb 3, 2013 at 2:17 PM, Mattias Gaertner nc-gaert...@netcologne.de wrote: Why not override InsertControl and RemoveControl? Because I didn't realize those methods existed. :) I will try them next ... Done. Juha -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
