Lazarus
Home
Help
TinyPortal
Search
Login
Register
Lazarus
»
Forum
»
Free Pascal
»
Beginners
(Moderators:
FPK
,
Tomas Hajny
) »
Adding event to a runtime component
Free Pascal
Website
Downloads
Wiki
Bugtracker
Mailing List
Lazarus
Website
Downloads (Laz+FPC)
Packages (OPM)
FAQ
Wiki
Bugtracker
IRC channel
Latest SVN
Mailing List
Other languages
Foundation
Website
Useful Wiki Links
Project Roadmap
Getting the Source
Screenshots
How to use the forum
About donations (wiki)
Bookstore
Computer Math and Games in Pascal
(preview)
Lazarus Handbook
Search
Advanced search
Recent
For S in [...] bug of FPC...
by
ASerge
[
Today
at 08:17:48 pm]
I can't change the code e...
by
winni
[
Today
at 08:16:38 pm]
No warning from FPC with ...
by
440bx
[
Today
at 07:51:27 pm]
Including translation fil...
by
fatmonk
[
Today
at 07:18:33 pm]
Custom Paths in Compiler ...
by
lazaruser
[
Today
at 07:05:00 pm]
Lazarus Release 2.0.12
by
Muso
[
Today
at 05:53:30 pm]
sparta в 2.0.12
by
avk
[
Today
at 05:18:32 pm]
Q: method replacement for...
by
d7_2_laz
[
Today
at 05:14:50 pm]
Is there a version of Ope...
by
Thaddy
[
Today
at 05:09:19 pm]
TReeView Multiline again
by
Weitentaaal
[
Today
at 03:51:41 pm]
« previous
next »
Print
Pages: [
1
]
Author
Topic: Adding event to a runtime component (Read 626 times)
justnewbie
Sr. Member
Posts: 273
Adding event to a runtime component
«
on:
March 02, 2021, 05:01:31 pm »
Guys, can you fix my code? Couldn't give an OnMouseUp event to it, doesn't compile.
Code: Pascal
[Select]
[+]
[-]
unit
Unit1
;
{$mode objfpc}{$H+}
interface
uses
Classes
,
SysUtils
,
Forms
,
Controls
,
Graphics
,
Dialogs
,
StdCtrls
,
ExtCtrls
,
LCLIntf
;
type
{ TForm1 }
TForm1
=
class
(
TForm
)
Button1
:
TButton
;
ColorDialog1
:
TColorDialog
;
procedure
Button1Click
(
Sender
:
TObject
)
;
procedure
ShapeMouseUp
(
Sender
:
TObject
;
Button
:
TMouseButton
;
Shift
:
TShiftState
;
X
,
Y
:
Integer
)
;
private
public
end
;
var
Form1
:
TForm1
;
implementation
{$R *.lfm}
{ TForm1 }
procedure
TForm1
.
Button1Click
(
Sender
:
TObject
)
;
// Make empty palette
var
shape
:
TShape
;
begin
shape
:
=
TShape
.
Create
(
Self
)
;
shape
.
Parent
:
=
Form1
;
shape
.
Left
:
=
100
;
shape
.
Top
:
=
100
;
shape
.
Width
:
=
20
;
shape
.
Height
:
=
20
;
shape
.
Pen
.
Width
:
=
1
;
shape
.
Pen
.
Color
:
=
clBlack
;
shape
.
Brush
.
Color
:
=
clDefault
;
shape
.
Visible
:
=
True
;
shape
.
Enabled
:
=
True
;
shape
.
OnMouseUp
:
=
ShapeMouseUp
;
end
;
procedure
TForm1
.
ShapeMouseUp
(
Sender
:
TObject
;
Button
:
TMouseButton
;
Shift
:
TShiftState
;
X
,
Y
:
Integer
)
;
begin
if
ColorDialog1
.
Execute
then
(
Sender as TShape
)
.
Brush
.
Color
:
=
ColorDialog1
.
Color
;
end
;
end
.
Logged
howardpc
Hero Member
Posts: 3671
Re: Adding event to a runtime component
«
Reply #1 on:
March 02, 2021, 05:10:32 pm »
You need an "@" for objfpc mode
Code: Pascal
[Select]
[+]
[-]
shape
.
OnMouseUp
:
=
@
ShapeMouseUp
;
Logged
justnewbie
Sr. Member
Posts: 273
Re: Adding event to a runtime component
«
Reply #2 on:
March 02, 2021, 05:17:34 pm »
Quote from: howardpc on March 02, 2021, 05:10:32 pm
You need an "@" for objfpc mode
Code: Pascal
[Select]
[+]
[-]
shape
.
OnMouseUp
:
=
@
ShapeMouseUp
;
Great, it works! Thank you!
BTW, why the @ needed here? For the OnClick it doesn't need.
Logged
Handoko
Hero Member
Posts: 4140
My goal: build my own game engine using Lazarus
Re: Adding event to a runtime component
«
Reply #3 on:
March 02, 2021, 05:58:27 pm »
Which OnClick did you mean?
If you want to pass a procedure as a variable then you need a @ symbol. It is not needed in Delphi Mode or if you use TypeAddressOn compiler switch.
Why do we need it? Because the syntax defines it so. That actually is a good thing, it can prevent programmers to do some stupid things.
Lazarus/FPC/Pascal is verbose and strict. Luckily all the rules can be found if you check the documentation:
https://wiki.lazarus.freepascal.org/@
https://www.freepascal.org/docs-html/user/usersu88.html#x132-1390007.3.3
https://www.freepascal.org/docs-html/prog/progsu76.html
«
Last Edit: March 02, 2021, 06:10:16 pm by Handoko
»
Logged
justnewbie
Sr. Member
Posts: 273
Re: Adding event to a runtime component
«
Reply #4 on:
March 02, 2021, 09:59:09 pm »
Thank you, Handoko!
Logged
Print
Pages: [
1
]
« previous
next »
Lazarus
»
Forum
»
Free Pascal
»
Beginners
(Moderators:
FPK
,
Tomas Hajny
) »
Adding event to a runtime component
TinyPortal
© 2005-2018