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
Documentation
Bugtracker
Mailing List
Lazarus
Website
Downloads (Laz+FPC)
Packages (OPM)
FAQ
Wiki
Documentation (RTL/FCL/LCL)
Bugtracker
CCR Bugs
IRC channel
GIT
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
FpDebug questions
by
Martin_fr
[
Today
at 11:25:02 am]
Parameter passing odditie...
by
Thaddy
[
Today
at 11:23:20 am]
splitting an image
by
Dzandaa
[
Today
at 11:15:40 am]
how to tweek fpmake to co...
by
marcov
[
Today
at 10:35:11 am]
Can function be used for ...
by
Thaddy
[
Today
at 10:24:31 am]
Why isn't TTIRadioGroup's...
by
egsuh
[
Today
at 08:09:35 am]
Lazarus for Windows on aa...
by
Wallaby
[April 23, 2024, 11:46:56 pm]
(Solved) TIndexedAVLTree ...
by
lainz
[April 23, 2024, 10:49:03 pm]
Demo Scene Picture sinwav...
by
KodeZwerg
[April 23, 2024, 10:26:21 pm]
fkInternalCalc
by
zraja
[April 23, 2024, 09:31:07 pm]
A fairly simple sound sol...
by
KodeZwerg
[April 23, 2024, 09:23:37 pm]
add new targets to make
by
marcov
[April 23, 2024, 08:38:42 pm]
Quirky windows
by
ASerge
[April 23, 2024, 07:07:16 pm]
[Request] Demo Scene Sub ...
by
Gigatron
[April 23, 2024, 06:29:39 pm]
Unlocking Files
by
KodeZwerg
[April 23, 2024, 06:03:08 pm]
[SOLVED] trunk bug for mi...
by
Key-Real
[April 23, 2024, 05:56:32 pm]
Demo Scene Bitmap Font Sc...
by
Gigatron
[April 23, 2024, 05:56:27 pm]
Compile/Convert Delphi pr...
by
Martin_fr
[April 23, 2024, 05:43:11 pm]
Generics - correct syntax
by
Thaddy
[April 23, 2024, 05:40:59 pm]
InstallAware Using Lazaru...
by
msintle
[April 23, 2024, 05:26:36 pm]
Xcode Command Line Tools ...
by
Joseph
[April 23, 2024, 05:16:39 pm]
Offical launch of the 1 B...
by
Hartmut
[April 23, 2024, 04:49:29 pm]
what to do if my target M...
by
nickysn
[April 23, 2024, 04:16:02 pm]
compiler error in unit
by
paule32
[April 23, 2024, 03:49:50 pm]
Multithreading - synchron...
by
mika
[April 23, 2024, 01:48:51 pm]
« previous
next »
Print
Pages: [
1
]
Author
Topic: Adding event to a runtime component (Read 1238 times)
justnewbie
Sr. Member
Posts: 292
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: 4144
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: 292
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: 5158
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: 292
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