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
Web Applications with Pas...
by
Handoko
[
Today
at 08:56:29 pm]
AI, NLP and CAI: Text Gen...
by
indydev
[
Today
at 08:54:00 pm]
Offical launch of the 1 B...
by
Gustavo 'Gus' Carreno
[
Today
at 08:48:22 pm]
Colore celle StringGrid
by
JuanBell
[
Today
at 08:47:28 pm]
Multidimensional arrays a...
by
KodeZwerg
[
Today
at 08:34:38 pm]
Ho Ho Ho IntraWeb in Laza...
by
Thaddy
[
Today
at 08:31:29 pm]
[SOLVED] System.Now gives...
by
alpine
[
Today
at 08:29:19 pm]
FpDebug likely bug
by
440bx
[
Today
at 08:26:20 pm]
open dialog - default dir...
by
Nicole
[
Today
at 08:02:40 pm]
Installing and using Vamp...
by
Odacir
[
Today
at 07:58:22 pm]
Demo Scene Picture sinwav...
by
circular
[
Today
at 07:27:02 pm]
Demo Scene Bitmap Font Sc...
by
KodeZwerg
[
Today
at 07:21:14 pm]
what's difference between...
by
ASerge
[
Today
at 07:09:52 pm]
splitting an image
by
KodeZwerg
[
Today
at 07:07:21 pm]
Debugger error
by
bobonwhidbey
[
Today
at 07:03:07 pm]
How to: create DLL file f...
by
paule32
[
Today
at 07:02:31 pm]
Your best UI design - con...
by
circular
[
Today
at 06:48:12 pm]
Converting a string/index...
by
1HuntnMan
[
Today
at 06:35:19 pm]
Drawing grid lines on a t...
by
KodeZwerg
[
Today
at 05:42:19 pm]
Compile/Convert Delphi pr...
by
Martin_fr
[
Today
at 05:29:03 pm]
Lazarus features in a non...
by
Lutz Mändle
[
Today
at 05:26:34 pm]
Lazarus for Windows on aa...
by
msintle
[
Today
at 05:03:57 pm]
Parameter passing odditie...
by
KodeZwerg
[
Today
at 03:41:49 pm]
Surf Units in Text Mode I...
by
mosquito
[
Today
at 01:58:21 pm]
Generics - correct syntax
by
Thaddy
[
Today
at 01:48:32 pm]
« previous
next »
Print
Pages: [
1
]
Author
Topic: Adding event to a runtime component (Read 1241 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: 5159
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