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[SOLVED] Undoing text editing in TEdit, etc.
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Topic: [SOLVED] Undoing text editing in TEdit, etc. (Read 423 times)
egsuh
Hero Member
Posts: 625
[SOLVED] Undoing text editing in TEdit, etc.
«
on:
September 18, 2019, 11:48:52 am »
Is it possible to undo editings in TEdit, etc.?
For example, the original Edit1.Text = 'Edit1'. And I tried to change some part of it, but I want to leave the EditBox just leaving the original 'Edit1' text, ignoring my own changes?
«
Last Edit: September 18, 2019, 12:13:33 pm by egsuh
»
Logged
wp
Hero Member
Posts: 8096
Re: Undoing text editing in TEdit, etc.
«
Reply #1 on:
September 18, 2019, 12:07:07 pm »
Press ESC to restore the original content. I think it is not ready-made, but you can easily add it by yourself:
Add a string variable to the form named FOldEdit1Text
Write a handler for Edit1's OnEnter event copying is Text to FOldEdit1Text.
Write a handler for Edit1's OnKeyDown event checking the pressed key for ESCAPE and replacing the Text by FOldEdit1Text.
Code: Pascal
[Select]
[+]
[-]
unit
Unit1
;
{$mode objfpc}{$H+}
interface
uses
Classes
,
SysUtils
,
Forms
,
Controls
,
Graphics
,
Dialogs
,
StdCtrls
;
type
{ TForm1 }
TForm1
=
class
(
TForm
)
Edit1
:
TEdit
;
Edit2
:
TEdit
;
procedure
Edit1Enter
(
Sender
:
TObject
)
;
procedure
Edit1KeyDown
(
Sender
:
TObject
;
var
Key
:
Word
;
Shift
:
TShiftState
)
;
procedure
Edit2Enter
(
Sender
:
TObject
)
;
procedure
Edit2KeyDown
(
Sender
:
TObject
;
var
Key
:
Word
;
Shift
:
TShiftState
)
;
private
FOldEdit1Text
:
String
;
FOldEdit2Text
:
String
;
public
end
;
var
Form1
:
TForm1
;
implementation
{$R *.lfm}
uses
LCLType
;
{ TForm1 }
procedure
TForm1
.
Edit1Enter
(
Sender
:
TObject
)
;
begin
FOldEdit1Text
:
=
Edit1
.
Text
;
end
;
procedure
TForm1
.
Edit1KeyDown
(
Sender
:
TObject
;
var
Key
:
Word
;
Shift
:
TShiftState
)
;
begin
if
Key
=
VK_ESCAPE
then
begin
Edit1
.
Text
:
=
FOldEdit1Text
;
Edit1
.
SelectAll
;
Key
:
=
0
;
end
;
end
;
procedure
TForm1
.
Edit2Enter
(
Sender
:
TObject
)
;
begin
FOldEdit2Text
:
=
Edit2
.
Text
;
end
;
procedure
TForm1
.
Edit2KeyDown
(
Sender
:
TObject
;
var
Key
:
Word
;
Shift
:
TShiftState
)
;
begin
if
Key
=
VK_ESCAPE
then
begin
Edit2
.
Text
:
=
FOldEdit2Text
;
Edit2
.
SelectAll
;
Key
:
=
0
;
end
;
end
;
end
.
Logged
Mainly Lazarus trunk / fpc 3.2.0 / all 32-bit on Win-10, but many more...
egsuh
Hero Member
Posts: 625
Re: Undoing text editing in TEdit, etc.
«
Reply #2 on:
September 18, 2019, 12:13:06 pm »
@wp
I see. The function is not built-in. Writing such codes is not big deal.
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