Tchecklistbox question
lazarus / 31-LCL

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rwebb616 · 2021-05-19 02:18

Is there a way to differenciate between the user clicking the checkbox
vs just selecting something in the list? 

I am using a checklist box right now and I put a on-click procedure to
make the selections easier so if you click any item it will reverse
the checked state of the item.  The problem is if I click on the
checkbox itself it will for example turn on and then back off or off
and then back on depending on it's state because on itemclick is
running as is on click.

Any way to tell if it's an item click vs selection?
Rich

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Handoko · 2021-05-19 02:39

Quote from: rwebb616 on May 19, 2021, 04:18:57 amI put a on-click
procedure to make the selections easier so if you click any item it
will reverse the checked state of the item.

You don't need to write code for the OnClick event to reverse the
state. TCheckListBox will do it automatically for you.

Or maybe I didn't fully understand your explanation.

Can you explain more or perhaps provide a simplified demo that can
show us the issue?

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rwebb616 · 2021-05-19 02:47

I'm sorry ... I wasn't clear..

I need to check these relatively fast and having to have the mouse
directly on the checkbox was problematic so I had coded the on-click
event to check or uncheck the box so all I had to do was click the
item rather than being right on the checkbox.. but then I had the
unintended behavior that when I DO click the checkbox it reverses
whatever state so if I click to check it, it checks with the item
selection event and then the checkbox unchecks because the checkbox
was clicked. 

I just got it sorted though .. Also I forgot to mention that I can
only select up to 6 items.  I did this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TfMainForm.clbCategoriesClick(Sender: TObject);var  index:integer; 
i:integer;  checked:integer;begin  checked:=0;  index :=
clbcategories.itemindex;  clbCategories.Checked[index]:=not
clbCategories.Checked[index];  for i:=0 to clbcategories.Count -1 do
begin    if clbCategories.Checked[i] then inc(checked);  end;  if
checked > options.maxcategories then begin  MessageDlg('Error','You
can only select up to ' + options.maxcategories.tostring + '
categories!',mtError,[mbOK],'');  if clbCategories.checked[Index]
then    clbCategories.Checked[Index]:=not
clbCategories.checked[Index];  end;end;  
and I assigned this to two events - onclick and onclickcheck.  Because
it runs the same code the checkbox reverses state I guess 3 times. 
Once for the actual check being clicked, then once for each event.
Ultimately it ends up in the state I want it to be in so now I can
click either the checkbox or the item and it will limit me to 6
categories.

Rich

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Handoko · 2021-05-19 03:05

I tested your code on both Windows and GTK2, I saw the problem. That
issue does not happen on Linux GTK2.

Give me some time, I am working on it.

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rwebb616 · 2021-05-19 03:10

Quote from: Handoko on May 19, 2021, 05:05:15 amI tested your code on
both Windows and GTK2, I saw the problem. That issue does not happen
on Linux GTK2.

Give me some time, I am working on it.

The code I posted is actually working for what I'm doing - or do you
mean the original problem I posted about?

Rich

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Handoko · 2021-05-19 03:21

The code you posted has problem on Win7 but it worked perfectly on
Ubuntu Mate GTK2.

Here is my workaround, which quickly tested on both Linux and Windows:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
Unit1; {$mode objfpc}{$H+} interface uses  SysUtils, Forms, Dialogs,
CheckLst; type   { TForm1 }   TForm1 = class(TForm)    CheckListBox1:
TCheckListBox;    procedure CheckListBox1Click(Sender: TObject);   
procedure CheckListBox1ClickCheck(Sender: TObject);  end; var  Form1:
TForm1; implementation {$R *.lfm} { TForm1 } procedure
TForm1.CheckListBox1Click(Sender: TObject);const  MaxCategories =
3;var  Index:   Integer;  i:       Integer;  Checked: integer;begin 
Index   := CheckListBox1.ItemIndex;  Checked := 0; 
CheckListBox1.Checked[Index] := not CheckListBox1.Checked[Index];  for
i := 0 to CheckListBox1.Count-1 do    if CheckListBox1.Checked[i] then
Inc(Checked);  if Checked > MaxCategories then begin   
MessageDlg('Error', 'You can only select up to ' +
MaxCategories.ToString +      ' categories!', mtError, [mbOK], '');  
if CheckListBox1.Checked[Index] then      CheckListBox1.Checked[Index]
:= not CheckListBox1.Checked[Index];  end;end; procedure
TForm1.CheckListBox1ClickCheck(Sender: TObject);var  Index:
Integer;begin{$IfDef Linux}  Exit;{$EndIf}  Index :=
CheckListBox1.ItemIndex;  CheckListBox1.Checked[Index] := not
CheckListBox1.Checked[Index];end; end.