Difference between revisions of "TCheckGroup"
From Lazarus wiki
Jump to navigationJump to search (→Usage: Small example added) |
(A few tips for using TCheckGroup) |
||
| (4 intermediate revisions by 4 users not shown) | |||
| Line 1: | Line 1: | ||
{{TCheckGroup}} | {{TCheckGroup}} | ||
| − | + | A '''TCheckGroup''' [[image:tcheckgroup.png]] is a control that comprises a group of [[TCheckBox]] items physically and logically grouped together on a container component. | |
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
==Usage== | ==Usage== | ||
| − | To use a | + | To use a TCheckGroup on a [[TForm|form]], you can simply select it on the [[Standard tab]] of the [[Component Palette]] and place it by clicking on the form. |
| − | + | ===Small example=== | |
It changes the background color of a form. This color is determined by adding the individual color components: | It changes the background color of a form. This color is determined by adding the individual color components: | ||
| Line 33: | Line 25: | ||
** select for ''cgGreen'' and ''cgBlue'' also this event handler, by choosing each next to the event ''OnItemClick'' ComboBox ''cgRedItemClick'' | ** select for ''cgGreen'' and ''cgBlue'' also this event handler, by choosing each next to the event ''OnItemClick'' ComboBox ''cgRedItemClick'' | ||
** write following code in the event handler: | ** write following code in the event handler: | ||
| − | <syntaxhighlight> | + | |
| − | procedure TForm1.cgRedItemClick(Sender: TObject; | + | <syntaxhighlight lang=pascal> |
| − | + | procedure TForm1.cgRedItemClick(Sender: TObject; Index: integer); | |
var | var | ||
i, c: Integer; | i, c: Integer; | ||
begin | begin | ||
| − | c:=$000000; | + | c := $000000; // first the color is black |
| − | for i:=0 to 7 do begin | + | for i:=0 to 7 do begin // test Items 0..7 of all Checkgroups |
| − | if cgRed.Checked[i] then c:=c + 1 shl i; | + | if cgRed.Checked[i] then c := c + 1 shl i; // amount of red $000000..$0000FF |
| − | if cgGreen.Checked[i] then c:=c + 1 shl (i + 8); | + | if cgGreen.Checked[i] then c := c + 1 shl (i + 8); // amount of green $000000..$00FF00 |
| − | if cgBlue.Checked[i] then c:=c + 1 shl (i + 16); | + | if cgBlue.Checked[i] then c := c + 1 shl (i + 16); // amount of blue $000000..$FF0000 |
end; | end; | ||
| − | Color:=c; | + | Color := c; |
end; | end; | ||
</syntaxhighlight> | </syntaxhighlight> | ||
| Line 51: | Line 43: | ||
[[image:ExampleTCheckGroup.png]] | [[image:ExampleTCheckGroup.png]] | ||
| + | |||
| + | |||
| + | ==Accessing the Check Boxes== | ||
| + | |||
| + | Each item in the TCheckGroup has a Checked property, to set them all to checked do | ||
| + | |||
| + | <syntaxhighlight lang=pascal>for i := 0 to MyCheckGroup.items.Count-1 do // check all the categories we found. | ||
| + | MyCheckGroup.Checked[i] := true; | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | You can add items at run time by using TCheckGroup.Items, its a TStrings list. To add an new checkbox to the set, just do MyCheckGroup.Items.add('CheckThis'); Similarly, to remove all items, clear the list, MyCheckGroup.Items.clear; | ||
==See also== | ==See also== | ||
| − | |||
| − | |||
| − | + | * [[doc:lcl/extctrls/tcheckgroup.html|TCheckGroup doc]] | |
| + | * [[TCheckBox]] | ||
| + | * [[TGroupBox]] | ||
| + | |||
{{LCL Components}} | {{LCL Components}} | ||
| − | |||
| − | |||
| − | |||
Latest revision as of 08:53, 8 March 2022
│
Deutsch (de) │
English (en) │
suomi (fi) │
français (fr) │
日本語 (ja) │
русский (ru) │
中文（中国大陆） (zh_CN) │
A TCheckGroup 
is a control that comprises a group of TCheckBox items physically and logically grouped together on a container component.
Usage
To use a TCheckGroup on a form, you can simply select it on the Standard tab of the Component Palette and place it by clicking on the form.
Small example
It changes the background color of a form. This color is determined by adding the individual color components:
- create a new application and place a TCheckGroup on your form
- in the object inspector change the property Name of CheckGroup1 to cgRed and the caption to Red
- add the checkboxes for cgRed:
- in the object inspector select the property Items of cgRed
- click on the button [...], the character chain editor opens
- write among one another 1 2 4 8 16 32 64 128 and complete the entry with the OK button
- copy this TCheckGroup by right click cgRed in the form and click on Copy
- right-click the form and click on Insert, which creates TCheckGroup named cgRed1
- now change the Name of cgRed1 to cgGreen and the Caption to Green
- insert even a TCheckGroup and change the name to cgBlue and the caption to Blue
- whenever a CheckBox is clicked, the color will change:
- in the object inspector create the OnItemClick event handler of cgRed by clicking the button [...] next to the event OnItemClick
- select for cgGreen and cgBlue also this event handler, by choosing each next to the event OnItemClick ComboBox cgRedItemClick
- write following code in the event handler:
procedure TForm1.cgRedItemClick(Sender: TObject; Index: integer);
var
i, c: Integer;
begin
c := $000000; // first the color is black
for i:=0 to 7 do begin // test Items 0..7 of all Checkgroups
if cgRed.Checked[i] then c := c + 1 shl i; // amount of red $000000..$0000FF
if cgGreen.Checked[i] then c := c + 1 shl (i + 8); // amount of green $000000..$00FF00
if cgBlue.Checked[i] then c := c + 1 shl (i + 16); // amount of blue $000000..$FF0000
end;
Color := c;
end;
- start your program, it could look like:
Accessing the Check Boxes
Each item in the TCheckGroup has a Checked property, to set them all to checked do
for i := 0 to MyCheckGroup.items.Count-1 do // check all the categories we found.
MyCheckGroup.Checked[i] := true;
You can add items at run time by using TCheckGroup.Items, its a TStrings list. To add an new checkbox to the set, just do MyCheckGroup.Items.add('CheckThis'); Similarly, to remove all items, clear the list, MyCheckGroup.Items.clear;
See also
