TCheckGroup: what changed

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1	1		A TCheckGroup ![](/wiki-images/1/1b/Tcheckgroup.png) is a control that comprises a group of [[TCheckBox]] items physically and logically grouped together on a container component.
2	2
3	3		## Usage
4	4
5	5		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.
6	6
7	7		### Small example
8	8
9	9		It changes the background color of a form. This color is determined by adding the individual color components:
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11	11		- create a new application and place a TCheckGroup on your form
12	12		- in the object inspector change the property Name of CheckGroup1 to cgRed and the caption to Red
13	13		- add the checkboxes for cgRed:
14	14		- in the object inspector select the property Items of cgRed
15	15		- click on the button \[...\], the character chain editor opens
16	16		- write among one another 1 2 4 8 16 32 64 128 and complete the entry with the OK button
17	17		- copy this TCheckGroup by right click cgRed in the form and click on Copy
18	18		- right-click the form and click on Insert, which creates TCheckGroup named cgRed1
19	19		- now change the Name of cgRed1 to cgGreen and the Caption to Green
20	20		- insert even a TCheckGroup and change the name to cgBlue and the caption to Blue
21	21		- whenever a CheckBox is clicked, the color will change:
22	22		- in the object inspector create the OnItemClick event handler of cgRed by clicking the button \[...\] next to the event OnItemClick
23	23		- select for cgGreen and cgBlue also this event handler, by choosing each next to the event OnItemClick ComboBox cgRedItemClick
24	24		- write following code in the event handler:
25	25
26	26		``` pascal
27	27		procedure TForm1.cgRedItemClick(Sender: TObject; Index: integer);
28	28		var
29	29		i, c: Integer;
30	30		begin
31	31		c := $000000; // first the color is black
32	32		for i:=0 to 7 do begin // test Items 0..7 of all Checkgroups
33	33		if cgRed.Checked[i] then c := c + 1 shl i; // amount of red $000000..$0000FF
34	34		if cgGreen.Checked[i] then c := c + 1 shl (i + 8); // amount of green $000000..$00FF00
35	35		if cgBlue.Checked[i] then c := c + 1 shl (i + 16); // amount of blue $000000..$FF0000
36	36		end;
37	37		Color := c;
38	38		end;
39	39		```
40	40
41	41		- start your program, it could look like:
42	42
43		-	~~<figure>~~
44		-	~~<img src="ExampleTCheckGroup.png" title="ExampleTCheckGroup.png" />~~
45		-	~~<figcaption>ExampleTCheckGroup.png</figcaption>~~
46		-	~~</figure>~~
	43	+	![](/wiki-images/c/ca/ExampleTCheckGroup.png)
47	44
48	45		## Accessing the Check Boxes
49	46
50	47		Each item in the TCheckGroup has a Checked property, to set them all to checked do
51	48
52	49		``` pascal
53	50		for i := 0 to MyCheckGroup.items.Count-1 do // check all the categories we found.
54	51		MyCheckGroup.Checked[i] := true;
55	52		```
56	53
57	54		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;
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59	56		## See also
60	57
61	58		- [[doc:lcl/extctrls/tcheckgroup.html\|TCheckGroup doc]]
62	59		- [[TCheckBox]]
63	60		- [[TGroupBox]]
64	61
65	62		---
66	63		From the Free Pascal wiki, page "TCheckGroup", as it stood on 2022-03-08 after a change by Dbannon, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

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