TCheckGroup: what changed

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Title: TCheckGroup

New		Line
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	+
3	+	## Usage
4	+
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	+
7	+	### Small example
8	+
9	+	It changes the background color of a form. This color is determined by adding the individual color components:
10	+
11	+	- create a new application and place a TCheckGroup on your form
12	+	- in the object inspector change the property Name of CheckGroup1 to cgRed and the caption to Red
13	+	- add the checkboxes for cgRed:
14	+	- in the object inspector select the property Items of cgRed
15	+	- click on the button \[...\], the character chain editor opens
16	+	- write among one another 1 2 4 8 16 32 64 128 and complete the entry with the OK button
17	+	- copy this TCheckGroup by right click cgRed in the form and click on Copy
18	+	- right-click the form and click on Insert, which creates TCheckGroup named cgRed1
19	+	- now change the Name of cgRed1 to cgGreen and the Caption to Green
20	+	- insert even a TCheckGroup and change the name to cgBlue and the caption to Blue
21	+	- whenever a CheckBox is clicked, the color will change:
22	+	- in the object inspector create the OnItemClick event handler of cgRed by clicking the button \[...\] next to the event OnItemClick
23	+	- select for cgGreen and cgBlue also this event handler, by choosing each next to the event OnItemClick ComboBox cgRedItemClick
24	+	- write following code in the event handler:
25	+
26	+	``` pascal
27	+	procedure TForm1.cgRedItemClick(Sender: TObject; Index: integer);
28	+	var
29	+	i, c: Integer;
30	+	begin
31	+	c := $000000; // first the color is black
32	+	for i:=0 to 7 do begin // test Items 0..7 of all Checkgroups
33	+	if cgRed.Checked[i] then c := c + 1 shl i; // amount of red $000000..$0000FF
34	+	if cgGreen.Checked[i] then c := c + 1 shl (i + 8); // amount of green $000000..$00FF00
35	+	if cgBlue.Checked[i] then c := c + 1 shl (i + 16); // amount of blue $000000..$FF0000
36	+	end;
37	+	Color := c;
38	+	end;
39	+	```
40	+
41	+	- start your program, it could look like:
42	+
43	+	<figure>
44	+	<img src="ExampleTCheckGroup.png" title="ExampleTCheckGroup.png" />
45	+	<figcaption>ExampleTCheckGroup.png</figcaption>
46	+	</figure>
47	+
48	+	## Accessing the Check Boxes
49	+
50	+	Each item in the TCheckGroup has a Checked property, to set them all to checked do
51	+
52	+	``` pascal
53	+	for i := 0 to MyCheckGroup.items.Count-1 do // check all the categories we found.
54	+	MyCheckGroup.Checked[i] := true;
55	+	```
56	+
57	+	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;
58	+
59	+	## See also
60	+
61	+	- [[doc:lcl/extctrls/tcheckgroup.html\|TCheckGroup doc]]
62	+	- [[TCheckBox]]
63	+	- [[TGroupBox]]
64	+
65	+	---
66	+	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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