TCheckGroup
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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
