Difference between revisions of "TRadioGroup"
("Usage" added) |
|||
Line 1: | Line 1: | ||
{{TRadioGroup}} | {{TRadioGroup}} | ||
− | >> [[LCL Components]] >> TRadioGroup | + | >> [[LCL Components]] >> TRadioGroup |
This page explains how to use the [[doc:lcl/extctrls/tradiogroup.html|TRadioGroup]] component. When I mention to click on something, unless I explicitly say to right-click, you always left-click on the item in question. | This page explains how to use the [[doc:lcl/extctrls/tradiogroup.html|TRadioGroup]] component. When I mention to click on something, unless I explicitly say to right-click, you always left-click on the item in question. | ||
Line 67: | Line 67: | ||
==See also== | ==See also== | ||
− | [[TRadioButton]] | + | * [[TRadioButton]] |
− | [[TGroupBox]] | + | * [[TGroupBox]] |
{{LCL Components Footer |TGroupBox|TCheckGroup}} | {{LCL Components Footer |TGroupBox|TCheckGroup}} | ||
Line 75: | Line 75: | ||
[[Category:LCL]] | [[Category:LCL]] | ||
[[Category:Components]] | [[Category:Components]] | ||
− |
Revision as of 23:54, 17 July 2016
│
Deutsch (de) │
English (en) │
suomi (fi) │
français (fr) │
日本語 (ja) │
русский (ru) │
>> LCL Components >> TRadioGroup
This page explains how to use the TRadioGroup component. When I mention to click on something, unless I explicitly say to right-click, you always left-click on the item in question.
Description
A group of related but mutually exclusive radio buttons, requiring the user to select one of a set of alternatives. It's like a TGroupBox with integrated TRadioButtons.
Usage
To use a TRadioGroup on a form, you can simply select it on the Standard component pallet and place it by clicking on the form.
Small example
Geometric figures should be drawn randomly and depending on the TRadioGroups to the form. RadioGroup1 determines the shape, the number RadioGroup2.
- create a new application and place two TRadioGroups on your form
- change in the Object Inspector the property Name of RadioGroup1 to rgShape, also RadioGroup2 to rgCount
- change identical Caption of rgShape to Shape and that of rgCount to Count
- add the RadioButtons for rgShape:
- in the Object Inspector select the property Items of rgShape
- click on the button [...], the character chain editor opens
- write among each other Lines Rectangles Ellipses and complete the entry with the button OK
- add identical the RadioButtons for rgCount (written among each other): 1 5 10 20 50 100
- set the first RadioButton as the currently selected, by setting the property ItemIndex of rgShape and rgCount from -1 to 0
- create the OnClick event handler of rgShape by double clicking rgShape
- also use these event handler for rgCount:
- in the Object Inspector select rgCount
- now select the tab Events in the Object Inspector
- go to the OnClick event and select in the adjacent ComboBox rgShapeClick
- whenever rgShape or rgCount is clicked, the form should be redrawn, therefore write following code in the event handler:
procedure TForm1.rgShapeClick(Sender: TObject);
begin
Repaint;
end;
- whenever the form is redrawn, the shapes should be drawn:
- in the Object Inspector select Form1
- select the tab Events
- click on the button [...] next to the event OnPaint
- the handler is created, enter the following code:
procedure TForm1.FormPaint(Sender: TObject);
var
i: Integer;
begin
if TryStrToInt(rgCount.Items[rgCount.ItemIndex], i) then
for i:=1 to i do begin
Canvas.Pen.Color:=Random($1000000);
Canvas.Brush.Color:=Random($1000000);
case rgShape.Items[rgShape.ItemIndex] of
'Lines': Canvas.Line(Random(ClientWidth), Random(ClientHeight), Random(ClientWidth), Random(ClientHeight));
'Rectangles': Canvas.Rectangle(Random(ClientWidth), Random(ClientHeight), Random(ClientWidth), Random(ClientHeight));
'Ellipses': Canvas.Ellipse(Random(ClientWidth), Random(ClientHeight), Random(ClientWidth), Random(ClientHeight));
end;
end;
end;
- start your program, it could look like:
See also
Return To: LCL Components | — Previous: TGroupBox | Next: TCheckGroup |