[Overview][Types][Classes][Procedures and functions][Index] | Reference for unit 'ExtCtrls' (#lcl)

# TCustomRadioGroup

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

TCustomRadioGroup is the base type for TRadioGroup.

## Declaration

Source position: extctrls.pp line 717

`type TCustomRadioGroup = class(TCustomGroupBox)`
`protected`
`class procedure WSRegisterClass; override;` |  | Registers this component class with the current WidgetSet.
`procedure UpdateInternalObjectList;` |  | Calls the private UpdateItems method to add or remove radio buttons for the grouped control.
`procedure UpdateAll;` |  | Updates the radio buttons and the number of radio buttons per line for the control.
`procedure InitializeWnd; override;` |  | Creates the visual components used in the radio group.
`procedure UpdateRadioButtonStates; virtual;` |  | UpdateRadioButtonStates including any pending changes.
`procedure ReadState(); override;` |  | Reads the values for the control and checks whether ItemIndex is valid.
`procedure SetItems();` |  | Sets the value for the Items property.
`procedure SetColumns();` |  | Sets the value for the Columns property.
`procedure SetItemIndex();` |  | Sets the value for the ItemIndex property.
`function GetItemIndex;` |  | Gets the value for the ItemIndex property.
`procedure CheckItemIndexChanged; virtual;` |  | Checks whether ItemIndex has been changed since the previous call to the method.
`procedure Notification(); override;` |  | Handles the notification for a components inserted into or deleted from the control.
`public`
`constructor Create(); override;` |  | Constructor for the class instance.
`destructor Destroy; override;` |  | Destructor for the class instance.
`function CanModify; virtual;` |  | Indicates if modification of the RadioGroup is permitted.
`procedure FlipChildren(); override;` |  | Flips the horizontal display order for child controls.
`function Rows;` |  | Indicates the number of rows in which Items (radio buttons) are held.
`property AutoFill: Boolean; [rw]` |  | Indicates if radio buttons are resized to fill the available space in the control.
`property Buttons []: TRadioButton; [r]` |  | Provides indexed access to the radio buttons on the group box control.
`property ItemIndex: Integer; [rw]` |  | The ordinal position in Items for the selected radio button in the group.
`property Items: TStrings; [rw]` |  | Contains the captions for the radio button displayed in the control.
`property Columns: Integer; [rw]` |  | Number of columns used to display radio buttons in the control.
`property ColumnLayout: TColumnLayout; [rw]` |  | Fill direction for columns on the grouped control.
`property OnClick: TNotifyEvent; [rw]` |  | Event called when the selected item is changed.
`property OnItemEnter: TNotifyEvent; [rw]` |  | Event handler signalled when a radio button in the group receives focus.
`property OnItemExit: TNotifyEvent; [rw]` |  | Event handler signalled when a radio button in the group loses focus.
`property OnSelectionChanged: TNotifyEvent; [rw]` |  | Event called when the selected item changes.
`end;`

## Inheritance

`TCustomRadioGroup` |  | TCustomRadioGroup is the base type for TRadioGroup.
`TCustomGroupBox` |  | The base class for TGroupBox, TRadioGroup and TCheckGroup.
`TWinControl` |  | Implements a windowed control which can contain other child controls.
`TControl` |  | The base class for visible controls.
`TLCLComponent` |  | The base class for LCL components which have an associated widget.
`TComponent`
?
`TObject`

## Description

A group of related but mutually exclusive radio buttons, selectable by the user.

This class defines Items, where the captions of the individual radio boxes are stored, Rows and Columns for arranging the radio boxes. The ColumnLayout property is used to determine whether the data are arranged down the columns first, or across the rows first.