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

# TCheckBox

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

A label with a box which can contain a check mark.

## Declaration

Source position: stdctrls.pp line 1370

`type TCheckBox = class(TCustomCheckBox)`
`public`
`constructor Create(); override;` |  | Constructor for the class instance.
`published`
`property Action: TBasicAction;` |  | The Action associated with the control.
`property Align: TAlign;` |  | Specifies the placement of the control on its Parent control.
`property Alignment: TLeftRight;` |  | Indicates the alignment for the caption text in the control.
`property AllowGrayed: Boolean;` |  | Allows the check box to use a "grayed" state.
`property Anchors: TAnchors;` |  | The set of anchor definitions for this control.
`property AutoSize: Boolean;` |  | Allows automatic adjustment of the size for the control, according to its content.
`property BidiMode: TBiDiMode;` |  | Indicates whether text controls use in bi-directional reading.
`property BorderSpacing: TControlBorderSpacing;` |  | Determines the inner and outer border spacing for this control.
`property Caption: TCaption;` |  | The text displayed for the control.
`property Checked: Boolean;` |  | Indicates the checked state for the control as a Boolean value.
`property Color: TColor;` |  | The background color for the control.
`property Constraints: TSizeConstraints;` |  | Contains the minimum and maximum Width and Height for the control.
`property DoubleBuffered: Boolean;` |  | When enabled, it reduces flicker when the control is painted.
`property DragCursor: TCursor;` |  | The cursor shape shown during a drag operation.
`property DragKind: TDragKind;` |  | Indicates the action performed for a drag operation: drag-and-drop or drag-and-dock.
`property DragMode: TDragMode;` |  | Determines how a drag operation is started for the control.
`property Enabled: Boolean;` |  | Determines whether the control responds to mouse or keyboard input.
`property Font: TFont;` |  | The font to be used for text display in this control.
`property Hint: TTranslateString;` |  | The text to show in the Hint window for the control.
`property ParentColor: Boolean;` |  | Use the Color from the Parent control, when enabled.
`property ParentDoubleBuffered: Boolean;` |  | Value for the DoubleBuffered property in a Parent control.
`property ParentFont: Boolean;` |  | Indicates if the Font from the Parent control is used in the control.
`property ParentShowHint: Boolean;` |  | If True, the value of ShowHint for the control will be the same as the one from the Parent. Default is True.
`property ParentBidiMode: Boolean;` |  | Indicates whether the BiDiMode settings in the Parent control are used.
`property PopupMenu: TPopupMenu;` |  | A context-sensitive menu that pops up when the right mouse button is clicked over this control.
`property ShowHint: Boolean;` |  | Enables Hint display for the control.
`property State: TCheckBoxState;` |  | The check, unchecked, or grayed state for the control.
`property TabOrder: TTabOrder;` |  | Indicates the navigation order for the control when the user presses the Tab or Shift+Tab key.
`property TabStop: Boolean;` |  | Enables keyboard navigation using the Tab or Shift+Tab keys.
`property Visible: Boolean;` |  | Allows the control, and all of its children, to be displayed or hidden.
`property OnChange: TNotifyEvent;` |  | Event handler signalled when the button control is clicked.
`property OnChangeBounds: TNotifyEvent;` |  | Event handler signalled when the Bounds for the control have been changed.
`property OnClick: TNotifyEvent;` |  | Notification handler for mouse clicks.
`property OnContextPopup: TContextPopupEvent;` |  | Invoked when a context-sensitive pop-up menu is requested.
`property OnDragDrop: TDragDropEvent;` |  | Event handler signalled when an object is dropped onto the control.
`property OnDragOver: TDragOverEvent;` |  | Event handler signalled when a control is dragged over the control instance.
`property OnEditingDone: TNotifyEvent;` |  | Event handler signalled when editing is completed for the control.
`property OnEndDrag: TEndDragEvent;` |  | Event handler signalled for the end of a drag-drop operation.
`property OnEnter: TNotifyEvent;` |  | Event handler signalled when the control receives focus.
`property OnExit: TNotifyEvent;` |  | Event handler signalled when the control loses focus.
`property OnKeyPress: TKeyPressEvent;` |  | Event handler signalled for character data entered by the user.
`property OnKeyDown: TKeyEvent;` |  | Event handler signalled for key down keyboard events.
`property OnKeyUp: TKeyEvent;` |  | Event handler signalled when a key up event has occurred for the control.
`property OnMouseDown: TMouseEvent;` |  | Event handler signalled when a mouse down event is handled for the control.
`property OnMouseEnter: TNotifyEvent;` |  | Event handler signalled when the mouse pointer has entered the control.
`property OnMouseLeave: TNotifyEvent;` |  | Event handler signalled when the mouse pointer has left the control.
`property OnMouseMove: TMouseMoveEvent;` |  | Event handler signalled when the mouse pointer is moved in the control.
`property OnMouseUp: TMouseEvent;` |  | Event handler signalled when a mouse up event is handled for the control.
`property OnMouseWheel: TMouseWheelEvent;` |  | Event handler for mouse wheel turned.
`property OnMouseWheelDown: TMouseWheelUpDownEvent;` |  | Event handler signalled for a downward movement of the mouse wheel.
`property OnMouseWheelUp: TMouseWheelUpDownEvent;` |  | Event handler signalled for an upward movement of the mouse wheel.
`property OnResize: TNotifyEvent;` |  | Notification handler for a resize of the control.
`property OnStartDrag: TStartDragEvent;` |  | Event handler signalled for the start of a dragging operation.
`property OnUTF8KeyPress: TUTF8KeyPressEvent;` |  | Handler for a character entered by the user.
`end;`

## Inheritance

`TCheckBox` |  | A label with a box which can contain a check mark.
`TCustomCheckBox` |  | The base class for a check box component.
`TButtonControl` |  | Specifies a base class for button controls.
`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

TCheckBox is a TCustomCheckBox descendant which implements a check box component. A check box control allows the user to choose the state for the control independent of other check box controls (unlike a radio button).

The State property contains the checked, unchecked, or grayed state for the control. The AllowGrayed property indicates if the grayed state is allowed in the control; otherwise only checked and unchecked are used. The Checked property allows the value in State to be updated by setting a Boolean value that indicates if the control is check or unchecked.

## See also

HowToUseStdCtrls |  | How to use StdCtrls, ComCtrls or ExtCtrls.
TButtonControl |  | Specifies a base class for button controls.
TCustomCheckBox |  | The base class for a check box component.
TToggleBox |  | A labelled box capable of being checked or unchecked.
TRadioButton |  | Implement a radio button control.