CheckBox

Inheritance Hierarchy

Description

The CheckBox component implements the checkbox which allows to enable or disable some options or is used to indicate a status of different settings.

Working with the Component

With each click on the CheckBox component its state changes. In general case it has three positions:

Selected. Check on the white background appears.
Intermediate. A rectangular, denoting checkbox status uncertainty appears.
Deselected. Empty window.

The intermediate state is only allowed if for the AllowGrayed property the True value is set. If the AllowGrayed = False (default value), then only two states are allowed: Selected and Deselected.

Primary event of the component is OnChange which occurs on changing a checkbox of the component. The handler of this event allows to analyze properties of the Checked and State components which already have new values.

Example

Properties of the CheckBox Component

	Property name	Brief description
	Align	The Align property determines the behavior of the component, when the size of its parent component is changed.
	Alignment	The Alignment property determines the position of a flag inside the component field.
	AllowDrag	The AllowDrag property determines whether an object can be dragged from the component.
	AllowDrop	The AllowDrop property determines whether the component can accept a dragged object.
	AllowGrayed	The AllowGrayed property determines, whether it is possible for a component to have an intermediate state.
	Anchors	The Anchors property returns settings determining % of the size change for the current component when the parent component is resized.
	Brush	The Brush property specifies the brush used to fill the component area.
	Checked	The Checked property determines whether the component is checked.
	ClientHeight	The ClientHeight property receives or specifies the height of the component’s client space.
	ClientWidth	The ClientWidth property receives or specifies the width of the component’s client space.
	Color	The Color property determines the background color of a component.
	ComponentCount	The ComponentCount property returns the number of child components.
	Components	The Components property returns the child component.
	Cursor	The Cursor property determines the look of the cursor over the component.
	Data	The Data property stores any custom data.
	Enabled	The Enabled property determines whether a component is available for a user.
	Focused	The Focused property returns True if the focus is set on the component.
	Font	The Font property determines the set of characteristics, describing the font, used to display text.
	Height	The Height property determines the component height.
	HelpContext	The HelpContext property determines the unique index for a section of a context help for this component.
	Hint	The Hint property determines the hint text for the component.
	Left	The Left property determines the coordinate of the left border of the component.
	Name	The Name property determines the component name.
	Parent	The Parent property determines the parent component.
	ParentColor	The ParentColor property determines whether a component inherits the color of the parent component.
	ParentFont	The ParentFont property determines whether a component should use the font of the parent component.
	ParentShowHint	The ParentShowHint property determines when a tooltip is displayed.
	PopupMenu	The PopupMenu property determines the context menu to be displayed on right-click.
	Scrolls	The Scrolls property returns parameters of component's scrollbars.
	ShowHint	The ShowHint property enables and disables showing a hint for the component.
	State	The State property determines whether the checkbox is selected.
	TabOrder	The TabOrder property determines the position of a component in a tab order.
	TabStop	The TabStop property determines whether the focus is set to a component when the TAB button is pressed.
	Tag	The Tag property is not used by the compiler. A user can change the value of the Tag property and use it as he wishes.
	Text	The Text property determines the row identifying a component for a user.
	Top	The Top property determines the coordinate of the top border of the component.
	Visible	The Visible property determines the visibility of the component during execution.
	Width	The Width property determines the component width.

Methods of the CheckBox Component

	Method name	Brief description
	BringToFront	The BringToFront method brings a component to front.
	ClientToScreen	The ClientToScreen method converts the coordinates of a point specified relative to the component coordinate system to screen coordinates.
	DoDragDrop	The DoDragDrop method starts drag-and-drop operation.
	GetImage	The GetImage method returns the image of the component with all the child components.
	ScreenToClient	The ScreenToClient method converts screen coordinates of a point to coordinates specified relative to the component coordinate system.
	SendToBack	The SendToBack method sends a component to back.
	SetFocus	The SetFocus method sets focus to this component.

Events of the CheckBox Component

	Event name	Brief description
	OnBeginDrag	The OnBeginDrag event occurs for a component, when a user starts to drag an object from the component.
	OnChange	The OnChange event occurs when the selection status of the CheckBox component is changed.
	OnClick	The OnClick event occurs if the user clicks component area using the main mouse button.
	OnDblClick	The OnDblClick event occurs if the user double-clicks a component area using the mouse button.
	OnDragDrop	The OnDragDrop event occurs for a component if a user drops a dragged object over it.
	OnDragEnter	The OnDragEnter event occurs when a dragged object crosses the borders of this component.
	OnDragLeave	The OnDragLeave event occurs when a dragged object leaves the borders of this component.
	OnDragOver	The OnDragOver event occurs for this component when a user drags a dragged object over it.
	OnEnter	The OnEnter event occurs when a component receives focus.
	OnExit	The OnExit event occurs when a component loses focus.
	OnHScroll	The OnHScroll event occurs when the horizontal scrollbar slider changes its position.
	OnKeyDown	The OnKeyDown event occurs if a component is focused and a keyboard key is pressed.
	OnKeyPress	The OnKeyPress event occurs if a component is focused when a user presses a character key.
	OnKeyPreview	The OnKeyPreview event occurs prior to each event requiring clicking.
	OnKeyUp	The OnKeyUp event occurs if a component is focused and a user releases any button previously pressed.
	OnMouseDown	The OnMouseDown event occurs when the pointer is in component area and a mouse button is pressed.
	OnMouseEnter	The OnMouseEnter event occurs when mouse cursor enters the component area.
	OnMouseHover	The OnMouseHover event occurs when mouse cursor is held in the component area.
	OnMouseLeave	The OnMouseLeave event occurs when mouse cursor leaves the component area.
	OnMouseMove	The OnMouseMove event occurs on moving the cursor over component.
	OnMouseUp	The OnMouseUp event occurs on releasing mouse button when the cursor is in component area.
	OnMouseWheel	The OnMouseWheel event occurs if a component is focused when a user rotates a mouse wheel.
	OnVScroll	The OnVScroll event occurs when the vertical scrollbar slider changes its position.