CheckBox

Inheritance Hierarchy

Description

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

Working with the Component

With each click on the CheckBox component its state changes. Generally, 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 the AllowGrayed property is set to True. 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 component checkbox status. The handler of this event enables the user 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 behavior of the component when its parent component is resized.
	Alignment	The Alignment property determines text alignment in the component.
	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 the component can have an intermediate state.
	Anchors	The Anchors property returns settings that determine the percentage of the size change for the current component when the parent component is resized.
	Brush	The Brush property determines the brush that is used to fill component area.
	Checked	The Checked property determines component checkbox status.
	ClientHeight	The ClientHeight property is used to receive or specify the height of the component’s client area.
	ClientWidth	The ClientWidth property is used to receive or specify the width of the component’s client area.
	Color	The Color property determines a component background color.
	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 is used to store any custom data.
	Enabled	The Enabled property determines whether the component is available for the 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 that is used to display text.
	Height	The Height property determines component height.
	HelpContext	The HelpContext property determines a unique index for the context help section for this component.
	Hint	The Hint property determines a component tooltip text.
	Left	The Left property determines the coordinate of the left border of the component.
	Name	The Name property determines a component name.
	Parent	The Parent property determines a parent component.
	ParentColor	The ParentColor property determines whether the component inherits the color of the parent component.
	ParentFont	The ParentFont property determines whether the component uses the font of the parent component.
	ParentShowHint	The ParentShowHint property determines whether a tooltip is displayed.
	PopupMenu	The PopupMenu property determines the context menu to be displayed on right-click on the component.
	Scrolls	The Scrolls property returns parameters of component's scrollbars.
	ShowHint	The ShowHint property enables and disables showing a component tooltip.
	State	The State property determines a component checkbox status.
	TabOrder	The TabOrder property determines the component position in the tab order.
	TabStop	The TabStop property determines whether the component is focused when the TAB key is pressed.
	Tag	The Tag property is not used by the compiler. The 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 the user.
	Top	The Top property determines the coordinate of the top border of the component.
	Visible	The Visible property determines visibility of the component during execution.
	Width	The Width property determines 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 into screen coordinates.
	DoDragDrop	The DoDragDrop method enables to start dragging 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 into 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 the 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 the component area with the main mouse button.
	OnDblClick	The OnDblClick event occurs if the user double-clicks a component area with the mouse button.
	OnDragDrop	The OnDragDrop event occurs for the component if the 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 the component when the user drags an object over it.
	OnEnter	The OnEnter event occurs when the component receives focus.
	OnExit	The OnExit event occurs when the component loses focus.
	OnHScroll	The OnHScroll event occurs when horizontal scrollbar slider changes its position.
	OnKeyDown	The OnKeyDown event occurs if the component is focused and the keyboard key is pressed.
	OnKeyPress	The OnKeyPress event occurs if the component is focused when the user presses a character key.
	OnKeyPreview	The OnKeyPreview event occurs prior to each event related to key pressing.
	OnKeyUp	The OnKeyUp event occurs if the component is focused and the user releases any button previously pressed.
	OnMouseDown	The OnMouseDown event occurs if the pointer is in component's area and a mouse key 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 the component is focused when the mouse wheel is rotated.
	OnVScroll	The OnVScroll event occurs when vertical scrollbar slider changes its position.