TCustomButton class

In unit StdCtrls

The base class for a push button control.

Declaration

pascal

TCustomButton = class(TButtonControl)

Inheritance

Descends from it: TButton TCustomBitBtn

Description

TCustomButton is a TButtonControl descendant which provides the base class for a push button control.

TCustomButton / TButton are used to perform an action when the control is clicked. An OnClick event handler is provided to perform actions needed when the push button is clicked.

Properties are provided to control the appearance and behavior for the control. This includes whether it is the Default or Cancel button on a modal form, and the modal result returned when the push button is clicked.

The control displays a text-based caption and is drawn using a style appropriate for the platform or widgetset. An accelerator key can be defined in the caption which simulates clicking on the push button when the shortcut key is pressed. Support for TBasicAction from the FPC Run-time Library (RTL) is present, but not published in the control.

Please note that the Caption is always center aligned on the push button. The values in properties like BiDiMode and UseRightToLeftAlignment are ignored in the control.

Please note that the Color for the control defaults to the system-defined color used for button controls (clDefault or clBtnFace).

Do not create instances of TCustomButton; use the TButton descendant instead.

Use TBitBtn for a push button control which displays a bitmap instead of a text-based caption.

Use TSpeedButton for a push button control which can remain in the pressed or down state.

Properties

`ParentColor`	protected	Indicates if the parent color is used to draw the control.
`Active`	public	True if the control is the Cancel or Default button.
`Default`	public	True if the button is the default button in a modal form.
`ModalResult`	public	Value returned when the control is clicked in a modal form.
`ShortCut`	public	Shortcut key for the control.
`ShortCutKey2`	public	Secondary shortcut key for the control.
`Cancel`	public	True if the button is the modal Cancel button.
`Color`	public	Color used for the button face.
`TabStop`	public	Enables keyboard navigation using the Tab or Shift+Tab keys.

Methods

`WSRegisterClass`	protected	Registers this component class with the current WidgetSet.
`CreateWnd`	protected	Creates the handle for the widgetset class instance.
`CreateParams`	protected	Updates creation parameters to use values needed for the control.
`ControlKeyDown`	protected	Handles key down events for special navigation keys used in a control.
`ControlKeyUp`	protected	Handles key up events for special navigation keys.
`DialogChar`	protected	Handles an accelerator key for the control.
`ChildClassAllowed`	protected	Checks whether the specified class type is allowed as a child control.
`GetControlClassDefaultSize`	protected	Gets the default size for new instances of the control.
`WSSetDefault`	protected	Notifies the widgetset class of a change to the Default property.
`WSSetText`	protected	Notifies the widgetset class of a change to the caption text for the control.
`TextChanged`	protected	Performs actions needed when the CM_TEXTCHANGED message is handled in the control.
`Loaded`	protected	Performs actions needed when LCL component streaming has been completed.
`UpdateDefaultCancel`	protected	Updates the Default and Cancel properties in the parent form.
`Create`	public	Constructor for the class instance.
`Click`	public	Handles a button click event for the control.
`ExecuteDefaultAction`	public	Performs the Click method if the control is an Active or a Default button.
`ExecuteCancelAction`	public	Performs the Click method if the control is the Cancel button.
`ActiveDefaultControlChanged`	public	Updates the button and/or parent form when the active default control has been changed.
`UpdateRolesForForm`	public	Internal method called by a Form when its DefaultControl or CancelControl has changed.
`UseRightToLeftAlignment`	public	True when BiDiMode is bdRightToLeft.