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

# TCustomTabControl.OnChange

Event handler signalled when the active page (or tab) for the control is changed.

## Declaration

Source position: comctrls.pp line 472

`protected property TCustomTabControl.OnChange : TNotifyEvent read FOnPageChanged write FOnPageChanged;`

## Description

OnChange is a TNotifyEvent property with the event handler signalled when the active page (or tab) for the control is changed. OnChange is enabled when the value nboDoChangeOnSetIndex has been included in the Options for the control.

Setting a new value in either PageIndex or TabIndex signals the assigned and enabled event handler. It is also called from the Change method when selection change messages are handled for the control, and when a tab is re-ordered using the MoveTab method.

## See also

TCustomTabControl.Change |  | Performs actions to show or hide pages when the current page is changed.
TCustomTabControl.Options |  | The set of Options enabled for the tabbed control.
TCustomTabControl.PageIndex |  | Ordinal position for the selected page on the tabbed control.
TCustomTabControl.TabIndex |  | Contains the ordinal position for the active Tab in the control.
TCTabControlOption |  | Represents the LCL options available for TCustomTabControl.