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

# TControl.VisibleChanged

Notifies all chtOnVisibleChanged handlers for the control.

## Declaration

Source position: controls.pp line 1541

`protected procedure TControl.VisibleChanged; virtual;`

## Description

VisibleChanged is called when a new value has been assigned to the Visible property. It occurs after the new property value is stored to its member in the class instance. It allows all of the TNotifyEvent routines registered for the chtOnVisibleChanged control handler type to be signalled for the new property value.

VisibleChanged calls the DoCallNotifyHandler method to signal each of the handler routines using the chtOnVisibleChanged control handler type. The class instance is used as the Sender argument for the event notification.

Use AddHandlerOnVisibleChanged and RemoveHandlerOnVisibleChanged to manage the TNotifyEvent handler routines for the chtOnVisibleChanged handler type used in the control.

See VisibleChanging for the actions performed before the value in Visible is updated.

## See also

TControl.Visible |  | Allows the control, and all of its children, to be displayed or hidden.
TControl.DoCallNotifyHandler |  | Signals handler routines for the specified control handler type.
TControl.AddHandlerOnVisibleChanged |  | Adds or inserts the specified OnVisibleChanged event handler.
TControl.RemoveHandlerOnVisibleChanged |  | Removes the specified OnVisibleChanged event handler.
TControl.VisibleChanging |  | Notifies all chtOnVisibleChanging handlers for the control.
TControlHandlerType |  | Notification handler types.
TNotifyEvent