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

# TCustomListView.OnChanging

Event handler signalled when a change notification is received for a list item.

## Declaration

Source position: comctrls.pp line 1602

`protected property TCustomListView.OnChanging : TLVChangingEvent read FOnChanging write FOnChanging;`

## Description

OnChanging is a TLVChangingEvent property with the event handler signalled when a change notification is handled for the list view control. It allows modifications to list items to be handled on an item-by-item basis. It is signalled from the CanChange method (when assigned), and occurs when the widgetset class handles change notification messages for the control.

An application can implement and assign a handler to the property to determine whether a pending change is accepted or rejected for a list item.

See TItemChange for the changes items or states available in the event notification.

See TLVChangingEvent for more information about the event type and its arguments.

Please note that CanChange and OnChanging are relevant for the Windows platform only. Other platforms do not currently generate or handle change notifications for list item values.

## Version info

Added in LCL version 4.0.

## See also

TCustomListView.CanChange |  | Indicates whether a change notification can be applied for an item on the list view control.
TLVChangingEvent |  | Defines an event handler signalled when a widgetset class is updating an item on a list view control.
TItemChange |  | TItemChange - enumerated type for kind of change: in text, in image, or in state.