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

# TCustomUpDown.OnChangingEx

Event handler signalled to determine if the control can change the value in the Position property.

## Declaration

Source position: comctrls.pp line 1999

`protected property TCustomUpDown.OnChangingEx : TUDChangingEventEx read FOnChangingEx write FOnChangingEx;`

## Description

OnChangingEx is a TUDChangingEventEx property with the event handler signalled prior to setting a new value for the Position property. The handler include a Boolean AllowChange argument which indicates if a change to the Position property is allowed in the control. Setting AllowChange to False in the handler routine prevents a change from being applied to the property value.

OnChangingEx also includes arguments with new value for the Position property and whether the change is an increase or decrease to the value.

OnChangingEx is signalled (when assigned) from CanChange, and is used to get the return value for the method.

Use OnChanging to implement an event handler which uses logic not based on the proposed new value for the Position property.

## See also

TCustomUpDown.CanChange |  | Indicates whether a change using the control can be applied.
TCustomUpDown.Position |  | The current position (or value) for the control as a SmallInt type.
TCustomUpDown.OnChanging |  | Event handler signalled prior to changing the value in the Position property.
TUDChangingEventEx |  | Specifies an event handler signalled prior to changing the value in a TUpDown control.