TCustomUpDown.OnChangingEx property
Event handler signalled to determine if the control can change the value in the Position property.
Declaration
property 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
An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.