Value Change Event

Requires: Base Development System

Class: Control Events

Type: Notify

Generated when the user changes the value of a control. You must read the terminal of a latched Boolean control in its Value Change event case.

LabVIEW generates this event even if the user enters the same value as the current control value. When used with a slide control, LabVIEW generates all intermediate values of the slide each time a user changes the value, including values that register before the user releases the mouse.

If you click a combo box control or I/O control but do not change the value, LabVIEW generates this event.

Event Data Fields

NameDescription
SourceSource of the event. LabVIEW UI refers to any built-in user interface event.

0LabVIEW UI
TypeType of event that occurred, such as Mouse Down, Value Change, Timeout, and so on.
TimeValue of the millisecond timer when the event occurred.
TimeValue of the millisecond timer when the event occurred.
OldValValue of the control before the data change.
NewValValue of the control after the data change.