XControl

XControls are introduced in LabVIEW 8.0 and enhance the power of front panel objects in great ways.

Essentially an XControl is a front panel object with dedicated code linked to react on certain user events.

An XControl exists of several parts, managed in a .xctl file. The .xctl file is a XML-file like the project-file. Other parts of the XControl are abilities. The following abilities are obliged

Ability	Function	Called if/when	LabVIEW file type	Optional?
Init	To initialize memory, convert from previous version, load data from a previous session	The first time a Xcontrol is added to a VI, an Xcontrol is upgraded, a VI with an XControl is opened	Instrument (VI)	No
Data	Interface to the calling VI	NA	Control (ctl)	No
State	Contains local data for the XControl	NA	Control (ctl)	No
Facade	Contains the code running when the XControl is active	Every time an event inside the Facade VI is triggered	Instrument (VI)	No
Uninit	To close items allocated in Init	The XControl is unloaded from memory	Instrument (VI)	Yes
Convert state for save	Change the data that is saved inside a VI	The VI containing the XControl is saved	Instrument (VI)	Yes

Facade Ability

The Facade VI is the running heart of the XControl. It decides on which events applied to the XControl should be reacted in which ways.

Example XControl Facade VI showing the Timeout frame