View source for LabVIEW Class

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A '''LabVIEW Class''' is a file with extension, ''[[LVCLASS File Extension|*.lvclass]]''.  It is an XML file that stores information about the files owned by the library.  The [[Project Explorer]] is used to view and edit these files. It is not recommended to edit the XML directly.  The '''LabVIEW Class''' is a specialization of the [[LabVIEW Project Library]] but has extended behavior to contain data and support encapsulation and inheritance for [[Object-oriented programming]].

== Project Items ==
Inside of a LabVIEW Class, there are many types of [[ProjectItem]]s.  A full list of [[ProjectItem]] can be viewed on the [[ProjectItem]]s page.  

'''Note:''' not all [[ProjectItem]] types are allowed in the LabVIEW Class for example:
* Unlike [[LabVIEW Project Library|LabVIEW Project Libraries]], LabVIEW Classes cannot contain nested libraries.
* [[Auto-populating Folder]]s are not allowed but [[Virtual Folder]]s are allowed.

== Class Members ==
A '''LabVIEW Class''' contains its private data and member VIs/CTLs that can operate on the private data. VIs owned by a class can be referred to by different names depending on its function:
* '''Accessor''' - Reads/Writes to the Private Data
* '''Property''' - An Accessor in a Property Definition Folder
* '''Method''' - Any other VI owned by the Class, usually operates on the Class data via a ''Class in'' and/or ''Class out'' on its connector pane
* '''Constructor''' - LabVIEW does not have a specific constructor node, instead the Object is considered constructed where a new Object constant exists. This could be just the constant or sometimes it is the constant wrapped in a VI with some initialization to its data. In the later case a ''"Constructor VI"'' only has a ''Class out''.

=== Creation of Members ===
The creation of the members is done by right-clicking on the Class in the [[Project Explorer]] window, then '''New''' and the item to create.
[[File:NewMembers.png|frameless|center|559x327px|New Members]]
[[File:CreateAccessorDialog.png|thumbnail]]
The Options are:
* '''VI''' - Creates a basic empty VI but still in the Class
* '''Virtual Folder''' - basic [[Virtual Folder]]
* '''Property Definition Folder''' - Accessors in this folder are available through [[Property Node]]
* '''VI from Dynamic Dispatch Template''' - Creates a Dynamic Dispatch Method
* '''VI from Static Dispatch Template''' - Creates a basic Method
* '''VI for Data Member Access...''' - Launches the '''Create Accessor dialog''' to create an Accessor or Property
* '''VI for Override''' - Launches the '''New Override dialog''' to select a Dynamic Dispatch method of the Parent or Ancestor to override (greyed out if there aren't any)
* '''Type Definition''' - Creates a basic Control (CTL) file with ''Type Definition'' already set

==== Create Accessor Dialog ====
This dialog displays the controls in the class's private data. One or more can be selected. You can also decide:
* Access - Read and/or Write
* Dynamic/Static
* Make as a Property
* Place in a specific Virtual Folder

==== Create Accessor Dialog ====
[[File:NewOverrideDialog.png|thumbnail]]
This dialog displays all of the Dynamic Dispatch methods owned by the Parent of this class or an ancestor (see [[Object-oriented programming]]). Methods with an asterisk ("*") if from means that it is a required override. Your class will be broken until all required overrides have been created.

=== Customizing Creation of Class Members ===
Much of the code used to script the creation of Class Members is written in [[G]] (LabVIEW) and is open for editing. Just be careful to backup the code before editing. The code is located in: ''[LabVIEW20xx]\resource\Framework\Providers\LVClassLibrary''

Some of the things you could edit include:
* Modify Template used to create Static/Dynamic Methods
** Location: ''[LabVIEW20xx]\resource\Framework\Providers\LVClassLibrary\CLSUIP_MemberTemplate.vit''
* Change template new member VIs
** Location: ''[LabVIEW20xx]\resource\Framework\Providers\LVClassLibrary\NewAccessors\*.vit''
** Conpane pattern, error case structure, location of bundle/unbundle, etc.
** '''Note: Accessors must have the Class in AND out, Error in AND out, and only one other input OR output otherwise it will be broken.'''
* Add custom scripting after new accessors are created
** Location: [LabVIEW20xx]\resource\Framework\Providers\LVClassLibrary\NewAccessors\Custom User Scripting for *.vi''
* Change default names of new member VIs
** Location: ''[LabVIEW20xx]\resource\Framework\Providers\LVClassLibrary\CLSUIP_LocalizedStrings.vi''
** Global VI that defines naming conventions
** Useful if you prefer Get/Set nomenclature to Read/Write
* Other changes
** The code in the LVClassLibrary folder is mostly open and unlocked, play with it at your own risk.

== See Also ==
* [[LVClassLibrary class]]
* [[LVCLASS File Extension]]
* [[LabVIEW Project]]
* [[LabVIEW Project Library]]

[[Category:Project]]
[[Category:LabVIEW Class]]