CLASS EXISTS()

From Lianjapedia
Revision as of 05:43, 19 March 2013 by Yvonne.milne (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Purpose

Function to check whether a class has been defined

Syntax

CLASS_EXISTS(<expC>)

See Also

DEFINE CLASS, FUNCTION_EXISTS(), ENDFUNC, FUNCTION, ISSET(), PEXIST(), PROCEDURE, RETURN, SET CLASSLIB, SET LIBRARY, SET PROCEDURE, TYPE(), UNSET(), VARTYPE()

Description

The CLASS_EXISTS() function can be used to check whether a class has been defined. CLASS_EXISTS() will return .T. (true) if the class named <expC> has been defined and .F. (false) if it has not been defined. Classes are defined using the DEFINE CLASS command. Class libraries are loaded using SET CLASSLIB.

Example

set classlib to myclasses1
? set([classlib])
list classes
? class_exists("mybutton1")