# Check box form helper includere il value solo se

**URL:** <https://www.ruby-forum.com/t/check-box-form-helper-includere-il-value-solo-se/208234>\
**Category:** IT\
**Created:** [June 13, 2011, 12:33am UTC](https://www.ruby-forum.com/t/check-box-form-helper-includere-il-value-solo-se/208234 "2011-06-13T00:33:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\
**Post date:** [June 13, 2011, 12:33am UTC](https://www.ruby-forum.com/t/check-box-form-helper-includere-il-value-solo-se/208234/1 "2011-06-13T00:33:11Z")

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check\_box\_tag “supplier[category\_ids][]”, category.id,  
@supplier.categories.include?(category).  
Tramite @supplier.categories.include?(category) risultano valorizzati  
i check box solo se @supplier ha delle categorie.  
Questo check box viene richiamato in varie parti dell’applicazione e  
alcune volte @supplier e’ nil quindi quel frammento di codice mi da  
errore.  
Vorrei far si che @supplier.categories.include?(category) venga  
incluso nel check box solo se @supplier esiste.  
Suggerimenti?