2011-09-06 46 views

回答

33

有三種方法可以做到這一點:符號,字符串或Proc。

class User < ActiveRecord::Base 

    after_create :send_welcome_email, unless: :is_celebrant? 
    after_create :send_welcome_email, unless: "is_celebrant?" 
    after_create :send_welcome_email, unless: Proc.new { self.role == "Celebrant" } 

end 

Documentation

+2

文檔細節已移到[這裏](http://guides.rubyonrails.org/active_record_callbacks.html#using-if-and-unless-with-a-symbol) – gotva

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