Rails 条件验证 [英] Rails Conditional Validation

问题描述

所以我这里有两个模型:

So I have two models here:

class Screen < ActiveRecord::Base
  belongs_to :user
  validates :screen_size, :numericality =>{:less_than_or_equal_to =>100,:greater_than_or_equal_to => 0},:if => "user.access==1"

class User < ActiveRecord::Base
  has_many :screens
  attr_accessible :access

但是这段代码不起作用，因为无论user.access是什么值，它仍然会执行验证.我在这里做错了什么?

But this code doesn't work, cause no matter what value the user.access is, it will still execute the validation. What am I doing wrong here?

谢谢

推荐答案

更改:

:if => "user.access==1"

与:

:if => lambda { |screen| screen.user.try(:access) ==1 }

因为:

• 您需要传递一个函数来即时评估条件

• you need to pass a function to evaluate condition on the fly

如果你的屏幕没有任何用户，仅仅一个screen.user.access就会抛出异常

if your screen doesn't have any user, a mere screen.user.access would throw an exception

这篇关于Rails 条件验证的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！