相关疑难解决方法(0)

我有一个简单的验证:

class Product < ActiveRecord::Base
  # include ActionView::Helpers::NumberHelper
  ...
  validates_numericality_of :price, :less_than => 1000000, 
                            :message => "must be less than #{number_with_delimiter(1000000)}"                       
  ...
end

在此代码中,我收到以下错误:

undefined method `number_with_delimiter' for #<Class:0x2665a58>

我试着添加:

include ActionView::Helpers::NumberHelper

但它没有帮助.

我错过了什么？