Question

当我调用Quote.new（）时，如何设置设置名字和姓氏的虚拟属性？

before_save：assign_name方法似乎不起作用。我收到错误

NoMethodError: undefined method `before_save' for Quote:Class

控制器：

  quote = {name: "John Doe", City: "New York"}
  Quote.new(quote)

MODEL：

class Quote
    include ActiveModel::Model

    before_save :assign_name

    attr_accessor :name, :first, :last, :city


    def assign_name
      title_split = self.name.split(" / ")
      self.first = title_split[0]
      self.last = title_split[1]
    end
end

Answer 1

你可以使用这样的东西

class Quote
  include ActiveModel::Model
  attr_accessor :name, :first, :last, :city

  def initialize(attributes={})
    super
    assign_name(name)
  end

  def assign_name(name)
    title_split = name.split(" / ")
    self.first = title_split[0]
    self.last = title_split[1]
  end
end

还链接到文档here

Answer 2

before_save在ActiveRecord中定义。您需要让您的类继承ActiveRecord :: Base，如下所示：

class Quote < ActiveRecord::Base
end

如果你把方法放在“before_save”回调中，这意味着只有在执行Quote＃save时才会调用该方法。例如，

quote = {name: "John Doe", City: "New York"}
q = Quote.new(quote)
q.save

设置虚拟属性Rails活动模型

2 个答案: