Getting NoMethodError, how do I define this method?

Question

I am using a virtual attribute called :all_dates on my form . The point of this field is to replace the :purchase_date attribute of my UserPrice model with the date of my :all_dates field. The reason for this is so user's don't have to change the :purchase_date of all of the user_price records they want to create on the form (they can create a maximum of 5), so what it suppose to do is update the columns of the user_prices with the date that is given from the :all_dates field.

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Problem

Unfortunately on creating 1 to 5 records of user_prices, I get a NoMethodError because of the :all_dates field:

NoMethodError (undefined method `user_prices' for #<UserPrice:0x485d918>):
  app/models/user_price.rb:54:in `save_all_dates_to_user_prices'
  app/controllers/user_prices_controller.rb:27:in `each'
  app/controllers/user_prices_controller.rb:27:in `create_multiple'

UPDATE

I got rid of the NoMethodError by putting this in my UserPrice model:

def user_prices
  @user_prices = Array.new() { UserPrice.new } 
end

But that isn't correct because the :all_dates field doesn't update my UserPrice :purchase_date fields. Does anyone have any ideas?

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Question

How do I define the method user_prices ? I am guessing its suppose to be able to loop several new records of UserPrice but how is that done?

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Code

This form acts like a nested form but instead of using two or more models its just using one single model which is my UserPrice to generate more records on the form, in my case being 5 new ones.

<%= form_tag create_multiple_user_prices_path, :method => :post do %>
 <%= date_select("user_price", "all_dates"  %>
   <% @user_prices.each_with_index do |user_price, index| %>
      <%= fields_for "user_prices[#{index}]", user_price do |up| %>
          <%= render "add_store_price_fields", :f => up %>
      <% end %>
   <% end %>
<% end %>

---

  class UserPrice < ActiveRecord::Base
  attr_accessible :price, :product_name, :all_dates
  attr_accessor :all_dates
  after_save :save_all_dates_to_user_prices

  protected

  def save_all_dates_to_user_prices
      self.user_prices.each {|up| up.purchase_date = self.all_dates if up.new_record?}
  end

---

class UserPricesController < ApplicationController

  def new
     @user_prices = Array.new(5) { UserPrice.new }
  end

  def create_multiple
    @user_prices = params[:user_prices].values.collect { |up| UserPrice.new(up) }
    if @user_prices.all?(&:valid?)
      @user_prices.each(&:save!)
      redirect_to :back, :notice => "Successfully added prices."
    else
      redirect_to :back, :notice => "Error, please try again."
    end
  end

Answer 1

Re: Why receiving error undefined method `user_prices' for...

Ans: You need to define the method user_prices

Since you named the model (object) UserPrice, normally user_price would be used to represent an instance of the model.

You need to re-think what user_prices represents, an array of UserPrice objects/records? Or something else?

Added Do you want method save_all_dates_to_user_prices to iterate through all of the UserPrice records?

If so, then:

• You probably want save_all_dates_to_user_prices to be a class method since it would be dealing with the multiple instances of the class.

• The method would need to first load an array with all of the current records. Do this with the class method find or scope

Answer 2

我采用了完全不同的方法，但在以下问题中仍然能够获得相同的结果： 如何使用虚拟属性更新模型的属性？