问Rails:将产品动态添加到订单

EN

class Order < ActiveRecord::Base
  attr_accessible :client_id, :order_total, :delivery_date
  has_many :orderedproducts
  has_many :products, through: :orderedproducts
  has_one :client

  before_save :generate_total

  def generate_total
    self.order_total = self.products.map(&:product_price).sum
  end
end

class OrdersController < ApplicationController
  def view
    @orders = Order.all
  end

  def new
    @order = Order.new
  end
end

<% if current_user %>
    <div id="dashboard">
        <div id="logo"></div>
        <table id="go_back_link_container">
            <tr>
                <td>
                    <div class="go_back_link">
                        <%= link_to "<- Go Back", root_url %>
                    </div>
                </td>
                <td>
                    <div id="user_display">
                        Logged in as <%= current_user.email %>.
                        <%= link_to "Log out", log_out_path %>
                    </div>
                </td>
            </tr>
        </table>
        <%= form_for @order do |f| %>
          <% if @order.errors.any? %>
            <div class="error_messages">
                <% for message in @order.errors.full_messages %>
                    * <%= message %> <br>
                <% end %>
            </div>
          <% end %>
          <p>
            <%= f.label 'Select The Client' %><br />
            <%= select :client, :client, Client.all().collect { |c| [ (c.firstname + " " + c.surname), c.id ] } %>
          </p>
           <p>
            <%= f.label 'Select The Client' %><br />
            <%= f.fields_for :products do |builder| %>
                <%= render '', f: builder %>
            <% end %>
          </p>
          <p class="button"><%= f.submit %></p>
        <% end %>
        <% flash.each do |name, msg| %>
            <%= content_tag :div, "* " + msg, :id => "flash_#{name}" %><br />
        <% end %>
        <div id="copyright-notice"><div id="copyright_border">Copyright © Conner McCabe, all rights reserved.</div></div>
    </div>
<% else %>
    <script type="text/javascript">
        window.location="<%= root_url %>"
    </script>
<% end %>

class Orderedproduct < ActiveRecord::Base
  attr_accessible :order_id, :product_id, :quantity_ordered
  belongs_to :order
  belongs_to :product
end

class Product < ActiveRecord::Base
    #This line makes these elements accessible outside of the class.
    attr_accessible :product_name, :product_price, :product_quantity, :product_supplier

    has_many :orderedproducts
    has_many :orders, through: :orderedproducts

    #These attributes ensure that the data entered for each element is valid and present.
    validates_presence_of :product_name
    validates_presence_of :product_price
    validates_numericality_of :product_price
    validates_presence_of :product_quantity
    validates_numericality_of :product_quantity
    validates_presence_of :product_supplier

end