Question

尝试在我的杂货店应用中显示单个项目。

使用item.product.title＆amp; item.quantity。

因为我想做订单的小计。目前我

NoMethodError in Orders#show - undefined method `product' for #<OrderItem:0x007fe53514d6e8>

orders.show.html

<h1>Your Order</h1>

<table class="table table-striped">
    <tr>
        <th>Customer</th>
        <td><%= @order.user_id %></td>
    </tr>

    <tr>
        <th>Status:</th>
        <td><%= @order.status %></td>
    </tr>

    <tr>
        <th>Items:</th>
        <td><%= @order.order_items.count %></td>
    </tr>
    <tr>
        <th>Items</th>
        <th>Title</th>
        <th>Quantity</th>
        <th>Unit Price</th>
        <th>Subtotal</th>
    </tr>

    <% @order.order_items.each do |item| %>
    <tr>
        <td></td>
        <td><%= item.product.title %></td>   <-----Error
        <td><%= item.quantity %></td>
        <td><%= item.product.price %></td>
        <td><%= print_price item.subtotal %></td>
    <% end %>

</table>


<%= link_to 'Edit', edit_order_path(@order) %> |
<%= link_to 'Back', orders_path %>

product.rb

class Product < ActiveRecord::Base
    validates_numericality_of :price
    validates :stock ,numericality: { greater_than_or_equal_to:  0 }

    has_many :order_items
end

order.item

class OrderItem < ActiveRecord::Base
    belongs_to :Order
    belongs_to :Product

    validates :order_id, :product_id, presence: true
end

完整错误

NameError in Orders#show
undefined local variable or method `product' for #<#<Class:0x007fe539003568>:0x007fe5391abd48>
app/views/orders/show.html.erb:30:in `block in _app_views_orders_show_html_erb__2160818799905733439_70311241143160'
app/views/orders/show.html.erb:27:in `_app_views_orders_show_html_erb__2160818799905733439_70311241143160'

Answer 1

订单商品需要

class OrderItem < ActiveRecord::Base
  belongs_to :order
  belongs_to :product

  validates :order_id, :product_id, presence: true
end

最容易想到的方法是，belongs_to定义了返回与连接关联的对象的方法。所以：产品 - 创建order_item.product。不是：产品

Rails 4：无法显示个别订单

1 个答案: