Ruby on rails Rails 5嵌套资源URL具有多个直通关联

我已经创建了一个小的测试应用程序，利用Has-Many-Through-Association方法，但我似乎可以在嵌套路由中使用link_

错误消息

categories/index.html

正如您在这里看到的，route:location\u category\u path需要两件事：：location\u id&:id您想要引用的类别的id

在您的情况下，您只指定一个，而不是另一个。您还需要指定：location\u id

还有一种较短的方法可以编写此URL:[位置\标识，类别\标识]。只需编写一个数组，其中两个id都以location_id开头。

用于路由：

location_category_path  GET /locations/:location_id/categories/:id(.:format)    

您需要几个对象，位置id对象和类别id对象：

<!-- /locations/:location_id/categories/:id -->
<%= link_to 'Show', [{location_id}, {category_id}] %>

---

再加上阿尔斯兰的回答

如果还没有，您可能需要在控制器中设置@location

app/controllers/categories_controller.rb

它遵循路由的顺序，即：location\u id然后：id，当您绑定exec-rake路由时，或者您也可以像下面这样指定：

location_category_path(location_id: @location.id, id: category.id)

---

您就快到了，只需添加两个ID，您将需要引用该特定类别：。希望有帮助！你的假设是错误的，请阅读问题有很多：地点。因此，您的解决方案不起作用。实际上，您会得到一个错误：未定义的方法id，无需担心：快乐编码！我如上所述添加了数组，并收到了错误未定义的局部变量或方法location\u id'..`然后我将链接格式化为'location\u id和category\u id'的“并收到了错误未定义的方法location”。我想说的是，您需要在数组中实际添加位置Id和类别Id。你明白我说的吗？

class Product < ApplicationRecord
  has_many :locations
  has_many :categories, through: :locations
end

Rails.application.routes.draw do
  resources :locations do
    resources :categories do
      resources :products
    end
  end
  root :to => 'locations#index'
end

...
<% @categories.each do |category| %>
   <tr>
     <td><%= category.name %></td>
     <td><%= link_to 'Show', location_category_path(category) %></td>
     <td><%= link_to 'Edit', edit_location_category_path(category) %></td>
     <td><%= link_to 'Destroy', location_categories_path(category), method: :delete, data: { confirm: 'Are you sure?' } %></td>
   </tr>
<% end %>
...

location_category_products_path GET /locations/:location_id/categories/:category_id/products(.:format)  
products#index

POST    /locations/:location_id/categories/:category_id/products(.:format)  
products#create

new_location_category_product_path  GET /locations/:location_id/categories/:category_id/products/new(.:format)  
products#new

edit_location_category_product_path GET /locations/:location_id/categories/:category_id/products/:id/edit(.:format) 
products#edit

location_category_product_path  GET /locations/:location_id/categories/:category_id/products/:id(.:format)  
products#show

PATCH   /locations/:location_id/categories/:category_id/products/:id(.:format)  
products#update

PUT /locations/:location_id/categories/:category_id/products/:id(.:format)  
products#update

DELETE  /locations/:location_id/categories/:category_id/products/:id(.:format)  
products#destroy

location_categories_path    GET /locations/:location_id/categories(.:format)    
categories#index

POST    /locations/:location_id/categories(.:format)    
categories#create

new_location_category_path  GET /locations/:location_id/categories/new(.:format)    
categories#new

edit_location_category_path GET /locations/:location_id/categories/:id/edit(.:format)   
categories#edit

location_category_path  GET /locations/:location_id/categories/:id(.:format)    
categories#show

PATCH   /locations/:location_id/categories/:id(.:format)    
categories#update

PUT /locations/:location_id/categories/:id(.:format)    
categories#update

DELETE  /locations/:location_id/categories/:id(.:format)    
categories#destroy

locations_path  GET /locations(.:format)    
locations#index

POST    /locations(.:format)    
locations#create

new_location_path   GET /locations/new(.:format)    
locations#new

edit_location_path  GET /locations/:id/edit(.:format)   
locations#edit

location_path   GET /locations/:id(.:format)    
locations#show

PATCH   /locations/:id(.:format)    
locations#update

PUT /locations/:id(.:format)    
locations#update

DELETE  /locations/:id(.:format)    
locations#destroy

root_path   GET /   
locations#index

location_category_path  GET /locations/:location_id/categories/:id(.:format)    

location_category_path  GET /locations/:location_id/categories/:id(.:format)    

<!-- /locations/:location_id/categories/:id -->
<%= link_to 'Show', [{location_id}, {category_id}] %>

class CategoriesController < ApplicationController
  def index
    @location = # your code here
  end
end

<% @categories.each do |category| %>
   <tr>
     <td><%= category.name %></td>
     <td><%= link_to 'Show', location_category_path(@location.id, category.id) %></td>
     <td><%= link_to 'Edit', edit_location_category_path(@location.id, category.id) %></td>
     <td><%= link_to 'Destroy', location_categories_path(@location.id, category.id), method: :delete, data: { confirm: 'Are you sure?' } %></td>
   </tr>
<% end %>

location_category_path(@location.id, category.id)

location_category_path(location_id: @location.id, id: category.id)