导轨 - 使用的link_to上application.html.erb嵌套资源没有得到ID

Question

我有application.html.erb一个侧边栏，并链接应该去/品牌/ [brand_id] /优惠券

我用brand_coupons_path（@brand），但我得到一个错误，说'没有路线匹配{：action =>“index”，：brand_id => nil，：controller =>“coupons”}缺少必需的键：[：brand_id]'

resources :brands do 
    resources :coupons, :sales 
end 


class Brand < ActiveRecord::Base 
    has_many :coupons 
    has_many :sales 
    accepts_nested_attributes_for :coupons 
    accepts_nested_attributes_for :sales 
end 



class Coupon < ActiveRecord::Base 
    belongs_to :brand 
end 


<div class="sidebar"> 
    <ul class="sidebar-list"> 
     <li><a class="sidebar-header">Most Popular Brands</a></li> 
     <% @brands.each do |brand| %> 
      <% if current_page?(:controller => 'coupons') %> 
       <li><%= link_to brand.name, brand_coupons_path(@brand), :class => "sidebar-link" %></li> 
      <% else %> 
       <li><%= link_to brand.name, brand_sales_path(@brand), :class => "sidebar-link" %></li> 
      <% end %> 
     <% end %> 
    </ul> 
</div> 

class CouponsController < ApplicationController 
      before_action :set_coupon, only: [:show, :edit, :update, :destroy] 
      # before_filter :load_brand 

     def new 
      @coupon = Coupon.new 
     end 

     def index 
      @coupons = Coupon.where(brand_id: params[:brand_id]) 
     end 

     def show 
     end 

     def create 
      @coupon = Coupon.new(coupon_params) 

      respond_to do |format| 
       if @coupon.save 
       format.html { redirect_to '/', notice: 'Coupon was successfully created.' } 
       format.json { render :show, status: :created, location: @coupon } 
       else 
       format.html { render :new } 
       format.json { render json: @coupon.errors, status: :unprocessable_entity } 
       end 
      end 
     end 

class BrandsController < ApplicationController 
    before_action :set_brand, only: [:show, :edit, :update, :destroy] 

    # GET /brands 
    # GET /brands.json 


    def index 
     @brands = Brand.all 
    end 

    # GET /brands/1 
    # GET /brands/1.json 
    def show 
    end 

    # GET /brands/new 
    def new 
     @brand = Brand.new 
    end 

    # GET /brands/1/edit 
    def edit 
    end 
# POST /brands 
    # POST /brands.json 
    def create 
    @brand = Brand.new(brand_params) 

    respond_to do |format| 
     if @brand.save 
     format.html { redirect_to @brand, notice: 'Brand was successfully created.' } 
     format.json { render :show, status: :created, location: @brand } 
     else 
     format.html { render :new } 
     format.json { render json: @brand.errors, status: :unprocessable_entity } 
     end 
    end 
    end 

    # PATCH/PUT /brands/1 
    # PATCH/PUT /brands/1.json 
    def update 
    respond_to do |format| 
     if @brand.update(brand_params) 
     format.html { redirect_to @brand, notice: 'Brand was successfully updated.' } 
     format.json { render :show, status: :ok, location: @brand } 
     else 
     format.html { render :edit } 
     format.json { render json: @brand.errors, status: :unprocessable_entity } 
     end 
    end 
    end 

    # DELETE /brands/1 
    # DELETE /brands/1.json 
    def destroy 
    @brand.destroy 
    respond_to do |format| 
     format.html { redirect_to brands_url, notice: 'Brand was successfully destroyed.' } 
     format.json { head :no_content } 
    end 
    end 

    private 
    # Use callbacks to share common setup or constraints between actions. 
    def set_brand 
     @brand = Brand.find(params[:id]) 
    end 

    # Never trust parameters from the scary internet, only allow the white list through. 
    def brand_params 
     params.require(:brand).permit(:name, :logo) 
    end 
end 

Answer 1

您将未定义的@brand变量传递给您的路由帮助程序，而不是块变量brand。变化：

<%= link_to brand.name, brand_coupons_path(@brand), :class => "sidebar-link" %> 
<%= link_to brand.name, brand_sales_path(@brand), :class => "sidebar-link" %> 

到

<%= link_to brand.name, brand_coupons_path(brand), :class => "sidebar-link" %> 
<%= link_to brand.name, brand_sales_path(brand), :class => "sidebar-link" %> 

Answer 2

@brand包含什么？我认为你应该把一个对象变为@brand变量。

像这样。 @brand = Brand.find(params[:id])

我们可以看到您的索引的控制器吗？