爲什麼我的鐵軌動作助手有TypeError？

Question

紅寶石版本：

ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux] 

Rails的版本：

Rails 4.1.4 

你好，

我做了一個幫手在我的管理指數的觀點我基本管理控制器動作。

application_helper.rb

(...) 
def actions_helper(object) 
    show_link = link_to "<span class=\"glyphicon glyphicon-file\"></span>".html_safe, [:admin, object], :class => 'btn btn-primary', :title => 'Voir '+@model_singular_name 
    edit_link = link_to "<span class=\"glyphicon glyphicon-pencil\"></span>".html_safe, [:edit, :admin, object], :class => 'btn btn-primary', :title => 'Modifier '+@model_singular_name 
    destroy_link = link_to "<span class=\"glyphicon glyphicon-trash\"></span>".html_safe, [:admin, object], :method => :delete, :data => { :confirm => 'Voulez-vous supprimer '+@model_singular_name+'?' }, :class => 'btn btn-primary', :title => 'Supprimer '+@model_singular_name 
    "<p class=\"btn-group btn-group-xs\">".html_safe+show_link+edit_link+destroy_link+"</p>".html_safe 
end 
(...) 

它非常適合我的管理頁面控制器，這裏是視圖：

的意見/管理/頁/ index.html.haml

(...) 
%td.col-sm-1 
    = actions_helper(page) 
(...) 

這裏是我的瀏覽器的結果：

<td class="col-sm-1 tac"> 
    <p class="btn-group btn-group-xs"> 
    <a class="btn btn-primary" href="/admin/pages/linge-de-lit" title="Voir la page"> 
     <span class="glyphicon glyphicon-file"></span> 
    </a> 
    <a class="btn btn-primary" href="/admin/pages/linge-de-lit/edit" title="Modifier la page"> 
     <span class="glyphicon glyphicon-pencil"></span> 
    </a> 
    <a class="btn btn-primary" data-confirm="Voulez-vous supprimer la page?" data-method="delete" href="/admin/pages/linge-de-lit" rel="nofollow" title="Supprimer la page"> 
     <span class="glyphicon glyphicon-trash"></span> 
    </a> 
    </p> 
</td> 

但是當我嘗試做同樣的事情與我的產品管理器，我有一個類型錯誤，這裏是視圖：

的意見/管理/產品/ index.html.haml

(...) 
%td.col-sm-1 
    = actions_helper(product) 
(...) 

這裏是我的日誌錯誤：

ActionView::Template::Error (no implicit conversion of nil into String): 
    58:    .badge.background-danger. 
    59:    %span.glyphicon.glyphicon-list-alt 
    60:  %td.col-sm-1. 
    61:   = actions_helper(product) 
    app/helpers/application_helper.rb:34:in `+' 
    app/helpers/application_helper.rb:34:in `actions_helper' 
    app/views/admin/products/index.html.haml:61:in `block in _app_views_admin_products_index_html_haml__1562039986179127831_70358450305840' 
    app/views/admin/products/index.html.haml:24:in `_app_views_admin_products_index_html_haml__1562039986179127831_70358450305840' 

我不認爲這個問題是在我的控制器或我的e因爲當我詢問我的actions_helper只返回#{object}時，我的管理頁面控制器的結果是#<Page:0x000000035ccaf8>和我的管理產品控制器#<Product:0x007ffb3618c480>。

UPDATE

這裏是我的管理產品控制器：

控制器/管理/ products_controller.rb

class Admin::ProductsController < Admin::ApplicationController 
    before_action :set_product, only: [:show, :edit, :update, :destroy, :check_favorite, :uncheck_favorite, :check_shop_disponibility, :uncheck_shop_disponibility, :check_web_disponibility, :uncheck_web_disponibility] 

    def index 
    @products = Product.all 
    end 

    def show 
    end 

    def new 
    @product = Product.new 
    @pages = Page.all 
    end 

    def edit 
    @pages = Page.all 
    end 

    def create 
    @product = Product.new(product_params) 

    if @product.save 
     redirect_to [:admin, @product], notice: 'Product was successfully created.' 
    else 
     render action: 'new' 
    end 
    end 

    def update 
    if @product.update(product_params) 
     redirect_to [:admin, @product], notice: 'Product was successfully updated.' 
    else 
     render action: 'edit' 
    end 
    end 

    def destroy 
    @product.destroy 
    redirect_to admin_products_url, notice: 'Product was successfully destroyed.' 
    end 

    def check_favorite 
    @product.update(favorite: true) 
    redirect_to admin_products_url 
    end 

    def uncheck_favorite 
    @product.update(favorite: false) 
    redirect_to admin_products_url 
    end 

    def check_shop_disponibility 
    @product.update(shop_disponibility: true) 
    redirect_to admin_products_url 
    end 

    def uncheck_shop_disponibility 
    @product.update(shop_disponibility: false) 
    redirect_to admin_products_url 
    end 

    def check_web_disponibility 
    @product.update(web_disponibility: true) 
    redirect_to admin_products_url 
    end 

    def uncheck_web_disponibility 
    @product.update(web_disponibility: false) 
    redirect_to admin_products_url 
    end 

    private 

    def set_product 
     @product = Product.find(params[:id]) 
    end 

    def product_params 
     params.require(:product).permit(:name, :description, :brand_id, :price, :minimum_price, :shop_disponibility, :web_disponibility, :purchase_link, :favorite, :page_ids => [], :post_ids => []) 
    end 
end 

這裏是我的routes.rb：

Rails.application.routes.draw do 

    concern :change_priority do 
    member do 
     patch :increase_priority 
     patch :decrease_priority 
    end 
    end 
    concern :change_favorite do 
    member do 
     patch :check_favorite 
     patch :uncheck_favorite 
    end 
    end 
    concern :change_visibility do 
    member do 
     patch :check_visibility 
     patch :uncheck_visibility 
    end 
    end 
    concern :change_disponibility do 
    member do 
     patch :check_shop_disponibility 
     patch :uncheck_shop_disponibility 
     patch :check_web_disponibility 
     patch :uncheck_web_disponibility 
    end 
    end 
    namespace :admin do 
    root 'dashboard#index' 
    resources :brands 
    resources :pages, concerns: [:change_priority, :change_favorite, :change_visibility] 
    resources :posts, concerns: [:change_priority, :change_favorite, :change_visibility] 
    resources :products, concerns: [:change_favorite, :change_disponibility] 
    end 

    root 'welcome#index' 
    get 'contact' => 'contact#index' 

    get '/:id', to: 'categories#show', as: 'category' 
    get '/:category/:id', to: 'pages#show', as: 'page' 

end 

Answer 1

變量@model_singular_name爲零。確保它設置在某個地方。