1

我创建了一个购物车，其中包含会话对象中存在的行项目。如果购物车存在，我不知道如何链接到我的购物车显示页面，如果不存在，我只是链接到“购物车为空”页面。我错过了什么？我的代码如下：

  • 购物车 has_many line_items, & lineitems 属于购物车

查看链接 ，我不确定我应该在这里放什么以及在哪里定义它，例如......“if current_cart.empty?cart”或“if @cart.line_items.empty?current_cart”等。

        <% if current_cart.line_items.empty?%>
        <%= link_to "cart", cart_path, :class =>'headertab' %>&nbsp;
    <% else %>
        <%= link_to "cart", cart_path(current_cart), :class =>'headertab' %>&nbsp;
    <% end %>

这给了我以下错误：

Showing /Users/dave/rails_projects/EquiptMe/app/views/layouts/_headerexterior.html.erb where line #20 raised:

undefined local variable or method `current_cart' for #<#<Class:0x007fae841cc8e0>:0x007fae83339698>
Extracted source (around line #20):

17:         <li><%= link_to "browse gear", '/gear', :class =>'headertab' %></li>
18:         <li><%= link_to "join", '/signup', :class =>'headertab' %></li>
19:         <li>
20:         <% if current_cart.line_items.empty?%>
21:             <%= link_to "cart", cart_path, :class =>'headertab' %>&nbsp;
22:         <% else %>
23:             <%= link_to "cart", cart_path(current_cart), :class =>'headertab' %>&nbsp;

路线

Outdoor::Application.routes.draw do
  resources :line_items

  resources :carts
.....

应用控制器

class ApplicationController < ActionController::Base
  protect_from_forgery

  private

  def current_cart
    Cart.find(session[:cart_id])
    rescue ActiveRecord::RecordNotFound
      cart = Cart.create
      session[:cart_id] = cart.id
      cart
  end
end

推车控制器“显示”、“销毁”和“创建”

 def show
    begin
    @cart = Cart.find(params[:id])
    rescue ActiveRecord::RecordNotFound
      logger.error "Attempt to access invalid cart #{params[:id]}"
      redirect_to '/gear', notice: 'Invalid cart'
    else
      respond_to do |format|
        format.html # show.html.erb
        format.json { render json: @cart }
      end
   end

  def destroy
    @cart = current_cart
    @cart.destroy
    session[:cart_id] = nil

    respond_to do |format|
      format.html { redirect_to carts_url, notice: 'Your cart is currently empty' }
      format.json { head :no_content }
    end
end

  def create
    @cart = Cart.new(params[:cart])

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

行项目控制器“创建”

 def create
    @cart = current_cart
    gear = Gear.find(params[:gear_id])
    @line_item = @cart.add_gear(gear.id)

    respond_to do |format|
      if @line_item.save
        format.html { redirect_to @line_item.cart }
        format.json { render json: @line_item, status: :created, location: @line_item }
      else
        format.html { render action: "new" }
        format.json { render json: @line_item.errors, status: :unprocessable_entity }
      end
    end
  end
  end

谢谢您的帮助！

4

1 回答 1

4

从您的代码中，您始终拥有一个已创建的Cart对象。您的current_cart方法将始终返回new或先前创建的Cart对象，因此您必须链接到cart_path(current_cart).

  <%= link_to "my cart", cart_path(current_cart), :class =>'headertab' %>

在另一种情况下，如果您想检查购物车是否为空？在这种情况下，您必须使用current_cart.line_items.empty?

已编辑

要current_cart在视图和控制器中访问，helper_method :current_cart请向 ApplicationController 添加声明。

代码更新：

class ApplicationController < ActionController::Base
  protect_from_forgery

  private

  def current_cart
    Cart.find(session[:cart_id])
    rescue ActiveRecord::RecordNotFound
      cart = Cart.create
      session[:cart_id] = cart.id
      cart
  end
  helper_method :current_cart
end
于 2012-05-28T05:08:11.287 回答