ruby - Rails 4 嵌套表单 link_to 编辑不在循环中工作

Question

我在 rails 中有一个嵌套的路由/模型/表单。在我的索引页面上，我列出了 todo_lists，下面是 todo_items。我希望能够单击我的待办事项列表标题，然后它会将我带到编辑页面。我研究多态路由和嵌套路由。

更新

这是我阻止它创建虚拟待办事项列表的修复程序。

<%  @current_todo_lists.each do |list| %>
    <% if list.id %>
        <div class="panel">
            <p><strong><%= link_to list.title ,edit_todo_list_path(list)%></strong></p>
            <% list.todo_items.each do |todo_item| %>
                <p><%= todo_item.description %></p>
            <% end %>
        </div>
    <% end %>
<% end %>

github link

Link_to rails nested form edit

polymorphic_path not generating correct path我已经做了很多相当多的研究来寻找茧，多态路线上的导轨指南和其他几个 stackoverflow 链接。

我没有成功完成这些工作。

这是索引页面，其中列出了我所有的 todo_lists 和 todo_items。它通过一个循环来列出每个待办事项列表及其创建的相应项目

更新:

我已经试过了 <%= link_to list.title, edit_todo_list_path(list) %>和 <%= link_to list.title, edit_todo_list_path(@list) %> .我收到的错误消息是:

ActionController::UrlGenerationError at /todo_lists
No route matches {:action=>"edit", :controller=>"todo_lists", :id=>nil} missing required keys: [:id]与 @todo_list 相同的配置给出了相同的错误。基本上它找不到带有 id 的待办事项列表。

在控制台中确实给了我一个结果。所以我错过了一些东西。

>> t = TodoList.find(1)
=> #<TodoList id: 1, title: "First todo List with a modal", created_at: "2014-09-09 23:02:27", updated_at: "2014-09-09 23:02:27", user_id: 1>
>>

更新 2: 这是我的待办事项列表 Controller 中发生错误的地方。没有id是找不到的。

def set_todo_list
@todo_list = TodoList.find(params[:id])
end


<% @todo_lists.each do |list| %> 
    <p><strong><%= link_to list.title, edit_polymorphic_path(@todo_list) %></strong></p>
    <% list.todo_items.each do |todo_item| %>
        <p><%= todo_item.description %></p>
    <% end %>
<% end %>

到目前为止 <p><strong><%= link_to list.title, edit_polymorphic_path(@todo_list) %参数有@todo_list(s)、@todo_lists(s)、todo_items等。

模型:

class TodoList < ActiveRecord::Base
    has_many :todo_items, dependent: :destroy
    accepts_nested_attributes_for :todo_items, allow_destroy: true
    validates_presence_of :title
end

class TodoItem < ActiveRecord::Base
    belongs_to :todo_list
end

Controller :

Class TodoListsController < ApplicationController
  before_filter :authenticate_user!
  before_filter except: [:index]
  before_action :set_todo_list, only: [:show, :edit, :update, :destroy]

  # GET /todo_lists
  # GET /todo_lists.json
  def index
    #@todo_lists = TodoList.all
    #find current user todo lists/items
    @todo_lists = current_user.todo_lists
    @todo_items = current_user.todo_items
    #create a new user todo list
    @todo_list = current_user.todo_lists.new
    # builder for todo list _form
    3.times{ @todo_list.todo_items.build }
  end

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

  # # GET /todo_lists/new
  def new
    @todo_list = current_user.todo_lists.new
    3.times{ @todo_list.todo_items.build }
  end

  # GET /todo_lists/1/edit
  def edit
    #@todo_list = TodoList.find(todo_list_params)
    @todo_list = TodoList.find(params[:id])
  end

  # POST /todo_lists
  # POST /todo_lists.json
  def create
    #@todo_list = TodoList.new(todo_list_params)
    @todo_list = current_user.todo_lists.new(todo_list_params)
    respond_to do |format|
      if @todo_list.save
        format.html { redirect_to @todo_list, notice: 'Todo list was successfully created.' }
        format.json { render :show, status: :created, location: @todo_list }
      else
        format.html { render :new }
        format.json { render json: @todo_list.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /todo_lists/1
  # PATCH/PUT /todo_lists/1.json
  def update
    @todo_list = TodoList.find(params[:id])
    respond_to do |format|
      if @todo_list.update(todo_list_params)
        format.html { redirect_to @todo_list, notice: 'Todo list was successfully updated.' }
        format.json { render :show, status: :ok, location: @todo_list }
      else
        format.html { render :edit }
        format.json { render json: @todo_list.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /todo_lists/1
  # DELETE /todo_lists/1.json
  def destroy
    #@todo_list.TodoList.find(params[:id])
    @todo_list.destroy
    respond_to do |format|
      format.html { redirect_to todo_lists_url, notice: 'Todo list was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    def owns_todolist
      if current_user != TodoList.find(params[:id]).user
        redirect_to todo_lists_path, error: "You can't do that!"
      end
    end
    # Use callbacks to share common setup or constraints between actions.
    def set_todo_list
      @todo_list = TodoList.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def todo_list_params
      params.require(:todo_list).permit(:title, todo_items_attributes: [:description, :_destroy])
    end
end



class TodoItemsController < ApplicationController
  before_action :set_todo_item, only: [:show, :edit, :update, :destroy]
  before_action :set_todo_list

  # GET /todo_items
  # GET /todo_items.json
  def index
    @todo_items = TodoItem.all
  end

  # GET /todo_items/1
  # GET /todo_items/1.json
  def show
    @todo_item = TodoItem.find(params[:id])
  end

  # GET /todo_items/new
  def new
    @todo_item = @todo_list.todo_items.build
  end

  # GET /todo_items/1/edit
  def edit
    @todo_item = TodoItem.find(params[:id])
  end

  # POST /todo_items
  # POST /todo_items.json
  def create
    @todo_item = @todo_list.todo_items.build(todo_item_params)

    respond_to do |format|
      if @todo_item.save
        format.html { redirect_to [@todo_list,@todo_item], notice: 'Todo item was successfully created.' }
        format.json { render :show, status: :created, location: @todo_item }
      else
        format.html { render :new }
        format.json { render json: @todo_item.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /todo_items/1
  # PATCH/PUT /todo_items/1.json
  def update
    @todo_item = TodoItem.find(params[:id])
    respond_to do |format|
      if @todo_item.update(todo_item_params)
        format.html { redirect_to @todo_item, notice: 'Todo item was successfully updated.' }
        format.json { render :show, status: :ok, location: @todo_item }
      else
        format.html { render :edit }
        format.json { render json: @todo_item.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /todo_items/1
  # DELETE /todo_items/1.json
  def destroy
    @todo_item = TodoItem.find(params[:id])
    @todo_item.destroy
    respond_to do |format|
      format.html { redirect_to todo_list_todo_items_url, notice: 'Todo item was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

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

    def set_todo_list
      @todo_list = TodoList.find(params[:todo_list_id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def todo_item_params
      params.require(:todo_item).permit(:description, :text, :todo_list_id)
    end
end

最后是表单。现在它允许添加一个 todo_list 和一些 todo_items 就像练习一样。我计划使用一些 Ajax 以允许稍后进行动态创建。并具有不同的编辑形式。

<%= form_for(@todo_list) do |f| %>
  <% if @todo_list.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@todo_list.errors.count, "error") %> prohibited this todo_list from being saved:</h2>

      <ul>
      <% @todo_list.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
  <div class="field">
    <%= f.label :title %><br>
    <%= f.text_field :title %>
  </div>
  <div>
    <%= f.fields_for :todo_items do |builder| %>
      <%= builder.label :description, "Items" %>
      <%= builder.text_field :description %>
      <%= builder.check_box '_destroy' %>
    <% end %>

  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

Answer 1

我认为这个问题实际上有点棘手，因为 edit_todo_list_path(list) 似乎会抛出同样的错误。

发生的事情是，当您运行 @todo_list = current_user.todo_lists.new 时，@todo_lists 变量(首先是一个持久列表数组)发生了变化。该命令实际上将一个新的(未保留的)列表添加到 @todo_lists 数组的末尾(对我来说似乎是错误的行为，但以前发生在我身上)，因此当您的 View 循环遍历它们时，最后一个没有id，无法为其创建路径。

解决方案是(我认为)在使用 @todo_lists 变量后创建该变量。

从 Controller 中取出 @todo_list，在 View 中使用它的地方，改为执行 current_user.todo_lists.build。这应该实例化一个新列表而不改变@todo_lists变量。