ruby-on-rails - 保存我的 "Stop"模型实例时未定义的方法

Question

我的 Rails 应用程序包含旅游路线。每条路线都有许多停靠点和航点，停靠点也有类别。

航点只是路线和停靠点之间的中间模型，因为停靠点可以属于多条路线。

因此，当我尝试保存停止时，出现错误:

undefined method `category' for #<Stop:0x007fa067acea90>

并且“if @stop.save”行以红色突出显示:

respond_to do |format|
  if @stop.save
    Waypoint.create(route_id: params[:route_id] , stop_id: @stop.id)
    #print out category id or name here
    category = params[:category]

在我的停止 Controller 中，我在创建时有这个:

def create
@stop = Stop.new(stop_params)

respond_to do |format|
  if @stop.save
    Waypoint.create(route_id: params[:route_id] , stop_id: @stop.id)
    #print out category id or name here
    category = params[:category]
    #once printed save it (stop category)
    StopCategory.create(category_id: category, stop_id:  @stop.id)
    format.html { redirect_to @stop, notice: 'Stop was successfully created.' }
    format.json { render :show, status: :created, location:@stop }
  else
    format.html { render :new }
    format.json { render json: @stop.errors, status: :unprocessable_entity }
  end
end

在我的航路点 Controller 上，我在创建时有这个:

    def create
    @waypoint = Waypoint.create(waypoint_params)

    redirect_to @waypoint.route

end

这是停止模型:

class Stop < ActiveRecord::Base
validates :description, length: { maximum: 140 }
validates :category, presence: true
#Image Uploader
mount_uploader  :stop_image, StopImageUploader

#Relationship with stops and waypoints
has_many :waypoints
has_many :routes, through: :waypoints

# Relationship with categories
has_many :stop_categories
has_many :categories, through: :stop_categories 

结束

这是表单所在的 View :

<h2>Create a new stop:</h2><br>
    <%= form_for(@stop) do |f| %>
      <% if @stop.errors.any? %>
        <div id="error_explanation">
          <h2><%= pluralize(@stop.errors.count, "error") %> prohibited this stop from being saved:</h2>
          <ul>
          <% @stop.errors.full_messages.each do |message| %>
            <li><%= message %></li>
          <% end %>
          </ul>
        </div>
        <% end %>
        <div class="field">
            <%= f.label :name %><br>
            <%= f.text_field :name %>
        </div>

        <select name="category" id=" " >

            <option value="" disabled selected> Select a Category </option>

            <% @categories.each do |category| %>
            <option value="<%= category.id %>"> <%= category.name %> </option>
            <% end %>
        </select>

        <div class="field">
            <%= f.label :description %><br>
            <%= f.text_area :description %>
        </div>


        <div class="field">
            <%= f.label :stop_image %><br>
            <%= f.file_field :stop_image %>
        </div>

        <div class="field">
            <%= f.label :stop_lat %><br>
            <%= f.number_field :stop_lat, :class => 'text_field', :step => 'any' %>
        </div>
        <div class="field">
            <%= f.label :stop_long %><br>
            <%= f.number_field :stop_long, :class => 'text_field', :step => 'any' %>
        </div>

            <%= hidden_field_tag  :route_id,  params[:id]    %>
        <div class="actions">
            <%= f.submit %>
        </div>
    <% end %> 


    <h2>Add existing stop</h2>
    <br>
    <%= form_for(@waypoint) do |f| %>
        <div class="field">
            <%= f.label :stop_id %><br>
            <%= f.number_field :stop_id %>
        </div>
        <%= f.hidden_field  :route_id    %>

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

    <%= link_to 'Edit', edit_route_path(@route) %> |
    <%= link_to 'Back', routes_path %>
    <br>
    <br>
    <br>
        </div>

有什么想法吗？

谢谢!

Answer 1

您的 Stop 模型中是否有“类别”属性？如果不是，则以下内容没有意义:

validates :category, presence: true

这就是它可能失败的地方。

如果你想验证类别的存在，你需要用这样的东西替换那个检查:

validate :has_categories

def has_categories # make this private
  if categories.blank?
    # add errors here
  end
end

以下也可能有效:

validates :categories, presence: true