Question

我正在尝试将模型Thing与Thing表单上的另一个things/new相关联。每件事都有很多东西：连接表中的东西：related_things。

当我提交表单时，我收到此错误：

NoMethodError in ThingsController#create
undefined method `each' for "1":String

我的代码在哪里出错？

Thing模型：我在行中添加了星号和错误消息。

class Thing < ActiveRecord::Base
  has_many :related_things
  has_many :things, :through => :related_things
  has_attached_file :avatar, :styles => { :medium => "300x300>", :thumb => "30x30!" }, :default_url => "/images/:style/missing.png"
  validates_attachment_content_type :avatar, :content_type => /\Aimage\/.*\Z/

  def related_things
    related_thing_ids = RelatedThing.
        where("thing_a_id = ? OR thing_b_id = ?", self.id, self.id).
        map { |r| [r.thing_a_id, r.thing_b_id] }.
        flatten - [self.id]
    Thing.where(id: related_thing_ids)
  end
  def related_thing_ids=(ids)
    ***ids.each do |id|***
      record = RelatedThing.where(thing_a_id: self.id, thing_b_id: id).first
      record ||= RelatedThing.where(thing_a_id: id, thing_b_id: self.id).first
      record ||= RelatedThing.create!(thing_a_id: self.id, thing_b_id: id)
    end
  end
end

RelatedThing型号：

class RelatedThing < ActiveRecord::Base
  has_many :things
end

Things控制器：

class ThingsController < ApplicationController
  def show
    @thing = Thing.find(params[:id])
    @related_thing = RelatedThing.all
    @thing.things.build
  end
  def new
    @thing = Thing.new
    @things = Thing.all
  end
  def create
    @thing = Thing.new(thing_params)
    if @thing.save
      redirect_to @thing
    else
      render 'new'
    end
  end

  private
  def thing_params
    params.require(:thing).permit(:name, :avatar, :related_thing_ids)
  end
end

观光/ new.html.erb：

<h1>Add Something!</h1>
<p>
  <%= form_for @thing, :url => things_path, :html => { :multipart => true } do |f| %>
    <%= f.text_field :name, :placeholder => "Name of the thing" %>
    <br>
    <%= f.label :related_things %>
    <%= f.collection_select :related_thing_ids, Thing.all, :id, :name %>
    <br>
    <%= f.label :display_picture %>
    <%= f.file_field :avatar %>
    <br>
    <%= f.submit "Submit", class: "btn btn-primary" %>
  <% end %>
</p>

Schema.rb：

ActiveRecord::Schema.define(version: 20141016190146) do
  create_table "related_things", force: true do |t|
    t.integer  "thing_a_id"
    t.integer  "thing_b_id"
    t.datetime "created_at"
    t.datetime "updated_at"
  end
  create_table "things", force: true do |t|
    t.string   "name"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.string   "avatar_file_name"
    t.string   "avatar_content_type"
    t.integer  "avatar_file_size"
    t.datetime "avatar_updated_at"
  end
end

我正在使用Rails 4.0.10。

Answer 1

尝试Array(ids).each ...，它转换数组中的任何对象并响应：每个

~ (main) > Array(nil)
=> []
~ (main) > Array([])
=> []
~ (main) > Array('')
=> [""]
~ (main) > Array(1)
=> [1]

请参阅Kernel#Array

错误：未定义的方法`每个＆＃39; for＆＃34; 1＆＃34;：String

1 个答案: