ruby-on-rails – rails 4 collection_select多个嵌套属性未正确

我是rails的新手,我在使用collection_select保存连接表的嵌套属性时遇到问题.我有模型post,tag和post_tagging. post_tagging是一个连接表.

我想为每个帖子设置多个标签,所以我尝试通过collection_select使用多选,但是当我保存时,只将post_id插入到数据库中.下面是我的代码和日志.

Post.rb

class Post < ActiveRecord::Base
  has_many :post_taggings,foreign_key: :post_id,dependent: :destroy
  has_many :tags,through: :post_taggings,source: :tag
  accepts_nested_attributes_for :post_taggings,reject_if: :all_blank,allow_destroy: true
end

Tag.rb

class Tag < ActiveRecord::Base
  has_many :post_taggings,foreign_key: :tag_id,dependent: :destroy
  has_many :posts,source: :post
end

post_tagging.rb(我在post_tagging模型中关闭了tag_id和post_id上的状态验证,因此我可以获得POST的日志.)

class PostTagging < ActiveRecord::Base
  belongs_to :post
  belongs_to :tag

  #validates :post_id,presence: true
  #validates :tag_id,presence: true
end

posts_controller.rb(缩写)

class PostsController < ApplicationController
  def new
    @post = Post.new
    @post.post_taggings.build
  end


  def new_post_params
    params.require(:post).permit(:title,post_taggings_attributes: { :tag_id => [] })
  end

  def update_post_params
    params.require(:post).permit(:title,post_taggings_attributes: [ { :tag_id => [] },:id,:_destroy ])
  end
end

视图/后/ new.html.erb

<%= form_for(@post) do |f| %>
<%= f.fields_for :post_taggings do | pt | %> 
    <%= pt.label :post_taggings,"Tags" %><br />
    <%= pt.collection_select(:tag_id,Tag.all,:name,{include_hidden: false},{multiple: true} ) %><br />
<% end %>

HTML

<select id="post_post_taggings_attributes_0_tag_id" multiple="multiple" name="post[post_taggings_attributes][0][tag_id][]">
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
  <option value="4">4</option>
  <option value="5">5</option>
  <option value="6">6</option>
  <option value="7">7</option>
  <option value="8">8</option>
  <option value="9">9</option>
  <option value="10">10</option>
</select>

当我保存表单时,我得到以下内容：

Started POST "/posts" for 127.0.0.1 at 2014-12-13 04:22:19 -0800
Processing by PostsController#create as HTML
  Parameters: {"utf8"=>"?","authenticity_token"=>"DaeMJb5b4PcLUz2YfQCjYk1r7pzcMd3NOmhYwEExz2U=","post"=>{"title"=>"The Title","post_taggings_attributes"=>{"0"=>{"tag_id"=>["1","2","6"]}}},"commit"=>"Create Post"}
  (0.1ms)  begin transaction
  SQL (0.5ms)  INSERT INTO "posts" ("created_at","title","updated_at") VALUES (?,?,?)  [["created_at","2014-12-13 12:22:19.789055"],["title","The Title"],["updated_at","2014-12-13 12:22:19.789055"]]
  SQL (0.4ms)  INSERT INTO "post_taggings" ("created_at","post_id","2014-12-13 12:22:19.791928"],["post_id",16],"2014-12-13 12:22:19.791928"]]
 (2.2ms)  commit transaction
Redirected to http://localhost:3000/posts/16
Completed 302 Found in 27ms (ActiveRecord: 3.3ms)

由于它不起作用,我知道我做错了什么.我也不相信编辑案例会起作用.

我觉得我很接近,因为如果我改变了强大的参数,它只需要一个选择

{ :tag_id => [] }

至

:tag_id

# in your form

 <%= form_for(@post) do |f| %>

##  your other fields
    <%= f.collection_select(:tag_ids,{multiple: true} ) %><br />
 <% end %>

#in your controller
 def post_params
  params.require(:post).permit([:title,:tag_ids => []])
 end