Rails:多层嵌套表单(接受嵌套属性) [英] Rails: multi level nested Forms (accepts nested attributes)

问题描述

我正在创建简单的博客级应用程序.下面是我的模型.

I am creating simple blog level application. below are my models.

class User < ActiveRecord::Base
  attr_accessible :name,:posts_count,:posts_attributes , :comments_attributes
  has_many :posts
  has_many :comments
  accepts_nested_attributes_for :posts , :reject_if => proc{|post| post['name'].blank?}  , :allow_destroy => true
end


class Post < ActiveRecord::Base
  attr_accessible :name, :user_id ,:comments_attributes
  belongs_to :user
  has_many :comments
  accepts_nested_attributes_for :comments
end

class Comment < ActiveRecord::Base
  attr_accessible :content, :post_id, :user_id
  belongs_to :user
  belongs_to :post  
end

我正在尝试通过使用rails的accepts_nested_attributes_for功能以一种形式创建用户，发布和评论.下面是我的控制器和查看代码.

I am trying to create user,post and comment in one form by using accepts_nested_attributes_for feature of rails. Below is my controller and view code.

控制器-----------

Controller-----------

class UsersController < ApplicationController
  def new
    @user = User.new
    @post = @user.posts.build
    @post.comments.build
  end

  def create
   @user = User.new(params[:user])
   @user.save
  end
end

表格----------

Form----------

<%= form_for @user do |f| %>
    <%= f.text_field :name %>

    <%= f.fields_for :posts do |users_post| %>
        <br>Post
        <%= users_post.text_field :name  %>
        <%= users_post.fields_for :comments do |comment| %>
             <%= comment.text_field :content %>
         <% end %>
    <% end %>
    <%= f.submit %>
<% end %>

使用上面的代码，我能够成功创建新用户，发布并发表评论，但是问题是我无法将新创建的用户分配给新创建的评论.当我将新创建的评论签入数据库时​​，我得到了低于结果.我得到的user_id字段值为"nil".

With the above code i am successfully able to create new user,post and comment but the problem is that i am not able to assign newly created user to newly created comment.when i checked the newly created comment into the database i got below result.I am getting user_id field value of "nil".

#<Comment id: 4, user_id: nil, post_id: 14, content: "c", created_at: "2014-05-30 09:51:53", updated_at: "2014-05-30 09:51:53">

所以我只想知道我们如何将新创建的注释分配给新创建的用户?

So I just want to know how we can assign newly created comment to newly created user???

谢谢

推荐答案

您将必须显式分配user_id进行注释！您是在帖子下嵌套评论，因此默认情况下将为评论分配post_id，但是尽管您是在用户表单下间接嵌套评论，但用户下没有直接嵌套评论，因此user_id在评论中保持空白.

You will have to explicitly assign user_id for comments! You are nesting comments under posts, so comments would be having post_id assigned by default but though you are nesting comments under user form indirectly, there is no direct nesting of comments under user, so user_id remains blank in comments.

在注释模型中创建回调以设置user_id后尝试编写

Try writing after create callback in Comment model to set user_id

在comment.rb

In comment.rb

after_create{|comment|
  comment.user_id = post.user_id
  comment.save
}

希望这会有所帮助:)

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