How to access hidden_field in controller in Ruby on rails

问题

Question: How to access hidden field value post_id from file view/comments/_comment.html.erb and use it in controllers/dashboards_controller.rb? - there are 2 controllers - dashboard and comments, and using gem act_as_commentable_with_threading

Now I get: ActiveRecord::RecordNotFound in DashboardsController#index Couldn't find Post without an ID

---

config/routes.rb

  resources :comments, :only => [:create, :destroy]

controllers/dashboards_controller.rb

class DashboardsController < ApplicationController
  def index
    @post = Post.new
    @user = current_user
    @newest_users = User.newest_players
    @feed_posts = Post.paginate(:page => params[:page], :per_page => 8)
    @last_clubs = Club.last_clubs


    @commented_post = Post.find(params[:post_id])
    # trying to access params from view/comments/_comment.html.erb
    # comments is another controller...

   # do other operations with @commented_post   
     @comments = @commented_post.comment_threads.order('created_at desc') 
     @new_comment = Comment.build_from(@commented_post, current_user, '')

  end

end

view/comments/_comment.html.erb Add comment

place for a comment form

<div class="comment-form">
  <%= form_for :comment, :remote => true do |f| %>
  <%=f.hidden_field 'post_id', post.id %>

  # need to use this value in dasboard controller
  <%=f.text_field :body %>

  <% end %>

</div>

view/dashboards/_feed_post.html.erb

<ul class="post-items">


  <%if @feed_posts.any? %>

    <% @feed_posts.each do |post| %>
    <li>
        <span class="image"><%= image_tag post.image.url(:message) if post.image?%></span>
        <span class="content"><%= post.text_html %></span>
        <span class="tags">Tags:<%= post.tag_list %></span>
        <span class="meta">

          Posted <%= time_ago_in_words(post.created_at) %> ago.
      |      <%= post.user.full_name %>
        </span>

      <%= render 'comments/form' ,:locals => { :comment => @new_comment, :post_id => post.id } %>
      <%= render 'comments/comment', :collection => @comments, :as => :comment, :post_id => post.id %>

    </li>
        <% end %>

  <% end %>
</ul>

view/dashboards/index

<div class="row">
  <div class="span7">


    <!--form for creating a new post-->
    <section>
    <%= render :template =>  'posts/new' %>
    </section>


    <!--dashboard feed_post-->
    <section>
    <%= render :partial => 'dashboards/feed_post' %>
    </section>    
  </div>

回答1:

you are using f.hidden_field so you will get

<%=f.hidden_field 'post_id', post.id %>

will create following html ref hidden_field

<input type="hidden" id="comment_post_id" name="comment[post_id]" value="#{comment.post_id}" />

so you can access this as following in your controller

params[:comment][:post_id]

so use following instead

@commented_post = Post.find(params[:comment][:post_id])

if you want 'post_id' in params[:post_id] use hidden_field_tag like following

<%= hidden_field_tag 'post_id', post.id %>

来源：https://stackoverflow.com/questions/18205875/how-to-access-hidden-field-in-controller-in-ruby-on-rails