CODEWITHSUNDEEP
ruby-on-rails
Reddirt
Reddirt

Reputation: 5953

Rails accepts_nested_attributes gives undefined method

I'm trying to create a single form that allows for the creation of a Comment and an associated Attachment

Comments Model has:

class Comment < ActiveRecord::Base
  has_many :attachments
  accepts_nested_attributes_for :attachments    
end

Comments Controller has:

  # GET /comments/new
  # GET /comments/new.json
  def new
    @comment = Comment.new
    @worequest = params[:worequest_id]

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @comment }
    end
  end

In the Comment Form, I'm trying to add this:

<%= simple_form_for @comment, :html => {:class => 'form-horizontal'} do |f| %>
  (CODE FOR COMMENT)
  <% f.fields_for @attachments do |builder| %>
    <%= builder.input :name, :label => 'Attachment Name' %>
    <%= builder.file_field :attach, :label => 'Attachment File' %>
  <% end %>

But, I'm getting this error:

undefined method `model_name' for NilClass:Class

Thanks for the help!

Upvotes: 0

Views: 80

Answers (1)

vee
vee

Reputation: 38645

As @Donovan commented, you're not defining @attachments, hence the error. I had guessed that error was from the form_for declaration.

Update your controller new action's code to build attachments on @comment:

  # GET /comments/new
  # GET /comments/new.json
  def new
    @comment = Comment.new
    @comment.attachments.build # Add this line

    @worequest = params[:worequest_id]

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @comment }
    end
  end

Then update your form view code to:

<%= simple_form_for @comment, :html => {:class => 'form-horizontal'} do |f| %>
  (CODE FOR COMMENT)
  <%= f.fields_for :attachments do |builder| %>
    <%= builder.input :name, :label => 'Attachment Name' %>
    <%= builder.file_field :attach, :label => 'Attachment File' %>
  <% end %>

You could also chose to define @attachments in your controller action and use that in your view instead. By doing f.fields_for :attachments the current object's (i.e. @comment in this case) attachments association is used, so defining @attachments in controller is not necessary.

Upvotes: 1

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