我开发了有文章和新闻页面的网站,我想增加对两者发表评论的机会。我使用多态关联。
class Article < ActiveRecord::Base
has_many :commentaries, :as => :commentable
end
class News < ActiveRecord::Base
has_many :commentaries, :as => :commentable
end
class Commentary < ActiveRecord::Base
belongs_to :commentable, :polymorphic => true
end
我想在可评论对象下方显示评论
意见/文章/show.html.erb
<p>
<b>Title:</b>
<%= @article.title %>
</p>
<p>
<b>Short text:</b>
<%= @article.short_text %>
</p>
<p>
<b>Full text:</b>
<%= @article.full_text %>
</p>
<%= render 'commentaries/form' %>
意见/新闻/show.html.erb
<p>
<b>Title:</b>
<%= @news.title %>
</p>
<p>
<b>Text:</b>
<%= @news.text %>
</p>
<p>
<b>Created:</b>
<%= @news.created %>
</p>
意见/评论/_form.html.erb
<h1>Comments</h1>
<ul id="comments">
<% @commentaries.each do |comment| %>
<li><%= comment.content %></li>
<% end %>
</ul>
<h2>New Comment</h2>
<% form_for [@commentable, Comment.new] do |form| %>
<ol class="formList">
<li>
<%= form.label :content %>
<%= form.text_area :content, :rows => 5 %>
</li>
<li><%= submit_tag "Add comment" %></li>
</ol>
<% end %>
我的控制器:
class CommentariesController < ApplicationController
def index
@commentable = find_commentable
@commentaries = @commentable.commentaries
end
end
class ArticlesController < ApplicationController
def show
@article = Article.find(params[:id])
end
end
当我转到 mysite/article/1 时,我收到错误 undefined method `each' for nil:NilClass,因为我的文章控制器中没有 @commentable 并且评论控制器的代码没有执行。
如何在文章/显示页面上执行评论控制器的索引操作?