ruby-on-rails-3 - Rails fields_for 文本哈希 : not working as expected

Question

我有一个 rails3 表单，允许用户编辑答案列表，作为评估的一部分。
我用的是 fields_for循环生成每个文本输入:

应用程序/模型/评估.rb:

class Assessment < ActiveRecord::Base
  serialize :answers, Hash   # answers is a t.text field used to store all answers.
end

应用程序/ View /评估/new.html.erb :

<p>Initialized answers: <%= @assessment.answers %></p>

<% item_counter = 0 %>
<% form.fields_for :answers do |answer_fields| %>
    <% item_id = "item" + item_counter.to_s %>
    <% item_counter = item_counter + 1 %>
    <div class="field">
      <%= answer_fields.label "the appropriate question, omitted for brevity" %>
      <br/>
      <% @assessment.answers[item_id] = "" %>
      <%= answer_fields.text_field item_id, :value => @assessment.answers[item_id] %>
    </div>
<% end %>

问题: fields_for循环执行零迭代，没有字段被打印。
(尽管“初始化答案:”显示正确: {"a"=>143, "b"=>42} )

Answer 1

这个应该可以。本地测试。

<p>Initialized answers: <%= @assessment.answers %></p>

<% @assessment.answers.each do |key, value| %>
  <%= form.fields_for :answers, @assessment.answers[key] do |answer_fields| %>
      <div class="field">
        <%= answer_fields.label key %>
        <br/>
        <%= answer_fields.text_field key, :value => value %>
      </div>
  <% end %>
<% end %>