Question

在rails 3.2。*中我有一个has_one belongs_to嵌套模型，如下所示：

class Unicycle < ActiveRecord::Base
  attr_accessible :brand, :wheel, :wheel_attributes
  has_one :wheel
  accepts_nested_attributes_for :wheel
end

class Wheel < ActiveRecord::Base
  attr_accessible :diameter, :unicycle
  belongs_to :unicycle
end

我的控制器看起来像这样：

class UnicyclesController < ApplicationController
  def index
    @unicycles = Unicycle.all
  end

  def edit
    @unicycle = Unicycle.find_by_id params[:id]
  end

  def update
    @unicycle = Unicycle.find_by_id params[:id]
    if @unicycle.update_attributes! params[:unicycle]
      redirect_to unicycles_path
    else
      render 'edit'
    end
  end
end

我的edit.html.erb是这样的：

<%= form_for @unicycle do |formbuilder| %>
  <%= formbuilder.text_field :brand %>

  <%= fields_for @unicycle.wheel do |fieldbuilder| %>
    <%= fieldbuilder.number_field :diameter %>
  <% end %>

  <%= formbuilder.submit %>
<% end %>

但是当我更新时，对wheel.diameter所做的更改会被默默忽略。

我发现即使我的fields_for调用嵌套在edit.html.erb的form_for块中，发送到我的更新功能的参数也没有嵌套

Params包含：

 {"utf8"=>"✓",
 "_method"=>"put",
 "authenticity_token"=>"owiV5xwbbt+ft8h4K4bIqshp5I6jrlj5XWEKeVXpoCQ=",
 "unicycle"=>{"brand"=>"Unibike"},
 "wheel"=>{"diameter"=>"70"},
 "commit"=>"Update Unicycle",
 "action"=>"update",
 "controller"=>"unicycles",
 "id"=>"1"}

但是根据rails文档（ActiveRecordNestedAttributes），wheel params应该真的嵌套在unicycle中：

 "unicycle"=>{"brand"=>"Unibike", "wheel"=>{"diameter"=>"68"}},

我在这里缺少什么？

Answer 1

这是生成嵌套字段的方法：

# ...
<%= formbuilder.fields_for :wheel do |fieldbuilder| %>
  <%= fieldbuilder.number_field :diameter %>
<% end %>
# ...

具有嵌套模型的表单不会更新也不会给出嵌套参数

1 个答案: