accept_nested_attributes_for和nested_form插件

Question

我在_form.html.haml部分中有以下代码，它用于新建和编辑操作。 （FYI我使用Ryan Bates的插件nested_form）

.fields 
    - f.fields_for :transportations do |builder| 
     = builder.collection_select :person_id, @people, :id, :name, {:multiple => true} 
     = builder.link_to_remove 'effacer' 
    = f.link_to_add "ajouter", :transportations 

正常工作新动作...... 的编辑操作，如DOC解释，我已经添加的：已经ID现有的协会，所以，我必须添加像

= builder.hidden_field :id, ?the value? if ?.new_record? 

我怎样才能得到的价值？

这里是accepts_nested_attributes_for作参考文档（来源：http://github.com/rails/rails/blob/master/activerecord/lib/active_record/nested_attributes.rb#L332）

# Assigns the given attributes to the collection association. 
# 
# Hashes with an <tt>:id</tt> value matching an existing associated record 
# will update that record. Hashes without an <tt>:id</tt> value will build 
# a new record for the association. Hashes with a matching <tt>:id</tt> 
# value and a <tt>:_destroy</tt> key set to a truthy value will mark the 
# matched record for destruction. 
# 
# For example: 
# 
# assign_nested_attributes_for_collection_association(:people, { 
# '1' => { :id => '1', :name => 'Peter' }, 
# '2' => { :name => 'John' }, 
# '3' => { :id => '2', :_destroy => true } 
# }) 
# 
# Will update the name of the Person with ID 1, build a new associated 
# person with the name `John', and mark the associatied Person with ID 2 
# for destruction. 
# 
# Also accepts an Array of attribute hashes: 
# 
# assign_nested_attributes_for_collection_association(:people, [ 
# { :id => '1', :name => 'Peter' }, 
# { :name => 'John' }, 
# { :id => '2', :_destroy => true } 
# ]) 

感谢您的帮助。

Answer 1

，我发现我的错误，这里是我FYI了解到：

当你accepts_nested_attributes_for使用具有多对多关联，保持：对于关联表ID主键。

干杯

Answer 2

Rails正式支持嵌套表单。你正在做什么（特别是与fields_for方法）可能与RAils内置的渲染fields_for方法相冲突。

这里的方式做fields_for的文档Rails的...这是非常透彻：

http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#M001605

我强烈建议你尝试内置的方式，而不是插件，因为这将继续几乎无限期地得到支持。

希望这会有所帮助！

Answer 3

矿用工程时 “：_delete” 而不是 “：_destroy”。我在轨道上2.3.4。 Ruby 1.8.7

看看这个：http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#M001605