fields_for和错误的参数数目(0表示1)错误

Amateur rails programmer struggling to use the fields_for form builder. My rails application (on v=2.3.11) tracks laboratory protocols and the animals used on those protocols (their weights, etc).

难以使用fields_for表单构建器的业余rails程序员。我的rails应用程序(on v=2.3.11)跟踪实验室协议和在这些协议上使用的动物(它们的重量等)。

My specific problem is that protocols can only have a certain number of animals, but that number allowed is specific to a species.

我的具体问题是协议只能有一定数量的动物，但是这个数量是特定于一个物种的。

The nested form behavior should display a listing of all the species of animals and an edit box for the number allowed on the protocol.

嵌套的表单行为应该显示所有动物种类的列表，以及在协议中允许的数量的编辑框。

Models: Protocol, Allowed_Animal, Species

模型:协议、Allowed_Animal物种

Species Model

物种模型

class Species < ActiveRecord::Base
  has_many :animals, :order => "band"
  has_many :allowed_animals
end

Protocol Model

协议模型

class Protocol < ActiveRecord::Base
  has_and_belongs_to_many :animals, :order => "band"
  has_many :allowed_animals
  accepts_nested_attributes_for :allowed_animals
end

Allowed_Animal Model

Allowed_Animal模型

class AllowedAnimal < ActiveRecord::Base
  belongs_to :protocol
  has_one :species
end

The table for allowed_animal includes:

allowed_animal的表包括:

id, protocol_id, species_id, number, created_at, updated_at

The nested form works like this:

嵌套的表单如下:

<% form_for(@protocol) do |f| %>
  <%= f.error_messages %>

  <p>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </p>
  <p>
    <%= f.label :number %><br />
    <%= f.text_field :number %>
  </p>

  <p>
    Number of animals allowed on protocol:
  </p>
  <div class="left_indent">
    <table>
      <% f.fields_for :allowed_animals, Species.all do |a| %>
      <tr>
        <td><i><%= a.object[:name] %></i></td>
        <td><%= a.text_field :number, :value => @protocol.allowed_animals(a), :size=>2 %></td>
        <%= a.text_field :species_id, :value => a.object[:id], :hidden => true %>
      </tr>
      <% end %>
    </table>
  </div>

  <p>
    Users on protocol:
  </p>
  <div class="left_indent">
    <%= render :partial => 'protocols/users_on_protocol_form', :locals =>{:protocol => @protocol, :users => User.current} %>
  </div>

  <p>
    <%= f.submit 'Save' %>
  </p>
<% end %>

The form displays how I would like it to, but after submission, I get the error:

表单显示了我想要的方式，但是提交后，我得到了错误:

wrong number of arguments (0 for 1)

in the controller as it tries to do:

在控制器中

@protocol = Protocol.new(params[:protocol])

I am not sure where to go from here. Do I need to have a build method in my model? Or do I need to do anything special in my controller? Is there something wrong with my form_builder code and how it iterates through the species?

我不知道从这里到哪里去。我需要在我的模型中有一个构建方法吗?或者我需要在控制器中做任何特别的事情?我的form_builder代码有什么问题吗?

Any ideas?

什么好主意吗?

Application trace:

应用程序跟踪:

/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/nested_attributes.rb:343:in `allowed_animals'
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/nested_attributes.rb:343:in `send'
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/nested_attributes.rb:343:in `assign_nested_attributes_for_collection_association'
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/nested_attributes.rb:244:in `allowed_animals_attributes='
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/base.rb:2918:in `send'
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/base.rb:2918:in `assign_attributes'
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/base.rb:2914:in `each'
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/base.rb:2914:in `assign_attributes'
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/base.rb:2787:in `attributes='
/var/lib/gems/1.8/gems/activerecord-2.3.11/lib/active_record/base.rb:2477:in `initialize'
/media/Data/Animal-Record-Keeping/app/controllers/protocols_controller.rb:42:in `new'
/media/Data/Animal-Record-Keeping/app/controllers/protocols_controller.rb:42:in `create'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/base.rb:1333:in `send'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/base.rb:1333:in `perform_action_without_filters'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/filters.rb:617:in `call_filters'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/var/lib/gems/1.8/gems/activesupport-2.3.11/lib/active_support/core_ext/benchmark.rb:17:in `ms'
/var/lib/gems/1.8/gems/activesupport-2.3.11/lib/active_support/core_ext/benchmark.rb:17:in `ms'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/rescue.rb:160:in `perform_action_without_flash'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/flash.rb:151:in `perform_action'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/base.rb:532:in `send'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/base.rb:532:in `process_without_filters'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/filters.rb:606:in `process'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/base.rb:391:in `process'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/base.rb:386:in `call'
/var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/routing/route_set.rb:438:in `call'

Parameters:

参数:

{"commit"=>"Save",
 "protocol"=>{"number"=>"Test number",
 "start_date(1i)"=>"2011",
 "start_date(2i)"=>"4",
 "title"=>"Test title",
 "start_date(3i)"=>"12",
 "flight_exempt"=>"0",
 "allowed_animals_attributes"=>{"0"=>{"number"=>"7",
 "id"=>"2",
 "species_id"=>"2"},
 "1"=>{"number"=>"11",
 "id"=>"3",
 "species_id"=>"3"},
 "2"=>{"number"=>"13",
 "id"=>"4",
 "species_id"=>"4"},
 "3"=>{"number"=>"17",
 "id"=>"5",
 "species_id"=>"5"}},
 "summary"=>"Test summary"},
 "user_id"=>{"33"=>"0",
 "6"=>"0",
 "14"=>"0",
 "9"=>"0",
 "37"=>"0",
 "38"=>"0",
 "1"=>"1",
 "39"=>"0",
 "40"=>"0",
 "18"=>"0",
 "31"=>"0",
 "21"=>"0",
 "32"=>"0",
 "5"=>"0"}}

Development Log

开发日志

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DEPRECATION WARNING: Giving :session_key to SessionStore is deprecated, please use :key instead. (called from new at /var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/middleware_stack.rb:72)
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Processing ProtocolsController#new (for 127.0.0.1 at 2011-04-12 18:11:14) [GET]
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Completed in 280ms (View: 266, DB: 4) | 200 OK [http://localhost/protocols/new]
DEPRECATION WARNING: Giving :session_key to SessionStore is deprecated, please use :key instead. (called from new at /var/lib/gems/1.8/gems/actionpack-2.3.11/lib/action_controller/middleware_stack.rb:72)
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Processing ProtocolsController#create (for 127.0.0.1 at 2011-04-12 18:11:43) [POST]
  Parameters: {"commit"=>"Save", "protocol"=>{"start_date(1i)"=>"2011", "number"=>"Test Number", "start_date(2i)"=>"4", "start_date(3i)"=>"12", "title"=>"Test Title", "allowed_animals_attributes"=>{"0"=>{"number"=>"7", "id"=>"2", "species_id"=>"2"}, "1"=>{"number"=>"11", "id"=>"3", "species_id"=>"3"}, "2"=>{"number"=>"13", "id"=>"4", "species_id"=>"4"}, "3"=>{"number"=>"17", "id"=>"5", "species_id"=>"5"}}, "flight_exempt"=>"0", "summary"=>"Test Summary"}, "user_id"=>{"6"=>"0", "33"=>"0", "9"=>"0", "14"=>"0", "37"=>"0", "38"=>"0", "40"=>"0", "39"=>"0", "1"=>"1", "18"=>"0", "31"=>"0", "32"=>"0", "21"=>"0", "5"=>"0"}}
::: Checking session expiry
::: Session has not expired. Reinitialising.
::: Initializing session expiry. Expires at Tue Apr 12 18:26:43 -0400 2011
  [4;36;1mProtocol Columns (0.6ms)[0m   [0;1mSHOW FIELDS FROM `protocols`[0m

ArgumentError (wrong number of arguments (0 for 1)):
  app/controllers/protocols_controller.rb:42:in `new'
  app/controllers/protocols_controller.rb:42:in `create'
  /var/lib/gems/1.8/gems/ruby-debug-ide-0.4.9/lib/ruby-debug-ide.rb:109:in `debug_load'
  /var/lib/gems/1.8/gems/ruby-debug-ide-0.4.9/lib/ruby-debug-ide.rb:109:in `debug_program'
  /var/lib/gems/1.8/gems/ruby-debug-ide-0.4.9/bin/rdebug-ide:87
  /var/lib/gems/1.8/bin/rdebug-ide:19:in `load'
  /var/lib/gems/1.8/bin/rdebug-ide:19

Rendered rescues/_trace (46.0ms)
Rendered rescues/_request_and_response (1.7ms)
Rendering rescues/layout (internal_server_error)

2 个解决方案

#1

I figured out that the problem was that I had a function in my Protocol model with the same name as the model I was trying to nest (AllowedAnimal). When calling protocol.allowed_animals it was calling the function (with not enough arguments) instead of returning the nested fields_for.

我发现问题在于，我的协议模型中有一个函数，其名称与我试图嵌套的模型(AllowedAnimal)相同。当调用协议。allowed_animals它调用函数(参数不足)而不是返回嵌套的fields_for。

I also had to change the relationship to belongs_to in my Allowed Animal Model to get my allowed_animal.species to work:

我还必须在允许的动物模型中改变belongs_to的关系，才能获得允许的动物。物种的工作:

class AllowedAnimal < ActiveRecord::Base
  belongs_to :protocol
  belongs_to :species
end

And add a method in my model to build out the allowed_animals for a new protocol:

在我的模型中添加一个方法来构建一个新协议的allowed_animals:

def build_allowed_animals
  abs = Array.new
  for sp in Species.all
    ab = AllowedAnimal.new
    ab.species = sp
    ab.number = 0
    abs << ab
  end
  self.allowed_animals = abs
end

Call the method in my Protocol Controller:

在我的协议控制器中调用该方法:

def new
  @protocol = Protocol.new
  @protocol.build_allowed_bats
  respond_to do |format|
    format.html # new.html.erb
    format.xml  { render :xml => @protocol }
  end
end

And make a few edits to my form:

并对我的表格做一些修改:

<% form_for(@protocol) do |f| %>
  <%= f.error_messages %>

  <p>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </p>
  <p>
    <%= f.label :number %><br />
    <%= f.text_field :number %>
  </p>

  <p>
    Number of animals allowed on protocol:
  </p>
  <div class="left_indent">
    <table>
      <% f.fields_for :allowed_animals do |a| %>
        <tr>
          <td><i><%= a.object.species.name %></i></td>
          <td><%= a.text_field :number, :value => @protocol.determine_allowed_animals(a.object.species), :size=>2 %></td>
          <%= a.text_field :species_id, :value => a.object.species.id, :hidden => true %>
        </tr>
      <% end %>
    </table>
  </div>

  <p>
    Users on protocol:
  </p>
  <div class="left_indent">
    <%= render :partial => 'protocols/users_on_protocol_form', :locals =>{:protocol => @protocol, :users => User.current} %>
  </div>

  <p>
    <%= f.submit 'Save' %>
  </p>
<% end %>

#2

In rails 3, You should just write:

在rails 3中，您应该写:

<%= f.fields_for :allowed_animals do |a| %>