ruby-on-rails - 强参数 has_many 通过

Question

试图找出 setter 不起作用的原因:

class Company < ActiveRecord::Base
  has_many :memberships 
  has_many :users, :through => :memberships, dependent: :destroy

end

class Membership < ActiveRecord::Base
  belongs_to :user
  belongs_to :company

  validates_presence_of :user
  validates_presence_of :company

end

class User < ActiveRecord::Base
  has_many :memberships
  has_many :companies, :through => :memberships, dependent: :destroy
  accepts_nested_attributes_for :companies
end

---

<%= form_for(@user) do |f| %>
  <% if @user.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@user.errors.count, "error") %> prohibited this user from being saved:</h2>

      <ul>
      <% @user.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.fields_for :company do |ff|%>
      <%= ff.label :name %><br>
      <%= ff.text_field :name %>
    <% end %>
  </div>

  <div class="field">
    <%= f.label :name %><br>
    <%= f.text_field :name %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

---

# Never trust parameters from the scary internet, only allow the white list through.
def user_params
  params.require(:user).permit(:name, companies_attributes:[:name])
end

当我这样做时它就起作用了:

# Never trust parameters from the scary internet, only allow the white list through.
def user_params
  params.require(:user).permit(:name, company:[:name])
end

所以对我来说还不太清楚，因为文档说 setter company_attributes在accepts_nested_attributes_for :companies时被删除

Answer 1

当将 fields_for 与 accepts_nested_attributes_for 一起使用时，它们需要匹配。请参阅http://apidock.com/rails/ActionView/Helpers/FormHelper/fields_for

您有 accepts_nested_attributes_for :company 但 f.fields_for :company 因此断开连接。

所以尝试更改您的表单以包含

<div class="field">
    <%= f.fields_for :companies do |ff|%>
      <%= ff.label :name %><br>
      <%= ff.text_field :name %>
    <% end %>
  </div>

你的 user_params 方法是

def user_params
  params.require(:user).permit(:name, companies_attributes:[:name])
end

这应该会导致它们填充在 companies_attributes 下，并且您原来的 user_params 方法可以正常工作。因为 fields_for 应该生成 user[companies_attributes[id][name]] 因为 user has_many Companies (您是否希望在要创建的列表？)