Ruby on rails Rails多态关联赢得'；不保存类型

我的项目中有几个模型：请求、工作、汽车和员工。工作是请求和Car/员工之间的中间模型

以下是协会：

请求

has_many :works, dependent: :destroy
def performers
  works.map {|x| x.performer}
end

工作

belongs_to :request
belongs_to :performer, polymorphic: true

汽车

has_many :works, as: :performer
has_many :requests, through: :works, as: :performer

  def new
    @work = @request.works.new
  end

  def create
    @work = @request.works.new(work_params)
  end

  def work_params
      params.require(:work).permit(:performer_id, :request_id)
  end

员工

has_many :works, as: :performer
has_many :requests, through: :works, as: :performer

视图用于创建作品：

<%= form_for([@request, @work]) do |f| %>
    <%= (f.collection_select :performer_id, Employee.all, :id, :name) if @request.type == "StaffRequest" %>
    <%= (f.collection_select :performer_id, Car.all, :id, :select_info) if @request.type == "CarRequest" %>
    <%= f.submit 'OK' %>
<% end %>

---

问题是我的performer\u type列始终为空，它不保存类名。有什么问题吗？有什么想法吗？

它是空的，因为您没有通过它，您应该为表单添加一个隐藏字段：

<%= form_for([@request, @work]) do |f| %>
  <% if @request.type == "StaffRequest" %>
    <%= (f.hidden_field :performer_type, value: "Employee")  %>
    <%= (f.collection_select :performer_id, Employee.all, :id, :name)  %>
  <% elsif @request.type == "CarRequest" %>
    <%= (f.hidden_field :performer_type, value: "Car") %>
    <%= (f.collection_select :performer_id, Car.all, :id, :select_info) %>
  <% end %>
    <%= f.submit 'OK' %>
<% end %>

---

除了：performer\u id，您还必须传递：performer\u类型，一种方法是通过表单select\u标签：

def create 
  @work = @request.works.new(work_params)
end

def work_params
  # use :performer if you use :performer as in the select form field
  params.require(:work).permit(:performer, :request_id)

  # OR

  # use :performer_id & :performer_type if you also use the hidden field
  params.require(:work).permit(:performer_id, :performer_type, :request_id)
end

有一个很好的例子（对于Rails 4.2），它使用一个选择表单字段来表示多态性，因此您可以这样编写：

<%= f.grouped_collection_select :global_performer, [ Car, Employee ], :all, :model_name, :to_global_id, :name %>

---

您能否提供正在使用的代码，以便在

works

表中创建一行？例如，

Work.create

或

Employee.new（…）.save

？在

中有许多：请求

为什么要添加

as:：performer

？通过应该足够了。我一直认为多态关联类型是rails为您计算的