ruby-on-rails - Rails 嵌套表单与 has_many :through

Question

我有 3 个模型，产品模型通过 product_categories 模型连接到公司模型。我想创建一个表格，我可以在公司表格中添加产品及其类别。

公司模式

class Firm < ApplicationRecord
 has_many :product_categories
 has_many :products, through: :product_categories
 accepts_nested_attributes_for :product_categories
end

产品型号

class Product < ApplicationRecord
 has_many :product_categories
 has_many :firms, through: :product_categories
 has_many :variants, class_name: 'ProductVariant'
end

产品分类

class ProductCategory < ApplicationRecord
 belongs_to :product
 belongs_to :firm
 accepts_nested_attributes_for :product
end

这就是我为公司创建表格的样子

<%= form_with(model: @firm, local: true) do |form| %>
  firm.fields...
  <%= form.fields_for :product_categories do |prod_c_f| %>
   product_category.fields...
     <%= prod_c_f.fields_for :product do |prod_f| %>
      product.fields...
     <% end %>
  <% end %>
  <%= form.submit "Create Firm", class: 'btn btn-primary 
  btn-block ' %>
<% end %>

这是我的控制器

def create
@firm = Firm.new

@firm.product_categories.build.build_product
 respond_to do |format|
  if @firm.save
   format.html { redirect_to firms_path, notice: '...' }
  else
  format.html { render :new }
  end
 end
end

这是参数

params.require(:firm).permit(:title, 
product_categories_attributes:[ product_attributes: 
[:title, :price, :description]])

并且表格不显示：

标签： ruby-on-railsrubymodel-view-controllernullaccepts-nested-attributes