如何使用rails多态关联创建对象

Question

我想使用多态关联创建对象，但它返回如下错误：

NoMethodError (undefined method `new' for nil:NilClass):

这里是参数：

  Parameters: {"utf8"=>"✓", "authenticity_token"=>"TAQdqSTXAFCrq6yZBUnjVXe7IsPqmxuLh/qM/2QvKaVvsfP
/Sy6VNF7H38IzOg8aMj39t6HR+aZLLtyj8uMzyw==", "search"=>"Newport-Mesa Unified 
School District", "id"=>"32", "type"=>"PrivateSchool", "commit"=>"Submit"}

这里是模型：

class PrivateSchool < ActiveRecord::Base
  has_many :popular_schools, as: :resource, :dependent => :destroy
end

class PopularSchool < ActiveRecord::Base
  belongs_to :resource, polymorphic: true
end

class School < ActiveRecord::Base
  has_many :popular_schools, as: :resource, :dependent => :destroy
end

控制器代码：

def index
    @popular_school = PopularSchool.new
    @popular_schools = PopularSchool.all
  end

  def create
    @popular_school.new.save
    respond_to do |format|
      format.html { redirect_to root_path }
      format.json { head :no_content }
      format.js
    end
  end

Answer 1

您尚未在任何地方定义@popular_school 变量。这就是您收到 NoMethodError (undefined method new for nil:NilClass): 错误的原因。

试试PopularSchool.create(your_params)