使用 has_many 嵌套表单：通过关系

Question

这是我的模型：

class Project < ActiveRecord::Base
  has_many :project_applications
  has_many :questions
  accepts_nested_attributes_for :questions,  :allow_destroy => true, :reject_if => proc { |a| a[:content].blank? }
end

class Question < ActiveRecord::Base
  belongs_to :project
  has_many :answers
  has_many :project_applications, through: :answers
end

class Answer < ActiveRecord::Base
  belongs_to :question
  belongs_to :project_application
end

class ProjectApplication < ActiveRecord::Base
  belongs_to :project
  belongs_to :student
  has_many :answers
  has_many :questions, through: :answers
end

项目由雇主创建，学生可以创建 project_application。 project_application 应该提出问题，然后显示与问题答案相对应的表单字段。我一生都无法弄清楚表单视图的外观。我需要一个 form_for ProjectApplication 接受嵌套属性作为答案。我的控制器中有以下内容：

class ProjectApplicationsController < ApplicationController
    def new
        @project = Project.find(params[:project_id])
        @project_application = ProjectApplication.new
        @project_application.project = @project  

        @project_application.project.questions.each do |question|
            @answer = question.answers.build
            @answer.project_application = @project_application  #this line does not work
            puts 'answer' + @answer.inspect.to_s
        end

        puts 'here are the answers' + @project_application.answers.inspect.to_s

    end
end

问题在于答案没有正确地与 project_applications 相关联，因为 project_applications 还没有 id（因为它们尚未创建），因此无法进行关联，因此答案字段不是显示。这是我现在拥有的视图代码（不起作用）：

<%= form_for @project_application, url: project_project_applications_path(@project.id), method: :post, remote: true do |f| %>
    <%= f.fields_for :project do |proj| %>
        <%= proj.fields_for :questions do |quest| %>
            <%= quest.fields_for :answers do |answer| %>
                <%= answer.text_area :content %>
            <% end %>
        <% end %>
    <% end %>

    <%= f.submit "APPLY" %>

<% end %>

如何更改视图和/或控制器以正确显示与问题和项目应用程序正确关联的答案字段？

Answer 1

我的理解：

1. 你有projects
2. 每个项目有很多questions & project_applications
3. 每个问题都属于一个project，有很多answers到project_applications

---

对于每个项目，您都希望创建具有适用答案的应用程序。这是我要做的：

模型

class Project < ActiveRecord::Base
  has_many :project_applications
  has_many :questions
end

class Question < ActiveRecord::Base
  belongs_to :project
  has_many :answers
  has_many :project_applications, through: :answers
end

class Answer < ActiveRecord::Base
  belongs_to :question
  belongs_to :project_application
end

class ProjectApplication < ActiveRecord::Base
  belongs_to :project
  belongs_to :student
  has_many :answers
  has_many :questions, through: :project

  accepts_nested_attributes_for :answers

  def self.build
      application = self.new
      application.answers.build
  end
end

控制器

#app/controllers/project_applications_controller.rb
def new
    @projectapplication = ProjectApplication.build
    @project = @projectapplication.project
end

def create

end

private
def application_params
    params.require(:project_application).permit(:application, :attributes, :here, answer_attributes: [:content])
end

观看次数

#app/views/project_applications/new.html.erb
<%= form_for @projectapplication do |f| %>
    <%= f.text_field :application_fields %>

    <% @project.questions.each do |question| %>
        <%= f.fields_for :answers, question do |answer| %>
            <%= answer.hidden_field :question_id, question.id %>
            <%= answer.text_field :content, placeholder: question.content %>
        <% end %>
    <% end %>

<% end %>

---

流程

这通过创建一个新的project_application 来工作，将答案直接发送到answer 模型。因为answers 与questions 和projects 直接关联到questions，所以您应该能够在不传递任何更多数据的情况下使其工作

这可能不会完全奏效，但我确信通过一些调整它会产生预期的结果