Ruby on rails 视图中的Rails多态帖子关联和表单_

在department视图中设置多态“department”帖子的表单时遇到了问题。我遵循rails cast教程了解多态关联

型号：

   class Course < ActiveRecord::Base
        belongs_to :department, inverse_of: :courses
        has_and_belongs_to_many :users, -> { uniq }
        has_many :posts, as: :postable  #allows polymorphic posts
    end
    class Department < ActiveRecord::Base
        has_many :courses, inverse_of: :department
        has_many :posts, as: :postable  #allows polymorphic posts
        has_and_belongs_to_many :users, -> {uniq}
    end
    class Post < ActiveRecord::Base
        belongs_to :user, touch: true #updates the updated_at timestamp whenever post is saved
        belongs_to :postable, polymorphic: true #http://guides.rubyonrails.org/association_basics.html#polymorphic-associations
        belongs_to :department, counter_cache: true #for counting number of posts in department
        belongs_to :course, counter_cache: true
        validates :department_id, :course_id, presence: true
    end

视图/部门/show.html.erb

  <div class="tab-pane" id="posts"><br>
    <center><h3>Posts:</h3></center>
    <%= render "posts/form", postable: @department %>
  </div>

错误为“未定义#的方法'posts_path'”

我认为这个错误与表单中的路径有关，但我不知道是什么。我也尝试过

[@postable，@postable.posts.build]

，但这只给了我未定义的方法：PostsController

---

有人知道发生了什么以及我如何修复它吗？

@department

作为一个局部变量传递到表单partial中，但是表单调用一个实例变量：

# views/departments/show.html.erb
<%= render "posts/form", postable: @department %> # <------ postable

# views/posts/_form.html.erb
<%= form_for [@postable, Post.new] do |f| %>      # <------ @postable

检查路线时，只能通过嵌套路线访问帖子<代码>发布路径不是有效的路由，其方法不存在，错误正确：未定义的方法“发布路径”

---

修正： 在departments controller中设置一个

@postable

实例变量，以便表单助手可以使用它：

def show
    id = params[:id]
    @postable, @department = Department.find(id)  # <-- add @postable

    @course = Course.new
    @course.department_id = @department
end

def显示
id=params[：id]
@可邮寄，@department=department.find（id）#非常感谢，这确实帮助我清除了错误。但是，现在当我提交表单时，它会在PostsController中点击create方法，但是“if@post.save”条件不满足，因此它会呈现新操作和相应的视图。显然，我希望它保存，然后重定向到部门显示页面（部门路径）或部门帖子查看页面（部门帖子路径）。为什么不节约？？再次感谢你的帮助！此验证将始终失败：
验证：部门id、：课程id、状态：true
。它检查两个ID是否存在，这在多态关联的情况下是不可能的。你想要一个或另一个，但不是两个，或是异或。看这个问题：谢谢！这就解决了问题，我让这些职位都在工作。非常感谢。
class PostsController < ApplicationController
    before_filter :find_postable
    load_and_authorize_resource 

    def new
        @postable = find_postable
        @post = @postable.posts.new
    end

    def create
        @postable = find_postable
        @post = @postable.posts.build(post_params)

        if @post.save
            flash[:success] = "#{@post.title} was sucessfully created!"
            redirect_to department_post_path#id: nil        #redirects back to the current index action
        else
            render action: 'new'
        end
    end

    def show
        @post = Post.find(params[:id])
    end

    def index
        @postable = find_postable
        @posts = @postable.posts
    end
...
    private
    def post_params
        params.require(:post).permit(:title, :description, :content)
    end

    def find_postable   #gets the type of post to create
        params.each do |name, value|
            if name =~ /(.+)_id$/
                return $1.classify.constantize.find(value)
            end
        end
        nil
    end

def show
    id = params[:id]
    @department = Department.find(id)

    @course = Course.new
    @course.department_id = @department
end

# views/departments/show.html.erb
<%= render "posts/form", postable: @department %> # <------ postable

# views/posts/_form.html.erb
<%= form_for [@postable, Post.new] do |f| %>      # <------ @postable

[@postable, Post.new]  # => departments_posts_path
[   nil   , Post.new]  # => posts_path

def show
    id = params[:id]
    @postable, @department = Department.find(id)  # <-- add @postable

    @course = Course.new
    @course.department_id = @department
end

<%= render "posts/form" %>