Question

我是Ruby on Rails的新手，我开始使用脚手架并手动添加另一个模型。我似乎无法从我手动生成的模型中获取值以在我的索引视图中显示。

我的第一个模型是高尔夫球场名称，城市，标准杆和洞穴。第二个模型是每个球场的洞数。出于某种原因，我无法获得显示的孔数以下是我的代码。模型

class Course < ActiveRecord::Base
    has_many :holes
end

class Hole < ActiveRecord::Base
    belongs_to :course
end

控制器

class CoursesController < ApplicationController
  before_action :set_course, only: [:show, :edit, :update, :destroy]

  # GET /courses
  # GET /courses.json
  def index
    @courses = Course.all
    @holes = Hole.all
  end

  # GET /courses/1
  # GET /courses/1.json
  def show
  end

  # GET /courses/new
  def new
    @course = Course.new

  end

  # GET /courses/1/edit
  def edit
  end

  # POST /courses
  # POST /courses.json
  def create
    @course = Course.new(course_params)

    respond_to do |format|
      if @course.save
        format.html { redirect_to @course, notice: 'Course was successfully created.' }
        format.json { render :show, status: :created, location: @course }
      else
        format.html { render :new }
        format.json { render json: @course.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /courses/1
  # PATCH/PUT /courses/1.json
  def update
    respond_to do |format|
      if @course.update(course_params)
        format.html { redirect_to @course, notice: 'Course was successfully updated.' }
        format.json { render :show, status: :ok, location: @course }
      else
        format.html { render :edit }
        format.json { render json: @course.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /courses/1
  # DELETE /courses/1.json
  def destroy
    @course.destroy
    respond_to do |format|
      format.html { redirect_to courses_url, notice: 'Course was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_course
      @course = Course.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def course_params
      params.require(:course).permit(:name, :city, :hole_id)
    end
end

查看

<p id="notice"><%= notice %></p>

<p>
  <strong>Name:</strong>
  <%= @course.name %>
</p>

<p>
  <strong>City:</strong>
  <%= @course.city %>
</p>

<p>
  <strong>Hole:</strong>
  <%= @course.holes %>
</p>

<%= link_to 'Edit', edit_course_path(@course) %> |
<%= link_to 'Back', courses_path %>

Answer 1

<%= @course.holes %>为您提供ActiveRecord_Associations_CollectionProxy

您需要提出 size ， length 或 count 才能获取属于@course的洞总数，这意味着您必须说@course.holes.size，@course.holes.length或@course.holes.count。请查看文档以了解这三者之间的差异。

无法显示我的rails模型中的值

1 个答案: