Question

所有课程都在index.html.erb上显示，我试图通过点击查看更多来查看单个课程。根据我的理解，哪个应链接到节目路径，它显示个别课程。这是我需要的结果。

但是，在网址http://ruby-on-rails-102039.nitrousapp.com:3000/courses/rails上通过此错误（在此网址栏中是该课程的标题，每个新课程都会创建标题。

ActiveRecord::RecordNotFound in CoursesController#show
Couldn't find Course with 'id'=rails

Extracted source (around line #7):

def show @course = Course.find(params[:id]) end

课程控制器

 class CoursesController < ApplicationController
 def index
 @courses = Course.all
 end

 def show
 @course = Course.find(params[:id])
end

路线

devise_for :users
root 'signups#new'
resources :signups, only: [:new, :create]

resources :courses

Prefix Verb   URI Pattern      Controller#Action
root GET    /   signups#new

  root GET    /                              signups#new
  signups POST   /signups(.:format)             signups#create
 new_signup GET    /signups/new(.:format)         signups#new
  courses GET    /courses(.:format)             courses#index
 POST   /courses(.:format)             courses#create
 new_course GET    /courses/new(.:format)         courses#new
 edit_course GET    /courses/:id/edit(.:format)    courses#edit
 course GET    /courses/:id(.:format)         courses#show
 PATCH  /courses/:id(.:format)         courses#update
 PUT    /courses/:id(.:format)         courses#update
 DELETE /courses/:id(.:format)         courses#destroy

index.html.erb

<div id="course-index">
  <%@courses.each_slice(4) do|course| %>

    <div class ="row">
    <% course.each do |course|%>
    <div class="col-md-3 col-sm-3">
    <h3><%= course.title %></h3><br />
    <h3><%= course. description %></h3><br />

    <%= link_to 'View More', course_path(course), class:'btn btn-primary' %>
 </div>
    <%end%>
   </div>
  <%end%>
 </div>

模型

class CreateCourses < ActiveRecord::Migration
def change
create_table :courses do |t|
  t.string :title
  t.string :desciption
  t.integer :course_id

  t.timestamps null: false
  end
  end
  end

show.html.erb

<h1>Courses#show</h1>
<h1><%= @course.title %></h1>
<p> <%= @course.description %></p>

解决方案：所有这三个都在show方法中工作。我只是不明白为什么@course = Course.find（params [：id]）。是因为我在模型中定义了这些列。

@course = Course.find_by(params[:title])
@course = Course.find_by(params[:course_id])
@course = Course.find_by(params[:description])

Answer 1

@course = Course.find(params[:id])按身份证号码查找课程，但您要传递标题而不是身份证号码。如果这就是你想保留它的方式

@course = Course.find_by(title: params[:id])

可能会做你想做的事情

Answer 2

你可以试试这个：

#route.rb
resources :courses, params :title

此路线：course GET /courses/:id(.:format) courses#show

变成这样：course GET /courses/:title(.:format) courses#show

#controller.rb

#like said Tom Walpole you can do this:
@course = Course.find_by(title: params[:title])
#but I prefer this syntax:
@course = Course.find_by_title(params[:title])

如果您遇到错误，请在viex：course_path(course.title)

中尝试此操作

CoursesController #show中的ActiveRecord :: RecordNotFound

2 个答案: