Question

我正在使用Ruby on Rails创建一个网站。我遇到了一个问题，我需要在我的网页上显示我的数据作为文本，例如<h2><%=@permits.permitstart%></h2>，但我一直收到此错误

NoMethodError in Permits#show
Showing C:/Users/GaryVLC/RubymineProjects/Parking_and_Safety_3/app/views/permits/show.html.erb where line #7 raised:

undefined method `permitstart' for #<Permit::ActiveRecord_Relation:0xb69e290>

我不确定我是否在控制器中输入了正确的内容。你们可以看一下吗？任何帮助表示赞赏！

这是我希望我的数据呈现的网页（show.html.erb）

<% provide(:title, 'New Permit') %>
<h1>Permit Application</h1>

<div class="row">
  <div class="col-md-6 col-md-offset-3">

    <h2><%=@permits.permitstart%></h2></br>

  </div>
</div>

这是按钮克隆到（show.html.erb）

的网页

<h2>My Permits</h2>
<table>
  <tr>
    <th>Permit Start Date</th>
    <th>Permit End Data</th>
    <th>Action</th>
    <th> </th>
  </tr>
  <% @permits.each do |permit| %>

      <tr>
        <td><%= permit.permitstart %></td>
        <td><%= permit.permitend %></td>
        <td><%= link_to 'Detail', viewpermit_path(permit) %></td>
        <td><%= link_to 'Edit', edit_permit_path(permit) %></td>
      </tr>

  <% end %>

</table>

这是我的许可控制器

class PermitsController < ApplicationController
  before_action :set_permit, only: [:destroy]
  def index
    @permits = Permit.where(:user_id => current_user.id)
  end

  def new
    @permits = Permit.new
  end

  def create
    @permits = current_user.permits.build(permit_params)
    if @permits.save
      redirect_to invoice_path
    else
      render 'new'
    end
  end


  def destroy
    Permit.destroy_all(user_id: current_user)
    respond_to do |format|
      format.html { redirect_to root_path, notice: 'Permit was successfully canceled.' }
      format.json { head :no_content }
    end
  end

  def confirm
    @fields = %i[vehicle_type, carplate, studentid, name, department, permitstart, permitend]
    @permit = current_user.permits.build(permit_params)
    render :new and return unless @permit.valid?
  end

  def show
    @permits = Permit.where(:user_id => current_user.id)
  end

  def update
    @permits = Permit.where(user_id: current_user).take
    respond_to do |format|
      if @permits.update(permit_params)
        format.html { redirect_to root_path}
        flash[:success] = "Permit successfully updated"
        format.json { render :show, status: :ok, location: @user }
      else
        format.html { render :edit }
        format.json { render json: @user.errors, status: :unprocessable_entity }
      end
    end
  end

  def edit
    @permits = Permit.find(params[:id])
    #@permits = Permit.find_or_initialize_by(user_id: params[:id])
  end
  def detail

  end

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

  # Never trust parameters from the scary internet, only allow the white list through.
  def permit_params
    params.require(:permit).permit(:vehicle_type, :name, :studentid, :department, :carplate, :duration, :permitstart, :permitend)
  end
end

这是我的route.db

Rails.application.routes.draw do
  resources :users
  resources :permits do
    collection do
      post :confirm
    end
  end
  resources :visitor_permits
  root 'static_pages#home'

  get 'viewpermit' =>'permits#show'

  get 'invoice' => 'permits#invoice'
  get 'payment' =>'transaction#new'
  get 'show_visitor_permit' =>'visitor_permits#show'
  get 'show_permit' =>'permits#index'
  get 'visitorpermit' => 'visitor_permits#new'
  post 'createpermit' => 'permits#create'
  get 'homepage/index'
  post 'permits' => 'permits#create'
  get 'permitapplication' => 'permits#new'
  get 'adminlogin' => 'admin_controller#index'
  get 'patrollogin' => 'patrol_officer_controller#index'
  get 'createcitation' => 'citations#new'
  get 'contact'=> 'static_pages#contact'
  get 'about' => 'static_pages#about'
  get 'signup' => 'users#new'
  get 'help' => 'static_pages#help'
  post 'users' => 

'users#create'
  get 'login' => 'sessions#new' #Page for a new session
  post 'login' => 'sessions#create' #Create a new session
  delete 'logout'=>'sessions#destroy' #Delete a session


  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
end

Answer 1

您正在集合对象上调用实例方法（该方法不存在）。

您需要遍历@permits对象并在其包含的每个模型对象上调用permitstart：

<% provide(:title, 'New Permit') %>
<h1>Permit Application</h1>

<div class="row">
  <div class="col-md-6 col-md-offset-3">

    <% @permits.each do |p| %>
      <h2><%= p.permitstart %></h2></br>
    <% end %>

  </div>
</div>

-

或者，如果您在show操作中看到此错误，则需要使用以下内容：

def show
  @permits = current_user.permits.find(params[:id])
end

Answer 2

因为这个方法

def show
  @permits = Permit.where(:user_id => current_user.id)
end

为您提供关系（ActiveRecord_Relation），而不是单个Permit对象。你可以拿第一个，但我不知道它是不是你想要的。无论如何，这就是问题所在。

@permits = Permit.where(:user_id => current_user.id).first

从我的模型RAILS渲染数据

2 个答案: