Ruby on Rails - 控制器方法中的問題在視圖中顯示

Question

現在我正在完成我的小型學習項目，但是我一直在困惑。該項目的功能是：register,login,logout爲作者; creating,editing,removing的事件;出席，不參加活動。

我想要實現的最後一件事是能夠看到誰參加了某個活動。參加/不參加的功能已經完成（參考事件和作者）製作了一個表Eventattendences。

唯一缺少的是顯示WHO正在參加不同的活動（即在show.html.erb中顯示events_id相等的eventattendance表中的Authors_key）。當我試圖這樣做時，我總是從eventattendacnes_controller的SHOW方法中獲得一個空對象。

在此處添加所有與此相關的代碼（如果缺少任何內容，請讓我知道，我將在此處添加它）。謝謝！

Versions: Rails(4.0.0), Ruby(2.3.3p222) 

eventattendances_controller

class EventattendancesController < ApplicationController 
    before_action only: [:show, :edit, :update, :destroy] 
    before_filter :require_login 



def new 
    if Eventattendance.exists?(events_id: params[:event_id].to_i, authors_id: current_user.id) 
    redirect_to event_path(params[:event_id]) 
    else 
    @eventattendance = Eventattendance.new(events_id: params[:event_id].to_i, authors_id: current_user.id) 
    @eventattendance.save 
    redirect_to event_path(params[:event_id]) 
    end 
end 

def destroy 
    if Eventattendance.exists?(events_id: params[:event_id].to_i, authors_id: current_user.id) 
    Eventattendance.where(events_id: params[:event_id].to_i, authors_id: current_user.id).first.destroy 
    redirect_to event_path(params[:event_id]) 
    else 
    redirect_to event_path(params[:event_id]) 
    end 
end 

def show 
    @eventattendances = Eventattendance.find(events_id= params[:event_id].to_i) 
end 


private 
def author_params 
    params.require(:author).permit(:username, :email, :password,:password_confirmation) 
end 

def event_params 
    params.require(:event).permit(:title, :body) 
end 
    end 

eventattendances.rb（型號）

class Eventattendance < ActiveRecord::Base 
    belongs_to :author 
    belongs_to :event 
    end 

的routes.rb

Events::Application.routes.draw do 

root to: 'events#index' 
resources :events 
resources :authors 
resources :author_sessions, only: [ :new, :create, :destroy ] 
resources :eventattendances, only: [:destroy, :new, :show] 
get 'login' => 'author_sessions#new' 
get 'logout' => 'author_sessions#destroy' 
end 

的意見/事件/ show.html.erb（在這裏，我想設置從eventattendances的放映功能正參加活動的作家的authors_id）

`<h1><%= @event.title %></h1> 
    <p><%= @event.body %></p>  
    <%= @at_list.blank? %> 
    <%= @at_list_att.blank? %> 
    <%=sql = "Select * from eventattendances" 
    at_list = ActiveRecord::Base.connection.execute(sql) %> 

    <% @event.eventattendances.map do |eventattendance| %> 
    <tr> 
    <td><%= eventattendance.author_id %></td> 
    </tr> 
    <% end %> 

    <%= link_to "<< Back to Event List", events_path %> 

    <p> </p> 
    <br> 

    <% if logged_in? %> 
    <%= link_to "edit", edit_event_path(@event) %> 
    <%= link_to "delete", event_path(@event), method: :delete, data: { confirm: "Are you sure?" } %> 
    <% end %> 


<%= link_to "Cancel atendance", eventattendance_path(event_id: @event.id), method: :delete, class: "btn btn-primary" %> 

<%= link_to "Attend", new_eventattendance_path(event_id: @event.id), class: "btn btn-success"%> 

`

events_controller

class EventsController < ApplicationController 
include EventsHelper 
before_filter :require_login, except: [:index] 

def index 
    @events = Event.all 
end 

def show 
    @event = Event.find(params[:id]) 
end 

def new 
    @event = Event.new 

end 



def create 
    @event = Event.new(event_params) 
    @event.save 

    redirect_to event_path(@event) 
end 

def destroy 
    @event = Event.find(params[:id]) 
    @event.destroy 
    redirect_to events_path 
end 

def edit 
    @event = Event.find(params[:id]) 
end 

def update 
    @event = Event.find(params[:id]) 
    @event.update(event_params) 

    redirect_to event_path(@event) 
end 



private 
def event_params 
    params.require(:event).permit(:title, :body) 
end 
end 

author.rb

`class Author < ActiveRecord::Base 
    authenticates_with_sorcery! 
    validates_confirmation_of :password, message: "should match confirmation", if: :password 
    has_and_belongs_to_many :events 


end` 

event.rb

class Event < ApplicationRecord 
    has_and_belongs_to_many :authors 
end 

Answer 1

解決的辦法是把它放到顯示的events_controller.rb（的eventattendances_controller代替）

@eventattendances = Eventattendance.find_by(events_id: params[:id])方法

+

更改find​​的參數：

從(events_id= params[:event_id])到(events_id: params[:id])

（也許這將幫助別人的未來）

Answer 2

排在首位，如果你是渲染views/events/show你可以做

<% @event.eventattendances.map do |eventattendance| %> 
     <tr> 
     <td><%= eventattendance.author_id %></td> 
     </tr> 
    <% end %> 

得到AUTHOR_ID。

但想好，也許你有關係的問題，你需要一個 has and belongs to many association