参数数量错误（给定 0，预期为 1）

Question

我想要做什么

我正在尝试each do 在一个表上创建一个新关系。

规则如下：

• 用户创建事件
• 一个活动可以有很多客人（用户）

我希望 current_user 能够加入活动。

我尝试了什么

class AttendingEventsController < ApplicationController

  def new
    @attending_event = AttendingEvent.new
  end

  def join event_id
    @attending_event = @attending_event.new(user_id: current_user.id, event_id: event_id)
  end
end

当以用户身份通过​​join 方法加入活动时，我收到了错误的参数错误。

我的按钮如下所示：

<% Event.all.each do |e| %>
      <tr>
        <td><%= e.title %></td>
        ...
        <td><%= button_to "join event", join_path e.id, method: :get %></td>
      </tr>
<% end %>

路线文件供参考：

Rails.application.routes.draw do
  devise_for :users
  get 'welcome/home'
  get 'events/all'
  get 'users/index'

  get '/join', to: 'attending_events#join', as: 'join'


  resources :users do
    resources :events
  end

  root 'welcome#home'
end

Answer 1

我认为您的路线看起来更像（我认为您不需要将其嵌套在users 下）：

resources :events do 
  member do 
    get :join
  end
end

这会给你：

join_event GET    /events/:id/join(.:format)                             events#join
    events GET    /events(.:format)                                      events#index
           POST   /events(.:format)                                      events#create
 new_event GET    /events/new(.:format)                                  events#new
edit_event GET    /events/:id/edit(.:format)                             events#edit
     event GET    /events/:id(.:format)                                  events#show
           PATCH  /events/:id(.:format)                                  events#update
           PUT    /events/:id(.:format)                                  events#update
           DELETE /events/:id(.:format)                                  events#destroy

然后，在您的EventsController 中，执行：

class EventsController < ApplicationController

  def new
    # I don't know if you need this, based on the code you posted
    @attending_event = AttendingEvent.new
  end

  def join
    @event = Event.find(params[:id])
    @attending_event = current_user.attending_events.new(event: @event)
    if @attending_event.save
      #do something
    else
      #do something else
    end
  end

end

这假设：

class User < ActiveRecord::Base 
  has_many :attending_events
end

还有：

class AttendingEvent < ActiveRecord::Base
  belongs_to :user
  belongs_to :event
end

那么在你看来：

<% Event.all.each do |e| %>
  <tr>
    <td><%= e.title %></td>
    ...
    <td><%= button_to "join event", join_event_path(e), method: :get %></td>
  </tr>
<% end %>