Question

我一直在尝试使用collection_select保存表单。我有3个模型（事件，用户，项目），还有一个将项目链接到事件（事件_项目）的联接模型。

我的目标是让每个用户都可以加入事件，并且每个用户可以从每个用户唯一的清单中指定要带入事件的项目列表。

我的部分带有集合选择的表单如下所示：

<%= form_for [@event, @event_items], remote: true do |f| %>
<%= f.hidden_field :user_id, value: current_user.id %>

<div class="form-group">

  <%= f.collection_select(:item_id, current_user.items.all, :id, :title, { :prompt => "Select an Item", :selected => @item_id}, { class: "form-control"}) %>
</div>

<%= f.submit "Submit", class: "btn btn-primary", id: "event-item-button" %>

我的event_items_controller如下：

 class EventItemsController < ApplicationController
  before_action :authenticate_user!

  def new
    @event_item = EventItem.new
  end


  def create
      @event_item = EventItem.new
      @event = Event.find(params[:id])

      if @event_item.save
        flash[:success] = "Item Added to List"   
        redirect_to @event
      else
        flash.now[:danger] = "Please try again"
        redirect_to @event
      end

  end

  def destroy
    @event_item = EventItem.find(params[:id])

  end

  private

    def event_item_params
      params.require(:event_item).permit(:event_id, :user_id, :item_id)
    end


end

在“活动展示”页面中，我有以下部分，在其中迭代每个参与者并呈现Event_Item部分：

            <% @event.attendees.each do |user| %>
             <div class="col-md-4">
                 #should render each existing item on the list. 
                 #Doesn't work yet
                 <%= render 'event_items/event_item' %>
             </div>     

             <% if user == current_user %>
                #renders dropdown with only current user's inventory
                #currently shows items correctly, just doesn't save to 
                #database
                <%= render 'event_items/form' %>
             <% end %>

            <% end %>

无论何时我在下拉列表中选择一个项目后单击“提交”按钮，都不会将任何内容保存到数据库，尽管服务器控制台显示：

Started POST "/Events/27/event_items" for 127.0.0.1 at 2018-09-26 19:54:32 -0500
Processing by EventItemsController#create as JS
  Parameters: {"utf8"=>"✓", "event_item"=>{"user_id"=>"5", "item_id"=>"2"}, "commit"=>"Submit", "event_id"=>"27"}
  User Load (0.3ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT ?  [["id", 5], ["LIMIT", 1]]
Completed 404 Not Found in 2ms (ActiveRecord: 0.3ms)



ActiveRecord::RecordNotFound (Couldn't find Event without an ID):

app/controllers/event_items_controller.rb:11:in `create'

Answer 1

在您的create操作中，您将执行以下操作：

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

但是，params没有:id，它有:event_id。因此，可能应该是：

@event = Event.find(params[:event_id])

而且，您的create动作应该看起来更像：

def create

  @event = Event.find(params[:event_id])
  @event_item = @event.event_items.new(event_item_params)

  if @event_item.save
    flash[:success] = "Item Added to List"   
    redirect_to @event
  else
    flash.now[:danger] = "Please try again"
    redirect_to @event
  end

end

这样做：

@event_item = @event.event_items.new(event_item_params)

event_id将在新的event_item中设置。（自然假设Event has_many :event_items和EventItem belongs_to :event。）

即使控制台中的参数正确，Collection_Select也不会保存到数据库

1 个答案: