Question

我不确定这里发生了什么。我在这里检查了所有内容，但我得到了这个双文件上传字段：

enter image description here

即使我只使用一个字段，它仍会呈现两个图像。

_form.html.erb：

<%= nested_form_for @home, :html=>{:multipart => true } do |f| %>
  <% if @home.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@home.errors.count, "error") %> prohibited this blog from being saved:</h2>
      <ul>
        <% @home.errors.full_messages.each do |msg| %>
          <li><%= msg %></li>
        <% end %>
      </ul>
    </div>
  <% end %>

  <p>
    <%= f.label :body %><br />
    <%= f.text_area :body %>
  </p>
  <p>
    <%= f.fields_for :attachments do |attachment_form|  %>
      <%= attachment_form.file_field :file %>
      <br /><br />
      <%= attachment_form.link_to_remove "Remove this attachment" %>
      <% for attachment in @home.attachments %>
        <div class="show_image">
          <%= image_tag attachment.file_url(:thumb).to_s %>
        </div>
      <% end %>      
    <% end %>
    <br /><br />
    <%= f.link_to_add "Add attachmnt", :attachments %>
  </p>
  <br /><br />
  <p><%= f.submit %></p>
  <br /><br />
<% end %>

型号： attachment.rb：

class Attachment < ActiveRecord::Base
   attr_accessible :description, :file
   belongs_to :attachable, :polymorphic => true
   mount_uploader :file, FileUploader
end

home.rb：

class Home < ActiveRecord::Base
  attr_accessible :body, :attachments_attributes
  has_many :attachments, :as => :attachable
  accepts_nested_attributes_for :attachments, :allow_destroy => true
end

homes_controller.rb：

class HomesController < ApplicationController
  # GET /homes
  # GET /homes.json
  def index
    @homes = Home.all

    respond_to do |format|
      format.html # index.html.erb
      format.json { render :json => @homes }
    end
  end

  # GET /homes/1
  # GET /homes/1.json
  def show
    @home = Home.find(params[:id])

    respond_to do |format|
      format.html # show.html.erb
      format.json { render :json => @home }
    end
  end

  # GET /homes/new
  # GET /homes/new.json
  def new
    @home = Home.new

    respond_to do |format|
      format.html # new.html.erb
      format.json { render :json => @home }
    end
  end

  # GET /homes/1/edit
  def edit
    @home = Home.find(params[:id])
  end

  # POST /homes
  # POST /homes.json
  def create
    @home = Home.new(params[:home])

    respond_to do |format|
      if @home.save
        format.html { redirect_to @home, :notice => 'Home was successfully created.' }
        format.json { render :json => @home, :status => :created, :location => @home }
      else
        format.html { render :action => "new" }
        format.json { render :json => @home.errors, :status => :unprocessable_entity }
      end
    end
  end

  # PUT /homes/1
  # PUT /homes/1.json
  def update
    @home = Home.find(params[:id])

    respond_to do |format|
      if @home.update_attributes(params[:home])
        format.html { redirect_to @home, :notice => 'Home was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render :action => "edit" }
        format.json { render :json => @home.errors, :status => :unprocessable_entity }
      end
    end
  end

  # DELETE /homes/1
  # DELETE /homes/1.json
  def destroy
    @home = Home.find(params[:id])
    @home.destroy

    respond_to do |format|
      format.html { redirect_to homes_url }
      format.json { head :no_content }
    end
  end
end

如何阻止这种情况发生？

对此的任何帮助都会很棒，我已经看了好几个小时了！

Answer 1

我的第一个猜测是在设置这个设置时创建的错误数据。也许Home对象上的先前附件未正确显示，但仍存在于数据库中。如果您创建新的Home并尝试添加附件，会发生同样的问题吗？

fields_for块正在为每个传递的attachment创建一个按钮和每张照片的显示。我认为这就是为什么你会看到重复的原因。 fields_for是attachments上的迭代器，其中有一个重复的迭代器（for attachment in @home.attachments）。

Rails与nested_form gem不需要重复

1 个答案: