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我使用Carrierwave將圖像字段添加到基於Ryan Bates修訂的＃196屏幕錄像的Rails嵌套模型。 Carrierwave位基於他的屏幕錄像＃253無法在嵌套模型編輯頁面的我的_form視圖中顯示圖像
Question and Answer模型嵌套在Categories模型中。
我可以上傳圖片並在Show頁面上顯示。但是當我回到編輯視圖時，沒有圖像，我仍然看到選擇文件按鈕旁邊的「無文件選擇」文本。我可以前往Show頁面來回顯示，但它仍然出現在Show中，但從未出現在Edit中。我的用戶會認爲他們每次都必須上傳新圖片！
我有這行代碼在我的節目的看法：
<%= image_tag question.image_url(:thumb).to_s if question.image? %>
，但如果我嘗試它放入_form視圖然後我得到一個未知的局部變量或方法的錯誤。
我試過幾個if語句，但還沒有得到它的工作。我試圖把它放在編輯視圖中，但無濟於事。
我_form觀點：
<%= form_for @category, :html => {:multipart => true} do |f| %>
<% if @category.errors.any? %>
<div class="error_messages">
<h2><%= pluralize(@category.errors.count, "error") %> prohibited this category from being saved:</h2>
<ul>
<% @category.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div id="categorytitle" class="field">
<%= f.label :name, "Category Name" %><br />
<%= f.text_field :name %>
</div>
<%= f.fields_for :questions do |builder| %>
<%= render 'question_fields', f: builder %>
<% end %>
<%= link_to_add_fields "Add Question", f, :questions %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
我_questions部分
<fieldset id="questionarea">
<%= f.label :content, "Question" %>
<%= f.text_field :content%>
<hr>
<div class="field">
<p>
<%= f.check_box :active, class: "pull-left" %>
<%= f.label :active %>
<span class="help-block">Turning questions on and off helps you customize the category.</span>
</p>
</div>
<hr>
<div class="field clearthat">
<%= f.label :image, "Add an Image"%>
<span class="help-block">Images will help non-readers understand the question.</span>
<%= f.file_field :image %>
<%= f.hidden_field :image_cache %>
</div>
<hr>
<!-- <%= link_to "remove", '#', class: "remove_fields" %> -->
<p class="clearthat"> </p>
<%= f.fields_for :answers do |builder| %>
<%= render 'answer_fields', f: builder %>
<% end %>
<%= link_to_add_fields "Add Answer", f, :answers %>
</fieldset>
有局部的_answer但似乎並沒有推測到它。
下面是錯誤消息我收到的時候我嘗試直接把圖像變成我的_question部分像這樣（剪斷從_question碼中心以上）：
<div class="field clearthat">
<%= f.label :image, "Add an Image"%>
<span class="help-block">Images will help non-readers understand the question.</span>
<%= image_tag question.image_url(:thumb).to_s if question.image? %>
<%= f.file_field :image %>
<%= f.hidden_field :image_cache %>
</div>
這是我得到的錯誤：
NameError in Categories#edit
undefined local variable or method `question'
我的類別模型：
class Category < ActiveRecord::Base
attr_accessible :name, :questions_attributes
has_many :questions
accepts_nested_attributes_for :questions, allow_destroy: true
end
我的問題型號：
class Question < ActiveRecord::Base
attr_accessible :content, :category_id, :answers_attributes, :active, :image, :image_cache
belongs_to :category
has_many :answers
accepts_nested_attributes_for :answers, allow_destroy: true
mount_uploader :image, ImageUploader
end
我的類別控制器：
class CategoriesController < ApplicationController
before_filter :signed_in_user, only: [:index, :edit, :update, :destroy]
before_filter :correct_user, only: [:edit, :update]
before_filter :admin_user, only: :destroy
def index
@categories = Category.all
end
def show
@category = Category.find(params[:id])
end
def new
@category = Category.new
end
def create
@category = Category.new(params[:category])
if @category.save
redirect_to @category, :notice => "Successfully created category."
else
render :action => 'new'
end
end
def edit
@category = Category.find(params[:id])
end
def update
@category = Category.find(params[:id])
if @category.update_attributes(params[:category])
redirect_to @category, :notice => "Successfully updated category."
else
render :action => 'edit'
end
end
def destroy
@category = Category.find(params[:id])
@category.destroy
redirect_to categories_url, :notice => "Successfully destroyed category."
end
private
def signed_in_user
unless signed_in?
store_location
redirect_to signin_path, notice: "Please sign in."
end
end
def correct_user
@user = User.find(params[:id])
redirect_to(root_path) unless current_user?(@user)
end
def admin_user
redirect_to(root_path) unless current_user.admin?
end
末
由於任何人誰可以提供幫助。