rails 3 关联错误 [英] rails 3 associations error

问题描述

我有一个表格页面和一个表格作者.每个页面属于一个作者.还为表和模型创建了迁移.但是在表单中使用它时出现此错误:

页面中没有方法错误#new显示 C:/rorapp/app/views/pages/_form.html.erb 其中第 1 行提出:nil:NilClass 的未定义方法`build'提取的源代码(围绕第 1 行):1: <%= form_for(@page, @page.author.build) 做 |f|％＞2: <% if @page.errors.any?％＞3:<div id="error_explanation">4:<h2><%=pluralize(@page.errors.count,error")%>禁止保存此帖子:</h2>模板包含的痕迹:app/views/pages/new.html.erbRails.root: C:/rorapp应用程序跟踪 |框架跟踪 |完整跟踪app/views/pages/_form.html.erb:1:在`_app_views_pages__form_html_erb___998576952_54480300'app/views/pages/new.html.erb:2:在`_app_views_pages_new_html_erb__638997451_40207104'要求参数:没有任何显示会话转储显示环境转储回复标题:没有任何

这是我的作者模型文件:

class Author 

和页面模型:

class Page 真的归属地:作者结尾

这是模型表单的片段:

<%= form_for(@page, @page.author.build) do |f|％＞<% if @page.errors.any?％＞<div id="error_explanation"><h2><%=pluralize(@page.errors.count, error") %>禁止保存此帖子:</h2><ul><% @page.errors.full_messages.each do |msg|％＞<li><%=msg%></li><%结束%>

<%结束%><p><%= f.label :title%><br/><%= f.text_field :title %></p>

有什么想法可以继续吗?

谢谢

编辑 - 1

这是我的操作方法 new :

def new@page = [e-mail]_author结尾

这是它呈现的表单:

<%= form_for(@page) do |f|％＞<% if @page.errors.any?％＞<div id="error_explanation"><h2><%=pluralize(@page.errors.count, error") %>禁止保存此帖子:</h2><ul><% @page.errors.full_messages.each do |msg|％＞<li><%=msg%></li><%结束%>

<%结束%><p><%= f.label :title%><br/><%= f.text_field :title %></p><p><%= f.label :body %><br/><%= f.text_area :body %></p><p><%= f.label :author %><br/><%= f.text_field :author %></p><p><%= f.label :email %><br/><%= f.text_field :email %></p><p><%= f.label :reference %><br/><%= f.select(:reference,[['google',1],['yahoo',2],['MSN',3],['Ask',4]]) %></p><%= f.submit 提交";％＞<%结束%>

编辑 - 2

这是我的控制器代码:

class PagesController <应用控制器定义索引@total = 页数@pages = Page.find(:all)结尾高清秀@page = Page.find(params[:id])结尾定义新@page = [e-mail]_author结尾定义创建@page = Page.new(params[:page])如果@page.saveredirect_to pages_path, :notice =>数据已保存！"别的呈现新"结尾结尾定义编辑@page = Page.find(params[:id])结尾定义更新@page = Page.find(params[:id])如果@page.update_attributes(params[:page])redirect_to pages_path, :notice =>您的帖子已更新！"别的渲染编辑"结尾结尾销毁@page = Page.find(params[:id])@page.destroyredirect_to pages_path, :notice =>您的页面已被删除！"结尾结尾

解决方案

需要在pages controller的新action中添加*@page.build_author*.

 def new@page = [e-mail]_authorresponse_to do |格式|format.html # new.html.erbformat.json { 渲染 json: @page }结尾结尾

I have a table pages and a table author. Each page belongs to one author. Created migrations for the tables and models as well. But getting this error while using it in form:

NoMethodError in Pages#new

Showing C:/rorapp/app/views/pages/_form.html.erb where line #1 raised:

undefined method `build' for nil:NilClass
Extracted source (around line #1):

1: <%= form_for(@page, @page.author.build) do |f| %>
2:   <% if @page.errors.any? %>
3:     <div id="error_explanation">
4:       <h2><%= pluralize(@page.errors.count, "error") %> prohibited this post from being saved:</h2>
Trace of template inclusion: app/views/pages/new.html.erb

Rails.root: C:/rorapp

Application Trace | Framework Trace | Full Trace
app/views/pages/_form.html.erb:1:in `_app_views_pages__form_html_erb___998576952_54480300'
app/views/pages/new.html.erb:2:in `_app_views_pages_new_html_erb__638997451_40207104'
Request

Parameters:

None
Show session dump

Show env dump

Response

Headers:

None

Here is my model file for author:

class Author < ActiveRecord::Base

has_one :page
end

And page model:

class Page < ActiveRecord::Base

validates :title, :presence => true

belongs_to :author
end

And here is the snippet of model form :

<%= form_for(@page, @page.author.build) do |f| %>
  <% if @page.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@page.errors.count, "error") %> prohibited this post from being saved:</h2>

      <ul>
      <% @page.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
  <p>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </p>

Any ideas how to go ahead with it?

thanks

EDIT - 1

Here is my action method called new :

def new
    @page = Page.new
    @page.build_author
    
  end

And here is the form it is rendering:

<%= form_for(@page) do |f| %>
  <% if @page.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@page.errors.count, "error") %> prohibited this post from being saved:</h2>

      <ul>
      <% @page.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>
  <p>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </p>
   <p>
    <%= f.label :body %><br />
    <%= f.text_area :body %>
  </p>
   <p>
    <%= f.label :author %><br />
    <%= f.text_field :author %>
  </p>
   <p>
    <%= f.label :email %><br />
    <%= f.text_field :email %>
  </p>
   <p>
    <%= f.label :reference %><br />
    <%= f.select(:reference,[['google',1],['yahoo',2],['MSN',3],['Ask',4]]) %>
  </p>
   <%= f.submit "Submit" %>
<% end %>

EDIT - 2

Here is my controller code:

class PagesController < ApplicationController
    
  def index
    @total = Page.count
    @pages = Page.find(:all)
  end
  
  def show
    @page = Page.find(params[:id])
  end
  
  def new
    @page = Page.new
    @page.build_author
    
  end
  
  def create
    @page = Page.new(params[:page])
    if @page.save
        redirect_to pages_path, :notice => "The data has been saved!"
    else
        render "new"
    end
  end 
    
  def edit
    @page = Page.find(params[:id])
    
    
  end
    
  def update
    @page = Page.find(params[:id])
    
        if @page.update_attributes(params[:page])
            redirect_to pages_path, :notice => "Your post has been updated!"
        else
            render "edit"
        end 
        
  end 
  
  def destroy
    @page = Page.find(params[:id])
    @page.destroy
    redirect_to pages_path, :notice => "Your page has been deleted!"
  end
end

解决方案

you need to add *@page.build_author* in the new action of pages controller.

  def new
    @page = Page.new
    @page.build_author
    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @page }
    end
  end

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