以下是我对Devise帮助方法current_user的用户的理解：
它仅适用于控制器和视图，但不适用于建模。
这是当前登录用户的用户对象。
那么，如果user_signed_in？然后我应该能够做一些事情，比如current_user.email，current_user.id（我在User对象中有电子邮件和id）。问题是我得到了
undefined method '[]' for nil:NilClass
当我使用current_user.email
时我可能会忘记什么？
undefined method '[]' for nil:NilClass
Extracted source (around line #12):
9: <% if user_signed_in? %>
10: <li class="right_line"><%= link_to(SIGN_OUT_TITLE, destroy_user_session_path, :method => :delete) %></li>
11: <li><%= link_to "Update user info", edit_user_path(current_user) %></li>
12: <% if !user_registered(current_user.email) %>
13: <%= link_to "Register", register_path(current_user.id) %>
14: <% end %>
15: <% else %
Trace of template inclusion: app/views/layouts/application.html.erb
Rails.root: /Users/mine/Documents/projects/rails/registrar
Application Trace | Framework Trace | Full Trace
lib/assets/common_lib.rb:355:in 'user_registered'
app/views/layouts/_header.html.erb:12:in '_app_views_layouts__header_html_erb__1686513977508462374_70171327747820'
actionpack (3.2.12) lib/action_view/template.rb:145:in 'block in render'
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actionpack (3.2.12) lib/action_view/template.rb:143:in 'render'
actionpack (3.2.12) lib/action_view/renderer/partial_renderer.rb:265:in 'render_partial'
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actionpack (3.2.12) lib/action_view/helpers/rendering_helper.rb:27:in 'render'
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actionpack (3.2.12) lib/action_view/template.rb:145:in 'block in render'
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/Users/mine/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/webrick/server.rb:295:in 'block in start_thread'
答案 0 :(得分：0)
这应该可行，我唯一看到会导致此错误的是你为用户设置了不同的模型名称，用户模型类是这样的：
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :token_authenticatable, :confirmable,
# :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
# Setup accessible (or protected) attributes for your model
attr_accessible :email, :password, :password_confirmation, :remember_me,
:cellphone, :address, :name, :lastname, :nit, :phone,
:verified, :level, :utype, :ustores, :image
validates_presence_of :name
has_many :products
end