未定义的方法

未定义的方法

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未定义的方法 'model_name' 为 nil:NilClass

本文介绍了未定义的方法 'model_name' 为 nil:NilClass的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在尝试获取用户的地址并将其保存在数据库中，但我得到了 undefined method 'model_name' for nil:NilClass.在同一页面中，名称可以更新，这是在注册过程中获得的.当按下保存更改按钮时，我希望将名称存储在用户表中，并将地址存储在数据库的地址表中.我不知道我哪里出错了.请任何人帮助解决此问题！

查看代码

<%= form_for(@user, url: { action: 'update_profile' }, html: { class: 'm-form m-form--fit m-form--label-align-right' } ) 做 |f|％＞<% if @user.errors.any?％＞<h4><%=pluralize(@user.errors.count, "error") %>禁止保存此配置文件:</h4><ul><% @user.errors.full_messages.each 做 |message|％＞<li><%=消息%></li><%结束%><%结束%><div class="form-group m-form__group row"><label for="name" class="col-2 col-form-label">名称<div class="col-7"><%= f.text_field :name, class: 'form-control m-input', placeholder: 'Full Name' %>

<div class="m-form__seperator m-form__seperator--dashed m-form__seperator--space-2x"></div><%= f.fields_for @user.address do |a|％＞<div class="form-group m-form__group row"><label for="example-text-input" class="col-2 col-form-label">地址<div class="col-7"><%= a.text_field :area, class: 'form-control m-input', placeholder: 'Address' %>

<div class="form-group m-form__group row"><label for="example-text-input" class="col-2 col-form-label">城市<div class="col-7"><%= a.text_field :city, class: 'form-control m-input', placeholder: 'City' %>

<div class="form-group m-form__group row"><label for="example-text-input" class="col-2 col-form-label">状态<div class="col-7"><%= a.text_field :state, class: 'form-control m-input', placeholder: 'State' %>

<%结束%><%= f.submit 'Save Changes', class: 'btn btn-accent m-btn m-btn--air m-btn--custom' %>&nbsp;&nbsp;<%= link_to 'Back', root_path, class: 'btn btn-secondary m-btn m-btn--air m-btn--custom' %>

控制器代码

class ProfileController

型号代码

地址.rb

类地址

用户.rb

class User

终端日志

在 2018-05-02 14:31:21 +0530 开始为 127.0.0.1 获取/profile"由 ProfileController#index 处理为 HTML用户负载 (0.3ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 11 ORDER BY `users`.`id` ASC LIMIT 1用户负载 (0.2ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 11 LIMIT 1在 layouts/application 中渲染 profile/index.html.erb渲染的 profile/_profile_card.html.erb (0.2ms)地址负载 (0.2ms) SELECT `addresses`.* FROM `addresses` WHERE `addresses`.`user_id` = 11 LIMIT 1渲染的 profile/_profile_detail.html.erb (3.4ms)在布局/应用程序中渲染 profile/index.html.erb(4.7 毫秒)8ms 内完成 401 Unauthorized (ActiveRecord: 0.7ms)[Rollbar] 报告异常:未定义方法`model_name' for nil:NilClass[滚动条] 调度项目[滚动条] 发送项目[滚动条] 成功[Rollbar] 详情:https://rollbar.com/instance/uuid?uuid=60dbe4e1-e5ef-4414-a9a5-e8a866c47740(仅在举报成功时可用)[Rollbar] 异常 uuid 保存在 env 中:60dbe4e1-e5ef-4414-a9a5-e8a866c47740NoMethodError - nil:NilClass 的未定义方法model_name":app/views/profile/_profile_detail.html.erb:45:在`阻止_app_views_profile__profile_detail_html_erb___3163788399910446599_70315531332300'app/views/profile/_profile_detail.html.erb:26:in`_app_views_profile__profile_detail_html_erb___3163788399910446599_70315531332300'app/views/profile/index.html.erb:7:在`_app_views_profile_index_html_erb__1161982046354726382_70315531116820'在 2018-05-02 14:31:22 +0530 为 127.0.0.1 开始 POST "/__better_errors/0227f950024c358e/variables"
解决方案

您的@address 可能为零.必须先在控制器或视图中初始化

class UsersController

或在上面的视图中:

 <%= f.fields_for :address do |a|％＞

I am trying to get address of users and save it in database but i am getting undefined method 'model_name' for nil:NilClass. In the same page the name can updated which is got during signup. I want name to be stored in users table and the address to be stored in addresses table in the database when the save changes button is presseed. I dont know where i am going wrong. please anyone help in fixing this issue!

View Code

<%= form_for(@user, url: { action: 'update_profile' }, html: { class: 'm-form m-form--fit m-form--label-align-right' } ) do |f| %>
  <% if @user.errors.any? %>
    <h4><%= pluralize(@user.errors.count, "error") %>
      prohibited this profile from being saved:</h4>
    <ul>
      <% @user.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
    </ul>
  <% end %>
  <div class="form-group m-form__group row">
    <label for="name" class="col-2 col-form-label">
      Name
    </label>
    <div class="col-7">
      <%= f.text_field :name, class: 'form-control m-input', placeholder: 'Full Name' %>
    </div>
  </div>
  <div class="m-form__seperator m-form__seperator--dashed m-form__seperator--space-2x"></div>
  <%= f.fields_for @user.address do |a| %>

  <div class="form-group m-form__group row">
    <label for="example-text-input" class="col-2 col-form-label">
      Address
    </label>
    <div class="col-7">
      <%= a.text_field :area, class: 'form-control m-input', placeholder: 'Address' %>
    </div>
  </div>
  <div class="form-group m-form__group row">
    <label for="example-text-input" class="col-2 col-form-label">
      City
    </label>
    <div class="col-7">
      <%= a.text_field :city, class: 'form-control m-input', placeholder: 'City' %>
    </div>
  </div>
  <div class="form-group m-form__group row">
    <label for="example-text-input" class="col-2 col-form-label">
      State
    </label>
    <div class="col-7">
      <%= a.text_field :state, class: 'form-control m-input', placeholder: 'State' %>
    </div>
  </div>
<% end %>
<%= f.submit 'Save Changes', class: 'btn btn-accent m-btn m-btn--air m-btn--custom' %>
&nbsp;&nbsp;
<%= link_to 'Back', root_path, class: 'btn btn-secondary m-btn m-btn--air m-btn--custom' %>

Controller code

class ProfileController < ApplicationController
  before_action :set_user, only: %i[index update_profile]

  def index; end

  def update_profile
    respond_to do |format|
      if @user.update(user_params)
        format.html { redirect_to profile_index_path, notice: 'Profile was successfully updated.' }
      else
        format.html { render :index }
      end
    end
  end

private

  def set_user
    @user = User.find(current_user.id)
  end

  def user_params
    params.require(:user).permit(:name)
  end

  def address_params
    params.require(:user).permit(address: %i[area state country])
  end
end

Model code

Address.rb

class Address < ApplicationRecord
  belongs_to :user
end

User.rb

class User < ApplicationRecord
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  has_one :address, dependent: :destroy

  validates :name, presence: true
  def admin?
    false
  end
end

Terminal log

Started GET "/profile" for 127.0.0.1 at 2018-05-02 14:31:21 +0530
Processing by ProfileController#index as HTML
  User Load (0.3ms)  SELECT  `users`.* FROM `users` WHERE `users`.`id` = 11 ORDER BY `users`.`id` ASC LIMIT 1
  User Load (0.2ms)  SELECT  `users`.* FROM `users` WHERE `users`.`id` = 11 LIMIT 1
  Rendering profile/index.html.erb within layouts/application
  Rendered profile/_profile_card.html.erb (0.2ms)
  Address Load (0.2ms)  SELECT  `addresses`.* FROM `addresses` WHERE `addresses`.`user_id` = 11 LIMIT 1
  Rendered profile/_profile_detail.html.erb (3.4ms)
  Rendered profile/index.html.erb within layouts/application (4.7ms)
Completed 401 Unauthorized in 8ms (ActiveRecord: 0.7ms)


[Rollbar] Reporting exception: undefined method `model_name' for nil:NilClass
[Rollbar] Scheduling item
[Rollbar] Sending item
[Rollbar] Success
[Rollbar] Details: https://rollbar.com/instance/uuid?uuid=60dbe4e1-e5ef-4414-a9a5-e8a866c47740 (only available if report was successful)
[Rollbar] Exception uuid saved in env: 60dbe4e1-e5ef-4414-a9a5-e8a866c47740

NoMethodError - undefined method `model_name' for nil:NilClass:
  app/views/profile/_profile_detail.html.erb:45:in `block in _app_views_profile__profile_detail_html_erb___3163788399910446599_70315531332300'
  app/views/profile/_profile_detail.html.erb:26:in `_app_views_profile__profile_detail_html_erb___3163788399910446599_70315531332300'
  app/views/profile/index.html.erb:7:in `_app_views_profile_index_html_erb__1161982046354726382_70315531116820'

Started POST "/__better_errors/0227f950024c358e/variables" for 127.0.0.1 at 2018-05-02 14:31:22 +0530
解决方案

Your @address is probably nil. You must initialize it first in the controller or view

class UsersController < ApplicationController
  def set_user
    @user = User.find(current_user.id)
    @user.address || @user.build_address
  end
end

or in the view above:

  <% @user.address || @user.build_address %>
  <%= f.fields_for :address do |a| %>

这篇关于未定义的方法 'model_name' 为 nil:NilClass的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！

09-05 01:43
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