Question

我在rails应用程序上有一个ruby，我正在尝试将类别数据保存到系统中，但每当我点击保存时我都会收到错误：

NoMethodError in CategoriesController#create
undefined method `category' for #<Category id: nil, genre: "", created_at: nil, updated_at: nil>
Extracted source (around line #29):

27 def create
28 @category = Category.new(category_params)
29 if @category.save
30 redirect_to @category, notice: 'Category was successfully created.'
31 else
32 render action: 'new'

Rails.root: C:/Sites/week_15/New/my_bookshop_test2 _basic

这是我在categories_controller.rb中的代码：

class CategoriesController < ApplicationController
   before_action :set_category, only: [:show, :edit, :update, :destroy]
   def new
     @category = Category.new
   end
   def create
     @category = Category.new(category_params)
     if @category.save
       redirect_to @category, notice: 'Category was successfully created.'
     else
       render action: 'new'
     end
   end

有人可以帮帮我吗。

Answer 1

您应该更新问题中的评论代码，因为您的模型中存在明显的错误：

您的代码：

class Category < ActiveRecord::Base 
  has_many :products
  validates :category, :presence => { :message => "cannot be blank ..."} 
  # display id and genre text e.g. 1 Detective, 2 Science Fiction, etc. 
  # used in category drop down selection box    
  def category_info 
    "#{id} #{genre}"
  end 
end

如果您查看验证，那么您正在尝试验证category本身而不是验证所需的内容（从您之前发布的代码看起来您需要验证genre ）

要使您的代码正常工作，您需要将其更改为：

class Category < ActiveRecord::Base 
  has_many :products
  validates :genre, :presence => { :message => "cannot be blank ..."} 
  # display id and genre text e.g. 1 Detective, 2 Science Fiction, etc. 
  # used in category drop down selection box    
  def category_info 
    "#{id} #{genre}"
  end 
end

您对属性（例如您的genre）使用验证，而不是对象本身。

Ruby on Rails Controller中没有方法错误，试图创建一条记录

1 个答案: