Question

我一直在寻找同样的问题，但没有找到它。

我正在关注此guide，我一直在为文本字段设置验证。

模型（article.rb）：

class Article < ActiveRecord::Base
  validates :title, presence: true, length: { minimum: 5 }
end

控制器：

class ArticlesController < ApplicationController:

    def new
      @article = Article.new
    end

    def create
      @article = Article.new(article_params)

      if @article.save
        redirect_to @article
      else
        render 'new'
      end
    end

    private
    def article_params
      params.require(:article).permit(:title, :text)
    end

查看（new.html.erb）：

<%= form_for :article, url: articles_path do |f| %>

  <% if @article.errors.any? %>
    <div id="error_explanation">
      <h2>
        <%= pluralize(@article.errors.count, "error") %> prohibited this article from being saved:
      </h2>
      <ul>
        <% @article.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 :text %><br>
    <%= f.text_area :text %>
  </p>

  <p>
    <%= f.submit %>
  </p>

<% end %>

<%= link_to 'Back', articles_path %>

当我尝试添加新文章时，我会打开http://localhost:3000/articles/new，但由于此行中的错误undefined method errors' for nil:NilClass

而不是表单，因此我看到错误<% if @article.errors.any? %>

我在这里缺少什么。看起来@article在创建之前正在验证？我该如何解决？

index.html.erb：

<h1>Listing articles</h1>

<%= link_to "New article", new_article_path %>

<table>
 <tr>
   <th>Title</th>
   <th>Text</th>
 </tr>

 <% @articles.each do |article| %>
   <tr>
     <td><%= article.title %></td>
     <td><%= article.text %></td>
   </tr>
 <% end %>
</table>

Answer 1

您需要致电：

HttpCookie cookie = new HttpCookie("User"); cookie.Values["UserType"] = usertype; cookie.Expires = DateTime.MaxValue; HttpContext.Response.SetCookie(cookie);

在new.html.erb的第一行

Answer 2

将form_for更改为

<%= form_for(@article) do |f| %>

  <% if @article.errors.any? %>
    <div id="error_explanation">
      <h2>
        <%= pluralize(@article.errors.count, "error") %> prohibited
   this article from being saved:
      </h2>
      <ul>
        <% @article.errors.full_messages.each do |msg| %>
          <li><%= msg %></li>
        <% end %>
      </ul>
    </div>
  <% end %>
  ........
<% end %>

articles_controller.rb

class ArticlesController < ApplicationController
  ....
end

nil的未定义方法`errors'：NilClass - Ruby教程

2 个答案: