Welcome＃show中的NoMethodError

Question

这是我得到的错误：

背景：

我试图根据动作是否完成显示一个按钮。这是我的代码

<% if @courses_user.complete! %>
  <%= link_to "Completed", course, class: "block text-lg w-full text-center text-white px-4 py-2 bg-green hover:bg-green-dark border-2 border-green-dark leading-none no-underline" %>
<% else %>
  <%= link_to "View Modules", course, class: "block text-lg w-full text-center text-grey-dark hover:text-darker px-4 py-2 border-2 border-grey leading-none no-underline hover:border-2 hover:border-grey-dark" %>
<% end %>

在我的courses_user模型中，我有

class CoursesUser < ApplicationRecord
  belongs_to :course
  belongs_to :user

  has_many :course_modules_users

  def completed!
    self.update_attributes(complete: true)
  end
end

在welcomeController中我有

class WelcomeController < ApplicationController
  def show
    @courses = Course.all.order(created_at: :asc)
    @courses_user = CoursesUser.all
  end
end

但我得到NoM​​ethodError，任何帮助表示赞赏。

Answer 1

您已经定义了@courses_user = CoursesUser.all，因此它的集合不是单个对象。你不能在集合上调用complete!，错误也是如此。

解：

通过@courses_user迭代并在每个实例上调用complete!

<% @courses_user.each do |cu| %>
  <% if cu.complete! %>
    <%= link_to "Completed", course, class: "block text-lg w-full text-center text-white px-4 py-2 bg-green hover:bg-green-dark border-2 border-green-dark leading-none no-underline" %>
  <% else %>
    <%= link_to "View Modules", course, class: "block text-lg w-full text-center text-grey-dark hover:text-darker px-4 py-2 border-2 border-grey leading-none no-underline hover:border-2 hover:border-grey-dark" %>
  <% end %>
<% end %>

注意：

为了避免另一个潜在的错误，您应该将complete!更改为completed!，因为complete!模型中没有CoursesUser方法。

所以最终的代码是

<% @courses_user.each do |cu| %>
  <% if cu.completed! %>
    <%= link_to "Completed", course, class: "block text-lg w-full text-center text-white px-4 py-2 bg-green hover:bg-green-dark border-2 border-green-dark leading-none no-underline" %>
  <% else %>
    <%= link_to "View Modules", course, class: "block text-lg w-full text-center text-grey-dark hover:text-darker px-4 py-2 border-2 border-grey leading-none no-underline hover:border-2 hover:border-grey-dark" %>
  <% end %>
<% end %>