ruby-on-rails - rails : undefined method error when move codes from view to helper file

Question

在approval.html.erb

<% @approval.each do |approval| %>
    <td><%= Material.find_by_id(approval.material_id).m_name%></td>
<% end %>

我想将 Material.find_by_id(approval.material_id) 移动到审批帮助文件。

在 approval_helper.rb 中

def approval_material
  Material.find_by_id(approval.material_id)
end

然后，我修改approval.html.erb

<% @approval.each do |approval| %>
    <td><%= approval_material.m_name%></td>
<% end %>

但是，它显示错误

undefined local variable or method `approval'

错误的原因是什么，如何解决？谢谢

Answer 1

您需要将参数传递给辅助方法approval_material 方法。像这样的东西:

def approval_material(approval)
  Material.find_by_id(approval.material_id)
end

然后在您的 View 中您可以这样调用它:

<% @approval.each do |approval| %>
    <td><%= approval_material(approval).m_name%></td>
<% end %>