Rails - 在表单中使用演示者

Question

我正在使用 Rails 4 制作应用程序。我使用简单的形式。

我正在制作在表单输入上显示略有不同标签的演示者。

我使用它们如下：

形式：

<%= f.input :description, :as => :text, :label => " <%= @project_presenter.description %> ", :input_html => {:rows => 10} %>

在演示者中：

class ProjectPresenter

    def initialize(project, profile)
        @project = project
        @profile = user.profile
    end

    def description

        if student?
            "What does the project involve? "
        elsif sponsor?
            "Describe the project. "
        elsif educator?
            "What does the project involve? How will students be involved in the project? "
        elsif researcher?
            "What's involved in the project? Describe the issues to be addressed."
        end
    end 

当我尝试这个时，我得到一个指向这一行的语法错误：

<%= f.input :description, :as => :text, :label => " <%=@project_presenter.description %> ", :input_html => {:rows => 10} %>

我认为它不希望在演示者周围出现 标记。

您如何在表单中使用演示者？

Presenter 定义为：

class ProjectPresenter

    def initialize(project, profile)
        @project = project
        @profile = user.profile
    end

    def description
    ....
    end 

用户模型中的关联是：

  has_many :articles
  has_many :authentications, :dependent => :delete_all

  has_many :comments

  belongs_to :organisation
  has_one :profile
  has_many :qualifications
  has_many :identities

  has_many :trl_assessments, as: :addressable

  has_and_belongs_to_many :projects

Answer 1

我不熟悉presenter，但我能注意到的一件事是Presenter 类中的description 方法中存在错误：您没有正确关闭字符串。

def description
  if student?
    "What does the project involve?"
  elsif sponsor?
    "Describe the project." 
  elsif educator?
    "What does the project involve? How will students be involved in the project? "
  elsif researcher?
    "What's involved in the project? Describe the issues to be addressed."
  end
end

而不是你现在拥有的：

def description
  if student?
    "What does the project involve? 
  elsif sponsor?
    "Describe the project. 
  elsif educator?
    "What does the project involve? How will students be involved in the project? "
  elsif researcher?
    "What's involved in the project? Describe the issues to be addressed."
  end
end

另外，在您看来：

<%= f.input :description, :as => :text, :label => " <%= @project_presenter.description %> ", :input_html => {:rows => 10} %>

由于您已经在erb 标记中调用@project_presenter.description，因此您无需在此处指定另一个<%= %>。如果您在这里尝试实现的是字符串插值，那么您只需将其称为："#{@project_presenter.description}"

<%= f.input :description, :as => :text, :label => "#{@project_presenter.description}", :input_html => {:rows => 10} %>

同时，我认为您应该可以直接调用@project_presenter.description，无需插值如下：

<%= f.input :description, :as => :text, :label => @project_presenter.description, :input_html => {:rows => 10} %>