def topmenu
    pages = {
      "projects" => projects_path,"photos" => photos_path
    }
    pages.map do |key,value|
      classnames = %( class="current") if controller.controller_name == key
      "<li#{classnames}>#{link_to(key,value)}</li>"
    end
  end

然后在我的application.html.erb文件中,我有：

<%= topmenu %>

出于某种原因,该页面生成的显示来自上述帮助程序的HTML为TEXT,而不是HTML.不知道为什么？谢谢