将Rails 3转换为Rails 2:带块的帮助器 [英] Converting Rails 3 to Rails 2: helpers with blocks

问题描述

在Rails 3中，我使用以下帮助程序来获得颜色奇数的表:

In Rails 3 I use the following helper in order to get a even-odd-coloured table:

def bicolor_table(collection, classes = [], &block)
  string = ""
  even = 0
  for item in collection
    string << content_tag(:tr, :class => (((even % 2 == 0) ? "even " : "odd ") + classes.join(" "))) do
        yield(item)
    end
    even = 1 - even
  end
  return string
end

我在这样的视图中使用它:

And I use it in my views like this:

<%= bicolor_table(services) do |service| %>
    <td><%= image_tag service.area.small_image %></td>
    <td><%= link_to service.title, service %></td>
<% end %>

现在，我必须将应用程序迁移到Rails2.问题是Rails 2不使用Erubis，因此，当它找到<％= what％>标签时，它仅调用what.to_s.因此，就我而言，这导致尝试执行

Now, I have to migrate the application to Rails 2. The problem is Rails 2 doesn't use Erubis, so when it finds a <%= whatever %> tag, it just calls whatever.to_s. So, in my case, this result in trying to execute

(bicolor_table(services) do |service|).to_s

具有明显的(不良的)后果.问题是:我原则上是错的吗(例如助手不应该这样工作，而要使用…")还是应该寻找解决方法?

With the obvious (bad) consequences. The question is: am I wrong in principle (like "helpers shouldn't work this way, use instead …") or should I look for a workaround?

谢谢.

推荐答案

这是完全可行的，并且实际上使某些类型的助手变得更加简单.您需要使用<% %>和concat来实现.

This is totally doable, and in fact makes certain types of helpers much simpler. You need to use <% %> and concat to achieve this.

def my_block_helper(param, &block)
  output = %(<div class="wrapper-markup">#{ capture(&block) }</div>)
  concat output
end

像这样在您的视图中使用它:

use it in your views like this:

<% my_block_helper do %>
  <span>Some Content</span>
<% end %>

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