Ruby-on-rails 视图中 .html.erb 中的 if else 语句
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If else statements in .html.erb in views
提问by dsp_099
In rails, I often run into the situation where inside the views I'll do something like
在 Rails 中，我经常遇到这样的情况，在视图中我会做一些类似的事情
<% if @some_condition_previusly_established_in_a_controller %>
<div class="one">123</div>
<% else %>
<div class="two">something else</div>
<% end %>
It looks a bit cluttery. Is this an acceptable way of working with views or not?
它看起来有点凌乱。这是一种可以接受的处理视图的方式吗？
采纳答案by tadman
Unless you can think of a way to re-write this as a helper method, you're basically stuck with it looking kind of ugly. That's just how ERB is, as it was intended to be a minimal way of injecting Ruby into an otherwise plain-text template, not as something necessarily streamlined or elegant.
除非你能想出一种方法将它重写为辅助方法，否则你基本上会被它看起来有点难看。这就是 ERB 的方式，因为它旨在作为将 Ruby 注入其他纯文本模板的最小方式，而不是作为必要的流线型或优雅的东西。
The good news is a syntax-highlighting editor will usually make your <% ... %>ERB blocks look visually different from your HTML so that can dramatically improve readability.
好消息是语法高亮编辑器通常会使您的<% ... %>ERB 块在视觉上与 HTML 不同，从而可以显着提高可读性。
It's also why other representations like HAMLhave been created where that syntax is a lot less cluttered:
这也是为什么创建了HAML 之类的其他表示，其中语法不那么混乱：
- if some_condition_previusly_established_in_a_controller
.one 123
- else
.two something else
回答by vee
For one or two such conditional logic in your views, I guess its fine but when your code gets bigger and you have multiple if..else..endand looks "cluttery", I think you should look at implementing "Presenter Pattern" which greatly cleans up your views by separating your logic to Presenters.
对于您视图中的一两个这样的条件逻辑，我想这很好，但是当您的代码变大并且您有多个if..else..end并且看起来“杂乱”时，我认为您应该考虑实现“演示者模式”，它通过分离极大地清理了您的视图您对演示者的逻辑。
Here is a great tutorial I followed from Ryan Bates in his Rails Casts series on "Presenter Patterns from scratch". http://railscasts.com/episodes/287-presenters-from-scratch.
这是我在 Ryan Bates 在他的 Rails Casts 系列“从头开始演示模式”中遵循的一个很棒的教程。 http://railscasts.com/episodes/287-presenters-from-scratch。
回答by ajthewebdev
Have you tried?
你有没有尝试过？
<% @some_condition_previusly_established_in_a_controller ? <div class="one">123</div> : <div class="two">something else</div> %>
回答by Sunda
If your view contains lots of tags and HTML elements, you can put them into partials and logic into model
如果您的视图包含大量标签和 HTML 元素，您可以将它们放入部分并将逻辑放入模型中
View:
看法：
<%= render :partial => @model.status %>
<%= render :partial => "file/path/#{@model.status}" %> # if your partial is in some different folder
If your status is one, then it would render the file _one.html.erb
如果您的状态为 1，则它将呈现文件 _one.html.erb
If it is two, then it would render the file _two.html.erb automatically.
如果是两个，那么它会自动渲染文件 _two.html.erb。
Model:
模型：
def status
if @some_condition
"one"
else
"two"
end
end
回答by Rebitzele
Yes, that is the standard (and yes, it looks cluttery).
是的，这就是标准（是的，它看起来很杂乱）。
If you're looking for a possibly cleaner alternative, check out: Conditional tag wrapping in Rails / ERB
如果您正在寻找可能更清洁的替代方案，请查看：Rails / ERB 中的条件标签包装
回答by Rebitzele
You can always move the logic to the controller and leave the view clean(er).
您始终可以将逻辑移动到控制器并保持视图干净（呃）。
Controller:
控制器：
if @some_condition
@div_class = :one
@div_content = 123
else
@div_class = :two
@div_content = 'something else'
end
View:
看法：
<div class="<%= @div_class %>"><%= @div_content %></div>
Or using a helper:
或者使用助手：
<%= content_tag :div, @div_content, class: @div_class %>
