Rails：如何在不同的视图中进行小的更改

Question

Is it possible to make small changes in different views?

The same partial is rendered in index.html.erb and show.html.erb as below.

index.html.erb

<%= render @schedules %> 

show.html.erb

<%= render @schedules %> 

What I'd like to do is not to display some value in the index.html.erb. (and display some value in both erb)

For example, I'd like to display start_at and end_at only in show.html.erb and display title in both erb.

_schedule.html.erb

<% schedule.rooms.each_with_index do |a, idx| %>

  <% a.events.each do |e| %>

    <%= l(e.start_at) %>-<%= l(e.end_at) %> # display only show.html.erb
    <%= e.title %>  #display both erb
    ...

  <% end %>

  ...
<% end %>

Althogh I come up with idea which I create two partials, it contradicts the DRY policy.

It would be appreciated if you could give me any idea.

Answer 1

You can use controller.action_name .

<% if controller.action_name == 'show' %>
  <%= l(e.start_at) %>-<%= l(e.end_at) %> # display only show.html.erb
<% end %>

The params hash also contains the action_name.

Answer 2

Can check current action and current controller on page. So we can call single partial from different actions and can customize as per action name or action and controller name.

eg.

<% schedule.rooms.each_with_index do |a, idx| %>

  <% a.events.each do |e| %>
    <% if @current_controller == "events" and @current_action == "show" %>
      <%= l(e.start_at) %>-<%= l(e.end_at) %> # display only show.html.erb
    <% end %>
    <%= e.title %>  #display both erb
    ...

  <% end %>

  ...
<% end %>

Also need to update Application Controller.

class ApplicationController < ActionController::Base
  before_filter :instantiate_controller_and_action_names

  def instantiate_controller_and_action_names
    @current_controller = controller_name
    @current_action = action_name
  end

end

Answer 3

action_name is enough and do the trick but personally I don't like this. I'd do two separate partials.

Answer 4

You could use CSS to hide/show the content based on context.

In practice, I have found this a good way to reuse partials that have small differences. Especially when those differences don't cost anything to compute ie printing a date

• You can cache the partials without worrying about where they are rendered
• Reduce conditional logic
• Remove duplication

<% if controller.action_name == 'show' %> is fine for a simple use case. If/When you come to have multiple places where the partial needs to be rendered, it will become unwieldy. The CSS solution would only require another wrapper <div class="schedules--whatever"> and the related CSS style.

show.html.erb

<div class="schedules--show">
  <%= render @schedules %> 
</div>

index.html.erb

<div class="schedules--index">
  <%= render @schedules %> 
</div>

_schedule.html.erb

<% schedule.rooms.each_with_index do |a, idx| %>
  <% a.events.each do |e| %>
    <div class="event__date">
      <%= l(e.start_at) %>-<%= l(e.end_at) %>
    </div>
    <%= e.title %>
    ...

  <% end %>
  ...
<% end %>

schedules.css

.schedules--show .event__date {
  display: block;
}

.schedules--index .event__date {
  display: none;
}