局部变量可以特定于控制器吗？

Question

In Rails, can partials be controller-specific? I have a controller for creating post and a view that went with it. After I renamed the view (added _) to make it a partial, it no longer seems to work.

Thank you in advance.

Answer 1

Partials are not views.

Partials cannot be rendered as views. Which makes perfect sense since partials are not views - they are reusable chunks of a view.

Lets say you have:

# app/controllers/posts_controller.rb
class PostsController < ApplicationController
  def new
    @post = Post.new
  end
end

# app/views/posts/new.html.erb
<%= form_for(@post) do |f| %>
  # ...
<% end %>

If you rename new.html.erb -> _new.html.erb Rails will no longer be able to find the view - because it no longer is a view.

Can partials be controller-specific?

Partials are by there very nature controller-specific. For example:

# app/views/posts/show.html.erb
<%= render partial: 'foo' %> 

Will look for app/views/posts/_foo.html.erb .

# app/views/stories/show.html.erb
<%= render partial: 'foo' %>

Will look for app/views/stories/_foo.html.erb .

Thats because Rails prepends the view lookup path with app/views/controller_name .

Can views be shared?

Yes. But you need to explicitly tell Rails where the view is located.

# app/controllers/posts_controller.rb
class PostsController < ApplicationController
  def new
    @resource = Post.new
    render 'resources/new'
  end
end

# app/controllers/stories_controller.rb
class StoriesController < ApplicationController
  def new
    @resource = Story.new
    render 'resources/new'
  end
end

Or you could append the view path .

class ResourcesController < ApplicationController
  prepend_view_path Rails.root.join('app/views/resources')
end

class PostsController < ResourcesController
  def new
    @resource = Post.new
    # will now default to rendering `app/views/resources/new.html.erb`
  end
end

Can partials be shared?

Yes. But you need to tell Rails where the partial is located.

<%= render partial: 'shared/social_media_icons' %>