I was curious: in an ERB file, when passing a block to a view helper, why does this work:
<%= div_for #thing do |x| %>
<%= x %>
<% end %>
while this doesn't?
<%= div_for #thing {|x| x.to_s} %>
In Ruby, do...end is exactly the same as {...}, so why not in ERB? Note aside: I can use x on its own on the second line above because its .to_s method returns the field I want to render. Sorry if this has been asked before, I wasn't able to find a similar question (found a similar answer though).
I suspect that the second block of code is exactly the same as:
<%= div_for #thing do |x| %>
<% x %>
<% end %>
Because the x doesn't have a "=" on it, it's not going to be output in your view.
Try :
<%= div_for #thing {|x| concat x.to_s} %>
Related
I'm looking for a way to include a specific element at a certain position inside an iteration
Not experienced enough to use the right pattern (hence to search here on stack overflow with the right keywords, afraid of getting some duplicate question with this one)… but the base idea would as the following :
<% Post.all.each do |post| %>
<% if Post.all.index(post) == 5 # or any position %>
# render some html element (some kind of exception)
<% else %>
<%= post.title %>
<% end %>
<% end %>
But just without skipping any records in my post array
I'm not sure I have totally understood your request. each_with_index may help you, and if you don't use the else, you won't skip any records :
<% Post.all.each_with_index do |post, index| %>
<% if index == 5 # or any position %>
# render some html element (some kind of exception)
<% end %>
<%= post.title %>
<% end %>
Let's say I have a schema in which an apple crate contains zero or more apples. While editing the apple crate in a form, I want to list the apples and provide a checkbox next to each apple, for deleting it when the form is submitted.
There is nothing going wrong that I can see. In my model I say
class AppleCrate < ActiveRecord::Base
has_many :apples
accepts_nested_attributes_for :apples, :allow_destroy => true
...
end
I have the form working, so far as I can tell. The checkboxes appear in the form html and when the form is processed by the controller each apple in the list has an attribute called "_destroy" which is set to either "1" or "0" depending on whether or not I checked the box before submitting.
According to the Rails API, when I set _destroy to 1 and save, the apple should be deleted. But when I submit the form I get
ActiveRecord::UnknownAttributeError in AppleCrateController#update
unknown attribute: _destroy
...
"apple_crate"=>{"id"=>"10101", "apples"=>{"1"=>{"id"=>"1",
"variety"=>"granny smith",
"apple_crate_id"=>"10101",
"_destroy"=>"1"},
"2"=>{"id"=>"2",
"variety"=>"fuji",
"apple_crate_id"=>"10101",
"_destroy"=>"1"},
"3"=>{"id"=>"3",
"variety"=>"macintosh",
"apple_crate_id"=>"10101",
"_destroy"=>"0"},
...
and so on.
I must be missing something obvious but after several days of futzing around I can't figure it out. I can successfully do everything else -- update, edit, index, etc -- so long as I leave out the :_destroy attribute. Any ideas?
(For what it's worth, I'm running rails 3.2.2 on Windows.)
Updated:
This is what I'm looking at in the documentation. (See the subsection "One-to-many".)
Updated:
As requested in comments, here is the view:
<%= form_for #apple_crate do |f| %>
<% #apples = #apple_crate.apples %>
<% #apples.each do |apple| %>
<%= fields_for "apples[]", apple do |apple_fields| %>
<%= apple_fields.text_field :variety %>
<%= apple_fields.hidden_field :apple_crate_id %>
<%= apple_fields.hidden_field :id %>
<%= apple_fields.check_box :_destroy %>
<% end %>
<% end %>
<%= f.submit "Save" %>
<% end %>
You should generate nested forms and forms with rails helpers, don't do it by your hands. So I think that's where your error at.
Try:
<%= form_for #apple_crate do |f| %>
<%= f.fields_for :apples do |apple_fields| %>
<%= apple_fields.text_field :variety %>
<%= apple_fields.hidden_field :apple_crate_id %>
<%= apple_fields.hidden_field :id %>
<%= apple_fields.check_box :_destroy %>
<% end %>
<% end %>
something like this, did not check if it's correct, but idea should be clear enough
I have a Picture model and i'd like to use <%= render #pictures %> in my view in order to display them.
I also want the pictures to be arranged as 3 columns across the screen.
If I use the render how can I know which picture I am rendering in order to know where to place it? (such as in a table or some other arrangement that is not 1 dimensional)
Is there a way to make the rendering automation to have a counter?
<% #pictures.each_index do |i| %>
<% #some routine here %>
<%= render #pictures[i] %>
<% end %>
I would suggest using each_with_index instead:
<% #pictures.each_with_index do |picture, i| %>
<%= render picture, :i => i %>
<% end %>
Notice that you can pass index to the partial as well.
Noob question here :)
I'm testing a variable, and if it exists, I'd like to display an .each loop with a title.
Of course, the title should be displayed only once. Is there a way to do it? Any best practice?
<%
#twitter_friends.each do |u|
if #user = User.is_a_member?(u.id)
%>
# HERE I'D LIKE TO DISPLAY THE TITLE ONLY AT FIRST ITERATION
<% #user.name %> is your twitter friend, and is a member.
<% end %>
<% end %>
Thanks !
I would normally recommend using each_with_index and checking for a zero index, but seeing as you have a conditional in the loop, you should use a check variable like so:
<% shown_title = false %>
<% #twitter_friends.each do |u| %>
<% if #user = User.is_a_member?(u.id) %>
# HERE I'D LIKE TO DISPLAY THE TITLE ONLY AT FIRST ITERATION
<% unless shown_title %>
<h1>My Title</h1>
<% shown_title = true %>
<% end %>
<% #user.name %> is your twitter friend, and is a member.
<% end %>
<% end %>
I would like to render structures like this:
<tag1>
<tag2 someattribute="somevalue">
<.. lot of things inside ..>
</tag2>
</tag1>
<tag1>
<tag2 someattribute="someothervalue">
<.. different inside things inside ..>
</tag2>
</tag1>
The tag1, tag2 are the same, they are just parametrized. The inner part of the code changes. I tried to implement the thing above like that (haml):
%div{id:['products', id]}
.products_content
%div{id:['products', id, 'content'], class:'products_mask'}
= yield
This was the partial _content_head.html.haml, which is called from a template:
= render 'shared/content_head', id: 'all' do
%h3= Title
%p= Body of the text.
My theory that yield inside the partial would lead to rendering of the passed block did not prove. Is there a way to use partials as code wrappers? Can you suggest me some solution how to reach this? Thank you.
This might be a good use of the capture method.
I'm only familiar with ERB, but here is the general idea:
<% structure = capture do %>
<h3>Title</h3>
<p>Body of text</p>
<% end %>
Then pass the variable into the partial:
<%= render 'shared/content_head', :structure => structure %>
And within the partial, spit out the structure variable:
<%= structure %>
Reset structure multiple times within the view as you render partials (or maybe more appropriately, in a helper?).
I've used the following (Rails 4, but I think it should work with Rails 3 too):
<%# app/views/users/_edit.html.erb %>
<%= render layout: 'modal_wrapping' do |f| %>
<%= f.input :email %>
...
<% end %>
.
<%# app/views/users/_modal_wrapping.html.erb %>
<div id='modal'>
<%= simple_form_for #user do |f| %>
<%= yield f %>
<% end %>
</div>