Rails - how to render two identical forms but with different element IDs?

Question

I would like to have two almost identical forms on a single page and use a partial for generating both with a render call.

<%= render 'form_template', data: @categories_one %>
<%= render 'form_template', data: @categories_two %>

The problem lies in their only difference - both forms use f.collection_select to provide dropboxes with categories for the user.

<%= f.collection_select :category_id, data, :id, :name %>

which creates two different forms with identical IDs for the SELECT tag, breaking my forms, and I would like to avoid that. But how can I do that?

Answer 1

You can pass :namespace parameter to the form_for

A namespace for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id.

Answer 2

If you look at the documentation for collection_select , you'll see that its last argument is for HTML options. So you can do this:

<%= f.collection_select :category_id, data, :id, :name, {}, {:id => "different_css_id"} %>

Since you said this is called within a partial though, from your identical render calls, you can pass along a variable to toggle this behaviour.

# Render calls
<%= render 'form_template', data: @categories_one %>
<%= render 'form_template', data: @categories_one, :locals => {:use_other_id => true} %>

And then use that flag in your partial.