# In the example below I'm grabbing and printing the Parent ID value for a category inside a Check Box Collection field.

<%= f.collection_check_boxes :category_ids, list_artwork_categories_by_type(@artwork.artwork_type_id), :id, :name do |b| %>
  <% p b.object.parent_id %>
  <div class="collection-check-box form-check">
    <%= b.check_box(class: "checkbox") %>
    <%= b.label %>
  </div>
<% end %>