app/views/admin/term_trade_codes_pairs/_form.html.erb
<%= form_for resource_instance_name, :url => collection_url, :remote => true do |f| %>
<%= error_messages_for(resource_instance_name) %>
<p>
<label>Term Code</label>
<%= f.hidden_field :term_id, class: 'term select22' %>
</p>
<p>
<label><%= params[:type] %> Code</label>
<%= f.select :trade_code_id,
options_from_collection_for_select(@trade_code_codes, :id, :code, @term_trade_codes_pair && @term_trade_codes_pair.trade_code_id), class: 'trade select', :include_blank => true
%>
</p>
<%= f.hidden_field :trade_code_type, :value => @trade_code_type %>
<br />
<% end %>