Rails has_many :through and collection_select with multiple

Question

I have the following problem using a has_many :through many-to-many relation in a multi-select via collection_select :multiple => true. I have Suppliers who deliver many Ing

Answer 1

I've got the problem solved. In this case, using fields_for was the error. The solution is using a collection_select, like this:

<%= collection_select(:ingredient, :supplier_ids, 
              Supplier.all(:order=>"name ASC"), 
              :id, :name, {:selected => @ingredient.supplier_ids, :include_blank => true}, {:multiple => true}) %>