如何在Rails中将表单选择输入用于多态的Emirates_to关联？

Question

I've got an Article model that has a polymorphic belongs_to association (resource). I've been trying to let it set the association from the article form via two select boxes, one with the type and the other with id of the association as shown below.

= form_for @article do
  = f.select :resource_type, ...
  = f.grouped_collection_select :resource_id, ...

My problem is that it doesn't select the correct model in the grouped_collection_select if the association id exists in two of the associated models.

There must be a better way to do this but I just can't seem to see it right now.

Answer 1

One way to handle it is to allow toggling between resources with a javascript function. You have a link that is bound to a javascript function that swaps out one resource select box for another.

There's a railscast that describes how to do this. Ignore the nested form and add/remove business and focus on the essentials (javascript-bound link, helper methods, etc): http://railscasts.com/episodes/197-nested-model-form-part-2 .