在form_for，rails中传递collection_selection和text_field值

Question

The Attraction model belongs to Destination.

I'm trying to create a new attraction (text_field :name) but also linking it to an already-created destination. These destinations are rendered in a drop-down menu with this collection_select tag. By clicking submit, I'm want the attraction to be created and saved in the activerecord database with the Destinations foreign key.

f.collection_select(:attraction, :destination_id, Destination.all, :id, :name) %>

The whole block looks like this at the moment:

<h1>New attraction</h1>

Select a City

<%= f.collection_select(:attraction, :destination_id, Destination.all, :id, :name) %>   

<div class ="field">
  <%= f.label :name %>
  <%= f.text_field :name %>
</div>

<div class="actions">
  <%= f.submit %>
</div>

How can I save the attraction to the database with the appropriate destinaton? Thanks in advance!!

Answer 1

I haven't use f.collection_select() so not sure what it is called inside the params, but lets assume for the following code that it's params[:attraction][:destination_id] . You can change your create action to:

def create
  @destination = Destination.find(params[:attraction][:destination_id])
  @attraction = @destination.attractions.build(params[:attraction])
  if @attraction.save
    ...
  else
    ...
  end
end

That's assuming that you've created a has_many and belongs_to association.

If you run into a mass-assignment error then change the first line to:

@destination = Destination.find(params[:attraction].delete(:destination_id))
# this will return the deleted value, and in the next line of code
# you'll have the rest of the params still available