Rails: Multiple dropdown menus collection_select -

super rails n00b here: have form following code:

<%= f.collection_select :account_ids, @accounts, :id, :name, include_blank: true %> 

and works how want have multiple drop down menus can select multiple accounts. not want multiple select on same dropdown.

if this:

<%= f.collection_select :account_ids, @accounts, :id, :name, include_blank: true %> <%= f.collection_select :account_ids, @accounts, :id, :name, include_blank: true %> <%= f.collection_select :account_ids, @accounts, :id, :name, include_blank: true %> 

only last selection appears in params. how can make params this:

"journal"=>{"account_ids"=>["1","2","3"]} 

can collection.select or should using different? appreciated. thanks!

you need add 1 option :multiple :

<%= f.collection_select :account_ids, @accounts,                          :id, :name, { include_blank: true },                          { multiple: true } %> 

note: :multiple- if set true selection allow multiple choices.

i wrote little snippet test it. code :

<%= form_for @track, url: fetch_path |f| %>   <%= f.collection_select :label, @tracks, :id, :title, {include_blank: true}, {multiple: true} %> <% end %> 

here page :

or, if want duplicate:

<% klass = f.object.class.model_name.param_key %> <%= f.collection_select :account_ids, @accounts, :id, :name, { include_blank: true } , { name: "#{klass}[account_ids][]" } %> 

write above line 3 times.