Select tag with multiple values pre-selected - Values inserted manually in database

问题

I have a problem, I don't planned my database correctly, so always I need to use 'alternatives'.

I want pre-selected multiple values in select_tag. But I'm adding the vacancies 'manually' in table vacancy. My controller:

def create
  @hr_curriculum_generic = HrCurriculumGeneric.new(params[:hr_curriculum_generic])

  # Tabela CandidatosxVagas
  unless params[:vacancy_ids].nil?
    @vacancies_ids = params[:vacancy_ids]

-- my form:

  @vacancies_ids.each do |vacancy_id|
    # Armazena os id do curriculum, vaga e do cargo na tabela CandidatosxVagas
    @candidates_vacancies = CandidatesVacancy.new 
    <% @vacancies = Vacancy.all %>
    <%= select_tag "vacancy_ids[]", options_from_collection_for_select(Vacancy.all, "id", "title"), :multiple => true, :id => "vacancy_ids", :class => "form-control" %>

.....

Its works, but when I click in edit, the fields are not pre-selected.

Someone passed for a trouble like this and can help me?

回答1:

options_from_collection_for_select has 4 parameters:

• collection
• id
• column
• selected

You can provide a single value, or a hash to denote selected values. Try this:

<%= select_tag "vacancy_ids[]", options_from_collection_for_select(Vacancy.all,"id","title",{:selected=>[1,2,3,4]})), :multiple => true, :id => "vacancy_ids", :class => "form-control" %>

I'm not sure where the values you are trying to select come from but pipe them into the selected hash.

来源：https://stackoverflow.com/questions/21667251/select-tag-with-multiple-values-pre-selected-values-inserted-manually-in-datab