ruby-on-rails - :id:Symbol的未定义方法 'map'

Question

ActionView::Template::Error (undefined method `map' for :id:Symbol):
    # duels/_user_challenges.html.erb
    1: <div id="dropdown-no-2">
    2:    <%= collection_select 'challenge_id', challenges, :id, :full_challenge, include_blank: true %>.
    3: </div>

当用户选择一个用户使用 duel时，则仅应显示该用户的质询。

决斗/_dueler_fields.html.erb

<%= f.collection_select :user_id, User.order(:name),:id, :full_name, include_blank: true, id: "id_of_the_user_id_select_box" %>
  will

<%= render :partial => 'user_challenges', locals: {challenges: Challenge.order(:deadline)} %>

<script>
  $( "#id_of_the_user_id_select_box" ).change(function() {
       $.ajax({
          type: "GET",
          url: '<%= user_challenges_path %>',
          data: {name: $('#id_of_the_user_id_select_box').prop('value')}
       });
  });
</script>

对决/user_challenges.js.erb

$("#dropdown-no-2").html('<%=j render :partial => "user_challenges", locals: {challenges: @challenges} %>'); 

duels_controller.rb

def user_challenges
  @user = User.find(params[:id])
  @challenges = @user.challenges.order(:deadline)
end

Answer 1

参见http://edgeapi.rubyonrails.org/classes/ActionView/Helpers/FormBuilder.html#method-i-select。

我建议使用select FormHelper实现此目的:

所以这

<%= f.collection_select :user_id, User.order(:name),:id, :full_name, include_blank: true, id: "id_of_the_user_id_select_box" %>

变成这个

<%= f.select :user_id, User.order(:name).map { |user| [user.full_name, user.id] }, include_blank: true, id: "id_of_the_user_id_select_box" %>