javascript - 为实例变量传递嵌套参数

Question

强文本我正在尝试通过 "data-remote attribute for select boxes" 制作动态选择框。在控制台中，我似乎获得了正确的参数(所选品牌的 id)，但我不知道如何将其传递给 Controller ​​以获取具有匹配 make_id:s 的模型。

这是来自_form.html.erb的attached_vehicles表单部分

<div class="vehicle_field">
    <%= f.fields_for :attached_vehicles do |av| %>
    <p>Select make</p>
    <%= av.select :make, (@makes.collect { |m| [m.make_name, m.id] }), { include_blank: "Select make" }, { data: { remote: true, url: "update_make_models", name: "make", update: "#diy_attached_vehicles_attributes_0_model"} } %><br>
    <p>Select model</p>
    <%= av.collection_select :model, @models, (render "make_models/make_model"), { prompt: "Select model" } %><br>
    ...
    <% end %>
</div>

../views/diys/update_make_models.coffee

$.empty()
    .append("<%= escape_javascript(render "make_models/make_model") %>")

../diys_controller.rb

...
def update_make_models
  @models = MakeModel.where("make_id = ?", params[:make])
end

def new
  @diy = Diy.new
  @step = @diy.steps.new
  @attached_vehicle = @diy.attached_vehicles.new
  @step.add_images_to_steps.new
  @makes = Make.all
  @models = MakeModel.where("make_id = ?", params[:make_id])
end
...

../views/make_models/_make_model.html.erb

<% @models.collect do |models| %>
   <option value="<%= models.id %>"><%= models.make_model_name %></option>
<% end %>

这是在 make 选择框中选择 make 后我在控制台中得到的内容

Started GET "/diys/update_make_models?diy%5Battached_vehicles_attributes%5D%5B0%5D%5Bmake%5D=12" for ::1 at 2016-02-18 20:22:35 +0200 Processing by DiysController#update_make_models as JS
  Parameters: {"diy"=>{"attached_vehicles_attributes"=>{"0"=>{"make"=>"12"}}}}
  MakeModel Load (1.0ms)  SELECT "make_models".* FROM "make_models" WHERE (make_id = NULL)
  Rendered make_models/_make_model.html.erb (3.0ms)
  Rendered diys/update_make_models.coffee (491.0ms)
Completed 200 OK in 628ms (Views: 626.5ms | ActiveRecord: 1.0ms | Solr: 0.0ms)

-------------------------------------------------------- -------------------------------------------------- -------------------------------------------------- 编辑

NameError (undefined local variable or method `attached_vehicles_attributes' for #<DiysController:0x5757648>):
  app/controllers/diys_controller.rb:28:in `update_make_models'

Answer 1

您的 params 哈希值是(根据日志):{"diy"=>{"attached_vehicles_attributes"=>{"0"=>{"make"=>"12"}}}}。所以，如果你想从中获取 :make_id ，你应该写:

def update_make_models
  @models = MakeModel.where(make_id: params["diy"]["attached_vehicles_attributes"]["0"]["make"])
end