RoR collection_select（不起作用）V collection_check_boxes（起作用！）——为什么？

Question

我正在尝试使用 collection_select 将一些数据保存到我的模型中，但这不起作用，我不明白为什么。我尝试使用 collection_check_boxes ，它很容易工作。我使用的是 HABTM 方法，我确信我的 model.rb 文件编码正确，所以我认为下面的视图代码中的某些内容不正确。

我能得到一些帮助吗

----以下不工作

 <div class="form-group control col-md-12 mb-4">
    <%= form.label :category, 'Pick A Category Most Appropriate' %>
        <div class= 'is-focused field has-addons control is-expanded select is-fullwidth'>
              <%= form.collection_select :category_ids , Category.all, :id, :name %>
        </div>
  </div>

----以下工作正常！

  <div class="field">
    <%= form.label "Pick A Category Most Appropriate" %><br />
    <%= form.collection_check_boxes :category_ids, Category.all, :id, :name do |b| %>
      <div class="collection-check-box">
        <%= b.label %>
        <%= b.check_box %>
      </div>
    <% end %>
  </div>

如下所示，我得到了一个不允许的错误，但在使用 collection_check_boxes

时却没有

Started PATCH "/listings/1" for ::1 at 2020-01-07 20:33:13 +0000
Processing by ListingsController#update as HTML
  Parameters: {"authenticity_token"=>"Y/rvJ3EcwV6iioSV8fXUkkwxRRiZ7o8ZV94sGS5G3liYnghcef2AWBc50g5gX4ULhmGyp163vtVfRAgil8gnMA==", "listing"=>{"name"=>"New Listing", "description"=>"This is a new listing", "category_ids"=>"1", "end_date(1i)"=>"2020", "end_date(2i)"=>"1", "end_date(3i)"=>"6", "end_date(4i)"=>"22", "end_date(5i)"=>"57"}, "commit"=>"Update Listing", "id"=>"1"}
  Listing Load (4.8ms)  SELECT "listings".* FROM "listings" WHERE "listings"."id" = ? LIMIT ?  [["id", 1], ["LIMIT", 1]]
  ↳ app/controllers/listings_controller.rb:69:in `set_listing'
Unpermitted parameter: :category_ids
Redirected to http://localhost:3000/listings/1
Completed 302 Found in 30ms (ActiveRecord: 4.8ms | Allocations: 1492)


Started GET "/listings/1" for ::1 at 2020-01-07 20:33:13 +0000
Processing by ListingsController#show as HTML
  Parameters: {"id"=>"1"}
  Listing Load (0.6ms)  SELECT "listings".* FROM "listings" WHERE "listings"."id" = ? LIMIT ?  [["id", 1], ["LIMIT", 1]]
  ↳ app/controllers/listings_controller.rb:69:in `set_listing'
  Rendering listings/show.html.erb within layouts/application
  Rendered listings/show.html.erb within layouts/application (Duration: 1.1ms | Allocations: 313)
[Webpacker] Everything's up-to-date. Nothing to do
Completed 200 OK in 50ms (Views: 44.4ms | ActiveRecord: 0.6ms | Allocations: 5953)

来自控制器的更新操作

def update
    respond_to do |format|
      if @listing.update(listing_params)
        format.html { redirect_to @listing, notice: 'Listing was successfully updated.' }
        format.json { render :show, status: :ok, location: @listing }
      else
        format.html { render :edit }
        format.json { render json: @listing.errors, status: :unprocessable_entity }
      end
    end
  end

强参数

def listing_params
  params.require(:listing).permit(:name, :description, :end_date, category_ids:[])
end

Answer 1

来自上面的评论：

你的 collection_select 正在传回一个 string/integer 而不是你的强参数所需的数组。

将 multiple: true 添加到 collection_select 调用时会发生什么？

我猜您需要的是 belongs_to :Listing 模型中的类别关系：

class Listing < ApplicationRecord
  belongs_to :category
  ...

end

RoR collection_select（不起作用）V collection_check_boxes（起作用！）——为什么？

RoR collection_select (does not work) V collection_check_boxes (works!) - Why?

ruby

ruby-on-rails-4

ruby-on-rails-5