rails select tag,获取nil的未定义方法映射:NilClass
在我的deals_controller.rb中,我在此处定义了新操作
class DealsController < ApplicationController def index @deals = Deal.all end def show @deal = Deal.find(params[:id]) end def new @vendors = Vendor.all # code for select tags on _form view @vendor_options = @vendors.map{|v| [v.name, v.id] } @items = Item.all @item_options = [] @items.each do |item| @item_options << [item.name, item.id] end @deal = Deal.new end def create @items = Item.all @vendors = Vendor.all @deal = Deal.new(deal_params) if @deal.save redirect_to @deal else render 'new' end end private def deal_params params.require(:deal).permit(:item_id, :vendor_id, :price) end end
然后,在我的new.html.erb里面
当我尝试创建一个新的交易程序错误
NoMethodError in Deals#create Showing /Users/andrewkim/wdi/work/app/small_time_grocer/app/views/deals/_form.html.erb where line #21 raised: undefined method `map' for nil:NilClass
提取的来源来自以下第21行:
我甚至没有看到地图的使用位置,或者是否在options_for_select方法中使用了这些内容?
select标签上的文档对我来说有点神秘,有人能发现我的错误吗?
尝试使用collection_select
而不是select_tag
:
<%= f.collection_select :vendor_id, @vendors, :id, :name, {include_blank: 'Please Select'}, {class: 'selectpicker chosen-select'} %>
我建议阅读有关collection_select的内容