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问题描述
我有几个这样的模型
class Bill < ActiveRecord::Base
has_many :bill_items
belongs_to :store
accepts_nested_attributes_for :bill_items
end
class BillItem <ActiveRecord::Base
belongs_to :product
belongs_to :bill
validate :has_enough_stock
def has_enough_stock
stock_available = Inventory.product_is(self.product).store_is(self.bill.store).one.quantity
errors.add(:quantity, "only #{stock_available} is available") if stock_available < self.quantity
end
end
以上验证显然不起作用,因为当我从票据表单内的嵌套属性读取bill_items时,在保存之前,属性bill_item.bill_id或bill_item.bill不可用.
The above validation so obviously doesn't work because when I'm reading the bill_items from nested attributes inside the bill form, the attributes bill_item.bill_id or bill_item.bill are not available before being saved.
那我该怎么做呢?
推荐答案
这是我最终解决问题的方法;通过在回调中设置父项
This is how I solved it eventually; by setting parent on callback
has_many :bill_items, :before_add => :set_nest
private
def set_nest(bill_item)
bill_item.bill ||= self
end
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