after_save回調：TypeError：出價不能被強制轉換爲Fixnum

Question

我在此出價模型中有after_save回調，但我不斷收到此錯誤：TypeError at/items/11/bids出價不能強制轉換爲Fixnum

下面是我的出價模式：

class Bid < ActiveRecord::Base 
    belongs_to :user 
    belongs_to :item 

    validates :amount, presence: true 
    validate :check_if_highest_bid 

    after_save :bid_logic 


    def check_if_highest_bid 
    errors.add(:amount, "You must enter a higher bid") unless self.item.price < self.amount 
    end 


    def bid_logic 
    add_previous_bidders_bid 
    update_items_current_price 
    subtract_current_users_price 
    end 


    def add_previous_bidders_bid 
     price = self.item.price 
     bid = Bid.find_by_amount(price) 
     unless bid.nil? 
     user = User.find(bid.user_id) 
     user.budget += bid 
     user.save 
     end 

    end 

    def update_items_current_price 
    self.item.price = self.amount 
    self.item.save 
    end 

    def subtract_current_users_price 
    user = User.find(self.user_id) 
    user.budget -= self.amount 
    user.save 
    end 

end 

的想法是在add_previous_bidders_bid方法，當用戶過去失控投標，資金就返回到用戶的預算多數民衆贊成設置在註冊。

這裏是架構：

create_table "bids", force: true do |t| 
    t.datetime "created_at" 
    t.datetime "updated_at" 
    t.integer "item_id" 
    t.integer "user_id" 
    t.integer "amount" 
    end 

    create_table "items", force: true do |t| 
    t.datetime "created_at" 
    t.datetime "updated_at" 
    t.integer "user_id" 
    t.string "title" 
    t.integer "price" 
    end 

    create_table "users", force: true do |t| 
    t.string "email",     default: "", null: false 
    t.string "encrypted_password",  default: "", null: false 
    t.string "reset_password_token" 
    t.datetime "reset_password_sent_at" 
    t.datetime "remember_created_at" 
    t.integer "sign_in_count",   default: 0 
    t.datetime "current_sign_in_at" 
    t.datetime "last_sign_in_at" 
    t.string "current_sign_in_ip" 
    t.string "last_sign_in_ip" 
    t.datetime "created_at" 
    t.datetime "updated_at" 
    t.integer "budget" 
    end 

    add_index "users", ["email"], name: "index_users_on_email", unique: true 
    add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true 

end 

任何提示嗎？

Answer 1

嘗試user.budget += bid.amount而不是user.budget += bid - 它不知道如何處理招標辦...