using System; using System.Collections.Generic; using WebApiStudy.Model; namespace WebApiStudy.IBll { public interface IUserBll { List GetAllUser(); User GetUser(int userId); (bool result, User user) InsertUser(User user); (bool result, User user) UpdateUser(User user); bool DeleteUser(int userId); decimal TotalIncome(int userId); decimal TotalCost(int userId); } }