public string Login <T>(T entity, out T t) where T : UserModel
        {
            t = default(T);

            var model = LoginDataAccess.GetUserModel(entity);

            if (model == null || String.IsNullOrEmpty(model.UserCode))
            {
                return("您输入的用户名不存在");
            }

            if (model.PassWord != entity.PassWord)
            {
                return("您输入的密码不正确");
            }

            t = model as T;

            return("OK");
        }