.NET 数据合理性校验浅谈

仅仅个人的一点小总结，把数据校验分为横向校验与纵向校验；

横向：对各个属性的单独或多个一起比较，如用户注册的信息，邮箱是否符合格式等，2次输入的密码是否一致，密码的复杂度等，这类验证方法很多，可以自己给属性加特性标志，然后统一方法验证，自己定规则啦，还有很多其他框架可以使用；

纵向：如用户注册的邮箱地址、手机号码，现有用户是否已经使用了，简单说就是和同类比，当然还有其他的；

来个例子：

还是2个实体

    public class Room
    {
        public int Id { get; set; }
        public string Number { get; set; }
        public string Building { get; set; }
        public string Address
        {
            get
            {
                if (Number != null && Building != null)
                {
                    return Building + Number;
                }
                return "";
            }
        }
        public int Max { get; set; }
    }

 public class Student
    {
        public int Id { get; set; }
        public string Name
        {
            get;
            set;
        }
        public DateTime Brithday
        {
            get;
            set;
        }

        public double High
        {
            get;
            set;
        }

        public decimal Money
        {
            get;
            set;
        }

        public bool Enable
        {
            get;
            set;
        }

        public int? RoomId
        {
            get;
            set;
        }
        public Room Room
        {
            get;
            set;
        }
        public double Qty
        {
            get;
            set;
        }
        public string TelNumber { get; set; }
        public decimal Price
        {
            get;
            set;
        }

    }

简单模拟一些数据：

    /// <summary>
    /// 模拟数据源
    /// </summary>
    public static class Database
    {
        public static List<Room> Rooms { get; set; }


        public static List<Student> Students { get; set; }
        static Database()
        {
            #region 添加模拟数据
            if (Rooms == null)
            {
                Rooms = new List<Room>{new Room { Id=1, Number="101", Building="A栋", Max=8 }};
            }
            #endregion
            if(Students==null)
            {
                Students = new List<Student>();
                Room r1 = Rooms.FirstOrDefault();
                for (int i = 0; i < 5; i++)
                {
                    Student stu = new Student { Id = i + 1, RoomId = r1.Id, Room = r1, Brithday = DateTime.Now.AddYears(-20), High = 170.5 + i, Money = 200000.5m + i, Name = "Jack" + i };
                    if (i == 2)
                        stu.TelNumber = "18866668888";
                    Students.Add(stu);
                }
            }
        }
    }

使用FluentValidation，添加AbstractValidator子类，在构造方法中添加对Student实体校验的规则，属于横向校验

 public class StudentValidator: AbstractValidator<Student>
    {
        public StudentValidator()
        {
            RuleFor(stu => stu.Brithday).LessThanOrEqualTo(DateTime.Now.AddYears(-18)).WithMessage("年龄不能小于18周岁");
            RuleFor(stu => stu.High).LessThanOrEqualTo(250).WithMessage("身高不能大于250cm");
            RuleFor(stu => stu.Money).InclusiveBetween(100000, 100000000).WithMessage("10万到1亿之间的资产才能读书");
            RuleFor(stu => stu.Price).GreaterThan(0).WithMessage("价格必须大于0");
        }
    }

控制台验证看看：

  class Program
    {
        static void Main(string[] args)
        {
            #region 横向校验，可以放到客户端校验，基本上服务器在api接收到数据也要校验
            ////提交上来的数据，身高3000cm,2年前出生
            //Student stu = new Student { High = 3000, Brithday = DateTime.Now.AddYears(-2),Money=100000,Price=-1 };
            //StudentValidator validator = new StudentValidator();
            //var result=validator.Validate(stu);
            //if (!result.IsValid)
            //{
            //    var msgList= result.Errors.Select(a => a.ErrorMessage);
            //    Console.WriteLine("实体验证失败：\r\n"+string.Join(";",msgList));
            //    return;
            //}
            #endregion

            #region 纵向校验,假设已经通过横向校验；一般放到业务层
            //业务场景：添加Student给他分配Room，检查该Room是否还有位置
            Room r1 = Database.Rooms.FirstOrDefault();

            Student stu = new Student { TelNumber = "18866668888", Name = "Bob", High = 180, Brithday = DateTime.Now.AddYears(-20), RoomId = r1.Id, Room = r1 };
            bool pass = false;
            string validResult = Valid(stu, out pass);
            Console.WriteLine(validResult);
            if (pass)
            {
                //通过校验，继续
                Console.WriteLine("写入数据库...");
                Database.Students.Add(stu);
        
                Console.WriteLine($"我住到{r1.Number}啦，我们一共{Database.Students.Where(a => a.RoomId == r1.Id).Count()}人");
            }

            #endregion
        }
        public static string Valid(Student stu, out bool pass)
        {
     
            if (Database.Students.Exists(a => a.TelNumber == stu.TelNumber))
            {
                pass = false;
                return "你这个电话号码有人用了";
            }
            Room r1 = Database.Rooms.FirstOrDefault(a => a.Id == stu.RoomId);
            if (r1 == null)
            {
                pass = false;
                return "不存在该宿舍啊";
            }


            int max = r1.Max;
            int currentNum = Database.Students.Where(a => a.RoomId == r1.Id).Count();
            if (max > currentNum)
            {
                pass = true;
                return $"最多住{max}人,现在住{currentNum}人,还有位置";
            }
            else
            {
                pass = false;
                return "人满了";
            }

        }
    }

Over

另外，在.NET MVC开发方式，给实体添加验证的特性，生成的视图模板同样可以在浏览器端进行验证，主要通过jquery.validate.js与jquery.validate.unobtrusive.js进行校验，都属于横向的校验。