认识Fluent Vaidation.
看到NopCommerce项目中用到这个组建是如此的简单，将数据验证从业务实体类中分离出来，真是一个天才的想法，后来才知道这个东西是一个开源的轻量级验证组建。
Fluent Validation 翻译为：流畅验证
开源Codeplex其主页简介：该组件是一个轻量级的.NET类库，使用流畅的接口定义和lambda表达式为构建一个业务类的验证规则（A small validation library for .NET that uses a fluent interface and lambda expression for building validation rules for you business objects.）
这个类库不仅仅可以使用的asp.net mvc项目中，普通的类库中也可以使用，当然在asp.net form项目中也支持。
怎么使用：
是不是好用，还要看使用时是否真的像其官网建议描述一样。我比较喜欢其官网上的例子，一眼就能看出用法上的感觉，绝对是如其名，流畅，这个也一种解释型语言常见的的一种用法，无限的对一个类型支持无限度个属性扩展。
业务实体类：
复制代码 代码如下:
public class Person
{
public string NameField;
public int Id { get; set; }
public string Surname { get; set; }
public string Forename { get; set; }
public List<Person> Children { get; set; }
public string[] NickNames { get; set; }
public DateTime DateOfBirth { get; set; }
public int? NullableInt { get; set; }
public Person()
{
Children = new List<Person>();
Orders = new List<Order>();
}
public int CalculateSalary()
{
return 20;
}
public Address Address { get; set; }
public IList<Order> Orders { get; set; }
public string Email { get; set; }
public decimal Discount { get; set; }
public double Age { get; set; }
public int AnotherInt { get; set; }
public string CreditCard { get; set; }
public int? OtherNullableInt { get; set; }
}
public interface IAddress
{
string Line1 { get; set; }
string Line2 { get; set; }
string Town { get; set; }
string County { get; set; }
string Postcode { get; set; }
Country Country { get; set; }
}
public class Address : IAddress
{
public string Line1 { get; set; }
public string Line2 { get; set; }
public string Town { get; set; }
public string County { get; set; }
public string Postcode { get; set; }
public Country Country { get; set; }
public int Id { get; set; }
}
public class Country
{
public string Name { get; set; }
}
public interface IOrder
{
decimal Amount { get; }
}
public class Order : IOrder
{
public string ProductName { get; set; }
public decimal Amount { get; set; }
}
对Person的指定验证规则：
复制代码 代码如下:
using FluentValidation;
public class CustomerValidator: AbstractValidator<Customer>
{
public CustomerValidator()
{
RuleFor(customer => customer.Surname).NotEmpty();
RuleFor(customer => customer.Forename).NotEmpty().WithMessage("Please specify a first name");
RuleFor(customer => customer.Discount).NotEqual(0).When(customer => customer.HasDiscount);
RuleFor(customer => customer.Address).Length(20, 250);
RuleFor(customer => customer.Postcode).Must(BeAValidPostcode).WithMessage("Please specify a valid postcode");
}
private bool BeAValidPostcode(string postcode)
{
// custom postcode validating logic goes here
}
}
// 手动验证规则
Customer customer = new Customer();
CustomerValidator validator = new CustomerValidator();
ValidationResult results = validator.Validate(customer);
bool validationSucceeded = results.IsValid;
IList<ValidationFailure> failures = results.Errors;