Data Annotations是在Asp.Net中用于表单验证的
它通过Attribute直接标记字段的有效性,简单且直观。在非Asp.Net程序中(如控制台程序),我们也可以使用Data Annotations进行手动数据验证的,一个简单的例子如下(需要添加System.ComponentModel.DataAnnotations.dll的引用):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel.DataAnnotations; namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
var user = new User();
var context = new ValidationContext(user, null, null); var results = new List<ValidationResult>();
Validator.TryValidateObject(user, context, results, true); foreach (var validationResult in results)
{
Console.WriteLine(validationResult.ErrorMessage);
} Console.Read();
}
} class User
{
[Required]
public string Name { get; set; } [Range(, )]
public int Age { get; set; }
}
}
输出:
aaarticlea/png;base64,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" alt="" />
若添加了 user.Name = "test";这一句,只把age不符合要求的输出来
var user = new User();
user.Name = "test";
var context = new ValidationContext(user, null, null);
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" alt="" />
比较完之后,相信大家应该知道了这个类的大概作用了。
编写自己的Data Annotations
虽然系统已经自带了常用的验证Attribute,但是,在实际应用中,我们仍然免不了要编写自己的验证规则,首先我们来看下其结构:
可以看出,要编写一个自己的验证规则是非常简单的,只需要继承自ValidationAttribute类,并重载IsValid方法即可。一个简单的示例如下:
[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
publicclassCountryAttribute : ValidationAttribute
{
publicstring AllowCountry { get; set; }
publicoverridebool IsValid(object value)
{
returnstring.Equals(value, AllowCountry);
}
protectedoverrideValidationResult IsValid(object value, ValidationContext validationContext)
{
if (string.Equals(value, AllowCountry))
returnValidationResult.Success;
else
returnnewValidationResult(string.Format("{0} 字段非法", validationContext.DisplayName), new []{ validationContext.MemberName});
}
}
从上我们可以看到,IsValid是有两个版本的,我们实际上只需要重载一个即可,如果需要自定义错误信息可以用下面那个。 如果两个版本都重载了默认情况下使用下面的那个高级的版本。
更多信息:
关于Data Annotations的更多知识这里就不做介绍了,感兴趣的朋友可以参看这篇文章:DataAnnotations Validation for Beginner
WPF中的数据验证:
实际上,数据验证往往并非用于前例所示的控制台程序程序,而是用于WPF这类GUI程序中。 WPF程序中也有一套非常完善的数据验证框架值得学习一下,限于篇幅这里就不多介绍了,感兴趣的朋友可以看看这篇文章:Data validation in WPF