环境：vs2015,net4.0

 

一、ValidationAttribute

继承ValidationAttribute自定义特性，重写IsValid方法

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, Inherited = false, AllowMultiple = false)]public class MyValidationAttribute : ValidationAttribute{public override bool IsValid(object value){if (value == null){this.ErrorMessage = "null";return false;}if (int.TryParse(value.ToString(), out int val)){return true;}this.ErrorMessage = "只能是数值类型";return false;}protected override ValidationResult IsValid(object value, ValidationContext validationContext){if (value == null){return new ValidationResult("null");}if (int.TryParse(value.ToString(), out int val)){return ValidationResult.Success;}return new ValidationResult("只能是数值类型");}}

二、net自带CustomValidation特性

特性参数分别为类名，验证的方法名

    public class User{
[System.ComponentModel.DataAnnotations.CustomValidation(typeof(ValidationExtension), "IsNumber")]public string Age { get; set; }}

 数据验证的方法：

public static class ValidationExtension{public static ValidationResult IsNumber(object input){var result = new ValidationResult("必须是数字");if (input == null)return result;if (int.TryParse(input.ToString(), out int val)){return ValidationResult.Success;}return result;}}

三、完整实体User

public class User{[MyValidation]public string ID { get; set; }public string NAME { get; set; }[System.ComponentModel.DataAnnotations.CustomValidation(typeof(ValidationExtension), "IsNumber")]public string Age { get; set; }}

四、测试(手动验证)

            User user = new User();user.ID = "ccc";user.Age = "ccc";user.NAME = "czj";//验证实体{ValidationContext vc = new ValidationContext(user, null, null);ICollection<ValidationResult> results = new List<ValidationResult>();bool isValid = Validator.TryValidateObject(user, vc, results, true);foreach (var item in results){Console.WriteLine($"Message:{item.ErrorMessage},Member:{string.Join(",", item.MemberNames)}");}}//验证实体某属性{ValidationContext vc = new ValidationContext(user, null, null);vc.MemberName = "Age";//验证指定属性ICollection<ValidationResult> results = new List<ValidationResult>();bool isValid = Validator.TryValidateProperty(user.Age, vc, results);foreach (var item in results){Console.WriteLine($"Message:{item.ErrorMessage},Member:{string.Join(",", item.MemberNames)}");}}

控制台输出：