1 // 根据不同的region 设定name不同的最大长度和提示信息Region=APAC时，Name最长可以255，其他的Region最长时30 2  3 public class QueryAddModels 4  { 5 [Required(ErrorMessage = "Please input Name")]  6 [RegularExpression(@"^([A-Za-z0-9_-]){1,300}$", ErrorMessage = "Only accept A-Z a-z 0-9 _ and -")] 7 //[MaxLength(255, ErrorMessage = "The maximum allowable length is 255")]  8  [NameMaxLength] // 自定义 9 public string Name10  {11 get; set;12  }13 14 [Required(ErrorMessage = "Please select Region")]15 public string Region16  {17 get; set;18  }19 20  [UserIDValidation] //自定义21 public string UserID { get; set; }22 23 }24 25 // NameMaxLength， Attribute 26 27 public class NameMaxLength : MaxLengthAttribute28  { 29 protected override ValidationResult IsValid(object value, ValidationContext validationContext)30  {31 var region = validationContext.ObjectType.GetProperty("Region")32 .GetValue(validationContext.ObjectInstance, null);33 34 var name = validationContext.ObjectType.GetProperty("Name")35 .GetValue(validationContext.ObjectInstance, null);36 37 if (region != null)38  {39 if (String.Equals(region.ToString(), "APAC") && name != null && name.ToString().Length>255)40  {41 return new ValidationResult("The maximum allowable length is 255.");42  }43 else if (!String.Equals(region.ToString(), "APAC") && name != null && name.ToString().Length > 30)44  {45 return new ValidationResult("The maximum allowable length is 30.");46  }47  }48 return ValidationResult.Success;49  }50  }51 52 public class UserIDValidation : ValidationAttribute53  {54 protected override ValidationResult IsValid(object value, ValidationContext validationContext)55  {56 var newUserID = validationContext.ObjectType.GetProperty("UserID")57 .GetValue(validationContext.ObjectInstance, null);58 59 if (newUserID !=null && !string.IsNullOrEmpty(newUserID .ToString()))60  {61 if (newUserID .ToString().ToUpper() != HttpContext.Current.Session["UserID "].ToString().ToUpper())62 return new ValidationResult("UserID can‘be changed");63 else64 return ValidationResult.Success;65  }66 return new ValidationResult("UserID can‘t be empty");67  }68 69 }