String MinLength and MaxLength validation don't work (asp.net mvc)

Question

I have this class

using System.ComponentModel.DataAnnotations;
using Argussoft.BI.DAL.Domain.Users;

namespace Argussoft.BI.DAL.DTOs.UserDTOs
{
    public cl         


        

Answer 1

MaxLength is used for the Entity Framework to decide how large to make a string value field when it creates the database.

From MSDN:

Specifies the maximum length of array or string data allowed in a property.

StringLength is a data annotation that will be used for validation of user input.

From MSDN:

Specifies the minimum and maximum length of characters that are allowed in a data field.

Non Customized

Use [String Length]

[RegularExpression(@"^.{3,}$", ErrorMessage = "Minimum 3 characters required")]
[Required(ErrorMessage = "Required")]
[StringLength(30, MinimumLength = 3, ErrorMessage = "Maximum 30 characters")]

30 is the Max Length
Minimum length = 3

Customized StringLengthAttribute Class

public class MyStringLengthAttribute : StringLengthAttribute
{
    public MyStringLengthAttribute(int maximumLength)
        : base(maximumLength)
    {
    }

    public override bool IsValid(object value)
    {
        string val = Convert.ToString(value);
        if (val.Length < base.MinimumLength)
            base.ErrorMessage = "Minimum length should be 3";
        if (val.Length > base.MaximumLength)
            base.ErrorMessage = "Maximum length should be 6";
        return base.IsValid(value);
    }
}

public class MyViewModel
{
    [MyStringLength(6, MinimumLength = 3)]
    public String MyProperty { get; set; }
}

Answer 2

    [StringLength(16, ErrorMessageResourceName= "PasswordMustBeBetweenMinAndMaxCharacters", ErrorMessageResourceType = typeof(Resources.Resource), MinimumLength = 6)]
    [Display(Name = "Password", ResourceType = typeof(Resources.Resource))]
    public string Password { get; set; }

Save resource like this

"ThePasswordMustBeAtLeastCharactersLong" | "The password must be {1} at least {2} characters long"

Answer 3

This can replace the MaxLength and the MinLength

[StringLength(40, MinimumLength = 10 , ErrorMessage = "Password cannot be longer than 40 characters and less than 10 characters")]

Answer 4

They do now, with latest version of MVC (and jquery validate packages). mvc51-release-notes#Unobtrusive

Thanks to this answer for pointing it out!

Answer 5

Try using this attribute, for example for password min length:

[StringLength(100, ErrorMessage = "Максимальная длина пароля 20 символов", MinimumLength = User.PasswordMinLength)]