Data Annotations Custom Validator not working (as I'd expect) in MVC2

Before I start ... I can't easily migrate the project to MVC3. So.

The problem I'm having is that I've defined a custom validator attribute to check the max AND min length of a s开发者_运维百科tring property, StringLengthInRangeAttribute.

When the Controller calls ModelState.IsValid, on a list of Passengers only the validation of a Date property is throwing invalid, when nothing has been supplied. I guess that means my problem is not with the custom validator but all validation?

Update (additional info for clarity):

I have two symptoms of this problem :

1.The Required validator on the strings doesn't fire when they are empty

and

2.My custom validator never gets called (a breakpoint I set never gets hit).

Model:

 public class Passenger
 {
    [Required(ErrorMessageResourceType = typeof(Resources.Messages.Passenger),
        ErrorMessageResourceName = "RequireNumber")]
    public int Number { get; set; }

    [Required(ErrorMessageResourceType = typeof(Resources.Messages.Passenger),
        ErrorMessageResourceName = "RequireSurname")]
    [StringLengthInRange(MinLength = 2, MaxLength = 30, ErrorMessageResourceType = typeof(Resources.Messages.Passenger),
        ErrorMessageResourceName = "MaxLengthSurname")]
    public string Surname { get; set; }
 } 

Custom Validator:

public class StringLengthInRangeAttribute:ValidationAttribute
{
    public int MinLength { get; set; }
    public int MaxLength { get; set; }

    public override bool IsValid(object value)
    {
        if (((string)value).Length < MinLength)
        {
            return false;
        }

        if (((string)value).Length > MaxLength)
        {
            return false;
        }

        return true;
    }
}

Controller Action:

 public ViewResult TailorHoliday(List<SearchAndBook.Models.ViewModels.Passenger> passengers, 
        int leadPassengerIndex)
    {
        if(!ModelState.IsValid)
        {
            return View("PassengerDetails", GetBookingState(_currentSession));
        }
    //...
    return View();
   }

Any advice appreciated. This is the first time I've used Data Annotations, so I'm quite prepared to feel stupid for missing something!

If you check the content of the ModelState property (in the debugger) you should be able to see every property that gets validated in ModelState.Keys and for each value you see the actual state in the ModelState.Values. If I look at your controller you seem to post a whole list of passengers. You should check as well, whether your values are really posted (use Firebug or Fiddler). Maybe your fields are outside the form.

Maybe you should show part of your view as well to spot the bug.