I just started messing around with regularexpressions, but basically with this one (which i found online btw) is supposed to require for the password to be between 8 - 10, but whenever i try it out and put in the correct length it's still showing the error message. any ideas?
i also need to include a 1 lowercase, 1 uppercase and 1 number on the validations.. 

```
public class password : IValidatableObject
{
    [Required]
    [RegularExpression("(?=^.{8,10}$)", ErrorMessage = "Password is invalid.")]
    public string ConfirmPWD { get; set; }
    [Required(ErrorMessage="Confirm Password field is required.")]
    public string ConfirmPWD { get; set; }

    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
    {
        if (ConfirmPWD != ConfirmPWD )
            yield return new ValidationResult("Not identical.");
    }
}

```