public abstract class BaseViewModel<TValidator> : IDataErrorInfo where TValidator : IValidator, new()
    {
        private readonly TValidator _validator = new TValidator();
        private ValidationResult _validationResult;

        public BaseViewModel()
        {
            Validate();
        }

        public virtual void Validate()
        {
            _validationResult = _validator.Validate(this);
        }

        string IDataErrorInfo.this[string columnName]
        {
            get
            {
                if (_validationResult == null || _validationResult.IsValid) return null;
                var ce = _validationResult.Errors.FirstOrDefault(x => x.PropertyName == columnName);
                return ce == null ? null : ce.ErrorMessage;
            }
        }

        public string Error
        {
            get
            {
                if (_validationResult == null) return "Newer validated";
                if (_validationResult.IsValid) return null;
                return string.Join("\n", _validationResult.Errors.Select(x => x.ErrorMessage));
            }
        }

        public bool IsValid
        {
            get
            {
                return ((IDataErrorInfo)this).Error == null;
            }
        }
    }

    public class PersonViewModel : BaseViewModel<PersonViewModelValidator>
    {
        private string _name;
        private int _age;

        public string Name
        {
            get { return _name; }
            set { _name = value; Validate();}
        }

        public int Age
        {
            get { return _age; }
            set { _age = value; Validate(); }
        }
    }


    public class PersonViewModelValidator : AbstractValidator<PersonViewModel>
    {
        public PersonViewModelValidator()
        {
            RuleFor(x => x.Name).NotEmpty().Length(2, 200);
            RuleFor(x => x.Age).GreaterThan(16);
        }
    }