protected override ValidationResult IsValid(object value, ValidationContext validationContext) { if (value == null) { return(ValidationResult.Success); } ICountryValidator validator = ServiceLocator.Current.GetService <ICountryValidator>(); var result = new ValidationResult(this.ErrorMessage); if (validator == null) { return(result); } bool validationResult = validator.IsCountryValid(value.ToString()); return(validationResult ? ValidationResult.Success : result); }