protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            HtmlHelperDbEntities db = new HtmlHelperDbEntities();
            string emailValor       = (string)value;
            int    count            = db.Usuario.Where(x => x.Email == emailValor).ToList().Count();

            if (count != 0)
            {
                return(new ValidationResult("Ya existe un usuario con ese correo electrónico"));
            }
            return(ValidationResult.Success);
        }
        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            HtmlHelperDbEntities db = new HtmlHelperDbEntities();

            var emailValor = (string)value;
            int unico      = db.Persona.Where(x => x.Email == emailValor).ToList().Count();

            if (unico != 0)
            {
                return(new ValidationResult("Ya hay una persona con este correo electrónico"));
            }
            return(ValidationResult.Success);
        }