protected override ValidationResult IsValid(object value, ValidationContext validationContext) { DB_A095E6_nomaddoorsEntities nomadDB = new DB_A095E6_nomaddoorsEntities(); if (value != null) { string Email = value.ToString(); int count = nomadDB.Users.Where(x => x.Email == Email).ToList().Count(); if (count != 0) { return(new ValidationResult("This email already exists")); } return(ValidationResult.Success); } return(new ValidationResult("Please provide your Email")); }