protected override ValidationResult IsValid(object value, ValidationContext validationContext) { BuyNSell_DbEntities objDB = new BuyNSell_DbEntities(); if (value != null) { String EmailId = value.ToString(); UserMaster CheckEmailId = objDB.UserMasters.Where(e => e.EmailId.Equals(EmailId)).FirstOrDefault(); if (CheckEmailId != null) { return(new ValidationResult("EmailId Already Exist")); } else { return(ValidationResult.Success); } } return(null); }