public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
 {
     if (!string.IsNullOrEmpty(Email))
     {
         using (客戶資料Entities db = new 客戶資料Entities())
         {
             var data = db.客戶聯絡人.FirstOrDefault(p => p.客戶Id == 客戶Id && p.Email == Email);
             if (data != null)
                 yield return new ValidationResult("此客戶Email不能重複!", new[] { "Email" });
         }
     }
 }
 public EFUnitOfWork()
 {
     Context = new 客戶資料Entities();
 }