c# - 一个或多个实体的验证失败 - SaveChanges EF4

Question

我正在尝试编写一个生成多张发票的方法。这是一所大学，其中客户在名为 Enrollments 的类(class)中​​与导师一起注册。通过这种方法，我试图将导师客户的月费乘以他们的佣金百分比，因为导师从他们提供的类(class)中赚取一定的佣金。这是我的代码:

public ActionResult CreateBulkCommissions()
{
    var month = DateTime.Now.ToString("MMMM");

    var enrolments = db.Enrollments.ToList();

    var newCommissions = from enrolment in enrolments
                         select new TutorCommission()
                         {
                             CommissionAmount = enrolment.MonthlyFee,
                             CommissionMonth = month,  // string constant 
                             CommissionStatus = "Unpaid",
                             Tutor = new Tutor { TutorNoID = enrolment.Tutor.TutorNoID, TutorCommissionPercentage = enrolment.Tutor.TutorCommissionPercentage }
                         };
    foreach (var newCommission in newCommissions)
    {
        List<TutorCommission> TutorComs = newCommissions.GroupBy(g => g.Tutor).Select(s => new TutorCommission
        {
            CommissionAmount = s.Sum(u => u.CommissionAmount) * s.Key.TutorCommissionPercentage,
            TutorNoID = s.Key.TutorNoID

        }).ToList();

        db.TutorCommission.Add(newCommission);
        db.SaveChanges();
    }

    return RedirectToAction("Index");
}

在 SaveChanges 上，我收到一个或多个实体验证失败的错误。当我在调试期间查看 newCommissions 的值时，我注意到在 TutorCommission 中，CommissionID 和 TutorNoID 为 0，这可能是问题所在？我该如何解决这个问题？这是屏幕截图:

这些是相关的类:

public class Enrollment
{
    [Key]
    [Display(Name = "Enrollment ID Number")]
    public long EnrollmentIDNumber { get; set; }
    [Display(Name = "Client ID Number")]
    public long ClientNumberID { get; set; }
    [Display(Name = "Tutor ID Number")]
    public long TutorNoID { get; set; }
    [Display(Name = "Course Name")]
    public string CourseName { get; set; }
    [Display(Name = "Lesson Time")]
    public string LessonTime { get; set; }
    [Display(Name = "Lesson Day")]
    public string LessonDay { get; set; }
    [Display(Name = "Lesson Location")]
    public string LessonLocation { get; set; }
    [Display(Name = "Lesson Type")]
    public string LessonType { get; set; }
    [Display(Name = "Lesson Level")]
    public string LessonLevel { get; set; }
    [Display(Name = "Monthly Fee")]
    public long MonthlyFee { get; set; }

    public virtual Client Client { get; set; }
    public virtual Tutor Tutor { get; set; }

}

public class TutorCommission
{
    [Key]
    [Display(Name = "Commission ID")]
    public long CommissionID { get; set; }
    [Display(Name = "Commission Month")]
    public string CommissionMonth {get; set;}
    [Display(Name = "Commission Amount")]
    public double CommissionAmount { get; set; }
    [Display(Name = "Commission Status")]
    public string CommissionStatus { get; set; }
    [Display(Name = "Tutor ID Number")]
    public long TutorNoID { get; set; }

    public virtual Tutor Tutor { get; set; }
    public virtual ICollection<CommissionPayments> CommissionPayments { get; set; }

}

public class Tutor
{
    [Key]
    [Display(Name = "Tutor ID Number")]
    public long TutorNoID { get; set; }
    [Required]
    [StringLength(50, ErrorMessage="First name must be less than 50 characters")]
    [Display(Name = "First Name")]
    public string TutorFirstName { get; set; }
    [StringLength(50, ErrorMessage = "Last name must be less than 50 characters")]
    [Display(Name = "Last Name")]
    public string TutorLastName { get; set; }
    [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
    [Display(Name = "Birth Date")]
    public DateTime? TutorBirthDate { get; set; }
    [Display(Name = "Cellphone Number")]
    public string TutorCellphoneNumber { get; set; }
    [Display(Name = "Home Number")]
    public string TutorHomeNumber { get; set; }
    [RegularExpression("^[a-z0-9_\\+-]+(\\.[a-z0-9_\\+-]+)*@[a-z0-9-]+(\\.[a-z0-9-]+)*\\.([a-z]{2,4})$", ErrorMessage = "Not a valid email address")]
    [Display(Name = "Email Address")]
    public string TutorEmailAddress { get; set; }
    [Display(Name = "Street Address")]
    public string TutorStreetAddress { get; set; }
    [Display(Name = "Suburb")]
    public string TutorSuburb { get; set; }
    [Display(Name = "City")]
    public string TutorCity { get; set; }
    [Display(Name = "Postal Code")]
    public string TutorPostalCode { get; set; }
    [Display(Name="Full Name")]
    public string FullName
    {
        get
        {
            return TutorFirstName + " " + TutorLastName;
        }
    }
    [Display(Name="Commission Percentage")]
    [Required]
    public double TutorCommissionPercentage { get; set; }

    public virtual ICollection<Enrollment> Enrollments { get; set; }
    public virtual ICollection<TutorCommission> TutorCommissions { get; set; }

}

在 EntityValidationErrors 中:

计数 = 1
{System.Data.Entity.Validation.DbEntityValidationResult}

谢谢，艾米

Answer 1

尝试改变:

...
from enrolment in enrolments
                     select new TutorCommission()
                     {
                         CommissionAmount = enrolment.MonthlyFee,
                         CommissionMonth = month,  // string constant 
                         CommissionStatus = "Unpaid",
                         Tutor = new Tutor { TutorNoID = enrolment.Tutor.TutorNoID, TutorCommissionPercentage = enrolment.Tutor.TutorCommissionPercentage }
                     };

收件人:

from enrolment in enrolments
                     select new TutorCommission()
                     {
                         CommissionAmount = enrolment.MonthlyFee,
                         CommissionMonth = month,  // string constant 
                         CommissionStatus = "Unpaid",
                         Tutor = enrolment.Tutor
                     };

因为当您尝试将新的 newCommissions 添加到数据库时，EF 会尝试插入新的导师而不是建立关联。