一对零或一个Entityframework导航属性null

Question

I have an context with one to zero or one relationship in entity Framework. but when i load my entity it will not load the related entity. It allways be null.

Here is my classes:

public class Timerow
    {
            [Key]
            public int Id { get; set; }

            [Required]
            public int BestNo { get; set; }

            [Required]
            public int PosNo { get; set; }

            [Required]
            public int EmpNo { get; set; }
            public virtual TimerowOvertime TimerowOvertimes { get; set; }
}

public class TimerowOvertime
    {
            [Key]
            [ForeignKey("Timerow")]
            public int Id { get; set; }
            [Required]
            public float Hours { get; set; }
            public DateTime? Transfered { get; set; }
            public bool Weekend { get; set; }
            public bool ATF { get; set; }
            [Required]
            public virtual Timerow Timerow { get; set; }
}

But when i try to select Timerow and the related timerowOvertimes, timerowOvertimes allways be null.

i try this:

    var timeRows = db.Timerows.ToList();

    foreach (var timeRow in timeRows)
                {
    TimeSheet modelRow = new TimeSheet
                    {
                        Id = timeRow.Id,
                        Date = timeRow.Date,
                        BestNo = timeRow.BestNo,
                        PosNo = timeRow.PosNo,
                        Comment = timeRow.Comment,
                        Hours = timeRow.Hours,
                        Ready = timeRow.Ready,
                        SkillsNoId = timeRow.SkillsNoId
                    };

     if(timeRow.TimerowOvertimes == null)
                    {
                        modelRow.ATF = false;
                        modelRow.Weekend = false;
                        modelRow.Overtime = 0;
                    }
                    else
                    {
                        modelRow.Overtime = timeRow.TimerowOvertimes.Hours;
                        modelRow.ATF = timeRow.TimerowOvertimes.ATF;
                        modelRow.Weekend = timeRow.TimerowOvertimes.Weekend;
                    }
}

Anyone has any idea about this?

Answer 1

You shouldn't have the Id property in TimerowOvertime annotated both as [Key] and [ForeignKey] . Currently it looks to bind the Timerow by using the primary key of TimerowOvertime entity. So you need to extend the TimerowOverTime entity to contain TimerowId property and annotate it with the [ForeignKey] attribute.

        [ForeignKey("Timerow")]
        public int TimerowId { get; set; }