Question

我正在上课：

public class LbsNetwork : BaseEntity
{
    public virtual Guid Uuid { get; set; }

    public virtual string Name { get; set; }

    public virtual  string Description { get; set; }

    [InverseProperty("Network")]
    public virtual ICollection<LbsSubNetwork> SubNetworks { get; set; } 
}

 public class LbsSubNetwork:BaseEntity
{
    public virtual int ForeignId { get; set; }

    public virtual string Name { get; set; }

    public virtual string Description { get; set; }

    public virtual int Major { get; set; }

    [InverseProperty("SubNetworks")]
    [Required]
    public virtual LbsNetwork  Network { get; set; }

    [InverseProperty("SubNetwork")]
    public virtual ICollection<LbsDevice> Devices { get; set; } 
}

public class LbsDevice:BaseEntity
{
    public virtual string Name { get; set; }

    public virtual string Description { get; set; }

    public virtual int Minor { get; set; }

    public virtual int ForeignId { get; set; }

    [InverseProperty("Devices")]
    [Required]
    public virtual LbsSubNetwork SubNetwork { get; set; }

    public virtual BeaconProximity Proximity { get; set; }
}

关注DbContext中的代码：

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<LbsNetwork>().ToTable("LbsNetworks");
        modelBuilder.Entity<LbsNetwork>().HasMany<LbsSubNetwork>(x=>x.SubNetworks)
            .WithRequired(x=>x.Network).HasForeignKey(x=>x.ForeignId).WillCascadeOnDelete();
        modelBuilder.Entity<LbsSubNetwork>().HasMany<LbsDevice>(x=>x.Devices)
            .WithRequired(x=>x.SubNetwork).HasForeignKey(x=>x.ForeignId).WillCascadeOnDelete();
    }

当我尝试在存储中更新LbsNetwork的现有实体时，我接收到Context.Save（）方法中的下一个异常：＆＃34; System.Data.Entity.Validation.DbEntityValidationException：Propetry：网络，消息：网络是必需的。＆＃34;

我认为实体中的一对多关系存在问题。我正在使用下一个代码来更新实体：

    public void Update(LbsNetwork network)
    {
        Context.LbsNetworks.Attach(network);
        ((DbContext)Context.GetRealization()).Entry(network).State = EntityState.Modified;
        Context.Save();
    }

如果你把我的错误告诉我，我将非常感激。谢谢。

Answer 1

[InverseProperty("SubNetworks")]
[Required]
public virtual LbsNetwork  Network { get; set; }

这会导致查询出现问题。我不认为在导航属性中放置Required验证属性是个好主意。你应该把它放在外键中。

[InverseProperty("SubNetworks")]
public virtual LbsNetwork  Network { get; set; }

实体框架，更新实体异常

1 个答案: