实体框架核心-插入多对多关系时出错 [英] Entity Framework Core - Error inserting many-to-many relation

问题描述

我使用Entity Framework Core 2.0.1，目标是通过辅助实体在DB中插入一些与许多相关的对象。但是，出现错误：

I use Entity Framework Core 2.0.1 and the goal is to insert some many-to-many related objects in the DB by an auxiliar entity. However, I get the error:

无法跟踪实体类型 ReferenciaFabricanteTieneReferenciaConstructor的实例，因为另一个实例的键值为 IdReferenciaConstructor：0，IdReferenciaFabricante ：0'已经被跟踪。在附加现有实体时，请确保仅附加一个具有给定键值的实体实例。。

我猜问题可能是在要插入的连接对象列表中，每个连接对象的外键（ID）为0，但是我认为EF会摆脱这种情况，从而为实体ID生成相应的值（如果是新的） ，插入/修改它们，最后更新具有这些值的联接之一。

I guess that the problem may be that in the list of join objects to be inserted, each of them have the foreign keys (ID's) as 0, but I thought EF would get rid of this generating the corresponding values for the entities ID's (if new), inserting/modifying them and finally the join one with these values updated.

要实现这种多对多插入，我应该改变什么？

What should I change in order to achieve this many-to-many insertion?

这些类是：

[Table("ReferenciasFabricante", Schema = "public")]
public class ReferenciaFabricante
{

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

    ...

    //JOIN TABLE
    public IList<ReferenciaFabricanteTieneReferenciaConstructor> ReferenciaFabricanteTieneReferenciaConstructor { get; set; }

}


[Table("ReferenciasConstructor", Schema = "public")]
public class ReferenciaConstructor
{

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

    ...

    //JOIN TABLE
    public IList<ReferenciaFabricanteTieneReferenciaConstructor> ReferenciaFabricanteTieneReferenciaConstructor { get; set; }

}


//JOIN TABLE
[Table("ReferenciaFabricanteTieneReferenciaConstructor", Schema = "public")]
public class ReferenciaFabricanteTieneReferenciaConstructor {

    [Key]
    public int IdReferenciaFabricante { get; set; }

    public ReferenciaFabricante ReferenciaFabricante { get; set; }

    [Key]
    public int IdReferenciaConstructor { get; set; }

    public ReferenciaConstructor ReferenciaConstructor { get; set; }
}

型号：

protected override void OnModelCreating(ModelBuilder modelBuilder) {

    modelBuilder.Entity<ReferenciaFabricanteTieneReferenciaConstructor>().HasKey(v => new { v.IdReferenciaFabricante, v.IdReferenciaConstructor });
}

代码：

foreach (ApplicationCore.Entities.ReferenciaFabricanteTieneReferenciaConstructor referenciaFabricanteTieneReferenciaConstructor in referenciaConstructor.ReferenciaFabricanteTieneReferenciaConstructor) {

    //ERROR
    _dbContext.ReferenciaFabricanteTieneReferenciaConstructor.Add(referenciaFabricanteTieneReferenciaConstructor);
}

推荐答案

正如GertArnold所说，一些属性不见了。
更新的类：

As GertArnold said, some properties were missing. Updated classes:

[Table("ReferenciasFabricante", Schema = "public")]
public class ReferenciaFabricante
{

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

    ...

    //JOIN TABLE
    [InverseProperty("ReferenciaFabricante")]
    public IList<ReferenciaFabricanteTieneReferenciaConstructor> ReferenciaFabricanteTieneReferenciaConstructor { get; set; }

}


[Table("ReferenciasConstructor", Schema = "public")]
public class ReferenciaConstructor
{

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

    ...

    //JOIN TABLE
    [InverseProperty("ReferenciaConstructor")]
    public IList<ReferenciaFabricanteTieneReferenciaConstructor> ReferenciaFabricanteTieneReferenciaConstructor { get; set; }

}


//JOIN TABLE
[Table("ReferenciaFabricanteTieneReferenciaConstructor", Schema = "public")]
public class ReferenciaFabricanteTieneReferenciaConstructor {

    [Key]
    public int IdReferenciaFabricante { get; set; }

    [ForeignKey("IdReferenciaFabricante")]
    public ReferenciaFabricante ReferenciaFabricante { get; set; }

    [Key]
    public int IdReferenciaConstructor { get; set; }

    [ForeignKey("IdReferenciaConstructor")]
    public ReferenciaConstructor ReferenciaConstructor { get; set; }
}

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