Question

使用Entity Framework Core 2.0，我试图构建一个查询以包含多态子实体的相关数据。

例如，给定以下类型：

    public class ParentEntity
    {
        public int Id { get; set; }

        public IList<ChildEntityBase> Children { get; set; }
    }

    public abstract class ChildEntityBase
    {
        public int Id { get; set; }
    }

    public class ChildEntityA : ChildEntityBase
    {
    }

    public class ChildEntityB : ChildEntityBase
    {
        public IList<GrandchildEntity> Children { get; set; }
    }

    public class GrandchildEntity
    {
        public int Id { get; set; }

    }

以及以下配置：

    public DbSet<ParentEntity> ParentEntities { get; set; }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        builder.Entity<ParentEntity>().HasKey(p => p.Id);
        builder.Entity<ParentEntity>().HasMany(p => p.Children).WithOne();

        builder.Entity<ChildEntityBase>().HasKey(c => c.Id);
        builder.Entity<ChildEntityBase>()
            .HasDiscriminator<string>("ChildEntityType")
            .HasValue<ChildEntityA>("a")
            .HasValue<ChildEntityB>("b");

        builder.Entity<ChildEntityA>()
            .HasBaseType<ChildEntityBase>();

        builder.Entity<ChildEntityB>()
            .HasBaseType<ChildEntityBase>()
            .HasMany(u => u.Children).WithOne();

        builder.Entity<GrandchildEntity>()
            .HasBaseType<ChildEntityBase>();

        base.OnModelCreating(builder);
    }

我正在尝试编写以下查询：

        var result = this.serviceDbContext.ParentEntities
            .Include(p => p.Children)
            .ThenInclude((ChildEntityB b) => b.Children);

不幸的是，这导致了语法错误。

但是，我相信我遵循https://github.com/aspnet/EntityFrameworkCore/commit/07afd7aa330da5b6d90d518da7375d8bbf676dfd

中指定的语法

任何人都可以建议我做错了吗？

由于

Answer 1

此功能在EFC 2.0中不可用。

它被跟踪为#3910 Query: Support Include/ThenInclude for navigation on derived type并根据当前的EFC Roadmap计划用于EFC 2.1发布（{strong>包含派生类型项目在 Features we have committed to complete下）

在Entity Framework Core 2.0中包含派生子属性

1 个答案: