entity-framework - 具有有效负载的 Entity Framework 代码优先自引用父子

Question

我正在尝试首先在 Entity Framework 中使用代码进行设置，但遇到了困难。描述我想要完成的事情:

有一个 Product 实体。该产品可选地可以具有一个或多个相关的“子”产品。一个产品可以是一个或多个父产品的子产品。

当我去生成一个与模型类“产品”相关的 Controller 时，我收到一个错误:(更新，更具体，匹配下面的代码)

 There was an error running the selected code generator:
'Unable to retrieve metadata for 'ProductCatalog.Models.Product'.
 Multiple object sets per type are not supported. The object sets 
'Product' and 'Products' can both contain instances of type
'ProductCatalog.Models.Product'.

这是不工作的模型类:

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;

namespace ProductCatalog.Models
{
    // Product
    public class Product
    {
        [Key]
        public int ProductId { get; set; } // ProductID (Primary key)
        public string ProductName { get; set; } // ProductName
        public string ProductSku { get; set; } // ProductSKU
        public int BaseQuantity { get; set; } // BaseQuantity
        public decimal BaseCost { get; set; } // BaseCost

        // Reverse navigation
        public virtual ICollection<RelatedProduct> ParentProducts { get; set; } // RelatedProduct.FK_RelatedProductChildID
        public virtual ICollection<RelatedProduct> ChildProducts { get; set; } // RelatedProduct.FK_RelatedProductParentID

        public virtual ICollection<RelatedProduct> RelatedProducts { get; set; }
    }


    // RelatedProduct
    public class RelatedProduct
    {
        [Key, Column(Order = 0)]
        public int ParentId { get; set; } // ParentID
        [Key, Column(Order = 1)]
        public int ChildId { get; set; } // ChildID
        public int Quantity { get; set; } // Quantity
        public bool Required { get; set; } // Required
        public bool Locked { get; set; } // Locked

        // Foreign keys
        public virtual Product ParentProduct { get; set; } //  FK_RelatedProductParentID
        public virtual Product ChildProduct { get; set; } //  FK_RelatedProductChildID
    }

    public class ProductDBContext : DbContext
    {
        public IDbSet<Product> Product { get; set; } // Product
        public IDbSet<RelatedProduct> RelatedProduct { get; set; } // RelatedProduct

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);

            modelBuilder.Entity<RelatedProduct>()
                .HasRequired(a => a.ParentProduct)
                .WithMany(b => b.ChildProducts)
                .HasForeignKey(c => c.ParentId) // FK_RelatedProductParentID
                .WillCascadeOnDelete(false);

            modelBuilder.Entity<RelatedProduct>()
                .HasRequired(a => a.ChildProduct)
                .WithMany(b => b.ParentProducts)
                .HasForeignKey(c => c.ChildId); // FK_RelatedProductChildID

        }
    }
}

Answer 1

通过复数 DbSet 来修复

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;

namespace ProductCatalog.Models
{
    // Product
    public class Product
    {
        [Key]
        public int ProductId { get; set; } // ProductID (Primary key)
        public string ProductName { get; set; } // ProductName
        public string ProductSku { get; set; } // ProductSKU
        public int BaseQuantity { get; set; } // BaseQuantity
        public decimal BaseCost { get; set; } // BaseCost

        // Reverse navigation
        public virtual ICollection<RelatedProduct> ParentProducts { get; set; } // RelatedProduct.FK_RelatedProductChildID
        public virtual ICollection<RelatedProduct> ChildProducts { get; set; } // RelatedProduct.FK_RelatedProductParentID

        public virtual ICollection<RelatedProduct> RelatedProducts { get; set; }
    }


    // RelatedProduct
    public class RelatedProduct
    {
        [Key, Column(Order = 0)]
        public int ParentId { get; set; } // ParentID
        [Key, Column(Order = 1)]
        public int ChildId { get; set; } // ChildID
        public int Quantity { get; set; } // Quantity
        public bool Required { get; set; } // Required
        public bool Locked { get; set; } // Locked

        // Foreign keys
        public virtual Product ParentProduct { get; set; } //  FK_RelatedProductParentID
        public virtual Product ChildProduct { get; set; } //  FK_RelatedProductChildID
    }

    public class ProductDBContext : DbContext
    {
        public IDbSet<Product> Products { get; set; } // Product
        public IDbSet<RelatedProduct> RelatedProducts { get; set; } // RelatedProduct

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);

            modelBuilder.Entity<RelatedProduct>()
                .HasRequired(a => a.ParentProduct)
                .WithMany(b => b.ChildProducts)
                .HasForeignKey(c => c.ParentId) // FK_RelatedProductParentID
                .WillCascadeOnDelete(false);

            modelBuilder.Entity<RelatedProduct>()
                .HasRequired(a => a.ChildProduct)
                .WithMany(b => b.ParentProducts)
                .HasForeignKey(c => c.ChildId); // FK_RelatedProductChildID

        }
    }
}