EntityFrameworkCore-指定多个属性时

Question

我正在将VS 2019与EF 6配合使用，以下是我用于开发的模型。当我尝试在EF配置中将外键“ CountryId”映射到“ Estore”模型时，我面临以下问题。

PM> EntityFrameworkCore\Enable-Migrations

两者都安装了Entity Framework Core和Entity Framework 6。实体框架核心工具正在运行。对实体框架6使用'EntityFramework6 \ Enable-Migrations'。Enable-Migrations已过时。使用添加迁移开始使用迁移。

PM> EntityFrameworkCore\Add-Migration Estore_Table

属性表达式'es => Convert（es.Address.CountryId，Object）'无效。该表达式应表示一个简单的属性访问：“ t => t.MyProperty”。指定多个属性时，请使用匿名类型：'t => new {t.MyProperty1，t.MyProperty2}'。 （参数“ propertyAccessExpression”）

请咨询。

    //Country Model:-
    public class Country
    {
        public int CountryId { get; set; }
        public string Name { get; set; }
        public string Code { get; set; }
        public ICollection<Estore> Estores { get; set; }
    }

    //Address Model:-
    public class Address
    {
        public string AddressLine1 { get; set; }
        public string AddressLine2 { get; set; }
        public string AddressLine3 { get; set; }
        public int CityId { get; set; }
        public string Pincode { get; set; }
        public int StateId { get; set; }
        public int CountryId { get; set; }
    }

    //Estore Model:-
    public class Estore
    {
        public int EstoreId { get; set; }
        public string Name { get; set; }
        public string Code { get; set; }
        public Address Address { get; set; }
        public Country Country { get; set; }
    }

    //Estore fields EF configuration
    public class EstoreConfiguration
    {
        public EstoreConfiguration(EntityTypeBuilder<Estore> entityBuilder)
        {
            //DB Table 
            entityBuilder.ToTable("Estores", Constants.Database.DEFAULT_SCHEMA);

            //Table Primary Key
            entityBuilder.HasKey(es => es.EstoreId);

            //Foriegn Key       
            entityBuilder.HasOne(es => es.Country).WithMany(es => es.Estores).HasForeignKey(es => es.Address.CountryId).OnDelete(DeleteBehavior.ClientSetNull);
            //StateId & CityId mapping pending

            //Table Fields
            entityBuilder.Property(es => es.EstoreId).ValueGeneratedOnAdd().IsRequired();
            entityBuilder.Property(es => es.Name).HasMaxLength(100).IsRequired();
            entityBuilder.Property(es => es.Code).HasMaxLength(25).IsRequired();

            //Address
            entityBuilder.OwnsOne(es => es.Address, adr => { adr.Property(es => es.AddressLine1).HasColumnName("AddressLine1").HasMaxLength(50).IsRequired(); });
            entityBuilder.OwnsOne(es => es.Address, adr => { adr.Property(es => es.AddressLine2).HasColumnName("AddressLine2").HasMaxLength(50); });
            entityBuilder.OwnsOne(es => es.Address, adr => { adr.Property(es => es.AddressLine3).HasColumnName("AddressLine3").HasMaxLength(50); });
            entityBuilder.OwnsOne(es => es.Address, adr => { adr.Property(es => es.Pincode).HasColumnName("Pincode").IsRequired(); });
            entityBuilder.OwnsOne(es => es.Address, adr => { adr.Property(es => es.CityId).HasColumnName("CityId").IsRequired(); });
            entityBuilder.OwnsOne(es => es.Address, adr => { adr.Property(es => es.StateId).HasColumnName("StateId").IsRequired(); });
            entityBuilder.OwnsOne(es => es.Address, adr => { adr.Property(es => es.CountryId).HasColumnName("CountryId").IsRequired(); });
        }
    }

    //Context 
    public class EcommerceContext : DbContext
    {
        public EcommerceContext()
        {

        }

        public EcommerceContext(DbContextOptions<EcommerceContext> options) : base(options)
        {

        }

        public DbSet<Estore> Estores { get; set; }

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

            new EstoreConfiguration(modelBuilder.Entity<Estore>());
        }
    }

Answer 1

entityBuilder.OwnsOne(es => es.Address)的返回类型为OwnedNavigationBuilder<Estore,Address>。您必须使用此构建器来定义拥有类型的导航属性。

var addressBuilder = entityBuilder.OwnsOne(es => es.Address);
addressBuilder.OwnsOne(p => p.Address)
            .HasOne(a => a.Country).WithMany().HasForeignKey(a => a.CountryID)
            .OnDelete(DeleteBehavior.ClientSetNull);

当然，您也可以使用此addressBuidlder设置列名，或使用this。

注意，HasOne(a => a.Country).WithMany(c => c.Estores)是不可能的。这是因为Address本身不是一个实体。外键CountryId是Estore实体的一部分，EF无法从该表中构建Address实体。

如果您希望Country具有地址集合和与Estore中的引用相同的地址，则必须使Address成为其自己的实体。