EF Core 拥有的类型不能用于加载数据，但可以用于保存

问题描述

我在我的项目中使用使用值对象的实体，我在文档中读到如果你想使用值对象，你必须使用拥有的类型。 当我用它的存储库保存我的实体时，这个工作完美，但是当我尝试加载数据时，这不起作用，它只加载我的 ID 值对象，而不加载其他对象

这是我的背景

public class WikiContext : DbContext
    {
        private string _sConnection;
        
        #region Constructs

        public WikiContext()
        {
        }
        public WikiContext(string sConnection)
        {
            _sConnection = sConnection;
        }

        #endregion

        #region Entities

        public DbSet<Customer> Customers{ get; set; }

        #endregion

        #region Mapping

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UsesqlServer(_sConnection);
            base.OnConfiguring(optionsBuilder);
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.ApplyConfiguration(new CustomerConfiguration());
           
            base.OnModelCreating(modelBuilder);
        }

        #endregion
    }

这是我的客户配置：

public class CustomerConfiguration : IEntityTypeConfiguration<Customer>
    {
        public void Configure(EntityTypeBuilder<Customer> builder)
        {
            // https://stackoverflow.com/questions/49607375/ef-core-dbcontext-map-custom-type-as-primary-key
            // http://thedatafarm.com/data-access/entity-framework-private-constructors-and-private-setters/
            builder.ToTable("Customers");
            builder.HasKey(customer=> new { customer.Id });
            builder
                .Property<CustomerId>("Id")
                .HasConversion(id => id.Value,guid => new CustomerId(guid));



            // https://www.edgesidesolutions.com/ddd-value-objects-with-entity-framework-core/
            builder.OwnsOne(c => c.Name,a =>
            {
                a.Property(p => p.Value).HasColumnName("Name");
                a.WithOwner();
            });

            builder.OwnsOne(c => c.StudioId,a =>
            {
                a.Property(p => p.Value).HasColumnName("StudioId").HasColumnType("uniqueidentifier");
                a.WithOwner();
            });

            
        }
    }

这是我的客户存储库方法

        public Customer[] Search()
        {
            var customers = Context.Customers.Select(customer=> customer);
            
            return customers.ToArray();
        }

我可以用下一个模型配置做一个解决方法，但我仍然对这种方式有疑问

 protected override void OnModelCreating(ModelBuilder modelBuilder)
        {

            modelBuilder.Entity<Customer>(builder =>
            {
                builder.ToTable("Customers");
                builder.HasKey(customer => new { customer.Id });
                builder
                    .Property<CustomerId>("Id")
                    .HasConversion(id => id.Value,guid => new CustomerId(guid));
            
                builder
                    .Property<CustomerName>("Name")
                    .HasColumnName("Name")
                    .HasConversion(name => name.Value,value => new CustomerName(value));
            
                builder
                    .Property<StudioId>("StudioId")
                    .HasColumnName("StudioId")
                    .HasConversion(p => p.Value,value => new StudioId(value));
            });
            
            base.OnModelCreating(modelBuilder);
        }

        #endregion

这是客户实体

    public class Customer: IAggregateRoot
    {
        #region Constructors

        private Customer()
        {
        }
        
        public Customer(CustomerId oId,CustomerName oCustomerName,StudioId oStudioId)
        {
            Id = oId;
            Name = oCustomerName;
            StudioId = oStudioId;
        }

        #endregion

        #region Public Methods

        public static Customer Create(CustomerId oId,CustomerName  oName,StudioId oStudioId)
        {
            var oCustomer = new Customer(oId,oName,oStudioId);

            //Todo: implement event sourcing here

            return oCustomer;
        }

        #endregion

        #region Property

        public CustomerId Id { get; set; }

        public CustomerName Name { get; set; }

        public StudioId StudioId { get; set; }

        #endregion
    }

    public class CustomerName
    {
        
        public string Value { get; set; }
        
        #region Constructors

        private CustomerName()
        {
        }

        public CustomerName(string sName)
        {
            Value = sName;
        }

        #endregion
    }

我不知道问题出在哪里，我尝试了几种模型配置，但我仍然可以理解为什么这不起作用。

我将 EntityFrameworkCore 5.0.1 与 sql Server 和 .Net Core 3.1 一起使用

解决方法

这是在官方 EFCore 的 github 存储库中回答的，这里是答案的链接 answer