克隆对象并将克隆保存到db会导致原始对象丢失关系数据

Question

当我尝试克隆一个Product-object 并将克隆保存到数据库时，原始对象会丢失它的所有关系数据，例如ProductPropertyOptionForProducts,IdentifierForProducts和InCategories。

这是产品型号：

public class Product

{

    public int Id { get; set; }

    public int ProductGroupId { get; set; }

    public int ProductGroupSortOrder { get; set; }

    [Required, MaxLength(30), MinLength(4)]     public string Title { get; set; }

    [MaxLength(200)]                            public string Info { get; set; }

    [MaxLength(4000)]                           public string LongInfo { get; set; }

    [Required, DataType(DataType.Currency)]     public decimal Price { get; set; }

                                                public int Weight { get; set; }

                                                public int ProductTypeId { get; set; }

    public ICollection<ProductImage> Images { get; set; }

    // Selected property options for this product

    public ICollection<PropertyOptionForProduct> ProductPropertyOptionForProducts { get; set; }

    // A product can have multiple identifiers (EAN, ISBN, product number, etc.)

    public ICollection<IdentifierForProduct> IdentifierForProducts { get; set; }

    public ProductType Type { get; set; }

    public ICollection<FrontPageProduct> InFrontPages { get; set; }

    public ICollection<ProductInCategory> InCategories { get; set; }

}

一些相关模型：

public class ProductInCategory

// A linking table for which products belongs to which categories

{

    public int Id { get; set; }

    public int ProductId { get; set; }

    public int ProductCategoryId { get; set; }

    public int SortOrder { get; set; }

    // Nav.props.:

    public Product Product { get; set; }

    public ProductCategory ProductCategory { get; set; }

}