C# 实体框架4自连接-延迟加载父对象和子集合

我正在尝试使用entity framework 4实现自连接，我的用例如下：

public class Category
{
    /// <summary>
    /// category id
    /// </summary>
    [Key]
    [DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
    public int CatID { get; set; }

    /// <summary>
    /// category name
    /// </summary>
    [Required(ErrorMessage="Vui lòng nhập tên.")]
    [MaxLength(100, ErrorMessage="Tên chỉ có độ dài tối đa 100 ký tự.")]
    public string CatName { get; set; }

    /// <summary>
    /// parent category id
    /// self join :)
    /// </summary>
    public int? ParentID { get; set; }

    /// <summary>
    /// parent category
    /// </summary>
    [ForeignKey("ParentID")]
    public virtual Category ParentCategory { get; set; }

    /// <summary>
    /// products list
    /// </summary>
    public virtual IEnumerable<Product> Products { get; set; }

    /// <summary>
    /// categories which are associate with this category
    /// </summary>
    public virtual IEnumerable<Category> Categories { get; set; }
}

Buf如果我筛选结果集，则不会延迟加载子集合

var cat = from entity in context.Category
          where entity.Parent == null
          select entity;
//child collection will be null

---

使用Include方法加载集合：

var selectedList = entity.where(m=>m.parent==null).include(m=>m.Categories).tolist();

---

不能，默认情况下应该启用它。检查你没有做像包括。。。在你的代码上。另外，您确定它不是延迟加载的吗？你真的看到一个SQL查询被激发到数据库中了吗？我的代码中没有使用任何include。子集合应具有valueQuestion update的位置始终为空！请看一看，并帮助meI使用Include方法使其成为延迟加载而不是急切加载。但是谢谢你的关注，安

var selectedList = entity.where(m=>m.parent==null).include(m=>m.Categories).tolist();