相关疑难解决方法(0)

在我的数据库中,我有一个表类别,列ID,CategoryName,ParentCategoryId,其中ParentCategoryId对Category.Id有约束.

我首先使用实体​​框架代码,实体看起来像:

public class Category
{
   public long Id { get; private set; }
   public string CategoryName { get; private set; }
   public long? ParentCategoryId { get; private set; }
   public Category ParentCategory { get; private set; }       
   public virtual ICollection<Category> SubCategories { get; private set; }
}

如果我尝试对此运行查询,我会得到异常:

 The relationship 'ComplaintModel.FK_Complaint_Category' was not loaded because the type 'ComplaintModel.Category' is not available.\r\nThe following information may be useful in resolving the previous error:\r\nThe required property 'Category1' does not exist on the …

我在这里发现了很多类似的问题,但似乎没有一个问题可以解决我的问题.流畅的api和属性没有帮助.数据库已创建,但在向其添加对象时,它已崩溃.我想要一个拥有自己的集合的类.这是我的代码:

[Table("UObjects")]
public class UObject
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    [Browsable(false)]
    public long ID { get; set; }
    public string Name { get; set; }
    [Browsable(false)]
    public long? ParentID { get; set; }

    public virtual UObject UParent { get; set; }
    [Browsable(false)]
    public virtual ICollection<UObject> UObjects { get; set; }
}


public class MyContext : DbContext
{
    public DbSet<UObject> UObjects { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        // This fluent API didn't help
        //modelBuilder.Entity<UObject>()
        //        .HasOptional(u => u.UParent)
        // …