我有一个nestedSetBuilder班。它具有MakeRootAsync方法：

public async Task<TEntity> MakeRootAsync<TEntity>(TEntity ownerNode) where TEntity: nestedSetEntity
{
    _operation = OperationmakeRoot;
    ownerNode.Lft = 1;
    ownerNode.Rgt = 2;
    ownerNode.Depth = 0;
    await _db.Set<TEntity>().AddAsync(ownerNode);
    await _db.SaveChangesAsync();
    return ownerNode;
}

有一个基类nestedSetEntity：

public class nestedSetEntity
{
    public Guid Id { get; set; }
    public int Lft { get; set; }
    public int Rgt { get; set; }
    public int Depth { get; set; }
    public Guid? Tree { get; set; }
}

有一个子班Category：

[Table("categories")]
public class Category: nestedSetEntity
{
    public Category()
    {
        Visible = true;
        CreatedAt = DateTime.Now;
        UpdatedAt = DateTime.Now;
    }

    [Column("id")]
    public Guid Id { get; set; }

    [Required]
    [StringLength(256)]
    [Column("title")]
    public string Title { get; set; }

    [Column("lft")]
    public int Lft { get; set; }

    [Column("rgt")]
    public int Rgt { get; set; }

    [Column("depth")]
    public int Depth { get; set; }

    [Column("tree")]
    public Guid? Tree { get; set; }

    [Column("visible")]
    public bool Visible { get; set; }

    [Required]
    [Column("created_at")]
    public DateTime CreatedAt { get; set; }

    [Column("updated_at")]
    public DateTime UpdatedAt { get; set; }
}

有一种方法叫makeRootAsync

[HttpGet]
public async Task<IactionResult> Categories()
{
    //var res = await _dnsParserService.ParseCategoriesAsync();
    var res = await _categoryParserService.ParseCategoryListAsync();

    var categoryIds = new Dictionary<string,string>();

    foreach (var categoryListResItem in res)
    {
        if (categoryIds.TryGetvalue(categoryListResItem.CategoryFirstTitle,out var parentCategory)) 
            continue;

        var node = Map(categoryListResItem,"CategoryFirstTitle");
        var addedCategory = await _nestedSetBuilder.MakeRootAsync(node); // this call
        categoryIds[categoryListResItem.CategoryFirstTitle] = addedCategory.Id.ToString();
    }

    return Ok(res);
}

在数据库中，列Lft，Rgt，Depth的值为零：

在调试器中，您可以看到字段是重复的（分别是基类和子类的字段）：

告诉我如何解决？我使用基类来处理LINQ