Question

我正在尝试映射实体及其子集合。首先，我从数据库中检索实体和子集合：

declare @tbl table (id int, grpid char );

insert into @tbl
values (1,'a'), (2,'b'), (null,'b'), (3, 'a'), (null, 'c');

with cte as 
( select id, grpid
  from @tbl 
  where id is null
)

select grpid, id
from cte 
union 
select grpid, sum(id) as val 
from @tbl
where not exists (select 1 from cte where cte.grpid = [@tbl].grpid)
group by grpid
order by grpid;

然后我使用mapper，但在这种情况下我丢失了EmailTemplateComponents中的EmailTemplate链接，我收到一个错误：

“$ id”：“1”， “消息”：“发生错误。”， “ExceptionMessage”：“操作失败：无法更改关系，因为一个或多个外键属性是非空的。当对关系进行更改时，相关 foreign-key属性设置为空值。如果是外键的话不支持null值，必须定义一个新的关系必须为foreign-key属性分配另一个非null值，或者必须删除不相关的对象。“， “ExceptionType”：“System.InvalidOperationException”，

我的实体是这样的：

public async Task<int> Update(EmailTemplateModel model, int id)
{
    var emailTemplate = _context.EmailTemplates.Include("EmailTemplateComponents").Include("Site").FirstOrDefault(x => x.Id == id);
    _mapper.Map(model, emailTemplate);

    return await _context.SaveChangesAsync();
}

映射是这样的：

[Serializable]
public class EmailTemplate : EntityBase
{
    [Key]
    public int Id { get; set; }
    public string Title { get; set; }
    public string AuthorDisplayName { get; set; }
    public int UserId { get; set; }
    public bool IsDeleted { get; set; }
    public virtual List<EmailTemplateComponent> EmailTemplateComponents { get; set; }

    //Site
    public int SiteId { get; set; }

    [ForeignKey("SiteId")]
    public virtual Site Site { get; set; }
}

[Serializable]
public class EmailTemplateComponent : EntityBase
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsTop { get; set; }
    public bool IsBottom { get; set; }
    public bool AlignRight { get; set; }
    public string Text { get; set; }
    public string Title { get; set; }
    public string Url { get; set; }
    public string ImageUrl { get; set; }
    //Email template
    public int EmailTemplateId { get; set; }

    [ForeignKey("EmailTemplateId")]
    public virtual EmailTemplate EmailTemplate { get; set; }
}

我似乎无法弄清楚为什么用null替换子集合中的值？

Automapper子集合在更新时丢失外键ID

0 个答案: