Question

我在两个元素Sfera和Contenuti之间有一个N-N关系。

在Sfera项目上，我看到了Contenuti实体集，在Contenuti中我看到了Sfera集......

当我按代码添加新项目时，我使用如下结构：

using (IndexDB DB = new IndexDB())
        {
            try
            {
                var newContenuto = new Contenuto();
                newContenuto.Cancellato = false;
                newContenuto.PK_Content_ID = tt_content_id;
                newContenuto.URL = URL;
                foreach(long sphere in SphereID)
                {
                    try
                    {
                        var sfere = from sfera in DB.Sfera where sfera.PK_Sfera == sphere select sfera;
                        newContenuto.Sfera.Add(sfere.First());
                        sfere.First().Contenuto.Add(newContenuto);
                    }
                    catch (Exception exc)
                    {
                        return new StandardResponse() {Success = false, Message = exc.Message};
                    }
                }
                DB.AddToContenuto(newContenuto);
                DB.SaveChanges();
                return new StandardResponse() {Success = true};
            }
            catch (Exception e)
            {
                return new StandardResponse() { Success = false, Message = e.Message + e.StackTrace };
            }

如果我查看我的数据库，它会很好地存储我在右边的两个元素之间的关系＆＃34; N-N＆＃34; table ....但是当我尝试访问元素Contenuto.Sfera和Sfera.Contenuto总是空集......

要访问我做类似的事情：

using (IndexDB DB = new IndexDB())
        {
            var sfere = from sfera in DB.Sfera where sfera.PK_Sfera == IDSfera && sfera.Attiva select sfera;

            if (!sfere.Any())
            {
                response.Add(new UrlResponse() { Success = false, ErrorMessage = "" });
            }
            var sferaSelezionata = sfere.First();
//HERE sferaSelezionata.Contenuto.Count == 0 even if on DB there are MANY "connections"
}

}

我该如何处理？

非常感谢！

Answer 1

尝试在查询中使用Include()。

var sfere = from sfera in DB.Sfera.Include("Contenuto") where sfera.PK_Sfera == IDSfera && sfera.Attiva select sfera;

如何在Entity Framework .NET 3.5中处理N-N关系

1 个答案: