我有如下所示的实体(使用带有存储库模式的.NET代码优先):
public abstract class BaseContent : Entity
{
public Guid ID { get; set; }
public virtual ICollection<AssignedMedia> AssignedMedias { get; set; }
}
public partial class Library : BaseContent
{
public Library()
{
this.AssignedMedias = new List<AssignedMedia>();
}
}
public class Media : BaseContent
{
public Media()
{
this.AssignedMedias = new List<AssignedMedia>();
}
}
public class AssignedMedia : Entity
{
public int ID { get; set; }
//BaseContent reference ID
public Guid AssignedId { get; set; }
public Guid MediaId { get; set; }
public virtual Media Media { get; set; }
public virtual BaseContent BaseContent { get; set; }
}
然后我尝试获取查询(作为Dictionary&lt; string,List&lt; Media&gt;&gt;)作为分组依据! 对于实例:
var list = from bc in Libraries
join a in AssignedMedias on bc.ID equals a.AssignedId
join m in Medias on a.MediaId equals m.ID
select new {
LibraryName = bc.Name, MediaList = ???
};
答案 0 :(得分:1)
当您已正确映射实体关联时,您不需要使用join
。您可以像这样编写查询:
var libraryAssignedMedia = Libraries.ToDictionary(
l => l.Name, // Key selection.
l => l.AssignedMedias.Select(am => am.Media)); // Value selection.