错误:实体或复杂类型不能在一个LINQ被构造为实体的查询 [英] Error: The entity or complex type cannot be constructed in a LINQ to Entities query
问题描述
我有一个问题,连接查询与MVC,我不知道为什么。
I have a problem with join query with MVC and i dont know why.
实体或复杂类型'Tusofona_Website.Models.site_noticias'不能在一个LINQ被构造为实体的查询。
The entity or complex type 'Tusofona_Website.Models.site_noticias' cannot be constructed in a LINQ to Entities query.
我的控制器:
private TusofonaDBs db = new TusofonaDBs();
//
// GET: /DestaquesMain/
public ActionResult Index()
{
var query = (from sd in db.site_desquesnoticias
join sn in db.site_noticias on sd.IDNoticia equals sn.IDNoticia
where sn.Destaque == 1
select new site_noticias {
CorpoNoticia = sn.CorpoNoticia,
TituloNoticia = sn.TituloNoticia
}).ToList();
//return View(db.site_desquesnoticias.ToList());
return View(query);
}
我的模型:
public class site_destaquesnoticias
{
[Key]
public Int32 IDDestaque { get; set; }
public Int32 IDNoticia { get; set; }
public string Foto { get; set; }
}
public class site_noticias
{
[Key]
public Int32 IDNoticia { get; set; }
public string CorpoNoticia { get; set; }
public string TituloNoticia { get; set; }
public string Foto { get; set; }
public Int32 Destaque { get; set; }
}
public class TusofonaDBs : DbContext
{
public DbSet<site_destaquesnoticias> site_desquesnoticias { get; set; }
public DbSet<site_noticias> site_noticias { get; set; }
}
任何人都可以帮我吗?
Anyone can help me?
推荐答案
您不能投射到一个映射实体(见<一href=\"http://stackoverflow.com/questions/12916080/the-entity-or-complex-type-cannot-be-constructed-in-a-linq-to-entities-query\">this答案)。
You can't project onto a mapped entity (see this answer).
不过,你可以做两件事情:
However, you can do a couple of things:
1)选择,而不是像实体匿名类型:
1) Select an anonymous type instead of entity like:
var query = (from sd in db.site_desquesnoticias
join sn in db.site_noticias on sd.IDNoticia equals sn.IDNoticia
where sn.Destaque == 1
select new {
CorpoNoticia = sn.CorpoNoticia,
TituloNoticia = sn.TituloNoticia
}).ToList();
2),反转您的查询直接选择site_noticias。这取决于查询和您想检索数据。例如,你可以去看看,如果下面的工作,给你,你需要的数据:
2) Invert your query to select the site_noticias directly. That depends on the query and the data that you would like to retrieve. For example, you can have a look if the following will work and give you the data that you need:
var query = (from sd in db.site_desquesnoticias
join sn in db.site_noticias on sd.IDNoticia equals sn.IDNoticia
where sn.Destaque == 1
select sn).ToList();
3)使用一些DTO(数据传输对象)项目要选择的属性:
3) Use some DTO (Data transfer object) to project the properties that you want to select on to:
public class SiteNoticiasDTO{
public string CorpoNoticia {get;set;}
public string TituloNoticia {get;set;}
}
var query = (from sd in db.site_desquesnoticias
join sn in db.site_noticias on sd.IDNoticia equals sn.IDNoticia
where sn.Destaque == 1
select new SiteNoticiasDTO {
CorpoNoticia = sn.CorpoNoticia,
TituloNoticia = sn.TituloNoticia
}).ToList();
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