Question

嘿我试图填充我的模型，它的List<T>和里面有List<T>，但我不能让linq不允许我在Linq中创建一个.ToList。

这些是我的模特

CTIPOCHECKLIST：

public class CTIPOCHECKLIST
{
    public int ID { get; set; }
    public int ID_DEPTO{ get; set; }
    public string DESCRIPCION { get; set; }
}

CTITLE：

public class CTITLE
{
    public int ID { get; set; }

    public int ID_TIPOCHECKLIST { get; set; }

    public string Descripcion { get; set; }

    public virtual CTIPOCHECKLIST Tipo_CheckList { get; set; }

    public List<CSUBTITLE> Subtitulos { get; set; }


    TROP.Models.TROPEntities db = new Models.TROPEntities();


    public List<CTITLE> getAll(string codigo, int tipoCheckList)
    {
        List<CTITLE> model = new List<CTITLE>();

        try
        {

            var result = (from a in db.TITLE
                          from t in db.Tipo_CheckList
                          where a.ID_TipoChecklist == t.ID
                          where a.ID_TipoChecklist == tipoCheckList
                          select new CTITLE
                          {
                              Descripcion = a.Descripcion,
                              ID = a.ID,
                              ID_TIPOCHECKLIST = a.ID_TipoChecklist,
                              Tipo_CheckList = new CTIPOCHECKLIST
                              {
                                  DESCRIPCION = t.Descripcion,
                                  ID = t.ID,
                                  ID_DEPTO = t.ID_Depto
                              },

                              Subtitulos = (from s in db.SUBTITLE
                                            where s.ID_TITLE == a.ID
                                            select new CSUBTITLE
                                            {
                                                AMOUNTCK = s.AMOUNT_CK,
                                                DESCRIPCION = s.DESCRIPCION,
                                                ID = s.ID,
                                                ID_IDTITLE = s.ID_TITLE,
                                                NUMERACION = s.NUMERACION,
                                                CHECKLIST = (from ck in db.CHECKLIST
                                                             where ck.ID_SUBTITLE == s.ID
                                                             && ck.CODIGO == codigo
                                                             select new CCHECKLIST
                                                             {
                                                                 CK = ck.CK,
                                                                 CODIGO = ck.CODIGO,
                                                                 ID = ck.ID,
                                                                 ID_IDSUBTITLE = ck.ID_SUBTITLE,
                                                                 USERCRE = ck.USERCRE,
                                                                 USERMOD = ck.USERMOD
                                                             }).FirstOrDefault()


                                            })//here I put ToList
                          }).ToList();


            return result;
        }
        catch
        {
        }
return model;

    }

CSUBTITLE：

public class CSUBTITLE
    {
        public int ID { get; set; }
        public int ID_IDTITLE { get; set; }
        public string NUMERACION { get; set; }
        public string DESCRIPCION { get; set; }
        public bool AMOUNTCK { get; set; }

        public CTITLE TITLE { get; set; }

        public CCHECKLIST CHECKLIST { get; set; }


    }

CCHECKLIST：

public class CCHECKLIST
{
    public int ID { get; set; }
    public int ID_IDSUBTITLE { get; set; }
    public string CODIGO { get; set; }
    public bool CK { get; set; }
    public string USERCRE { get; set; }
    public string USERMOD { get; set; }

    public CSUBTITLE SUBTITLE { get; set; }

}

我的主类是CTITLE，其GetAll方法类型为List 我只是想填充这个查询，但CTITLE的Subtitulos属性，它的列表当我使用类型IEnumerable填充它工作，但我不希望它返回IEnumerable我需要列表但当我把属性Subtitle转为List和在查询LinQ中添加.ToList（）不允许我，我花了3天时间试图解决这个问题。我想不出来。

Answer 1

这里的问题是，您希望在Linq-to-entities操作中执行Linq-to-objects查询操作。

Linq-to-entities表达式树被转换为SQL并从数据库中获取数据。之后，对象被实现为.Net对象。只有在此步骤之后，才能调用.ToList()

因此，这意味着，您可以稍微重新构建查询并延迟.ToList()次调用：

var result = 
   (from a in db.TITLE
    from t in db.Tipo_CheckList
    where a.ID_TipoChecklist == t.ID
    where a.ID_TipoChecklist == tipoCheckList
    let subtitulos =  from s in db.SUBTITLE
                      where s.ID_TITLE == a.ID
                      select new CSUBTITLE {
                            AMOUNTCK = s.AMOUNT_CK,
                            DESCRIPCION = s.DESCRIPCION,
                            ID = s.ID,
                            ID_IDTITLE = s.ID_TITLE,
                            NUMERACION = s.NUMERACION,
                            CHECKLIST = (from ck in db.CHECKLIST
                                         where ck.ID_SUBTITLE == s.ID
                                         && ck.CODIGO == codigo
                                         select new CCHECKLIST
                                         {
                                             CK = ck.CK,
                                             CODIGO = ck.CODIGO,
                                             ID = ck.ID,
                                             ID_IDSUBTITLE = ck.ID_SUBTITLE,
                                             USERCRE = ck.USERCRE,
                                             USERMOD = ck.USERMOD
                                         }).FirstOrDefault()


                        }
    let ctitle = new CTITLE {
                          Descripcion = a.Descripcion,
                          ID = a.ID,
                          ID_TIPOCHECKLIST = a.ID_TipoChecklist,
                          Tipo_CheckList = new CTIPOCHECKLIST
                          {
                              DESCRIPCION = t.Descripcion,
                              ID = t.ID,
                              ID_DEPTO = t.ID_Depto
                          }
                        }
    select new { CTITLE = ctitle, SUBTITULOS = subtitulos }
    )
    .Select(t => t.CTITLE.Subtitulos = t.SUBTITULOS.ToList())
    .Select(t => t.CTITLE)
    .ToList()

这可以像上面的陈述一样（模拟一些拼写错误和括号）。

在List <t> </t> </t>中填充List <t>

1 个答案: