左连接linq无法正常工作

Question

我有这个linq查询

var x = (from d in detalle
from n in nlj.DefaultIfEmpty()
join nd in nuevodetalle
on new { d.ope_idsku ,d.ope_tipo } equals new {nd.ope_idsku ,nd.ope_tipo }into nlj
from n in nlj.DefaultIfEmpty()


select new { d, n } ).ToList();

现在，如果我这样做

x[0].d==null this return false
x[0].n==null this return false
x[1].d==null this return false
x[1].n==null this fails, why? 

我真正的选择不是{d，n}它是

select new ope_detalle_autoventa()
{
CreatedOn = d.CreatedOn,
ModifiedOn = d.ModifiedOn,
ope_autoventaid = d.ope_autoventaid,
ope_Codope = d.ope_Codope,
ope_detalle_autoventaId = (tiene_nuevo_primarykey) ? Guid.NewGuid() : d.ope_detalle_autoventaId,
ope_entregado = (d.ope_entregado - (n != null ? n.ope_entregado : 0)),
ope_envase = d.ope_envase,
ope_estado = d.ope_estado,
ope_icono = d.ope_icono,
ope_idsku = d.ope_idsku,
ope_name = d.ope_name,
ope_pedido = d.ope_pedido,
ope_precioV = d.ope_precioV,
ope_prestamo = d.ope_prestamo,
ope_promocion = d.ope_promocion,
ope_skuid = d.ope_skuid,
ope_tipo = d.ope_tipo,
ope_autoventaidTarget = d.ope_autoventaidTarget,
ope_skuidTarget = d.ope_skuidTarget,
Ope_NumVenta = d.Ope_NumVenta,
ope_descuento = d.ope_descuento,
ope_cancelado = d.ope_cancelado,
ope_folio = d.ope_folio,
ope_cantcanc = 0,
ope_estimado = "0"
}

但是这个失败的原因x[1].n==null失败了（我相信）， 我相信这在这一行失败了

ope_entregado = (d.ope_entregado - (n != null ? n.ope_entregado : 0)),

然而 此查询不会失败

var restaragregados = (from r in resultadoregresar
group new { r.ope_entregado } by new { r.ope_idsku } into agrupacion
select new { agrupacion.Key.ope_idsku, entregadototal=(agrupacion.Sum (x=> x.ope_entregado) ) }
);
List<ope_detalle_autoventa> nuevodetalle = (from d in detalle
join c in cargainventario
on d.ope_idsku equals c.ope_idsku into clj
from c in clj.DefaultIfEmpty()
join r in restaragregados on
d.ope_idsku equals r.ope_idsku into rlj
from r in rlj.DefaultIfEmpty ()
where (c!=null?c.ope_carga == cargausada:c==null  )
&& (d.ope_entregado > ((c==null ?0:c.ope_disponibles ) - (r==null?0:r.entregadototal)))
&& d.ope_tipo ==tipos[i]
select new ope_detalle_autoventa()
{
ModifiedOn = DateTime.Now,
ope_autoventaid = ope_autoventaid,
ope_detalle_autoventaId = d.ope_detalle_autoventaId,
ope_entregado = (d.ope_entregado - ((c== null ? 0 : c.ope_disponibles) - (r == null ? 0 : r.entregadototal))),
ope_envase = d.ope_envase,
ope_estado = d.ope_estado,
ope_icono = d.ope_icono,
ope_idsku = d.ope_idsku,
ope_name = d.ope_name,
ope_pedido = 0,//0 por que no pidio de esta carga sino de la que ya se gastó
ope_precioV = d.ope_precioV,
ope_prestamo = d.ope_prestamo,
ope_promocion = d.ope_promocion,
ope_skuid = d.ope_skuid,
ope_tipo = d.ope_tipo,
ope_autoventaidTarget = d.ope_autoventaidTarget,
ope_skuidTarget = d.ope_skuidTarget,
Ope_NumVenta = d.Ope_NumVenta,
ope_descuento = d.ope_descuento,
ope_cancelado =d.ope_cancelado ,
CreatedOn =DateTime.Now ,
ope_Codope =d.ope_Codope ,
ope_folio =d.ope_folio,
ope_cantcanc =0,
ope_estimado="0"
}
).ToList();

我用c重命名n并且我改变了

on new { d.ope_idsku ,d.ope_tipo } equals new {nd.ope_idsku ,nd.ope_tipo }into nlj
by d.ope_idsku equals nd.ope_idsku into nlj

但我得到同样的错误。

Answer 1

我用这个解决了

 if (nuevodetalle.Count == 0)
                nuevodetalle.Add(detalle [0]);
            ope_detalle_autoventa clone = (ope_detalle_autoventa)detalle[0].Clone();
            clone.ope_idsku = 0;
            clone.ope_entregado = 0;
            clone.ope_tipo = 0;
            List<ope_detalle_autoventa> detallecargaactual = new List<ope_detalle_autoventa>();


            var x = (
                from d in detalle
                join c in nuevodetalle
                //on new { d.ope_idsku, d.ope_tipo } equals new { c.ope_idsku, c.ope_tipo } into clj
                on d.ope_idsku equals c.ope_idsku into clj
                from c in clj.DefaultIfEmpty (clone)
                select new{ d, c}).ToList();`enter code here

你可以看到我改变了clj.DefaultIfEmpty (clone)