How to use GroupBy in lambda? - linq

I am trying to convert the following code into lambda style but without success.
DiscCurrentLocation[] old =
(from v in volumeDC.Volumes
join d in volumeDC.Disc_Vs
on v.VolumeID equals d.DiscVolumeID
group d by new { v.VolumeLibID, d.DiscCurrentLocation } into g
where (g.Key.VolumeLibID == libraryId && g.Key.DiscCurrentLocation > -1
&& g.Count() > 1)
select (DiscCurrentLocation)g.Key.DiscCurrentLocation
).ToArray<DiscCurrentLocation>();
Can somebody show me how to convert it?
Thanks

This should be identical:
DiscCurrentLocation[] old = volumeDC.Volumes
.Join(volumeDC.Disc_Vs, (v) => v.VolumeID, (d) => d.DiscVolumeID,
(v, d) => new { Volume = v, Disc_V = d })
.GroupBy(vd => new { vd.Volume.VolumeLibID, vd.Disc_V.DiscCurrentLocation })
.Where (grp => grp.Key.VolumeLibID == libraryId
&& grp.Key.DiscCurrentLocation > -1 && grp.Count() > 1)
.Select (grp => (DiscCurrentLocation)grp.Key.DiscCurrentLocation)
.ToArray<DiscCurrentLocation>()
;

Related

Linq query dynamic

I've this linq query:
var query = (from l in _contexto.lineasencargos
join a in _contexto.articulos on l.IDARTICULO equals a.IDARTICULO
join af in _contexto.articulofamilia on a.IDARTICULO equals af.IDARTICULO
join f in _contexto.familias on af.IDFAMILIA equals f.IDFAMILIA
join e in _contexto.encargos on l.IDENCARGO equals e.IDENCARGO
where e.FECHAHORAENCARGOS >= _finder.FechaDe &&
e.FECHAHORAENCARGOS <= _finder.FechaA &&
e.FECHAHORARECOGERENCARGOS >= _finder.FechaRecogerDe &&
e.FECHAHORARECOGERENCARGOS <= _finder.FechaRecogerA &&
e.clientes.RAZONSOCIALCLIENTE.Contains(_finder.Cliente)
group l by new { l.IDARTICULO, l.CANTIDADLINEAENCARGO,a.DESCRIPCIONARTICULO,f.DESCRIPCION,f.IDFAMILIA }
into g
select new listaEncargosAgrupados
{
IdArticulo=(int)g.Key.IDARTICULO,
DescripcionArticulo=g.Key.DESCRIPCIONARTICULO,
IdFamilia=g.Key.IDFAMILIA,
DescripcionFamilia=g.Key.DESCRIPCION,
SumaCantidad = (decimal)g.Sum(x => x.CANTIDADLINEAENCARGO),
SumaPrecio = (decimal)g.Sum(x => x.PRECIOLINEAENCARGO),
Total = (decimal)((decimal)g.Sum(x => x.CANTIDADLINEAENCARGO) * g.Sum(x => x.PRECIOLINEAENCARGO))
});
and i need create a condition in Where, that filter dynamically:
if (_finder.IdTienda > 0)
{
query = query.Where(x=>x.IDTIENDA == _finder.IdTienda);
}
But this Where it is not correct because IDTIENDA is contained in _context.encargos and not in listaEncargosAgrupados
How i can revolve this problem?
Thanks
Add e into grouping statement and IDTIENDA list into the result:
var query = (from l in _contexto.lineasencargos
join a in _contexto.articulos on l.IDARTICULO equals a.IDARTICULO
join af in _contexto.articulofamilia on a.IDARTICULO equals af.IDARTICULO
join f in _contexto.familias on af.IDFAMILIA equals f.IDFAMILIA
join e in _contexto.encargos on l.IDENCARGO equals e.IDENCARGO
where e.FECHAHORAENCARGOS >= _finder.FechaDe &&
e.FECHAHORAENCARGOS <= _finder.FechaA &&
e.FECHAHORARECOGERENCARGOS >= _finder.FechaRecogerDe &&
e.FECHAHORARECOGERENCARGOS <= _finder.FechaRecogerA &&
e.clientes.RAZONSOCIALCLIENTE.Contains(_finder.Cliente)
group new { l, e} by new { l.IDARTICULO, l.CANTIDADLINEAENCARGO,a.DESCRIPCIONARTICULO,f.DESCRIPCION,f.IDFAMILIA }
into g
select new { Result = new listaEncargosAgrupados
{
IdArticulo=(int)g.Key.IDARTICULO,
DescripcionArticulo=g.Key.DESCRIPCIONARTICULO,
IdFamilia=g.Key.IDFAMILIA,
DescripcionFamilia=g.Key.DESCRIPCION,
SumaCantidad = (decimal)g.Sum(x => x.l.CANTIDADLINEAENCARGO),
SumaPrecio = (decimal)g.Sum(x => x.l.PRECIOLINEAENCARGO),
Total = (decimal)((decimal)g.Sum(x => x.l.CANTIDADLINEAENCARGO) * g.Sum(x => x.l.PRECIOLINEAENCARGO))
},
IDTIENDAs = new HashSet<int>(from x in g
let id = x.e.IDTIENDA
where id.HasValue
select (int)id.Value)
});
...
if (_finder.IdTienda > 0)
{
query = query.Where(x => x.IDTIENDAs.Contains (_finder.IdTienda));
}
var query1 = query.Select(x => x.Result);
Finally the solution to my problem was to employ executestorequery in the context of my EF, and creat a SQL query :
List<ListaEncargosAgrupados> lista;
string queryString = #"SELECT l.IDARTICULO,a.DESCRIPCIONARTICULO,f.DESCRIPCION descripcionFamilia,f.IDFAMILIA,sum(l.CANTIDADLINEAENCARGO) sumaCantidad,avg(l.PRECIOLINEAENCARGO)
sumaPrecio,sum(l.CANTIDADLINEAENCARGO)*avg(l.PRECIOLINEAENCARGO) Total " +
"FROM lineasencargos l,articulos a,articulofamilia af,familias f,encargos e " +
"where a.IDARTICULO=l.IDARTICULO and a.IDARTICULO=af.IDARTICULO " +
"and af.IDFAMILIA=f.IDFAMILIA and l.IDENCARGO=e.IDENCARGO ";
if (_finder.IdTienda > 0)
{
queryString = queryString + " and e.idtienda=" + _finder.IdTienda;
}
queryString = queryString + " group by l.IDARTICULO,a.DESCRIPCIONARTICULO,f.DESCRIPCION,f.IDFAMILIA order by a.DESCRIPCIONARTICULO ";
var salidaQuery = _contexto.ExecuteStoreQuery<ListaEncargosAgrupados>(queryString).AsQueryable().ToList();
lista = salidaQuery;

where does not contain array

my below query looks ok to me but im not sure why im getting errors.
The error is "the best overload for string.containts(string) has some invalid arguments". what am i missing here?
Thanks
string[] strHiddenESXi = {"Internal","Support","Archived"};
var tblvirtualservers = from d in db.tblVirtualServers.Include(t => t.ChangeLog).Include(t => t.ESXi)
where (!d.ESXi.ESXiName.Contains(strHiddenESXi)) && d.ESXiID != 20
string[] strHiddenESXi = {"Internal","Support","Archived"};
var tblvirtualservers = from d in db.tblVirtualServers.Include(t => t.ChangeLog)
.Include(t => t.ESXi)
where (!strHiddenESXi.Contains(d.ESXi.ESXiName)) && d.ESXiID != 20
You have to use Contains with strHiddenESXi that is an Array.
Can you try?
string[] strHiddenESXi = {"Internal","Support","Archived"};
var tblvirtualservers = from d in db.tblVirtualServers.Include(t => t.ChangeLog)
.Include(t => t.ESXi)
where (!strHiddenESXi.Any( a=> d.ESXi.ESXiName.Contains(a) )) && d.ESXiID != 20

Finding bounds with LINQ

This code works ok, but I was wondering whether there isn't some way to write it in one LINQ expression so a single pass can be done by the database server instead of realising a result set and then looping through it, which is what my code will produce.
var logs = from AssetLog log in dc.AssetLogs
where log.AssetId == assetId && log.Recorded >= start && log.Recorded <= finish
select log;
return new GetInteractionBoundsResult()
{
N = logs.Max(log => log.Latitude),
S = logs.Min(log => log.Latitude),
W = logs.Min(log => log.Longitude),
E = logs.Max(log => log.Longitude)
};
So, LINQ gurus, how would you write the above so that it produces more or less this at the database:
SELECT MIN(Latitude) S, MAX(Latitude) N, MIN(Longitude) W, MAX(Longitude) E
FROM ASSETLOG WHERE etc etc
Sure, just trick your LINQ provider into thinking it's still working with a query until the very end:
var logs = from asset in dc.Assets
where asset.AssetId == assetId
let g = asset.AssetLogs
.Where(log => log.Recorded >= start && log.Recorded <= finish)
select new GetInteractionBoundsResult
{
N = g.Max(log => log.Latitude),
S = g.Min(log => log.Latitude),
W = g.Min(log => log.Longitude),
E = g.Max(log => log.Longitude)
};
return logs.Single();
A Group By may perform better than the join that the above query would produce:
var logs = from log in dc.AssetLogs
where log.AssetId == assetId &&
log.Recorded >= start && log.Recorded <= finish
group log by log.AssetId into g
select new GetInteractionBoundsResult
{
N = g.Max(log => log.Latitude),
S = g.Min(log => log.Latitude),
W = g.Min(log => log.Longitude),
E = g.Max(log => log.Longitude)
};
return logs.Single();
It would take a pretty sophisticated LINQ provider, but a subquery may work:
var res = from asset in dc.Assets
where log.AssetId == assetId
let logs = (from AssetLog log in asset.AssetLogs
where log.Recorded >= start && log.Recorded <= finish
select log)
select new GetInteractionBoundsResult()
{
N = logs.Max(log => log.Latitude),
S = logs.Min(log => log.Latitude),
W = logs.Min(log => log.Longitude),
E = logs.Max(log => log.Longitude)
};
return res.Single();

Linq PredicateBuilder multi criteria

List<Product> Prs = data.Products
.Where(x=> x.ProductColors
.Where(y=> y.Color=="blue")
.Select(z=> z.ProductID)
.Contains(x.ID) && x.ProductColors
.Where(y=> y.Color== "red")
.Select(z=> z.ProductID)
.Contains(x.ID))
.ToList();
How to PredicateBuilder multi-criteria?
Something like the following:
var inner = PredicateBuilder.False<Product>();
inner = inner.Or (p => p.Description.Contains ("foo"));
inner = inner.Or (p => p.Description.Contains ("far"));
var outer = PredicateBuilder.True<Product>();
outer = outer.And (p => p.Price > 100);
outer = outer.And (p => p.Price < 1000);
outer = outer.And (inner);
var results = data.Products.AsExpandable().Where(outer)
You can read more about PredicateBuilder here

linq where condition on subselect

how can we add a where condition to a linq subselect query.
i.e.
List<CallLog> callLog = CallLog.SampleData();
List<Contacts> contacts = Contacts.SampleData();
var q = from call in callLog
where call.Incoming == true
group call by call.Number into g
select new contacts {
contact.FirstName = g.FirstName,
contact.LastName = g.LastName,
Count = g.Count(),
Avg = g.Average( c => c.Duration ) <--- WHERE c.Duration > 5,
Total = g.Sum( c => c.Duration ) <--- WHERE c.Duration >= 60
};
How can we add a "Where condition" to the LINQ statement as shown above?
Simply add a Where method with the clause you described!
Avg = g.Where(c => c.Duration > 5).Average(c => c.Duration),
Total = g.Where(c => c.Duration >= 60).Sum(c => c.Duration)
You almost had it:
var q = from call in callLog
where call.Incoming == true
group call by call.Number into g
select new contacts {
contact.FirstName = g.FirstName,
contact.LastName = g.LastName,
Count = g.Count(),
Avg = g.Where(c => c.Duration > 5).Average( c => c.Duration ),
Total = g.Where(c => c.Duration >= 60).Sum( c => c.Duration )
};

Resources