In Linqpad, i can see the correct list. But in code, after putting in the list collection, order by doesn't work for BeginDate. If i use BeginDate with Max, it works. I don't understand where i am wrong?
var templist = contentRepository
.Get(q => (q.Status == (int)StatusEnum.Active) &&
(q.CategoryId == category.GetHashCode() || q.Category.ParentId == category.GetHashCode())
&& q.MinorVersion == 0
&& q.MajorVersion > 0)
.GroupBy(q => q.VersionId)
.OrderByDescending(q => q.Key)
.Select(q => new
{
VersionId = q.Key,
Id = q.Max(x => x.Id),
MajorVersion = q.Max(x => x.MajorVersion),
UpdatedAt = q.Max(x => x.UpdatedAt),
//BeginDate = q.Max(x=>x.BeginDate),
BeginDate = (q.OrderByDescending(x => x.Id).Take(1).Select(x=>x.BeginDate)).First(),
Title = (q.OrderByDescending(x => x.Id).Take(1).Select(x => x.Title)).First(),
ShowOnHomePage = (q.OrderByDescending(x => x.Id).Take(1).Select(x=>x.ShowOnHomePage)).First()
})
.OrderByDescending(x => x.BeginDate)
.Take(maxItemCount)
.ToList();
List<ContentEntity> contents = new List<ContentEntity>();
templist.ForEach(q => contents.Add(
contentRepository
.Get(x => x.VersionId == q.VersionId && x.MajorVersion == q.MajorVersion && x.MinorVersion == 0)
.FirstOrDefault()
));
return contents.Where(q => q.ShowOnHomePage == true)
.OrderByDescending(q => q.MajorVersion)
.OrderByDescending(q => q.BeginDate)
.Take(maxItemCount)
.ToList();
You are ordering by Id, not by BeginDate. Equivalent code for
q.Max(x => x.BeginDate)
Will be
q.OrderByDescending(x => x.BeginDate).Take(1).Select(x => x.BeginDate).First()
Or simplified
q.OrderByDescending(x => x.BeginDate).First().BeginDate
Related
I have a following query
return _context.Table1
.Where(x => x.ContactId == contactKey.Id)
.Include(x => x.Table2)
.Include(x => x.Table3.Table4)
.Select(a =>
new MyReadModel
{
PriorityAssignment = true,
LastContactedDate = (a.Table3.Table4 != null && a.Table3.Table4.FirstOrDefault(h =>
h.Id == a.Table2.FkId
) != null ?
a.Table3.Table4.FirstOrDefault(h => && h.Id == a.Table2.FkId
).LastContactedDatetime : default
)
}
)
.ToListAsync();
What i wants is to simplify LastContactedDate assignment with in select. I think we can assign
a.Table3.Table4.FirstOrDefault(h =>
h.Id == a.Table2.FkId
)
to some variable but can't able to do it
can someone identify what is needed
With EF Core you don't have to check for null, LINQ Translator do not execute your code, but uses it for translation to the SQL. Also Includes is not needed if you do not retrieve whole objects.
return await _context.Table1
.Where(x => x.ContactId == contactKey.Id)
.Select(a => new MyReadModel
{
PriorityAssignment = true,
LastContactedDate = (DateTime?)a.Table3.Table4.Where(h => h.Id == a.Table2.FkId)
.OrderByDescending(h => LastContactedDatetime)
.Select(h => LastContactedDatetime)
.FirstOrDefault()
}).ToListAsync();
you can use it like this example
List<string> someList= new List<string>();
someList= someList.Select(x =>
{
var newVariable= "newVariable";
return newVariable;
}).ToList();
in your case
return _context.Table1
.Where(x => x.ContactId == contactKey.Id)
.Include(x => x.Table2)
.Include(x => x.Table3.Table4)
.Select(a => {
Table4 newVariable = null;
if(a.Table3.Table4 != null)
newVariable = a.Table3.Table4.FirstOrDefault(h => h.Id == a.Table2.FkId;
var result = new MyReadModel
{
PriorityAssignment = true,
LastContactedDate = (newVariable != null ? newVariable.LastContactedDatetime : default
)
};
}
) .ToListAsync();
I have a list of FlightTicketRequestDocument used for both Patients and their Escorts requesting a plane ticket. Theses are grouped with a GUID named GroupId.
I'm trying to group them inside this object:
public class FlightTicketRequestDocumentGroup
{
public Guid GroupId { get; set; }
public FlightTicketRequestDocument PrincipalDocument { get; set; }
public List<FlightTicketRequestDocument> GroupDocuments { get; set; }
}
PrincipalDocument holds the Patient if there's one. (If there isn't we just want the first Escort)
GroupDocuments holds the Escorts. (Except the first one that is placed in PrincipalDocument)
I'm attempting to use different expressions to set my values inside a Select New statement depending if there's a Patient or not but I'm getting the error:
The nested query is not supported. Operation1='Case' Operation2='VarRef'
Here's the code (Note: StayEscortId is null when the person is a Patient.):
var indexGroups = await _db.FlightTicketRequests
.OrderBy(f => f.FirstName)
.ProjectTo<FlightTicketRequestDocument>()
.GroupBy(f => f.GroupId)
.Select(g => new FlightTicketRequestDocumentGroup
{
GroupId = g.Key,
PrincipalDocument = g.Any(f => f.StayEscortId == null)
? g.FirstOrDefault(f => f.StayEscortId == null)
: g.FirstOrDefault(),
GroupDocuments = g.Any(f => f.StayEscortId == null)
? g.Where(c => c.StayEscortId != null).ToList()
: g.Where(c => c.StayEscortId != null).OrderBy(f => f.FullName).Skip(1).ToList()
})
.ToListAsync(cancellationToken);
What can I use instead of the conditional operator ?: ?
The solution that I ended up using:
As specified by #mjwills, since I simply want the values where StayEscordId is null first, all I need to do is to sort as a boolean (false values end up at the top).
For the rest of the group, I do the same operation while Skipping 1 (the first one I chose).
Modified code:
var indexGroups = await _db.FlightTicketRequests
.OrderBy(f => f.FirstName)
.ProjectTo<FlightTicketRequestDocument>()
.GroupBy(f => f.GroupId)
.Select(g => new FlightTicketRequestDocumentGroup
{
GroupId = g.Key,
PrincipalDocument = g.OrderBy(f => f.StayEscortId != null).ThenBy(f => f.FullName).FirstOrDefault(),
GroupDocuments = g.OrderBy(f => f.StayEscortId != null).ThenBy(f => f.FullName).Skip(1).ToList()
})
.ToListAsync(cancellationToken);
Here's what the query would look like if you were to use if/else instead of the ternary conditions. You would just use a code block inside of the .Select() to return the results:
var flightTicketRequestDocuments = await _db.FlightTicketRequests
.OrderBy(f => f.FirstName)
.ProjectTo<FlightTicketRequestDocument>()
.GroupBy(f => f.GroupId)
.ToListAsync(cancellationToken);
var indexGroups = flightTicketRequestDocuments
.Select(g =>
{
FlightTicketRequestDocument principalDocument;
List<FlightTicketRequestDocument> groupDocuments;
if (g.Any(f => f.StayEscortId == null))
{
principalDocument = g.FirstOrDefault(f => f.StayEscortId == null);
groupDocuments = g.Where(c => c.StayEscortId != null).ToList();
}
else
{
principalDocument = g.FirstOrDefault();
groupDocuments = g.Where(c => c.StayEscortId != null).OrderBy(f => f.FullName).Skip(1).ToList();
}
return new FlightTicketRequestDocumentGroup
{
GroupId = g.Key,
PrincipalDocument = principalDocument,
GroupDocuments = groupDocuments
};
})
.ToList();
Note that this approach requires enumerating the IQueryable before performing the .Select() so that it's applied against an IEnumerable.
Needs a check or two (or a tweak or two) but if i remember correctly expression trees accept null coalescence operator you may try to swap in the place of the ternary.
Starting (and BASING) from your example, maybe something like the following?
var indexGroups = await _db.FlightTicketRequests
.OrderBy(f => f.FirstName)
.ProjectTo<FlightTicketRequestDocument>()
.GroupBy(f => f.GroupId)
.Select(g => new FlightTicketRequestDocumentGroup
{
GroupId = g.Key,
PrincipalDocument = g.FirstOrDefault(f => f.StayEscortId == null) ?? g.OrderBy(f => f.FullName).FirstOrDefault(),
GroupDocuments = g.Where(c => c.StayEscortId != null).OrderBy(f => f.FullName).Skip(Math.Max(x.Count(y => y.StayEscortId == null), 1)).ToList()
})
.ToListAsync(cancellationToken);
I have a LINQ query which has three Where clauses. In each Where clause I am looking up the same set of items in order to compare values:
var items = _umbracoHelper.GetPage(ItemsPage.ModelTypeAlias).Children
.Where(x => level1Category == 0 || x
.GetPropertyValue<IEnumerable<IPublishedContent>>(UmbracoAlias.Item.Categories)
.Select(y => y.Id).Contains(level1Category))
.Where(x => !level2Categories.Any() || x
.GetPropertyValue<IEnumerable<IPublishedContent>>(UmbracoAlias.Item.Categories)
.Select(y => y.Id).Intersect(level2Categories.AsEnumerable()).Any())
.Where(x => !level3Categories.Any() || x
.GetPropertyValue<IEnumerable<IPublishedContent>>(UmbracoAlias.Item.Categories)
.Select(y => y.Id).Intersect(level3Categories.AsEnumerable()).Any());
Is there a way I can get the value of UmbracoAlias.Items.Categories once and store that value to be used in the other where clauses without causing the GetPropertyValue method to execute more than once?
You can pair up each item with category IDs, like this:
var items = _umbracoHelper.GetPage(ItemsPage.ModelTypeAlias).Children
.Select(c => new {
Child = c
, CategoryIds = c
.GetPropertyValue<IEnumerable<IPublishedContent>>(UmbracoAlias.Item.Categories)
.Select(y => y.Id)
.ToList()
})
.Where(x => level1Category == 0 || x.CategoryIds.Contains(level1Category))
.Where(x => !level2Categories.Any() || x.CategoryIds.Intersect(level2Categories.AsEnumerable()).Any())
.Where(x => !level3Categories.Any() || x.CategoryIds.Intersect(level3Categories.AsEnumerable()).Any())
.Select(x => x.Child);
This does the filtering on children paired up with their category IDs, and then keeps only the Child object in the final projection.
You could further simplify this by combining all three Where clauses:
var items = _umbracoHelper.GetPage(ItemsPage.ModelTypeAlias).Children
.Where(c => {
var categoryIds = c
.GetPropertyValue<IEnumerable<IPublishedContent>>(UmbracoAlias.Item.Categories)
.Select(y => y.Id)
.ToList();
if (level1Category != 0 && !categoryIds.Contains(level1Category)) {
return false;
}
if (level2Categories.Any() && !categoryIds.Intersect(level2Categories.AsEnumerable()).Any()) {
return false;
}
if (level3Categories.Any() && !categoryIds.Intersect(level3Categories.AsEnumerable()).Any()) {
return false;
}
return true;
});
I've written this code which works:
var uniqueCustomerIdList = services
.GroupBy(x => x.CustomerId)
.Select(cl => new Customer
{
CustomerId = cl.First().CustomerId,
CustomerName = cl.First().CompanyName,
PdfServices = services.Where(x => x.CustomerId == cl.First().CustomerId).ToList(),
PdfServiceLines = services.Where(x => x.CustomerId == cl.First().CustomerId).ToList()
.GroupBy(l => l.ServiceDescription)
.Select(cy => new PdfServiceLine
{
ServiceName = cy.First().ServiceDescription,
Quantity = cy.Count(),
UnitPrice = cy.First().PlanCharge,
ServiceCharges = services.Where(x => x.CustomerId == cl.First().CustomerId && x.ServiceDescription == cy.First().ServiceDescription).Sum(y => y.TotalBill),
UsageCharges = usage.Where(x => x.CustomerId == cl.First().CustomerId && x.ServiceDescription == cy.First().ServiceDescription).Sum(y => y.Charge),
Total = cy.Sum(c => c.PlanCharge),
}).ToList(),
PdfUsages = usage.Where(x => x.CustomerId == cl.First().CustomerId).ToList()
})
.ToList();
I wanted to know if it's possible to reference values from the outer Select statement in the inner statement? As it looks rather clunky at the moment.
For instance in the outer Customer select I use PdfServices - can I use that in the inner select where I have ServiceCharges?
ServiceCharges = PdfServices.Where(s => s.ServiceDescription == cy.First().ServiceDescription).Sum(y => y.TotalBill)
instead of
ServiceCharges = services.Where(x => x.CustomerId == cl.First().CustomerId && x.ServiceDescription == cy.First().ServiceDescription).Sum(y => y.TotalBill),
Thanks,
Lee.
The results that you want to re-use are members of an anonymous object, not variables. As such, you cannot expect them to be available, like a variable would be, to the inner lambda. If you re-wrote your statement, you could store them in intermediate variables:
var uniqueCustomerIdList = services
.GroupBy(x => x.CustomerId)
.Select(cl =>
{
var pdfServices = services.Where(x => x.CustomerId == cl.First().CustomerId).ToList();
return new Customer
{
CustomerId = cl.First().CustomerId,
CustomerName = cl.First().CompanyName,
PdfServices = pdfServices,
PdfServiceLines = pdfServices
.GroupBy(l => l.ServiceDescription)
.Select(cy => new PdfServiceLine
{
ServiceName = cy.First().ServiceDescription,
Quantity = cy.Count(),
UnitPrice = cy.First().PlanCharge,
ServiceCharges = services.Where(x => x.CustomerId == cl.First().CustomerId && x.ServiceDescription == cy.First().ServiceDescription).Sum(y => y.TotalBill),
UsageCharges = usage.Where(x => x.CustomerId == cl.First().CustomerId && x.ServiceDescription == cy.First().ServiceDescription).Sum(y => y.Charge),
Total = cy.Sum(c => c.PlanCharge),
}).ToList(),
PdfUsages = usage.Where(x => x.CustomerId == cl.First().CustomerId).ToList()
};
})
.ToList();
Note that the lamda body now uses curly braces and a return statement. This is not convertible to an expression tree, and some ORM frameworks, like Entity Framework, will not be able to translate the lamda into SQL.
This works fine.g.Key is not null and has appropriate data:
var result = db.JournalEntries.Include(je => je.JournalRecords.Select(jr => jr.Account).Select(j => j.AccountParticulars))
.Where(je => je.Date >= existingLedgerTransaction.From && je.Date <= existingLedgerTransaction.To)
.SelectMany(s => s.JournalRecords)
.GroupBy(d => d.AccountParticular.Account.AccountCategory)
.Select(g => new { Name = g.Key.Name });
But this does not work as g.Key is null:
var DateFilter = new Func<JournalEntry, bool>(je => je.Date >= existingLedgerTransaction.From && je.Date <= existingLedgerTransaction.To);
var result = db.JournalEntries.Include(je => je.JournalRecords.Select(jr => jr.Account).Select(j => j.AccountParticulars))
.Where(DateFilter)
.SelectMany(s => s.JournalRecords)
.GroupBy(d => d.AccountParticular.Account.AccountCategory)
.Select(g => new { Name = g.Key.Name });
I tried the same thing in a simple console app with static collection and passing in predicate works fine. What could be the problem here?
NOTE: Lazy loading/dynamic proxy is disabled
Try
var DateFilter = new Expression<Func<JournalEntry, bool>>(je => je.Date >= existingLedgerTransaction.From && je.Date <= existingLedgerTransaction.To);
as you need to pass an expression tree to EF