I am trying to write a LINQ statement using Entity Framework. I am getting an error stating "Expanding the Results View will enumerate the Enumerable"
My query is as follows :
IQueryable lis = (from que in _repo.Query<Question>()
where que.PresentationImageId == 1 join map in
_repo.Query<UserChildCourseQuestionMap>() on que.Id equals map.QuestionId into t
from rt in t.DefaultIfEmpty()
group t by que.Id
into g
select new
{
Id = g.Key,
QuestionBody = (from q in _repo.Query<Question>() where q.Id == g.Key select q.QuestionBody),
value = (from p in _repo.Query<UserChildCourseQuestionMap>()
where p.QuestionId == g.Key
select new
{
Name = gg.Key.AnswerOption,
Count = gg.Count(),
}).Union(from p in _repo.Query<UserChildCourseQuestionMap>()
where p.QuestionId == g.Key && p.UserInputText != null
group p by p.UserInputText into gg
select new
{
Name = gg.Key,
Count = gg.Count(),
}).Where(x => x.Name != null)
}
);
In LINQPad its working fine but in Visual Studio its not. Following is the image result which i am getting in LINQPad :
Please let me know where am I going wrong?
Following is the Screen Shot which i am getting when i expand the resultset:
Expand Image
The message " "Expanding the Results View will enumerate the Enumerable"" is not an error, it's a warning saying that if you expand the + sign the query will be run against the DDBB.
Just click in the + and expand the results tree, it should be ok.
Related
I want to get all AddOns(without duplication) with the combination HealthInsuranceQuotationMemberPlanBenefit data. AddOnsID at HealthInsuranceQuotationMemberPlanBenefit is the primary key of AddOns table.
(from mq in context.HealthInsuranceQuotationMember
join mp in context.HealthInsuranceQuotationMemberPlanBenefit on mq.ID equals mp.HealthInsuranceQuotationMemberID
join ao in context.AddOns on mp.AddOnsID equals ao.ID
where mq.HealthInsurancePlanID == 1 && ao.Category != 2
group mp by new { ao.ID, ao.Name, ao.Category } into g
let fmp = g.First()
select new HealthInsurancePlanAddOnsViewModel
{
ID = g.Key.ID,
Name = g.Key.Name,
CategoryID = (int)g.Key.Category,
Category = g.Key.Category.ToDescription(),
Value = fmp.Description,
Premium = fmp.Premium,
})
.ToList();
When I am trying to get the first item of HealthInsuranceQuotationMemberPlanBenefit using fmp = g.First() it raising following error:
Processing of the LINQ expression '(GroupByShaperExpression:
KeySelector: new {
ID = (a.ID),
Name = (a.Name),
Category = (a.Category)
},
ElementSelector:(EntityShaperExpression:
EntityType: HealthInsuranceQuotationMemberPlanBenefit
ValueBufferExpression:
(ProjectionBindingExpression: EmptyProjectionMember)
IsNullable: False
)
)' by 'RelationalProjectionBindingExpressionVisitor' failed. This may indicate either a bug or a limitation in EF Core. See https://go.microsoft.com/fwlink/?linkid=2101433 for more detailed information.
If I remove the selection of HealthInsuranceQuotationMemberPlanBenefit(let fmp = g.First(), Value = fmp.Description, Premium = fmp.Premium) data, it is working.
I investigate the occurred because of g.First()
Also, how can I solve & improve this query?
I wrote a query and worked on LINQPAD
from x in FacilityData
from y in FavInformation
where y.UserID == 1 && x.ID == y.FacilityID
select new
{
xID = x.ID,
xDistrictName = (from y in _Ilcelers
where y.ID == x.DistrictID
select y.IlceAd).FirstOrDefault(),
xName = x.Name,
Value = (from o in Tags
from p in Table_tags
where o.Prefix != null && o.Prefix == p._NAME && o.Facility == y.FacilityID
orderby p.İd descending
select new
{
FType = o.TagType,
Name = o.TagsName,
Value = p._VALUE,
Time = p._TIMESTAMP
}).Take(Tags.Count(h => h.Facility == y.FacilityID))
}
result
the result is perfect
but does not work in visual studio,
Value = (from o in DB.Tags
from p in DB.table_tags
where o.Prefix != null && o.Prefix == p.C_NAME && o.Facility == 11
orderby p.id descending
select new
{
FType=o.TagType,
Name = o.TagsName,
Value = p.C_VALUE,
Time = p.C_TIMESTAMP
}).Take(Tags.Count(h => h.Facility == y.FacilityID))
and it gives an error.
I guess the part with .Take() doesn't work because it's linq to EF.
error:
Limit must be a DbConstantExpression or a Db Parameter Reference Expression. Parametre name: count]
error image
thank you have a good day
Not sure but I will just throw it in. If you are talking about linq to ef/sql, it is possible they dont know a thing about C#. If take() would be the problem try to get the select result local first by doing .tolist(). Afterwards use your take funtion.
.ToList().Take(Tags.Count(h => h.Facility == y.FacilityID))
Work on DF 4 vs 2010.Face problem on join on SalSalesOrderDetail with SalSalesOrderFinancial table.
In SalSalesOrderFinancial one record have SalesOrderDetailID=null. Want to get those records whose SalesOrderDetailID is not present in SalSalesOrderFinancial.
To get desired out put write bellow linq syntax,it’s working .Looking for better join syntax .Is there any way to get desired in one join.
var tempBDwithSODetail = (from p in this.Context.SalSalesOrderFinancials
where p.SalesOrderDetailID != null
select p.SalesOrderDetailID).AsEnumerable();
var tempBDwithOutSODetail = (from p in this.Context.SalSalesOrderFinancials where p.SalesOrderDetailID == null select p).AsEnumerable();
var querySOD = (this.Context.SalSalesOrderDetails.Where(item => !tempBDwithSODetail.Contains(item.SalesOrderDetailID))).AsEnumerable();
var tempBDetail = (from p in querySOD
join q in tempBDwithOutSODetail on p.SalesOrderID equals q.SalesOrderID
where q.SalesOrderDetailID == null
select new
{
q.SalesOrderID,
p.SalesOrderDetailID,
q.CurrencyID,
q.BillingPolicyID,
q.BillTypeID,
q.BillingTypeID
}).AsEnumerable();
If have any query please ask.Thanks in advanced.
if i got you, you just need to simple left join between SalSalesOrderDetail and SalSalesOrderFinancial...
var query = (from u in this.Context.SalSalesOrderDetail
join t in this.Context.SalSalesOrderFinancials
on u.SalesOrderDetailID equals t.SalesOrderDetailID into JoinedList
from t in JoinedList.DefaultIfEmpty()
select new
{
SalSalesOrderDetail = t,
SalSalesOrderFinancials = u
})
.Where(u => u.SalSalesOrderFinancials == null)
.ToList();
I want to do a LINQ NOT EXISTS on query MULTIPLE TABLES.
All examples on Google or SO are handling two tables I'm working with three so I'm struggling as a newbie on LINQ on how to reference them correctly.
First I tried this LINQ query
var nocertificates = (
from x in rmdb.t_certificates
from ce in rmdb.t_user_certificates
from u in rmdb.t_users
where u.id == ce.uid && ce.value != x.id
select x).AsEnumerable().Select(x => new ViewModelCheckBox()
{
Value = x.id.ToString(),
Name = x.name,
Checked = false
});
I used the ugly three times from as I'm not that good with creating types for joining.
But that gave wrong result and I realized I had to go for a NOT EXISTS
So I built a new query in T-SQL
This is the SQL query it works!
select distinct * from t_certificates tc
where NOT EXISTS
(
select distinct * from t_users tu, t_user_certificates tuc
WHERE tu.email = 'user#email.com'
and tu.id = tuc.[uid]
and tuc.value = tc.id
)
How would I do that in LINQ?
This is the question, I will award my answer for that!
BUT!
When we are at it... I'm really curious on the answer.. Is it possible to do one LINQ query that return an Ienumerable with both those that EXISTS and NOT EXISTS resulting in an object which will hold DIFFERENT VALUES on the checked property EXISTS -> CHECKED = true NOT EXISTS -> CHECKED = false
This is how I create my object.
.Select(x => new ViewModelCheckBox()
{
Value = x.id.ToString(),
Name = x.name,
Checked = this should be different based on exists or not
});
The LINQ answer should look something like this (untested):
var nocertificates =
from x in rmdb.t_certificates
join tuc in (
from u in rmdb.t_users
join ce in rmdb.t_user_certificates on u.id == ce.uid
select ce.value
) on tuc.value = tc.id into tuc
from y in tuc.DefaultIfEmpty()
where y == null
select x;
This is what I ended up using!
var query = (from tc in rmdb.t_certificates
where !(
from tu in rmdb.t_users
from tuc in rmdb.t_user_certificates
where tu.email == username
&& tu.id == tuc.uid
&& tuc.value == tc.id select tc).AsEnumerable().Any()
select new ViewModelCheckBox()
{ Checked = false,
intconverter = tc.id,
Name = tc.name
});
First Table is the View and Second is the result I want
This below query works fine
List<BTWStudents> students = (from V in db.vwStudentCoursesSD
where classIds.Contains(V.Class.Value)
select new BTWStudents
{
StudentId = V.StudentId
Amount= V.PaymentMethod == "Cashier Check" ? V.Amount: "0.00"
}).Distinct().ToList();
But I changed it to List to add string formatting(see below)
List<BTWStudents> students = (from V in db.vwStudentCoursesSD
where classIds.Contains(V.Class.Value)
select new {V}).ToList().Select(x => new BTWStudents
{
StudentId = V.StudentId
Amount= V.PaymentMethod == "Cashier Check" ? String.Format("{0:c}",V.Amount): "0.00"
}).Distinct().ToList();
With this Second Query I get this
Why is distinct not working in the second query?
When working with objects (in your case a wrapped anonymous type because you are using Select new {V} rather than just Select V), Distinct calls the object.Equals when doing the comparison. Internally, this checks the object's hash code. You'll find in this case, the hash code of the two objects is different even though the fields contain the same values. To fix this, you will need to override Equals on the object type or pass a custom IEqualityComparer implementation into the Distinct overload. You should be able to find a number of examples online searching for "Distinct IEqualityComparer".
Try this (moved your distinct to the first query and corrected your bugged if/then/else):
List<BTWStudents> students = (from V in db.vwStudentCoursesSD
where classIds.Contains(V.Class.Value)
select new {V}).Distinct().ToList().Select(x => new BTWStudents
{
classId = V.Class.HasValue ? V.Class.Value : 0,
studentName = V.StudentName,
paymentAmount = V.PaymentMethod == "Cashier Check" ? String.Format("{0:c}",x.V.AmountOwed): "0.00"
}).ToList();
You can get around using Distinct all together if you Group by StudentID
var studentsGroupedByPayment =
(from V in db.vwStudentCoursesSD
where classIds.Contains(V.Class.Value)
group V by V.StudentId into groupedV
select new
{
StudentID = groupedV.Key,
Amount = string.Format("{0:C}",
groupedV.First().PaymentMethod == "Cashier Check" ?
groupedV.First().Amount : 0.0)
}
).ToList();