I am getting a null refrence exception when im filtering EF but I am absolultely clueless.
public IEnumerable<TonalityBatchModel> GetTonalityBatch(int briefID)
{
try
{
var brief = NeptuneUnitOfWork.Briefs.FindWhere(b => b.ID == briefID).FirstOrDefault();
if (brief != null && brief.TonalityCriteria != null)
{
return brief.TonalityCriteria.TonalityBatches
.Select(b => new TonalityBatchModel()
{
BriefID = b.BriefID,
Status = b.TonalityCriteria.IsActive == true ?"Active":"Ended",
BatchID = b.ID,
CompetitorID = b.BriefCompetitorID,
Competitor = brief.BriefCompetitors.Where(i=>i.ID == b.BriefCompetitorID).Select(c=>c.Organisation.Name).First(),
Size = b.BatchSize,
StartDate = b.StartDate,
EndDate = b.EndDate,
IsPublished = b.Lookup_TonalityBatchStatus.ID == (int)TonalityBatchStatus.Published?"Yes":"No",
IsCompleted = b.Lookup_TonalityBatchStatus.ID == (int)TonalityBatchStatus.Completed ? "Yes" : "No",
IsAssigned = b.Lookup_TonalityBatchStatus.ID == (int)TonalityBatchStatus.Allocated ? "Yes" : "No",
ImportantCount = b.TonalityItems.Count(i=> i.IsImportant),
ArticlesCount = b.TonalityItems.Count,
FavourableCount = b.TonalityItems.Count(i => i.Lookup_TonalityScoreTypes.ID ==(int)TonalitySourceType.Favourable),
UnfavourableCount = b.TonalityItems.Count(i => i.Lookup_TonalityScoreTypes.ID ==(int)TonalitySourceType.Unfavourable),
NeutralCount = b.TonalityItems.Count(i => i.Lookup_TonalityScoreTypes.ID ==(int)TonalitySourceType.Neutral)
}).ToList();
}
return new List<TonalityBatchModel>();
}
catch (Exception ex)
{
Logger.Error(ex);
throw;
}
}
You'll need to reduce your query to a simpler query, and then start building it back up again until the NullReferenceException occurs. Looking at your code, here are some likely places (I'm making some assumptions since I don't know everything about your model):
Competitor = brief.BriefCompetitors.Where(i=>i.ID == b.BriefCompetitorID).Select(c=>c.Organisation.Name).First()
BriefCompetitors could be null. c.Organisation could be null.
IsPublished = b.Lookup_TonalityBatchStatus.ID == (int)TonalityBatchStatus.Published?"Yes":"No",
(and other similar lines) b.Lookup_TonalityBatchStatus might be null.
ImportantCount = b.TonalityItems.Count(i=> i.IsImportant),
(and other similar lines) b.TonalityItems might be null.
I believe this is because your count is returning null records. I could be wrong but the SQL that's being produced here is something like:
INNER JOIN TonalityItems i on i.Lookup_TonalityScoreTypes == x
Where x is the value of (int)TonalitySourceType.Favourable. Because this join has no matching results there is nothing to do a count on. You could try adding ?? 0 to the end of the query:
FavourableCount = b.TonalityItems.Count(i => i.Lookup_TonalityScoreTypes.ID ==(int)TonalitySourceType.Favourable) ?? 0,
Related
I made a method on the back-end side to handle the filter of my datatable.
On the other hand, this one does not manage the accents of the French language, so if I have "école" and I write "ecole" it cannot find it.
I found this method on another question on stackoverflow
public static String RemoveDiacritics(this String s)
{
String normalizedString = s.Normalize(NormalizationForm.FormD);
StringBuilder stringBuilder = new StringBuilder();
for (int i = 0; i < normalizedString.Length; i++)
{
Char c = normalizedString[i];
if (CharUnicodeInfo.GetUnicodeCategory(c) != UnicodeCategory.NonSpacingMark)
{
stringBuilder.Append(c);
}
}
return stringBuilder.ToString().Normalize(NormalizationForm.FormC);
}
and it works, but only for part of my problem. It works on the letter or the word that is written in the search, but I am not able to apply it in my linq query, so with the .RemoveDiacritics() method my "école" becomes "ecole", but I don't am not able to apply it in the column of my table and it always looks for "école".
Here the code for the search:
if (search != null)
{
int n;
search = search.Trim();
var isNumeric = int.TryParse(search, out n);
if (isNumeric)
{
IdFilter = n;
query = query.Where(x => x.UsagerId == IdFilter || x.Niveau == IdFilter);
}
else if (search != "")
{
// this line work
textFilter = search.ToLower().RemoveDiacritics();
// This is the full line, but absolutely takes the accents out to get the right information out
// query = query.Where(x => x.Nom.ToLower().Contains(textFilter) || x.Prenom.ToLower().Contains(textFilter) || x.Username.ToLower().Contains(textFilter) || x.Email.ToLower().Contains(textFilter) || x.EtabNom.ToLower().Contains(textFilter) || x.ActifStatut.ToLower().Contains(textFilter));
// This is the line that will replace the line above, which I try and it doesn't work ( this part: x.Prenom.ToLower().RemoveDiacritics())
query = query.Where(x => x.Prenom.ToLower().RemoveDiacritics().Contains(textFilter));
}
}
This is the basic query:
IQueryable<ListeUsagers> query = (from u in db.USAGERs
join e in db.ETABLISSEMENTs on u.USAGER_INST equals e.ETAB_CODE
where u.USAGER_INST == instId && u.USAGER_NIVEAU > 3 && u.USAGER_NIVEAU < 5 //&& u.USAGER_ACTIF == 1
select new ListeUsagers()
{
UsagerId = u.USAGER_id,
Nom = u.USAGER_NOM,
Prenom = u.USAGER_PRENOM,
EtabCode = e.ETAB_CODE,
EtabNom = e.ETAB_NOM_COURT,
EtabType = e.ETAB_TYPE,
Niveau = u.USAGER_NIVEAU,
Username = u.USAGER_USERNAME,
UserPassword = u.USAGER_MP,
DateCreation = u.USAGER_DATE_INSC,
Sexe = u.USAGER_SEXE,
Lang = u.USAGER_LANGUE,
Telephone = u.USAGER_TELEPHONE,
Email = u.USAGER_EMAIL,
FonctionTravail = u.USAGER_FONCTION,
LieuTravail = u.USAGER_LIEUTRAVAIL,
Note = u.USAGER_NOTE,
Actif = u.USAGER_ACTIF,
ActifStatut = u.USAGER_ACTIF == 0 ? "Inactif" : "Actif"
});
This is the error:
LINQ to Entities does not recognize the method 'System.String RemoveDiacritics(System.String)' method, and this method cannot be translated into a store expression.
There's built-in functionality to do this in entityframework: https://learn.microsoft.com/en-us/ef/core/miscellaneous/collations-and-case-sensitivity if you're using EF 5+
You'll want an accent insensitive collation ("AI", not "AS" in the examples on that page.)
I have a function doing a complicated Where query on my db context and then applies another transformation passed to it:
static IQueryable<T> Query<T>(Func<IQueryable<ServicesData>, IQueryable<T>> f, string path1 = null, string path2 = null, string path3 = null, string path4 = null, string path5 = null) {
try {
using (var dbc = new MyDbContext() ) {
var res = dbc.ServicesData
.Where(sd =>
(path1 == null || (path1.Contains("%") || path1.Contains("_") ? EF.Functions.Like(sd.Path1, path1) : sd.Path1 == path1))
&& (path2 == null || (path2.Contains("%") || path2.Contains("_") ? EF.Functions.Like(sd.Path2, path2) : sd.Path2 == path2))
&& (path3 == null || (path3.Contains("%") || path3.Contains("_") ? EF.Functions.Like(sd.Path3, path3) : sd.Path3 == path3))
&& (path4 == null || (path4.Contains("%") || path4.Contains("_") ? EF.Functions.Like(sd.Path4, path4) : sd.Path4 == path4))
&& (path5 == null || (path5.Contains("%") || path5.Contains("_") ? EF.Functions.Like(sd.Path5, path5) : sd.Path5 == path5)));
return f(res.ToList().AsQueryable());
//return f(res).ToList().AsQueryable();
}
} catch (Exception ex_) {
return VList<T>.Empty.AsQueryable();
}
}
This is used ie like this:
IQueryable<int> Int1InLastHour(IQueryable<ServicesData> input) {
var lastHour = DateTimeOffset.Now.AddHours(-1).ToUnixTimeMilliseconds();
return input
.Where(v => (v.Time <= lastHour) && (v.Int1 is object))
.Select(v => v.Int1.Value);
}
var lastHourProcessTime = Query(Int1InLastHour, "Publisher", "%", "ItemProcessTime").Sum();
This works, however since I call res.ToList() before calling f the linq in f is done in memory and not on the DB SQL
If I try to replace f(res.ToList().AsQueryable()) with f(res).ToList().AsQueryable() I get an exception:
{"Processing of the LINQ expression '[EntityShaperExpression][ServicesData]' 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."}
Is there any way for me to solve this ? can I somehow pass the query (Func<IQueryable<ServicesData>, IQueryable<T>>) and then combine it to the query in Query before excecuting it on the dbc ?
A few issues. You can split the querying to break down your results, but the scope of your DbContext needs to be at the outermost point of the chain, not inside the inner-most:
This here:
static IQueryable<T> Query<T>(Func<IQueryable<ServicesData>, IQueryable<T>> f, string path1 = null, string path2 = null, string path3 = null, string path4 = null, string path5 = null) {
try {
using (var dbc = new MyDbContext() ) { // DbContext should not be scoped here...
var res = dbc.ServicesData
As the simplest re-factor:
static IQueryable<T> Query<T>(MyDbContext dbc, Func<IQueryable<ServicesData>, IQueryable<T>> f, string path1 = null, string path2 = null, string path3 = null, string path4 = null, string path5 = null) {
try
{
var res = dbc.ServicesData.AsQueryable();
if(path1 != null)
if(path1.Contains("%") || path1.Contains("_"))
res = res.Where(EF.Functions.Like(sd.Path1, path1));
else
res = res.Where(sd.Path1 == path1);
// Repeat for Path 2 - 5 ....
return f(res);
}
catch (Exception ex_)
{
return VList<T>.Empty.AsQueryable();
}
}
Firstly, we pass in the DbContext. If the context is scoped here, the list must be materialized before being returned. The goal is to allow callers to further reduce the expression before executing the list. This means the DbContext needs to be scoped outside of this initial generation and passed in. With IoC containers managing lifetime scope you can bypass this if the DbContext is injected and scoped to a Request or common lifetime scope.
The next improvement suggestion is to move the conditional checks for the parameters out of the Linq and into regular conditions so that the Like / Equals check will only be added if the condition was provided. This will result in simpler, faster SQL being run on the server.
So the end result would look something like:
using (var dbContext = new MyDbContext())
{
var lastHourProcessTime = Query(dbContext, Int1InLastHour, "Publisher", "%", "ItemProcessTime").Sum();
}
I sort of get where you're trying to go here, but abstracting expressions from EF is bound to lead to confusing code and still prone to limitations and bugs. IMO keeping it simpler generally leads to less issues, but give this a go and see if it gets you closer.
Hi I have tried below query to get the distinct record but I am not able to get the distinct record from below query.
var query = (from sr in db.StudentRequests
join r in db.Registrations on sr.RegistrationId equals r.RegistrationId
join cc in db.Campus on r.CampusId equals cc.CampusId
join c in db.Classes on sr.ClassId equals c.ClassId
from tc in db.TutorClasses.Where(t => t.ClassId == sr.ClassId).DefaultIfEmpty()
from srt in db.StudentRequestTimings.Where(s => s.StudentRequestId == sr.StudentRequestId).DefaultIfEmpty()
from tsr in db.TutorStudentRequests.Where(t => t.StudentRequestId == srt.StudentRequestId && t.TutorId == registrationid).DefaultIfEmpty()
where tc.RegistrationId == registrationid
select new
{
StudentRequestId = sr.StudentRequestId,
RegistrationId = sr.RegistrationId,
Location = sr.Location,
PaymentMethod = sr.PaymentMethod,
CreatedOn = sr.CreatedOn,
ClassName = c.ClassName,
CampusName = cc.CampusName,
StatusId = tsr.StatusId == null ? 1 : tsr.StatusId,
Time = db.StudentRequestTimings.Where(p => p.StudentRequestId == sr.StudentRequestId)
.Select(p => p.FromTime.ToString().Replace("AM", "").Replace("PM", "") + "-" + p.ToTime)
}).Distinct().ToList().ToPagedList(page ?? 1, 3);
But I am getting error as
The 'Distinct' operation cannot be applied to the collection
ResultType of the specified argument.\r\nParameter name: argument
So I had removed the .Distinct() from the above query and below that code I had written code as
query = query.Distinct().ToList();
But still the duplicate record was showing
So I had tried Group by clause to get distinct record but over there also I am facing the issue.Please Review below code
query = query.ToList().GroupBy(x => new { x.StudentRequestId, x.StatusId, x.Location, x.RegistrationId, x.PaymentMethod, x.CreatedOn, x.ClassName, x.CampusName})
.Select(group => new
{
StudentRequestId = group.Key.StudentRequestId,
StatusId = group.Key.StatusId,
Location = group.Key.Location,
RegistrationId = group.Key.RegistrationId,
PaymentMethod = group.Key.PaymentMethod,
CreatedOn = group.Key.CreatedOn,
ClassName = group.Key.ClassName,
CampusName = group.Key.CampusName,
Time1 = group.Key.Time
});
But I am getting error for time as
How can I get the distinct Value?
Also make in concern that I am using ToPagedList in the query
The actual issue is coming from Time column, If I remove that column all things are working fine.
I had added Group by clause at the end of the query as suggested by #Rajaji and that worked for me.
var query = (from sr in db.StudentRequests
join r in db.Registrations on sr.RegistrationId equals r.RegistrationId
join cc in db.Campus on r.CampusId equals cc.CampusId
join c in db.Classes on sr.ClassId equals c.ClassId
from tc in db.TutorClasses.Where(t => t.ClassId == sr.ClassId).DefaultIfEmpty()
from srt in db.StudentRequestTimings.Where(s => s.StudentRequestId == sr.StudentRequestId).DefaultIfEmpty()
from tsr in db.TutorStudentRequests.Where(t => t.StudentRequestId == srt.StudentRequestId && t.TutorId == registrationid).DefaultIfEmpty()
where tc.RegistrationId == registrationid
select new
{
StudentRequestId = sr.StudentRequestId,
RegistrationId = sr.RegistrationId,
Location = sr.Location,
PaymentMethod = sr.PaymentMethod,
CreatedOn = sr.CreatedOn,
ClassName = c.ClassName,
CampusName = cc.CampusName,
StatusId = tsr.StatusId == null ? 1 : tsr.StatusId,
Time = db.StudentRequestTimings.Where(p => p.StudentRequestId == sr.StudentRequestId).Select(p => p.FromTime.ToString().Replace("AM", "").Replace("PM", "") + "-" + p.ToTime)
}).ToList().GroupBy(p => new { p.StudentRequestId }).Select(g => g.First()).ToList();
I'm using WCF RIA in a Lightswitch project to create some query results. This query brings back all results regardless. I cannot make it filter the records based on the parameter passed (string Town).
public IQueryable<Enquiries> TestQuery(string Town)
{
List<Enquiries> riaenqs = new List<Enquiries>();
var enqs = this.Context.ClientEnquiries
.Include("Client")
.Include("Client.Town")
.OrderBy(enq => enq.Id);
if (Town != null)
{
enqs.Where(enq => enq.Client.Town.TownName == Town);
}
foreach (ClientEnquiry item in enqs.ToList())
{
Enquiries enq = new Enquiries();
enq.Id = item.Id;
enq.ClientName = item.Client.FirstName + " " + item.Client.Surname;
enq.Town = item.Client.Town != null ? item.Client.Town.TownName : null;
riaenqs.Add(enq);
}
return riaenqs.AsQueryable();
}
During debugging I can see that the Town is correctly populated and I can see that the query is built accordingly if Town is not null. However, when I hit the foreach statement where the linq to ef query is executed I always get all the results. I just cannot figure out where I'm slipping up.
The LINQ methods like the Where do not modify the collection/expression but always returning a new one.
So you need to reassign the result of the Where to your original variable enqs:
if (Town != null)
{
enqs = enqs.Where(enq => enq.Client.Town.TownName == Town);
}
Does anyone know how to return an ordered list of strings with null values last? I have something like this:
using(var context = new DomainEntities())
{
var result = context.Users.OrderBy(u => u.LastName).ThenBy(u => u.FirstName);
}
My problem though is that this query returns null values before non-null values.
Any thoughts?
I would do:
using(var context = new DomainEntities())
{
var result = context.Users.OrderBy(u => u.LastName == null)
.ThenBy(u => u.LastName)
.ThenBy(u => u.FirstName == null)
.ThenBy(u => u.FirstName);
}
...which should produce reasonable SQL.
EDIT: explanation (taken from Craig's comment):
Because false sorts before true.
I don't know if there's some switch somewhere that you can flip. Otherwise, the straight forward approach would probably be something along the lines of
using (var context = new DomainEntities())
{
var FirstPart = context.Users.Where(u => u.LastName != null);
var SecondPart = context.Users.Where(u => u.LastName == null);
var Result = FirstPart.Union(SecondPart);
}
var result = context.Users.OrderBy(x => x.FirstName ?? x.LastName);