we have the datasource as :
rgSubjects.DataSource = entity.Student_Subject_MM.Include("Subjects").
Where(p => p.StudentID == _currentStudent.StudentID
&& (p.Subject.SchoolYear == schoolyear || schoolyear == "0")
&& (p.Subject.Semester.Value == sem || sem == 0)
&& (p.Subject.SubjectCode.Contains(searchSubject) || p.Subject.Description.Contains(searchSubject) || p.Subject.Title.Contains(searchSubject))
).Select(p => new {
SubjectCode = p.Subject.SubjectCode.Trim(),
Description = p.Subject.Description.Trim(),
Schedule = p.Subject.Schedule.Trim(),
Room = p.Subject.Room.Trim(),
Instructor = p.Subject.Instructor.LastName + ", " + p.Subject.Instructor.FirstName,
Grade = p.Grade,
Remarks = p.Remarks
});
rgSubjects.DataBind();
How can we change the sizes per column using code-behind in c#.net? thanks a lot.
Does setting the Width property of your columns makes sense? Check out this article about how to operate with auto-generated and declarative columns
Related
I want to return a customer which is in this city and buy ItemID = 1, 2 or NULL
List<int?> AcceptableValues = new List<int?>
{
1,2
};
List<Customer> Customers = ListOfCustomer.Where(x => x.CountryTbl.City == 1
&& x.ItemTbl.Any(p => p.ItemID == 1 || p.ItemID ==2 || p.Item is null)
&& x.SellTbl.SellType == 10).ToList();
Is there any way we can use LINQ to filter the customer who only buys itemID in the AcceptableValues ?
I've tried with ItemTbl.SingleOrDefault, or ItemTbl.Where, or AppeptableValues.Contains(m => m.ItemID) but didn't work.
List<Customer> Customers = ListOfCustomer
.Where(c => c.CountryTbl.City == 1
&& c.ItemTbl.Any(i => i.ItemID == null || AcceptableValues.Contains(i.ItemID))
&& c.SellTbl.SellType == 10).ToList();
I'm not sure if I'm barking up the wrong tree but I wanted to create a function to check if an account exists based on all optional parameters so it can be used to pull data depending on whatever you'd like to check on.
Basically the query should be:
where loginName = p1 or loginName = p2 or loginName = p3 but with the paramters all being optional, however at least one will be provided.
This is what I tried so far:
public async Task<bool> CheckAccountExistsAsync(string loginName = "", string authenticatorId = "", string eId = "")
{
if (string.IsNullOrWhiteSpace(loginName) && string.IsNullOrWhiteSpace(authenticatorId) && string.IsNullOrWhiteSpace(eId))
throw new InvalidOperationException("You must pass at least one parameter");
return await _context.Accounts.AnyAsync(a =>
(string.IsNullOrWhiteSpace(loginName) || a.LoginName == loginName)
|| (string.IsNullOrWhiteSpace(authenticatorId) || a.AuthenticatorId == authenticatorId)
|| (string.IsNullOrWhiteSpace(eId) || a.EmployeeId == eId));
}
Problem with this approach is that if I just pass the loginName, then the query is as follows with the condition completely omitted.:
SELECT CASE
WHEN EXISTS (
SELECT 1
FROM [Accounts] AS [a]) THEN CAST(1 AS bit)
ELSE CAST(0 AS bit)
END
I'm sure I'm missing something, is there a better approach?
What you are using is applicable for optional and expressions, e.g.
return await _context.Accounts.AnyAsync(a =>
(string.IsNullOrWhiteSpace(loginName) || a.LoginName == loginName)
&& (string.IsNullOrWhiteSpace(authenticatorId) || a.AuthenticatorId == authenticatorId)
&& (string.IsNullOrWhiteSpace(eId) || a.EmployeeId == eId));
For optional or you have to use optional and sub conditions and add additional check for all optional parameters missing, e.g.
return await _context.Accounts.AnyAsync(a =>
(string.IsNullOrWhiteSpace(loginName)
&& string.IsNullOrWhiteSpace(authenticatorId)
&& string.IsNullOrWhiteSpace(eId))
|| (!string.IsNullOrWhiteSpace(loginName) && a.LoginName == loginName)
|| (!string.IsNullOrWhiteSpace(authenticatorId) && a.AuthenticatorId == authenticatorId)
|| (!string.IsNullOrWhiteSpace(eId) && a.EmployeeId == eId));
I have a datatable and want to select some records with LinQ in this format:
var result2 = from row in dt.AsEnumerable()
where row.Field<string>("Media").Equals(MediaTp, StringComparison.CurrentCultureIgnoreCase)
&& (String.Compare(row.Field<string>("StrDate"), dtStart.Year.ToString() +
(dtStart.Month < 10 ? '0' + dtStart.Month.ToString() : dtStart.Month.ToString()) +
(dtStart.Day < 10 ? '0' + dtStart.Day.ToString() : dtStart.Day.ToString())) >= 0
&& String.Compare(row.Field<string>("StrDate"), dtEnd.Year.ToString() +
(dtEnd.Month < 10 ? '0' + dtEnd.Month.ToString() : dtEnd.Month.ToString()) +
(dtEnd.Day < 10 ? '0' + dtEnd.Day.ToString() : dtEnd.Day.ToString())) <= 0)
group row by new { Year = row.Field<int>("Year"), Month = row.Field<int>("Month"), Day = row.Field<int>("Day") } into grp
orderby grp.Key.Year, grp.Key.Month, grp.Key.Day
select new
{
CurrentDate = grp.Key.Year + "/" + grp.Key.Month + "/" + grp.Key.Day,
DayOffset = (new DateTime(grp.Key.Year, grp.Key.Month, grp.Key.Day)).Subtract(dtStart).Days,
Count = grp.Sum(r => r.Field<int>("Count"))
};
and in this code, I try to iterate it with the following code:
foreach (var row in result2)
{
//... row.DayOffset.ToString() + ....
}
this issue occurred :
Object reference not set to an instance of an object.
I think it happens when there's no record with above criteria.
I tried to change it to enumerator like this , and use MoveNext() to check the data is on that or not:
result2.GetEnumerator();
if (enumerator2.MoveNext()) {//--}
but still the same error.
whats the problem?
I guess in one or more rows Media is null.
You then call Equals on null, which results in a NullReferenceException.
You could add a null check:
var result2 = from row in dt.AsEnumerable()
where row.Field<string>("Media") != null
&& row.Field<string>("Media").Equals(MediaTp, StringComparison.CurrentCultureIgnoreCase)
...
or use a surrogate value like:
var result2 = from row in dt.AsEnumerable()
let media = row.Field<string>("Media") ?? String.Empty
where media.Equals(MediaTp, StringComparison.CurrentCultureIgnoreCase)
...
(note that the last approach is slightly different)
I'm busy rewriting a system and are using Linq queries to extract data from the database. I am used to plain old TSQL and stored procedures so my Linq skills are not the best.
I have a sql query that I try to rewrite in Linq that contains a join, where clause and IN statements. I do get it right but when I run the sql query I get a different value as from the Linq query. Somewhere I'm missing something and can't find the reason.
Here is the SQL:
select
isnull(Sum(QtyCC) + Sum(QtyEmployee), 0) *
isnull(Sum(UnitPrice), 0)[TotalRValue]
from
tbl_app_KGCWIssueLines a
inner join tbl_app_KGCWIssue b on b.IssueNrLnk = a.IssueNrLnk
where
b.CreationDate >= '2011-02-01' and
a.IssueNrLnk IN (
select
IssueNrLnk
from
tbl_app_KGCWIssue
where
CustomerCode = 'PRO002' and
ISNULL(Tier1,'') = 'PRO002' and
ISNULL(Tier2,'') = 'HAMD01' and
ISNULL(Tier3,'') = '02' and
ISNULL(Tier4,'') = '02001' and
ISNULL(Tier5,'') = 'PTAHQ001' and
ISNULL(Tier6,'') = '035' and
ISNULL(Tier7,'') = '' and
ISNULL(Tier8,'') = '' and
ISNULL(Tier9,'') = '' and
ISNULL(Tier10,'') = ''
)
And here is the Linq:
ctx.ObjectContext.tbl_app_KGCWIssue
.Join(ctx.ObjectContext.tbl_app_KGCWIssueLines,
i => i.IssueNrLnk, l => l.IssueNrLnk, (i, l) => new { i, l })
.Where(o => o.i.CreationDate >= IntervalStartDate)
.Where(p => ctx.ObjectContext.tbl_app_KGCWIssue
.Where(a =>
a.CustomerCode == CustomerCode &&
a.Tier1 == employee.Tier1 &&
a.Tier2 == employee.Tier2 &&
a.Tier3 == employee.Tier3 &&
a.Tier4 == employee.Tier4 &&
a.Tier5 == employee.Tier5 &&
a.Tier6 == employee.Tier6 &&
a.Tier7 == employee.Tier7 &&
a.Tier8 == employee.Tier8 &&
a.Tier9 == employee.Tier9 &&
a.Tier10 == employee.Tier10)
.Select(i => i.IssueNrLnk)
.Contains(p.l.IssueNrLnk))
.Sum(p => p.l.UnitPrice * (p.l.QtyEmployee + p.l.QtyCC));
In my code below, is there any way I can use the results in the object 'WasteRecordsExcluded' to join with searchResults, essentially excluding the WasteId's I don't want.
If I debug to the last line I get the error :
base {System.SystemException} = {"The query contains references to items defined on a different data context."}
Or if joining is impossible then i could change bHazardous from TRUE to FALSE and FALSE to TRUE and do some kind of 'NOT IN' comparison.
Going bananas with this one, anyone help? Kind Regards :
var allWaste = _securityRepository.FindAllWaste(userId, SystemType.W);
var allWasteIndicatorItems = _securityRepository.FindAllWasteIndicatorItems();
// First get all WASTE RECORDS
var searchResults = (from s in allWaste
join x in allWasteIndicatorItems on s.WasteId equals x.WasteId
where (s.Description.Contains(searchText)
&& s.Site.SiteDescription.EndsWith(searchTextSite)
&& (s.CollectedDate >= startDate && s.CollectedDate <= endDate))
&& x.EWC.EndsWith(searchTextEWC)
select s).Distinct();
var results = searchResults;
if (hazardous != "-1")
{
// User has requested to filter on Hazardous or Non Hazardous only rather than Show All
var WasteRecordsExcluded = (from we in _db.WasteIndicatorItems
.Join(_db.WasteIndicators, wii => wii.WasteIndicatorId, wi => wi.WasteIndicatorId, (wii, wi) => new { wasteid = wii.WasteId, wasteindicatorid = wii.WasteIndicatorId, hazardtypeid = wi.HazardTypeId })
.Join(_db.HazardTypes, w => w.hazardtypeid, h => h.HazardTypeId, (w, h) => new { wasteid = w.wasteid, hazardous = h.Hazardous })
.GroupBy(g => new { g.wasteid, g.hazardous })
.Where(g => g.Key.hazardous == bHazardous && g.Count() >= 1)
select we);
// Now join the 2 object to eliminate all the keys that do not apply
results = results.Where(n => WasteRecordsExcluded.All(t2 => n.WasteId == t2.Key.wasteid));
}
return results;
Maybe something like this:
.....
var results = searchResults.ToList();
.....
.....
.Where(g => g.Key.hazardous == bHazardous && g.Count() >= 1)
select we).ToList();
.....