I am trying to fill a viewmodel(List) from Datatable.
Customer and WorkingTime
WorkingTime is a child List of Customer. There are several entries for a Customer.
Using Adapter.Fill Meathod
DataTable dtCust=GetCustomersInTable(Uid);
DataTable dtWorking=GetAllCustWorkTimeInTable(Uid);
var Customers = (from C in dtCust.AsEnumerable()
select new CustomerViewModel
{
CustomerId = (long)C["CustomerId"],
Address1 = DBNull.Value == C["Name"] ? "" : Convert.ToString(C["Name"]),
Address2 = DBNull.Value == C["Address"] ? "" : Convert.ToString(C["Address"]),
City = DBNull.Value == C["City"] ? "" : Convert.ToString(C["City"]),
WorkingTime = GetCustWorkingTime(dtWorking, Convert.ToInt64(C["CustomerId"])),
}}).ToList();
private List<CustomerWorkingTime> GetCustWorkingTime(DataTable dtWorking, long CustomerId)
{
var CustomerWorkingTimes = (from C in dtWorking.AsEnumerable()
where Convert.ToInt64(C["CustomerId"]) == CustomerId
select new CustomerWorkingTime
{
AfterNoonFrom = Convert.ToDateTime(C["AfterNoonFrom"]),
AfterNoonUntil = Convert.ToDateTime(C["AfterNoonUntil"])
}).ToList();
return result;
}
I need to take whole data. It used not for displaying in UI.
This meathod is taking too much time to fill data. especially CustomerWorkingtime Filling.
Please suggest a better method to fill data.
Pagination is not possible here.
Existing setup is in EntityFramework and performance is poor.
Yu can try playing around with the TPL Parallel.ForEach, I think in your case this might give you a boost.
for example:
var Customers = Parallel.ForEach(dtCust.AsEnumerable(), c =>
select new CustomerViewModel
{
CustomerId = (long)C["CustomerId"],
Address1 = DBNull.Value == C["Name"] ? "" : Convert.ToString(C["Name"]),
Address2 = DBNull.Value == C["Address"] ? "" : Convert.ToString(C["Address"]),
City = DBNull.Value == C["City"] ? "" : Convert.ToString(C["City"]),
WorkingTime = GetCustWorkingTime(dtWorking, Convert.ToInt64(C["CustomerId"])),
}}).ToList();
Or in your "GetCustWorkingTime":
var result= dtWorking
.AsEnumerable()
.AsParallel()
.Where(c => Convert.ToInt64(C["CustomerId"]) == CustomerId)
.Select(c= > new CustomerWorkingTime
{
AfterNoonFrom = Convert.ToDateTime(C["AfterNoonFrom"]),
AfterNoonUntil = Convert.ToDateTime(C["AfterNoonUntil"])
}).ToList();
you should try them separately, and together, to see which one gives you the best performance (depends on the size of the tables).
Note: using both together might cause problems since in "GetCustWorkingTime" you'll end up iterating over the same table by multiple tasks in the same time.
Related
I have this service:
//seroiunoiweucroewr
///wercewrwerwerwer
//wcererewrwerwer
public List<UserRoleContract> GetRolePagesByUserId(long plngUserId, DisplayType displayType)
{
List<UserRoleContract> result = new List<UserRoleContract>();
using (CitiCallEntities context = new CitiCallEntities())
{
try
{
//var DisplayList = Utility.GetEnumDescriptions(typeof(DisplayType)).ToList();
//var selectValue = DisplayList.Where(i => i.Key == (byte) DisplayType.Windows).FirstOrDefault();
result = (from oUser in context.User
join oUserRole in context.UserRole on oUser.Id equals oUserRole.UserId
join oRoleRightsPage in context.RoleRightsPage.Where(i => i.IsActive == true)
on oUserRole.RoleId equals oRoleRightsPage.RoleId
join oApplicationPage in context.ApplicationPage.Where(i => i.IsActive == true)
on oRoleRightsPage.PageId equals oApplicationPage.Id
join oRole in context.Role on oUserRole.RoleId equals oRole.Id
join oEmployee in context.Employee on oUser.EmployeeId equals oEmployee.Id
join oSection in context.Section on oEmployee.SectionId equals oSection.Id
where oUser.IsActive == true && oUser.Id == plngUserId
&& oRole.IsActive == true && (((DisplayType)oRoleRightsPage.DisplayType).HasFlag(displayType))
//am getting error in has flag
// am having three display type web, windows and all
// how to overcome
select new UserRoleContract
{
UserId = oUser.Id,
RoleId = oRole.Id,
RoleName = oRole.RoleName,
PageID = oApplicationPage.Id,
PageName = oApplicationPage.PageName,
IsOPsCtrl = oRole.IsOPsCtrl,
ISOPsCtrlFor = oRole.OPsCtrlFor,
SectionId = oSection.Id,
DisplayType = oRoleRightsPage.DisplayType,
}).Distinct().ToList();
}
catch (Exception exception)
{
HandleExpcetion(exception);
//throw new CitiCallException(exception.Message);
}
}
return result;
}
I am getting Linq error in has flag conversion, how do I overcome this problem?
you are geeting error because HasFlag method is not paresent in database i.e. it might be part of language or local function in code which is not present in database.
So when query is translated it found this method is not available and that is the reason you are getting error.
one solution to avoid this error is
Brind all data from databae
Than filter than data, i.e. apply HasFlag method of it.
But this will bring all data and might decrease performance.
Example is
remove this line (((DisplayType)oRoleRightsPage.DisplayType).HasFlag(displayType) from your query
var list = querieddata //first fetch data without hasflag condition/method
.AsEnumerable() // Rest of the query in-process
.Where(oRoleRightsPage=> ((DisplayType)oRoleRightsPage.DisplayType).HasFlag(displayType))//apply condition here once fetching done
.ToList();
The HasFlag method has no equivalent in Linq to Entities which is why you get that error. You can get around it by using bitwise comparison instead of using HasFlag, for example this:
((DisplayType)oRoleRightsPage.DisplayType).HasFlag(displayType)
Becomes:
(oRoleRightsPage.DisplayType & displayType) > 0
I was doing project in MVC3 with Entity framework. I have a LINQ query with foreach. Everything is fine. But when the data size goes up, i was facing performance issues. I dont have much experience with LINQ. So I couldn't fix my issue. Pls have a look at my code and provide a better suggestion for me.
Code
List<int> RouteIds = db.Cap.Where(asd => asd.Type == 3).Select(asd => asd.UserId).ToList();
var UsersWithRoutingId = (from route in db.RoutingListMembers
where RouteIds.Contains(route.RoutingListId.Value) && route.User.UserDeptId == Id
select
new RoutingWithUser
{
UserId = route.UserId,
RoutingId = route.RoutingListId
});
var ListRouteValue = (from cap in db.CareAllocationPercents
where cap.Type == 3
select new UserWithDeptId
{
Year = (from amt in db.CareAllocations where amt.CareItemId == cap.CareItemId select amt.Year).FirstOrDefault(),
UserId = cap.UserId,
UserDeptId = (from userdept in db.Users where userdept.Id == cap.UserId select userdept.UserDeptId).FirstOrDefault(),
});
List<UserWithDeptId> NewRouteList = new List<UserWithDeptId>();
ListRouteValue = ListRouteValue.Where(asd => asd.Year == Year);
foreach (var listdept in ListRouteValue)
{
foreach (var users in UsersWithRoutingId)
{
if (users.RoutingId == listdept.UserId)
{
UserWithDeptId UserwithRouteObj = new UserWithDeptId();
UserwithRouteObj.UserId = users.UserId;
UserwithRouteObj.Year = listdept.Year;
UserwithRouteObj.UserDeptId = db.Users.Where(asd => asd.Id == users.UserId).Select(asd => asd.UserDeptId).FirstOrDefault();
NewRouteList.Add(UserwithRouteObj);
}
}
}
NewRouteList = NewRouteList.Where(asd => asd.UserDeptId == Id).ToList();
Thanks,
You have to use join in first statement. Examples of how to do this are for example here: Joins in LINQ to SQL
I have some idea for you:
First:
Take care to complete your where close into your linq query to get just what you need to.
With Linq on collection, you can remove one foreach loop. I don't know the finality but, i've tryied to write something for you:
var UsersWithRoutingId = (from route in db.RoutingListMembers
where RouteIds.Contains(route.RoutingListId.Value) && route.User.UserDeptId == Id
select
new RoutingWithUser
{
UserId = route.UserId,
RoutingId = route.RoutingListId
});
var ListRouteValue = (from cap in db.CareAllocationPercents
where cap.Type == 3
select new UserWithDeptId
{
Year = (from amt in db.CareAllocations
where amt.CareItemId == cap.CareItemId && amt.Year == Year
select amt.Year).FirstOrDefault(),
UserId = cap.UserId,
UserDeptId = (from userdept in db.Users
where userdept.Id == cap.UserId && userdept.UserDeptId == Id
select userdept.UserDeptId).FirstOrDefault(),
});
List<UserWithDeptId> NewRouteList = new List<UserWithDeptId>();
foreach (var listdept in ListRouteValue)
{
var user = UsersWithRoutingId.Where(uwri => uwri.RoutingId == listdept.UserId).FirstOrDefault();
if (user != null)
{
NewRouteList.Add(new UserWithDeptId { UserId=user.UserId, Year=listdept.Year, UserDeptId=listdept.UserDeptId });
}
}
return NewRouteList
Is that right for you ?
(i don't poll the db.user table do get the UserDeptId for the NewRouteList assuming that the one in the listdept is the good one)
Second:
Take care of entity data loading, if you have tables with foreign key, take care to remove the lazy loading if you don't need the children of your table to be loaded at same time. Imagine the gain for multiple table with foreign key pointing to others.
Edit:
Here is a link that explain it:
http://msdn.microsoft.com/en-us/library/vstudio/dd456846%28v=vs.100%29.aspx
I've looked at the various solutions here but none of them seem to work for me, probably because I'm too new to all this and am groping in the dark a bit. In the code below, the object "appointment" contains some basic LDAP information. From a list of such objects I want to be able to get a single record, based on employee id. I hope the code here is sufficient to illustrate. FTR, I've tried various formulations, including trying to use from and a select. All fail with the error given in the Title above.
IQueryable<appointment> query = null;
foreach(var record in results)
{
BoiseStateLdapDataObject record1 = record;
query = db.appointments.Where(x => x.student_id == record1.Values["employeeid"]);
}
if (query != null)
{
var selectedRecord = query.SingleOrDefault();
}
Try to move employee id getting out of query:
IQueryable<appointment> query = null;
foreach(var record in results)
{
var employeeId = record.Values["employeeid"];
query = db.appointments.Where(x => x.student_id == employeeId);
}
if (query != null)
{
var selectedRecord = query.SingleOrDefault();
}
Following Linq to Entities query is causing the "Unable to create a constant value of type 'Data.InhouseUnit'. Only primitive types ('such as Int32, String, and Guid') are supported in this context" exception.
IList<FaultReport> faultReports = (from fr in _session.FaultReports
where fr.CreatedOn > dateTime
select new FaultReport
{
Id = fr.Id,
ExecutionDate = fr.ExecutionDate ?? DateTime.MinValue,
FaultType = fr.FaultType,
Quarters = fr.Quarters,
InhouseSpaceId = fr.InhouseSpaceId,
InhouseSpace = new InhouseSpace { Id = fr.InhouseSpace.Id, Name = fr.InhouseSpace.Name },
InhouseUnitId = fr.InhouseUnitId ?? Guid.Empty,
**InhouseUnit = fr.InhouseUnitId == Guid.Empty ? null : new InhouseUnit { Id = fr.InhouseUnit.Id, Name = fr.InhouseUnit.Name }**
}).ToList();
Specifically, it is the if expression in bold font which causes the exception. I need to make the check as fr.InhouseUnitId is a nullable. If I take out the the bolded expression, the rest of the statement works just fine. I have spent a fair amount of time, in msdn forum and on web, to understand what is causing the exception but still cannot quite understand. Guid is scalar so it should work, right? Even this expression InhouseUnit = true ? null: new InhouseUnit() in place of the bolded expression in the above statement wouldn't work. Can we even write if/else
If i try to write an extension method to take away the logic and just return a result, following exception is thrown:
LINQ to Entities does not recognize the method 'System.Object
GuidConversion(System.Nullable`1[System.Guid], System.Object)' method, and this method
cannot be translated into a store expression
It looks like you are projecting into new objects of the same type that you are querying from. Is that the case? It seems a little weird, but assuming you have a good reason for doing this, you could split the query into two parts. The first part would get what you need from the database. The second part would run locally (i.e. LINQ-to-Objects) to give you the projection you need. Something like this:
var query =
from fr in _session.FaultReports
where fr.CreatedOn > dateTime
select new {
fr.Id,
fr.ExecutionDate,
fr.FaultType,
fr.Quarters,
InhouseSpaceId = fr.InhouseSpace.Id,
InhouseSpaceName = fr.InhouseSpace.Name,
InhouseUnitId = fr.InhouseUnit.Id,
InhouseUnitName = fr.InhouseUnit.Name,
};
IList<FaultReport> faultReports = (
from fr in query.ToList()
select new FaultReport {
Id = fr.Id,
ExecutionDate = fr.ExecutionDate ?? DateTime.MinValue,
FaultType = fr.FaultType,
Quarters = fr.Quarters,
InhouseSpaceId = fr.InhouseSpaceId,
InhouseSpace = new InhouseSpace { Id = fr.InhouseSpaceId, Name = fr.InhouseSpaceName },
InhouseUnitId = fr.InhouseUnitId ?? Guid.Empty,
InhouseUnit = fr.InhouseUnitId == Guid.Empty ? null : new InhouseUnit { Id = fr.InhouseUnitId, Name = fr.InhouseUnitName }
}).ToList();
I am having some trouble with a linq query I am trying to write.
I am trying to use the repository pattern without to much luck. Basically I have a list of transactions and a 2nd list which contains the description field that maps against a field in my case StoreItemID
public static IList<TransactionViewModel> All()
{
var result = (IList<TransactionViewModel>)HttpContext.Current.Session["Transactions"];
if (result == null)
{
var rewardTypes = BusinessItemRepository.GetItemTypes(StoreID);
HttpContext.Current.Session["Transactions"] =
result =
(from item in new MyEntities().TransactionEntries
select new TransactionViewModel()
{
ItemDescription = itemTypes.FirstOrDefault(r=>r.StoreItemID==item.StoreItemID).ItemDescription,
TransactionDate = item.PurchaseDate.Value,
TransactionAmount = item.TransactionAmount.Value,
}).ToList();
}
return result;
}
public static List<BusinessItemViewModel>GetItemTypes(int storeID)
{
var result = (List<BusinessItemViewModel>)HttpContext.Current.Session["ItemTypes"];
if (result == null)
{
HttpContext.Current.Session["ItemTypes"] = result =
(from items in new MyEntities().StoreItems
where items.IsDeleted == false && items.StoreID == storeID
select new BusinessItemViewModel()
{
ItemDescription = items.Description,
StoreID = items.StoreID,
StoreItemID = items.StoreItemID
}).ToList();
}
return result;
However I get this error
Unable to create a constant value of type 'MyMVC.ViewModels.BusinessItemViewModel'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.
I know its this line of code as if I comment it out it works ok
ItemDescription = itemTypes.FirstOrDefault(r=>r.StoreItemID==item.StoreItemID).ItemDescription,
How can I map ItemDescription against my list of itemTypes?
Any help would be great :)
This line has a problem:
ItemDescription = itemTypes.FirstOrDefault(r=>r.StoreItemID==item.StoreItemID)
.ItemDescription,
Since you are using FirstOrDefault you will get null as default value for a reference type if there is no item that satifies the condition, then you'd get an exception when trying to access ItemDescription - either use First() if there always will be at least one match or check and define a default property value for ItemDescription to use if there is none:
ItemDescription = itemTypes.Any(r=>r.StoreItemID==item.StoreItemID)
? itemTypes.First(r=>r.StoreItemID==item.StoreItemID)
.ItemDescription
: "My Default",
If itemTypes is IEnumerable then it can't be used in your query (which is what the error message is telling you), because the query provider doesn't know what to do with it. So assuming the that itemTypes is based on a table in the same db as TransactionEntities, then you can use a join to achieve the same goal:
using (var entities = new MyEntities())
{
HttpContext.Current.Session["Transactions"] = result =
(from item in new entities.TransactionEntries
join itemType in entities.ItemTypes on item.StoreItemID equals itemType.StoreItemID
select new TransactionViewModel()
{
ItemDescription = itemType.ItemDescription,
TransactionDate = item.PurchaseDate.Value,
TransactionAmount = item.TransactionAmount.Value,
CustomerName = rewards.CardID//TODO: Get customer name
}).ToList();
}
I don't know the structure of your database, but hopefully you get the idea.
I had this error due a nullable integer in my LINQ query.
Adding a check within my query it solved my problem.
query with problem:
var x = entities.MyObjects.FirstOrDefault(s => s.Obj_Id.Equals(y.OBJ_ID));
query with problem solved:
var x = entities.MyObjects.FirstOrDefault(s => s.Obj_Id.HasValue && s.Obj_Id.Value.Equals(y.OBJ_ID));