In my Code, i've got three (or more...) different objects, that all have the same properties (e.g. TrackingItemType, ReaderID etc).
They are derived from CounterBase (which does not have the Properties needed, but others).
Now i want to iterate through a Collection of those objects. In the Collection, all of the three objects can occur. Therefore, currently i've implemented the "update" for each object seperately.
Question: How can I avoid that duplicate Code written? Is there any
pattern available to update the different objects with same
properties?!
THANKS!
Method of interest:
private void UpdateTrackingCounters(Reading readingData, TrackingItemType trackingItemType, string trackingCounterType)
{
try
{
foreach (CounterBase counter in this.TrackingCounters)
{
if (typeof(TrackingSimpleCounter).IsInstanceOfType(counter))
{
TrackingSimpleCounter trackingCounter = (TrackingSimpleCounter)counter;
if (trackingCounter.TrackingCounterType == trackingCounterType)
{
if ((trackingCounter.ReaderID == 0
&& trackingCounter.TrackingItemType == null)
|| (trackingCounter.ReaderID == 0
&& trackingCounter.TrackingItemType == trackingCounter.TrackingItemType)
|| (trackingCounter.ReaderID == readingData.ReaderId
&& trackingCounter.TrackingItemType == null)
|| (trackingCounter.ReaderID == readingData.ReaderId
&& trackingCounter.TrackingItemType == trackingCounter.TrackingItemType)
)
{
trackingCounter.IncreaseOne();
}
}
}
else if (typeof(TrackingIntervalBasedRollingCounter).IsInstanceOfType(counter))
{
TrackingIntervalBasedRollingCounter trackingCounter = (TrackingIntervalBasedRollingCounter)counter;
if (trackingCounter.TrackingCounterType == trackingCounterType)
{
if ((trackingCounter.ReaderID == 0
&& trackingCounter.TrackingItemType == null)
|| (trackingCounter.ReaderID == 0
&& trackingCounter.TrackingItemType == trackingCounter.TrackingItemType)
|| (trackingCounter.ReaderID == readingData.ReaderId
&& trackingCounter.TrackingItemType == null)
|| (trackingCounter.ReaderID == readingData.ReaderId
&& trackingCounter.TrackingItemType == trackingCounter.TrackingItemType)
)
{
trackingCounter.IncreaseOne();
}
}
}
else if (typeof(TrackingTriggerBasedRollingCounter).IsInstanceOfType(counter))
{
TrackingTriggerBasedRollingCounter trackingCounter = (TrackingTriggerBasedRollingCounter)counter;
if (trackingCounter.TrackingCounterType == trackingCounterType)
{
if ((trackingCounter.ReaderID == 0
&& trackingCounter.TrackingItemType == null)
|| (trackingCounter.ReaderID == 0
&& trackingCounter.TrackingItemType == trackingCounter.TrackingItemType)
|| (trackingCounter.ReaderID == readingData.ReaderId
&& trackingCounter.TrackingItemType == null)
|| (trackingCounter.ReaderID == readingData.ReaderId
&& trackingCounter.TrackingItemType == trackingCounter.TrackingItemType)
)
{
trackingCounter.IncreaseOne();
}
}
}
}
}
catch (Exception ex)
{
this.Trace.Error(ex);
}
}
Define an interface that contains the properties and method you need:
interface ITrackable
{
int ReaderID;
string TrackingItemType;
void IncreaseOne();
}
And add it to the declaration of each class that has them:
class TrackingSimpleCounter : CounterBase, ITrackable
class TrackingIntervalBasedRollingCounter: CounterBase, ITrackable
class TrackingTriggerBasedRollingCounter : CounterBase, ITrackable
If all the classes truly share those properties, you won't have to implement any of the interface, since it'll already be present.
Then all you need is
foreach (ITrackable counter in this.TrackingCounters)
{
if ((counter.ReaderID == 0 && counter.TrackingItemType == null)
|| (counter.ReaderID == 0 && counter.TrackingItemType == counter.TrackingItemType)
|| (counter.ReaderID == readingData.ReaderId && counter.TrackingItemType == null)
|| (counter.ReaderID == readingData.ReaderId && counter.TrackingItemType == counter.TrackingItemType)
)
{
counter.IncreaseOne();
}
}
Although unless I misunderstand your logic all you truly need is:
foreach (ITrackable counter in this.TrackingCounters)
{
if (counter.ReaderID == 0 || counter.ReaderID == readingData.ReaderID)
{
counter.IncreaseOne();
}
}
Or if you want to use LINQ:
foreach (var counter in this.TrackingCounters.OfType<ITrackable>().Where(c => c.ReaderID == 0 || c.ReaderID = readingData.ReaderID))
{
counter.IncreaseOne();
}
Factorize
You can extract the common properties into one new common Object, and make both of your class have a reference property to that object.
This way, when you update this object, both of your original objects will have the most up-to-date values, without risk to forgot to update one of the properties.
Related
public JsonResult SearchApplicantList(string SSession, string ApStatus, string StudyLevel, string SLPrograms)
{
ab db = new ab();
var SearchList = db.Students
.Where(x => x.SemesterSessioin == SSession
&& x.OverAllStatus == ApStatus
&& x.StudyLvl == StudyLevel
&& x.ProgPref1 == SLPrograms
&& x.ProgPref2 == SLPrograms
&& x.ProgPref3 == SLPrograms
&& x.progPref4 == SLPrograms).ToList();
return Json(SearchList, JsonRequestBehavior.AllowGet);
}
I want to get a list on the basis of parameters, but few cases the many parameters can be null, null means all.
How can I do this?
Programming. Step by step.
Let me explain:
There is no need to have only one line for the query.
var searchQuery = db.Students (possibly with .Where that is constant).
if (ApStatus != null) {
searchQuery = searchQuery.Where(x => x.OverAllStatus = ApStatus
}
Btw., plenty of spelling. It is App (not Ap) and Overall not OverAll - it is ONE word as per dictionary.
Anyhow, you can repeat adding where conditions as often as you want, then at the end materialize.
All where conditions are ANDed together.
This is one thing most people overlook - LINQ allows a TON of programming and manipulation of the query tree.
public JsonResult SearchApplicantList(string SSession, string ApStatus, string StudyLevel, string SLPrograms)
{
ab db = new ab();
var SearchList = db.Students;
SearchList = SearchList.Where(x => (x.SemesterSessioin == SSession || SSession ==null || SSession =="")
&& (x.OverAllStatus == ApStatus || ApStatus ==null || ApStatus =="")
&& (x.StudyLvl == StudyLevel || StudyLevel ==null || StudyLevel =="")
&& (x.ProgPref1 == SLPrograms || SLPrograms ==null || SLPrograms =="")
&& (x.ProgPref2 == SLPrograms || SLPrograms ==null || SLPrograms =="")
&& (x.ProgPref3 == SLPrograms || SLPrograms ==null || SLPrograms =="")
&& (x.progPref4 == SLPrograms|| SLPrograms == null|| SLPrograms == "").ToList();
return Json(SearchList, JsonRequestBehavior.AllowGet);
}
Apply filter by parameter/s which can not be null, for instance SSession and StudyLevel are those parameters which can not be null. So apply filter by them first
var SearchList = db.Students.Where(x => x.SemesterSessioin == SSession && x.StudyLvl == StudyLevel).ToList();
Then check rest of parameters one by one, for SLPrograms will be like:
if(!string.IsNullOrEmpty(SLPrograms))
{
SearchList = SearchList.Where(Apply Filter By SLPrograms).ToList();
}
And then for rest of Parameters. Remember, use if and if to check each parameters. Like
if(Param1)
{
//Code
}
if(Param2)
{
//Code
}
I have created two views that return exactly the same columns from the same tables. The only difference between the two views is they filter on different parameters. I have added these into my .dbml file
(Picture of views in dbml) This has then auto generated two classes for these two views.
In my code depending on the value of the property Filter one of the two views is queried, either current or previous. I need these views to be returned as the same type. So that IOrderedQueryable<> items has one return type.
Currently they are returning as either clientOrdersQueryCurrent or clientOrdersQueryPrevious. If I set IOrderedQueryable<> items to either one of these and attempt to cast the other type then this causes a runtime error.
IOrderedQueryable<> items;
bool filterQuery = false;
if (!string.IsNullOrEmpty(OrderNumber) || DateFrom != null || Dateto != null || !string.IsNullOrEmpty(TrackingNumber) || UserId != null)
{
filterQuery = true;
}
if (Filter == "Current")
{
if (filterQuery)
{
items = dataContext.clientOrdersQueryCurrents.Where(o => o.client_id == currentClientIdProvider.GetCurrentClientId()
&& (string.IsNullOrEmpty(OrderNumber) || o.OrderNumber.Contains(OrderNumber))
&& (DateFrom == null || o.OrderPlaced >= DateFrom)
&& (Dateto == null || o.OrderPlaced <= Dateto)
&& (string.IsNullOrEmpty(TrackingNumber) || o.TrackingReference.Contains(TrackingNumber))
&& (UserId == null || o.UserId == UserId)).OrderByDescending(o => o.OrderPlaced);
}
else
{
items = dataContext.clientOrdersQueryCurrents.Where(o => o.client_id == currentClientIdProvider.GetCurrentClientId()).OrderByDescending(o => o.OrderPlaced);
}
}
else if (Filter == "Previous")
{
if (filterQuery)
{
items = dataContext.clientOrdersQueryPrevious.Where(o => o.client_id == currentClientIdProvider.GetCurrentClientId()
&& (string.IsNullOrEmpty(OrderNumber) || o.OrderNumber.Contains(OrderNumber))
&& (DateFrom == null || o.OrderPlaced >= DateFrom)
&& (Dateto == null || o.OrderPlaced <= Dateto)
&& (string.IsNullOrEmpty(TrackingNumber) || o.TrackingReference.Contains(TrackingNumber))
&& (UserId == null || o.UserId == UserId)).OrderByDescending(o => o.OrderPlaced);
}
else
{
items = dataContext.clientOrdersQueryPrevious.Where(o => o.client_id == currentClientIdProvider.GetCurrentClientId()).OrderByDescending(o => o.OrderPlaced);
}
}
else
{
//Default call - current orders
items = dataContext.clientOrdersQueryCurrents.Where(o => o.client_id == currentClientIdProvider.GetCurrentClientId()).OrderByDescending(o => o.OrderPlaced);
}
The only thing I can currently think of to resolve this is to create a class and have the query map the result to the class after it returns.
What is the best way to do this?
The ORM I am currently using is NHibernate.
Better to map to some common class
IOrderedQueryable<CommonItem> items;
items = dataContext.clientOrdersQueryCurrents.Select(e => new CommonItem{...});
...
items = dataContext.clientOrdersQueryPrevious.Select(e => new CommonItem{...});
It can be AutoMapper's ProjectTo method
items = dataContext.clientOrdersQueryPrevious.ProjectTo<CommonItem>();
hi guys i was using Dynamic SQL for search queries where i used to attach WHERE & AND clause piece by piece and form a statement, i recently came to below alternate for this, and life was amazing
cool alternates of Dynamic WHERE-Clause
Select * From tblEmployees
where EmployeeName = Coalesce(#EmployeeName, EmployeeName) AND
Department = Coalesce(#Department, Department ) AND
Designation = Coalesce(#Designation, Designation) AND
JoiningDate >= Coalesce(#StartDate, JoiningDate) AND
JoiningDate <= Coalesce(#EndDate, JoiningDate) AND
Salary >= Coalesce(#Salary, Salary)
now the issue is since i implemented entity framework i need to achieve same with Linq queries. i have nullable Byte type and nullable boolean which i am currently unable to handle
just like Coalesce my stupid attempt was
&& (s.Floors == deal.Floors.HasValue ? null : s.Floors)
below code not matching any results
[HttpPost]
public ActionResult Results(Deal deal, bool exactMatch)
{
List<Deal> deals;
if (exactMatch)
{
deals = dataBase.Deals.Where(s =>
(s.OwnerName.Contains(deal.OwnerName) || s.OwnerName == null)
&& (s.Rooms == deal.Rooms || s.Rooms == null)
&& (s.BathRooms == deal.BathRooms || s.BathRooms == null)
&& (s.Floors == deal.Floors || s.Floors == null)
&& (s.Builtin == deal.Builtin || s.Builtin == null)
&& (s.Kitchens == deal.Kitchens || s.Kitchens == null)
&& (s.DoubleUnit == deal.DoubleUnit || s.DoubleUnit == null)
&& (s.Corner == deal.Corner || s.Corner == null)
&& (s.Remarks.Contains(deal.Remarks) || s.Remarks == null)
).ToList();
}
else
{
deals = dataBase.Deals.Where(s =>
(s.OwnerName.Contains(deal.OwnerName) || s.OwnerName == null)
|| (s.Rooms == deal.Rooms || s.Rooms == null)
|| (s.BathRooms == deal.BathRooms || s.BathRooms == null)
|| (s.Floors == deal.Floors || s.Floors == null)
|| (s.Builtin == deal.Builtin || s.Builtin == null)
|| (s.Kitchens == deal.Kitchens || s.Kitchens == null)
|| (s.DoubleUnit == deal.DoubleUnit || s.DoubleUnit == null)
|| (s.Corner == deal.Corner || s.Corner == null)
|| (s.Remarks.Contains(deal.Remarks) || s.Remarks == null)
).ToList();
}
return View(deals);
}
table has values like
id Bathroom Floors
1 1 2
2 1 4
3 2 6
4 3 1
i need results which has id 1 & 2
for instance in front end user want to only fill bathroom field with "1" and leave floor field empty
Not really the same. In your query your coalesce is on the parameter then taking the record value as the default if it is null. In your c# lambda you are checking if the parameter is the same as the table value and then checking if the table value is null but that omits the possibility of having a null value in the parameter.
Example
Sql
Department = Coalesce(#Department, Department )
would be
(s.Department == deal.Department || deal.Department == null)
not this which is what you have now
(s.Department == deal.Department || s.Department == null)
Edit
If you wanted to duplicate the COALESCE expression you have now you could write it this way although I am not sure if it would decrease efficiency / performance.
(s.Department == (deal.Department ?? s.Department))
You are testing whether the field in the table equals the 'deal' property or the field is null rather than doing this:
s.Remarks.Contains(deal.Remarks) || deal.Remarks == null
If you do this, it should be the equivalent query.
You can do this cumulatively too. For example with the exact match case you can do:
deals = dataBase.Deals;
if (deal.OwnerName != null)
deals = deals.Where(s => s.OwnerName.Contains(deal.OwnerName));
if (deal.Rooms != null)
deals = deals.Where(s => s.Rooms == deal.Rooms)
That can make the resulting query more efficient. There's a similar way to do this with the non exact match through using unions. I don't know the syntax off hand.
I am receiving the error listed when executing a linq query on my RosterSummaryData_Subject_Local entity. I cannot seem to figure out what is wrong or a solution.
Unable to create a null constant value of type 'System.Int32[]'. Only
entity types, enumeration types or primitive types are supported in
this context.
My LINQ query on my code first entity context:
var subjLocal = customerContext.RosterSummaryData_Subject_Local.Where(s =>
(s.fkRosterSetID == 0) &&
(statsInfo.TestInstanceIDsList.Contains(s.fkTestInstanceID)) &&
(s.fkTestTypeID == statsInfo.TestTypeID) &&
(statsInfo.SchoolYearIDsList.Contains(s.fkSchoolYearID)) &&
(s.fkRosterTypeID == 1) &&
(s.fkSchoolID == 0) &&
(s.fkDepartmentID == 1) &&
(s.fkCourseID == 1) &&
(s.fkPeriodID == 1) &&
(statsInfo.DemoCatIDsList.Contains(s.fkDemoCommonCategoryID)) &&
(statsInfo.DemoCodeIDsList.Contains(s.fkDemoCommonCodeID)) &&
(statsInfo.TestSubjectIDsList.Contains(s.fkTest_SubjectID)));
It sounds like one of your Int32[] types is null. Try adding a check for that before accessing the .Contains methods:
var subjLocal = customerContext.RosterSummaryData_Subject_Local.Where(s =>
(s.fkRosterSetID == 0) &&
(statsInfo.TestInstanceIDsList != null &&
statsInfo.TestInstanceIDsList.Contains(s.fkTestInstanceID)) &&
(s.fkTestTypeID == statsInfo.TestTypeID) &&
(statsInfo.SchoolYearIDsList != null &&
statsInfo.SchoolYearIDsList.Contains(s.fkSchoolYearID)) &&
(s.fkRosterTypeID == 1) &&
(s.fkSchoolID == 0) &&
(s.fkDepartmentID == 1) &&
(s.fkCourseID == 1) &&
(s.fkPeriodID == 1) &&
(statsInfo.DemoCatIDsList != null &&
statsInfo.DemoCatIDsList.Contains(s.fkDemoCommonCategoryID)) &&
(statsInfo.DemoCodeIDsList != null &&
statsInfo.DemoCodeIDsList.Contains(s.fkDemoCommonCodeID)) &&
(statsInfo.TestSubjectIDsList != null &&
statsInfo.TestSubjectIDsList.Contains(s.fkTest_SubjectID)));
Alternatively, if it is Ok for them to be null (I assume it isn't, but just in case), you can change the above checks to follow this pattern:
(statsInfo.DemoCatIDsList == null ||
statsInfo.DemoCatIDsList.Contains(s.fkDemoCommonCategoryID)) &&
I was writing a LINQ query to filter the records based on user input and selection. Some of the inputs may not be given from the user. So i need to filter based on the given input. I tried giving value for only 1 out of 5 optional inputs. But the query is not returning anything. Please help me to find the proper query. you can better understand after seeing the query.
Code
var model = (from items in Db.Items
where ((items.ItemNo == null ||
items.ItemNo == String.Empty) ||
((items.ItemNo.CompareTo(DD.FromItemNo) >= 0) &&
(items.ItemNo.CompareTo(DD.ToItemNo) <= 0))) &&
(items.InfoTypeId == 0 ||
(items.InfoTypeId == DD.InfoType)) &&
(items.CreatedOn == null ||
(items.CreatedOn >= DD.Start &&
items.CreatedOn <= DD.End)) &&
(items.StatusId == 0 ||
(items.StatusId == DD.Status)) &&
(items.LocationId == 0 ||
(items.LocationId == DD.Location)) &&
(items.CollectionId == 0 ||
(items.CollectionId == DD.Collection))
select new ViewModel()
{
Itemid = items.Id,
INo = items.ItemNo,
BTags = (from asd in Db.BibContents
where asd.BibId == items.BibId &&
asd.TagNo == "245" &&
asd.Sfld == "a"
select asd.Value).FirstOrDefault(),
Sid = (from stat in Db.ItemStatus1
where stat.Id == items.StatusId
select stat.Description).FirstOrDefault(),
Option = DD.Option,
CurrItemNo = DD.ItemNumber
}).ToList();
You've got to check the values of DD for nulls or 0s, not those of items:
var model = (from items in Db.Items
where
(
(DD.ItemNo == null || DD.ItemNo == String.Empty)
|| (items.ItemNo.CompareTo(DD.FromItemNo) >= 0 && items.ItemNo.CompareTo(DD.ToItemNo) <= 0)
)
&& (DD.InfoTypeId == 0 || (items.InfoTypeId == DD.InfoType))
&& (DD.CreatedOn == null || (items.CreatedOn >= DD.Start && items.CreatedOn <= DD.End))
&& (DD.StatusId == 0 || (items.StatusId == DD.Status))
&& (DD.LocationId == 0 || (items.LocationId == DD.Location))
&& (DD.CollectionId == 0 || (items.CollectionId == DD.Collection))
select ...