I have a code like this:
using (var ws = new WebService())
using (var db = new EntityFrameworkModel())
{
var originalFolders = ws.GetFolders();
foo.folders = originalFolders.Select(c => new FolderType()
{
Id = c.Description,
Items = ws.ListDocs(c.Id)
.Select((d, i) =>
new DocType()
{
Id = StaticMethod(d, c),
Order = i,
SomeValue = db.docs.Single(doc => doc.Id == StaticMethod(d, c)).SomeValue
}
).ToArray()
}).ToArray();
}
But I get a "LINQ to Entities does not recognize the method 'StaticMethod' method, and this method cannot be translated into a store expression" exception. Does exist any way to pass a static value as a parameter? Something like this:
using (var ws = new WebService())
using (var db = new EntityFrameworkModel())
{
var originalFolders = ws.GetFolders();
foo.folders = originalFolders.Select(c => new FolderType()
{
Id = c.Description,
Items = ws.ListDocs(c.Id)
.Select((d, i, string myValue = StaticMethod(d, c)) =>
new DocType()
{
Id = myValue,
Order = i,
SomeValue = db.docs.Single(doc => doc.Id == myValue).SomeValue
}
).ToArray()
}).ToArray();
}
I can't modify DocType class constructor. Does exist any way?
Usually this is a matter of making sure you don't inline functions in linq-to-SQL expressions that can't be turned into valid SQL.
Try this:
using (var ws = new WebService())
using (var db = new EntityFrameworkModel())
{
var originalFolders = ws.GetFolders();
foo.folders = originalFolders.Select(c => new FolderType()
{
Id = c.Description,
Items = ws.ListDocs(c.Id)
.Select((d, i) =>
{
var id = StaticMethod(d, c);
return new DocType()
{
Id = id,
Order = i,
SomeValue = db.docs.Single(doc => doc.Id == id).SomeValue
};
}).ToArray()
}).ToArray();
}
Related
public ActionResult EditArticle(int id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
var typeId = 0;
var catId = 0;
var subCatId = 0;
var viewModel = (from sa in ems.SupportArticles
join ssc in ems.SupportSubCategories on sa.SubCatID equals ssc.SubCatID
join sc in ems.SupportCategories on ssc.CatID equals sc.CatID
join st in ems.SupportTypes on sc.TypeID equals st.TypeID
where sa.ArcticleId == id
select new SupportArticleViewModel { supportArticle = sa, supportSubCat = ssc, supportCat = sc, supportType = st });
foreach (var vm in viewModel)
{
typeId = vm.supportType.TypeID;
catId = vm.supportCat.CatID;
subCatId = vm.supportSubCat.SubCatID;
}
I want to convert it into Lambda Notation.But, I am unable to do it.Please help.I am using SupportViewModel which contains property of SupportType,SupportCategory ,SupportSubCategoryand SupportArticle.
Following is functional way do query , you have to make use of join function and than you get data
var filteredArtciles = SupportArticles.Where(sa=> sa.ArcticleId == id);
var query =
SupportArticles.
Join(SupportSubCategories,sa => sa.SubCatID ,ssc => ssc.SubCatID,(sa, ssc) => new {sa,ssc}).
Join(SupportCategories,sassc => sassc.ssc.CatID ,sc=>sc.CatID ,(sassc, sc) => new {sassc,sc}).;
Join(SupportTypes,sasscsc => sasscsc.sc.TypeID ,st=>st.TypeID ,(sc, st) => new {sasscsc,st}).
Select(j=>
new SupportArticleViewModel
{
supportArticle = j.sasscsc.sassc.sa,
supportSubCat = j.sasscsc.sassc.ssc,
supportCat = j.sasscsc.sc,
supportType = j.st
}
));
I've table with following data.
I want to group the data by DocumentID and then want to marge the DocPropIdentifyName and meta value together using comma separator. The output will be like following:
I'm doing it by using a foreach like below:
var test = (from r in lstDocSearch
group r by r.DocumentID
into g
select new
{
DocumentID = g.Key,
MetaValues = g.ToList()
}).ToList();
List<DocSearch> list = new List<DocSearch>();
foreach (var item in test)
{
foreach (var item2 in item.MetaValues)
{
var check = list.Exists(x => x.DocumentID == item2.DocumentID);
if (check)
{
var find = list.FirstOrDefault(x => x.DocumentID == item2.DocumentID);
find.MetaValue = find.MetaValue + ", " + item2.MetaValue;
find.DocPropIdentifyName = find.DocPropIdentifyName + ", " + item2.DocPropIdentifyName;
}
else
{
DocSearch objDocSearch = new DocSearch();
objDocSearch.DocumentID = item2.DocumentID;
objDocSearch.DocPropIdentifyID = item2.DocPropIdentifyID;
objDocSearch.DocPropIdentifyName = item2.DocPropIdentifyName;
objDocSearch.MetaValue = item2.MetaValue;
list.Add(objDocSearch);
}
}
}
But I would like to do this with linq rather than looping through the collection. Is it possible?
Do you mean something like this ? :
var test = (from r in lstDocSearch
group r by r.DocumentID
into g
select new
{
DocumentID = g.Key,
MetaValues = String.Join(",", g.Select(o => o.MetaValue)),
DocPropIdentifyNames = String.Join(",", g.Select(o => o.DocPropIdentifyName)),
}).ToList();
I have a ControlMeasure table that holds information on each control measure and a ControlMeasurepeopleExposed Table that holds a record for each person exposed in the control measure this could be 1 record or many records.
I Have a controller that populates a List view
For each item in the list, Control Measure, I would like to create a string that shows all the People at risk
e.g.
PeopleString = "Employees, Public, Others";
Ive added a foreach in the controller to show what I'm trying to do however I'm aware that this wont work.
The controller is this:
public ActionResult ControlMeasureList(int raId)
{
//Populate the list
var hazards = new List<Hazard>(db.Hazards);
var controlMeasures = new List<ControlMeasure>(db.ControlMeasures).Where(x => x.RiskAssessmentId == raId);
var cmcombined = (
from g in hazards
join f in controlMeasures
on new { g.HazardId } equals new { f.HazardId }
select new CMCombined
{
Activity = f.Activity,
ControlMeasureId = f.ControlMeasureId,
ExistingMeasure = f.ExistingMeasure,
HazardName = g.Name,
LikelihoodId = f.LikelihoodId,
Rating = f.Rating,
RiskAssessmentId = f.RiskAssessmentId,
SeverityId = f.SeverityId,
}).OrderBy(x => x.Activity).ToList();
var cmPeopleExp = new List<ControlMeasurePeopleExposed>(db.ControlMeasurePeopleExposeds).Where(x => x.RiskAssessmentId == raId);
var peopleExp = from c in cmPeopleExp
join d in db.PeopleExposeds
on c.PeopleExposedId equals d.PeopleExposedId
orderby d.Name
select new RAPeopleExp
{
RAPeopleExpId = c.PeopleExposedId,
PeopleExpId = c.PeopleExposedId,
PeopleExpName = d.Name,
RiskAssessmentId = c.RiskAssessmentId,
ControlMeasureId = c.ControlMeasureId
};
var model = cmcombined.Select(t => new FullControlMeasureListViewModel
{
ControlMeasureId = t.ControlMeasureId,
HazardName = t.HazardName,
LikelihoodId = t.LikelihoodId,
Rating = t.Rating,
SeverityId = t.SeverityId,
Activity = t.Activity,
ExCM = t.ExistingMeasure,
//This section here is where I'm struggling
var PeopleString = new StringBuilder();
foreach (var p in peopleExp)
{
PeopleString.AppendLine(p.PeopleName);
{
PeopleExposed = PeopleString,
});
return PartialView("_ControlMeasureList", model);
}
I know I cant directly put this code in the controller but it does represent what I want to do.
You can't foreach within an object initializer (which is what you're trying to do when instantiating FullControlMeasureListViewModel). You can, however, use a combination of string.Join and peopleExp.Select:
var model = cmcombined.Select(t => new FullControlMeasureListViewModel
{
//other props
PeopleExposed = string.Join(",", peopleExp
.Where(p => p.ControlMeasureId == t.ControlMeasureId)
.Select(p => p.PeopleExpName));
//other props
});
I have this code:
List<MyObjectOne> myListOne = new List<MyObjectOne>(){new MyObjectOne { ID = 1, field2 = 2}};
List<MyObjectTwo> myListTwo = new List<MyObjectTwo>(){new MyObjectTwo { ID = 4, field6 = "string"}};
bool hasSomething = false;
var result = new[] { new {ID = 0 }}.ToList();
if (hasSomething)
{
// Use list one.
result = myListOne.Select(x => new { ID = x.ID});
}
else
{
// Use list two.
result = myListTwo.Select(x => new { ID = x.ID });
}
foreach (var item in result)
{
// Some logic to manipulate item.ID.
item.ID;
}
What I trying to do it's to use the same anonymous type to select a list of IDs from two different lists. So I use the Select(x => new { ID = x.ID }) in order to create the anonymous type for each table in order to have only one for loop.
The error raised is "Cannot implicitly convert type IEnumerable to List"
¿any idea?
Assuming ID in MyObjectOne and MyObjectTwo are both int's, your code will work if you replace ToList with AsEnumerable:
var result = new[] { new { ID = 0 } }.AsEnumerable();
If the ID properties are some other type (e.g. long's), you need to specify that when creating the anonymous type here:
var result = new[] { new { ID = 0L } }.AsEnumerable();
Or like this:
var result = new[] { new { ID = (long)0 } }.AsEnumerable();
However, this kind of code is kind of confusing, and I wouldn't recommend it for a production environment. Here's an alternative solution that avoids creating a 'dummy' object just for implicit anonymous typing:
var result = hasSomething
? myListOne.Select(x => new { ID = x.ID })
: myListTwo.Select(x => new { ID = x.ID });
I have some working code that retrieves data from data base. It is interesting for me to get some better code for my solution. Are there some ways to combine two queries into one or something like this?
Dim customerTitlesAndIDs = contex.CustomerTable.Select(Function(row) New
With {.ID = row.ID, .CustomerTitle = row.Title}).ToList()
Dim cutomerIdPayment = contex.CustomerPayments.Select(Function(table) New
With
{
.ID = table.CustomerID,
.Range = table.PaymentsRange,
.Values = table.Values
}).ToList()
Dim customerInfos As New List(Of SCustomerInfo)
For Each customer In customerTitlesAndIDs
Dim cID As Integer = customer.ID
customerInfo.Add(New SCustomerInfo(CreateCustomerTable(), cID, customer.CustomerTitle))
For Each cutomerPayments In cutomerIdPayment
If cutomerPayments.ID = cID Then
Dim rangeValue(1) As Object
rangeValue(0) = cutomerPayments.Range
rangeValue(1) = cutomerPayments.Values
Dim dtRow As DataRow = customerInfos.Last().PaymentTable.NewRow()
dtRow.ItemArray = rangeValue
customerInfos.Last().PaymentTable.Rows.Add(dtRow)
End If
Next
Next
Return customerInfos
Same code with C# (hope no syntax errors occurred):
var customerTitlesAndIDs = contex.CustomerTable.Select(row => new
{ .ID = row.ID, .CustomerTitle = row.Title }).ToList();
var cutomerIdPayment = contex.CustomerPayments.Select(table => new
{
.ID = table.CustomerID,
.Range = table.PaymentsRange,
.Values = table.Values
}).ToList();
List<SCustomerInfo> customerInfos = new List<SCustomerInfo>;
foreach (var customer in customerTitlesAndIDs)
{
int cID = customer.ID;
customerInfos.Add(new SCustomerInfo(CreateCustomerTable(), cID, customer.CustomerTitle));
foreach (var cutomerPayments in cutomerIdPayment)
{
if (cutomerPayments.ID = cID)
{
object[] rangeValue = new object[1] {cutomerPayments.Range, cutomerPayments.Values};
DataRow dtRow = customerInfos.Last().PaymentTable.NewRow();
dtRow.ItemArray = rangeValue;
customerInfos.Last().PaymentTable.Rows.Add(dtRow);
}
}
}
SCustomerInfo represented by folowing Structure (code is simplified):
Public Structure SWindAltitude
Public PaymentTableAs DataTable
Public Title As String
Public ID As Integer
End Structure
Both C# and VB.NET solutions will be helpful.
Try something like this, utilizing navigation properties (you'll probably have to massage it as I don't know the exact makeup of your data structures):
var customerQuery = context.CustomerTable.Select( ct =>
new {
ct.ID,
ct.CustomerTitle,
// use nav property to get customer payments
CustomerPayments = ct.CustomerPayments.Select( cp =>
new {
Range = cp.Range,
Values = cp.Values } ) } );
return customerQuery.ToArray()
.Select( cq =>
{
var retVal = new SCustomerInfo( CreateCustomerTable(), cq.ID, cq.CustomerTitle );
foreach( var customerPayment in cq.CustomerPayments )
{
var dtRow = cq.PaymentTable.NewRow();
dtRow.ItemArray = new object[] { customerPayment.Range, customerPayment.Values };
retVal.PaymentTable.Rows.Add( dtRow );
}
return retVal;
} );
if i understand right in c# with linq it will be something like this
var customerInfos = customerTitlesAndIDs.Select((c)=>{
var ci = new SCustomerInfo(CreateCustomerTable(), c.ID, customer.CustomerTitle);
ci.PaymentTable = ci.PaymentTable.AsEnumerable().Union(
cutomerIdPayment.Where(j=>j.ID == c.ID)
.Select(j=>{
var dtRow = ci.PaymentTable.NewRow();
dtRow.ItemArray = new object[] {
customerPayment.Range,
customerPayment.Values
};
return dtRow;
})).CopyToDataTable();
return ci;
}).ToList();
I think you can use the Linq provided function Sequence.concat() as described here: http://msdn.microsoft.com/en-us/library/vstudio/bb386979(v=vs.100).aspx