.NET LINQ Group Joining?

Dec 2, 2010

I have a list of object with 3 properties (quantity, service, name)I want to have all names and services in my list (kinda cross join) and the grouped quantity of the row corresponding. Not clear i guess

Quantity Service Name
3 Srv2 Bob
4 Srv2 Paul
2 Srv1 Paul
1 Srv2 Nick

I want as output All the services and all the names and corresponding quantities (0 if none)

Srv1 Paul 2
Srv1 Bob 0
Srv1 Nick 0

[code]....

Here is what I got so far, but I dont even get the expected resultsAnd I am acutally certain there is a pretty easy way of achieving what i want...

Dim services = (From a In interventions Select New With {.Service = a.Service}).Distinct()
Dim months = (From b In interventions Select New With {.Month = b.DateHeureIntervention.Month}).Distinct()
'Dim query = (From s In services _

[code]....

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I'm working on becoming familiar with LINQ, and getting my head around the syntax and usage.

[Code]...

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I'm really struggling with this. I have two XML files. The first one has items, and then sub elements for properties:

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In my application, I have a search query textbox (txtSearch) that works well with one-word queries with the following LINQ:[code]So how would I make the above query more generic (ie: able to handle any number of words in a query)?I should note that the object being queried is a List of strings pulled from an Access database. As it stands, this application only queries the database once and I'd like to keep it that way if possible.

Pass A Parameter From The Select List Into A Function For Joining A Linq Query?

May 25, 2010

I have a query that can be summarised in SQL as follows;

Select
S.StockCode
From
StockToCheck As S

[Code]....

Where the S var is a list of strings. This gives the error 'S' is not declared and points to the S in the function call / join (GetPOSStock). So it does not seem possible to do this in Linq, can anyone confirm?

Datatables Left Join Linq - Joining 2 Datatables And Have The Joined Datatable As Result

Jun 1, 2012

I'm having a hard time joining 2 datatables and have the joined datatable as result. First datatable (labels) holds data including a printerid. Second datatable (printers) holds printer references (id > unc). I would like to have as endresult (joined) a datatable with all data from the first datatable with the field (unc) of the second datatable. [Code]

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Aug 9, 2010

I have the following LINQ statement, which performs a simple linq query and assigns the resulting values labels on an asp.net web form:

Dim db As New MeetingManagerDataContext
Dim q = From s In db.vwRoomAvailabilities _
Where s.MeetingID = lblMeetingID.Text _

[code]....

Originally, there was going to be only a single row result and you can see I'm using FirstOrDefault() to grab that single value which works great. But the design has changed, and multiple rows can now be returned by the query. I need to now Group By the MeetingID above, and SUM each of the selected columns (i.e. s.AllRequestedDoubles).

LINQ Group By SUM

May 28, 2012

[code]how can i group by SUM of the c.ct?

C# - LINQ To SQL Group People By Age?

Nov 3, 2011

Sample in C# and VB.NET are OK.

I have a table "People" with the following columns:

-FullName (nvarchar not null)
-DOB (datetime null)

I want to write a LINQ to SQL to group the people by age, like following result:

Age 19: 4 ppl
Age 20: 5 ppl
Age 21: 6 ppl
Here's my try:
Dim query = From ppl In db.People _
Select New With {.Age = DateTime.Now.Year - CDate(ppl.DOB).Year, .CountAge = ppl.Count}

Notice that there are no DOB record for some people in the tables, so these shall not be included. The DOB column has record like this 1982-10-24 10:12:45 AM because it's a DateTime column.

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I have two tables Students and Origami. Origami has Foreign Key of Students table. Each student can make one or more origami for each month.

[code]...

This query give only total origami of each student. But I want monthly count of origami for each student.

Linq InvalidCastException For Group By

Dec 12, 2010

I have a Linq Group By query that works. Here's the query:

Dim query = From fb As Feedback In lst Where fb.Seller.login_name.ToLower = UserName.ToLower
Order By fb.transaction_id Descending, fb.creation Descending _

[Code]...

I don't like working with anonymous types so I'm trying to delare the result and am hitting an InvalidCastException.

Here's the type information:

Debug.Print(query.GetType.ToString)
Returns:
System.Linq.GroupedEnumerable`4[Feedback,System.Nullable`1[System.Int32],Feedback,VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]]

[Code].....

Linq InvalidCastException For Group By?

Aug 12, 2011

I have a Linq Group By query that works. Here's the query:

Dim query = From fb As Feedback In lst Where fb.Seller.login_name.ToLower = UserName.ToLower
Order By fb.transaction_id Descending, fb.creation Descending _
Group fb By fb.transaction_id _
Into Group

I don't like working with anonymous types so I'm trying to delare the result and am hitting an InvalidCastException.

Here's the type information:

Debug.Print(query.GetType.ToString)

Returns:

System.Linq.GroupedEnumerable`4[Feedback,System.Nullable`1[System.Int32],Feedback,VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]]

and the inner type:

Debug.Print(item.GetType.ToString)

Returns:

VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]

So, armed with this information, here's the declaration used:

Dim query As IEnumerable(Of IGrouping(Of Int32?, IEnumerable(Of Feedback)))

Here's the error returned:

Unable to cast object of type 'System.Linq.GroupedEnumerable`4[Feedback,System.Nullable`1[System.Int32],Feedback,VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]]' to type

[code]....

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Oct 18, 2011

I'm trying to figure out how to use Group Joins in LINQ queries under VB.net. For some reason, every example I seem to find on the syntax is just plain At least, that's what my compiler keeps telling me. This is a simple example where I want to join orders to their order items so that I end up with a type that contains a collection of order items grouped together by their orderId's:

Dim groupedOrders = (From o In orders
Group Join i In orderItems On o.OrderId Equals a.OrderId Into myOrders
Select o.OrderId, myOrders).ToList()

What I'm currently running into in this example is that the 'myOrders' group I'm creating errors out with: Definition of method 'myOrders' is not accessible in this context.

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In proper sql my query would be something like:

select c.id, c.name, count(i.id)
from cats c, items i
where c.id=i.catid

[code].....

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[Code]...

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Dec 23, 2009

I have the following query that groups parking spaces by their garage, but I can't figure out how to iterate the data in the view.

Public Function FindAllSpaces() Implements ISpaceRepository.FindAllSpaces
Dim query = _
From s In db.spaces _
Order By s.name Ascending _

[code]....

The controller is taking the query object as is and putting it into the viewdata.model and as stated the view is not currently strongly typed as I haven't been able to figure out how to do this. I have run the query successfully in linqpad.

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I have a list of attachments that I need to group by clientCLID and EmailAddress. From this grouped list I only need a list of clientCLIDs. After fiddling for a while I've managed to get it to work as follows:

[Code]...

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I spent a lot of time on this problem. I am able to do simple Group By LINQ queries (on one property) but for multiple fields I'm a little stuck... Here is a LINQPad sample of what I want to do :

dim lFinal={new with {.Year=2010, .Month=6, .Value1=0, .Value2=0},
new with {.Year=2010, .Month=6, .Value1=2, .Value2=1},
new with {.Year=2010, .Month=7, .Value1=3, .Value2=4},

[Code]....

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Dec 5, 2011

I have this linq to entity

From r In ReceiptRepository.Fetch
Where
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[Code]....

This is working fine, except the count property, it is just giving the number of group count. I don't know how to find out each Tender Count

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I have to perform the following SQL query: select answer_nbr, count(distinct user_nbr)
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[Code]...

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[Code]...

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Can't Use A Where Clause On Both Tables In A LINQ Group Join?

Jun 7, 2011

Here's what I want to do:

Dim queryX = From m In db.Master
Where m.Field = value
Group Join d In db.Detail
On m.Id Equals d.MasterId Into Group
Where d.Field = value

In English, I want to join the master and detail tables, specifying conditions on each. But this causes the following compiler error:

"Name 'd' is either not declared or not in the current scope."

It works if I put this same condition in functional form:

Group Join d In db.Detail.Where(Function(x) x.Field = value)

but I think this is more typing, harder to understand, and introduces that irritating dummy variable. I really would prefer to use the query comprehension syntax. Is there a way to accomplish this?

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I'm trying to write a linq to object query in vb.net, here is the c# version of what I'm trying to achieve (I'm running this in linqpad):

void Main()
{
var items = GetArray(

[code].....

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I have a list of data as shown below

Original Data
Genre Name Year
Comedy Shrek Forever After 2010
Drama The Karate Kid 2010
Action Iron Man 2 2010

[Code]...

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Nov 4, 2010

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Jan 16, 2012

I have the following:

myFilteredContractors = (From c In myFilteredContractors
Join cc In myConClasses On c.ContractorId Equals cc.ContractorId
Where inClassifications.Contains(cc.ClassificationId)[code].....

This is properly ordering this list of contractors by the number of classifications that they have.I also want to order them by whether or not they have a field set (CompanyOverview), which if is an empty string should be below those contractors who have set their CompanyOverview. Also, after the CompanyOverview is ordered I want to order by Registration Date.So it should order by:

Number of Classifications
Whether Overview has been set (c.CompanyOverview)
Registration Date (c.AppliedDate)

Is it possible to all of this in LINQ?

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[Code]...

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How do I order by and group by in a Linq query?I tried..Dim iPerson = From lqPersons In objPersons Where Len(lqPersons.Person) > 0 Group lqPersons By key = lqPersons.Name Into Group Order By Group descending Select Group, key

For Each i In iPerson
tmp = tmp & vbNewLine & i.key & ", " & i.Group.Count
Next

[code].....

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