.net - Linq Query To List?

Sep 2, 2011

Dim query = From o In myContainer.MyObjects Select o.MyStringProperty Distinct
Dim myProperties As List(Of String) = query.ToList????? 'no way!!!'
"query" type is IEnumerable(Of String)

I tried to use the query directly as a DataSource of a (infragistic) combobox, but it throws me NullReferenceException, so I decided to convert it to a listof strings, to be a more "classical" datasource.

Dim values As List(Of String) = query.AsQueryable().ToList()
does not work either: Value of type 'System.Collections.Generic.List(Of System.Linq.IQueryable(Of String))' cannot be converted to 'System.Collections.Generic.List(Of String)'.

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Copy Linq Query To List?

Sep 12, 2011

'Read RESX file and returns a List(Of ResXDataNode)[code]...

Provide two separate copies of the node? Or will the List and Linq query still be referencing the same data?

LINQ Query For Deleting One Column From List(Of)

Jun 28, 2011

I have this code:

[Code]...

.net - LINQ Query Returns List Of Empty Objects?

May 3, 2012

I have a query that 'selects' object of a type:

Dim l as IList(Of Foo) = (From dataRow As DataRow In table.Select()
Where CStr(dataRow("Column1")) = "A"
Select New Foo(CStr(dataRow("Column1")), _
CStr(dataRow("Column2")))).ToList()

What's happening is that if i set a break-point to the constructor of Foo and step, the constructor is hit and the parameters are loaded with the arguments. However, l has empty Foo objects (the members in every object are Nothing). What could be happening here?

Assign Result (from LINQ To XML Query) To List(Of String)?

Jul 6, 2011

Is it wrong? Please suggest me correct way.

Public Function ReadXML() As List(Of String)
Dim list As New List(Of String)
Dim xmlDoc As XDocument = XDocument.Load("C:\MappingFile.xml")

[code].....

Linq Query To Compare If Collection Contains List Of String?

Feb 3, 2012

I am using a path comparison to find any children tags which works well when there is only 1 tag selected. This is my code for when multiples tags are selected but it is not working. Can you point me in the right direction?

Single Tag Selection (working)
Dim tagpath = uxTags.SelectedItem.Text
lnqCases = From i In lnqCases Where i.HelpDeskTagItems.Any(Function(x)

[code]...

Linq To Xml Query Returning A List Of All Child Elements?

Mar 8, 2010

I have got an xml document which looks something like this.

<Root>
<Info>
</Info>
<Info>

[Code]...

How can i write a linqToXML query so that it returns me an IEnumerable containing each child element, in this case all five child elements of , so that i could iterate over them. The order of child elements is not definite, neither is number of times the may appear.

VS 2008 Get Original List Index Of LINQ Query

Oct 24, 2010

If I use a LINQ query over some type of collection, is there any way to know the initial index of an element of the result?

Purpose: I make a query to set as source of a DataGridView, and on a (button)cellclick event I want to a call a method that needs to reference the collection at the correct index.

View 13 Replies

.net - LINQ Query For Filter By Selected Items In Checkbox List?

Jun 30, 2011

Could not find this through Google or in SO questions.I have a checkbox listbox on my form. I want to filter my List by the list of selected Ids from that listbox that are checked, in SQL I would have done this like "Where TypeId In (1, 4, 5, 7)"... how do I do that in LINQ?

I feel like I am missing a really obvious answer, but cannot get it.

For argument sake... here is the what I have for sample data:

In Colors (List<of currentColors>)
ID, Name, TypeId
1, Red, 1
2, Blue, 1
3, Green, 2
4, Pink, 3

Selected Types 2 and 3 in CheckboxList: filteredColors

[Code]...

Asp.net - Convert SQL (Pseudocode) To Dymanic LINQ Query From List<Custom> Parameters?

Apr 5, 2012

GOAL: Bind nested ListViews to LINQ generated iQueryable of anonymous type. I want to use LINQ because you can use GroupBy and bind the nested ListView to the 'it' keyword.

SETUP: I have groups of sets of conditions. Each set of conditions is stored in the BillingCodes table. Each group of BillingCodes is stored in the BillingGroups table.

I have a custom object that stores the ID, Name, and NumCodes for each BillingGroup that the user has chosen.I have a collection of these objects called GroupsList that has a list of the groups that the user has chosen.

Problem 1: I can iterate through GroupsList and grab all the IDs. How do I translate the SQL 'WHERE ID IN(a string of comma delineated IDs)' for LINQ to SQL? Is that the best way to do that?

Problem 2: Once I have the list of BillingGroups I need to iterate through each group. For each group, I need to iterate through the BillingCodes. For each BillingCode I need to generate a WHERE clause that has all of the conditions in the BillingCode. I propose something like so:

for each BillingGroup in BillingGroups
for each BillingCode in BillingGroup.BillingCodes
where1 = "..."
next
next

Problem 3: Here's the part where I don't have a clue. I need to dynamically create a query in LINQ to SQL. Keep in mind that I don't know how many groups there'll be or how many codes are in each group.

There are 2 tables:

**transactions**
transaction_id
patient_id

[code]....

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?

LINQ Query To Group Data Between Two List Collections, Populating A Nested Object

Oct 26, 2011

I have these objects:[code]Using LINQ I need to take a List(Of MakeInfo) and a List(Of ModelInfo) and aggregate the StockInfo from ModelInfo into the List(Of MakeInfo).So for each MakeInfo I will have a total count of all stock where MakeInfo.Name = ModelInfo.Make, and also a minimum price.I think it's going to be something like this, but I'm having trouble accessing the nested object and not sure if it's going to be possible with a single query.[code]

LINQ Query Is Enumerated - Turn On Some Kind Of Flag That Alerts Me Each Time A LINQ Query Is Enumerated?

Sep 22, 2009

I know that LINQ queries are deferred and only executed when the query is enumerated, but I'm having trouble figuring out exactly when that happens.Certainly in a For Each loop, the query would be enumerated.What's the rule of thumb to follow? I don't want to accidentally enumerate over my query twice if it's a huge result.

For example, does System.Linq.Enumerable.First enumerate over the whole query? I ask for performance reasons. I want to pass a LINQ result set to an ASP.NET MVC view, and I also want to pass the First element separately. Enumerating over the results twice would be painful.It would be great to turn on some kind of flag that alerts me each time a LINQ query is enumerated. That way I could catch scenarios when I accidentally enumerate twice.

LINQ Queries - Combine The First 3 Queries Into A Single Query And Place In A List?

Jan 6, 2010

I am writing a message system on my server, the xml is something like this

<xml>
<entry>
<sender>[code]....

my problem now i guess is 2 fold, i wish to combine the first 3 queries into a single query and place in a list or a collection or is there a way to do this with a single query that will give me my desired result?

.net - ActiveRecord Linq/NHibernate Linq Not Building Query Completely?

Jul 14, 2011

given this function:

Public Function Search(ByVal StartIndex As Integer, _
ByVal MaxResults As Integer, _
ByVal AccountNumber As String, _
ByVal LastName As String, _

[Code]....

instead of what I expected:

Select count(*) from remitline where lastname = "smith"

What am I doing wrong building up the where clause? I'm using Castle ActiveRecord 2.1

Performance Gain In LINQ Query Vs LINQ Stored Procedure?

Aug 6, 2009

if there is that much of a performance gain in running a LINQ stored procedure versus a LINQ query?

Asp.net - Complex Linq Query - Add A .Where() Or .Any() Predicate To Reduce Query Complexity (in VB)?

Sep 14, 2010

I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.

I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.

The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.

Protected Sub LoadResults()
'Get Dictionary of Filters
Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary")
' Initialize LinqToSql

[code]....

LINQ Query Using The Dynamic LINQ Library?

Mar 31, 2011

Forgive my ignorance on this.I have this LINQ Query:Dim ngBikersDataContext As New CarBikeWalkDataContext

bikersList = (From c In ngBikersDataContext.Reg_Bikers _
Order By c.L_Name _
Select New Bikers() With { _
.BikerID = c.BikerID, _
.F_Name = c.F_Name, _

[Code]...

with the error "Overload resolution failed because no accesible 'Select' accepts this number of arguments."
Over the "NEW" I get an error " ')'expected."

"System.ArgumentException: An Item With The Same Key Has Already Been Added." When Trying To Order An In-memory LINQ Query By A LINQ Association?

Jan 27, 2011

We are doing a query against an in-memory collection of LINQ data objects. The wrinkle is that we are ordering by a column in a related table whose records have not necessarily been loaded yet (deferred loading:)

Dim oPkgProducts = _
From b In oBillPkg.BillProducts _
Where b.Successful.GetValueOrDefault(Common.X_INDETERMINATE) = _

[code]....

LINQ To SQL - Add In Row_Number To A LINQ To SQL Query?

Aug 31, 2011

How do I add ROW_NUMBER to a LINQ query or Entity? How can I convert this solution to VB.NET?

[Code]...

I'm having trouble porting that last line. I have been unable to locate a VB.NET example. I'm actually not looking for any paging functionality like the example provides, just good old-fashioned Row_Number(Order By X) row index.

VS 2008 Linq Possible To Use Query In Another Query?

Apr 16, 2011

I was wandering is it possible to use a query within another query below is the code I am trying to use.

Public Function GetInventByComp(ByVal CompID As String) Using DC As New DataClassDataContext
'need to get company id's based off names? thats bad should be name from Id need to rethink this
Dim invent = (From C In DC.Inventors_Companies _
Where C.CompID = CompID _
Select C.InventorID).ToString

[Code]...

I was trying to us multiple values in a string like "1, 3, 5" but I can't seem to get that working either so I am trying to use just a single value now. Can anyone help me? "Yes I am new to this"

Convert A List Linq Expression To Defined List Class?

May 26, 2012

y have this class

Private Class MyClass
Public Property propertyOne() as String
Public Property propertyTwo() as String

[code].....

.net - Create New Distinct List(of T) From Existing List(of T) Using LINQ?

Jun 1, 2011

How can I get a new distinct list from an existing list using LINQ? This is what I have so far and it is not distinct but does give me a new list.

Dim tmpQryColumn = (From a In _allAudits
Select New CheckBoxListItem
With {.Id = a.AuditColumn, .Name = a.AuditColumn}
).Distinct()
_columnList = New List(Of CheckBoxListItem)(tmpQryColumn)

.net - Searching A List Of Objects In An Object List Using Linq?

Dec 22, 2010

I have 2 classes

Public Class Shipper
Public Property ShipperID As Long
Public Property CreateDate As DateTime

[Code].....

Create New Distinct List(of T) From Existing List(of T) Using LINQ?

Mar 12, 2010

How can I get a new distinct list from an existing list using LINQ? This is what I have so far and it is not distinct but does give me a new list.

Dim tmpQryColumn = (From a In _allAudits
Select New CheckBoxListItem
With {.Id = a.AuditColumn, .Name = a.AuditColumn}

[code]......

Finding Items In One List That Aren't In A Second List Using Linq

Jan 25, 2011

I have two generic lists, named ListA and ListB. Both ListA and ListB could potentially have duplicate items. What I would like to do is use LINQ to grab the items in ListB that are not in ListA, but I'm unsure how to do so.

Linq - Create A List Of Integers From A List Of Objects?

Nov 23, 2011

I'm trying to create a list of days(integer) from a list of dates(date).

I tryed to do this....

[Code]...

Loop Against A List And Fill Another List From Its Data Using Linq

Jul 29, 2010

This is what I want to do as seen in C#(loop against a list and fill another list from its data using Linq)

[Code]...

Getting List Of Items Not In Parent List Using LINQ

Mar 28, 2011

I am writing app in vb.net

I have two variables one with list of RoomRate and other with list of RoomTypes.

We have RoomRates and RoomTypes linked with RoomTypeInfo variable insite the RoomRate.

So how do i find the RoomTypes which donot have the RoomRates Defined.

My Sample Code:

class RoomType
property UIN as integer
property Title as string
end class

[Code]......

XML To LINQ - Get List Of All Products From XML Doc And Put Them Into A Generics List

Jun 30, 2009

I'm basically brand new to LINQ. I've seen some examples that allow me to strong type objects using LINQ but I don't really understand them because they're in C#, which I guess lets you do different things with LINQ(I think?). [Code] I just want to get a list of all the products from the XML doc and put them into a Generics list.

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