LINQ To XML To Query Attributes Values

Oct 25, 2011

I am trying to use Linq to Xml to query attribute values that will be used to populate a combo box. My xml looks like this:

<Records>
<Record id="1">
<LogoPositioning>
<Brand id="26">
<Xpos>100</Xpos>
<Ypos>200</Ypos>
[Code] .....

My issue is with getting the attribute values. I tried this:
For
Each xattr
As
XAttribute
In
attr
cboBrandChoice.Items.Add(test.Value)
Next

However, I keep getting the following error:
{"Unable to cast object of type '<GetAttributes>d__8' to type 'System.Xml.Linq.XAttribute'."}
I'm new to using Linq so this error isn't making a whole lot of sense to me.

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XML Query On Attributes Using LINQ

Feb 27, 2009

I'm trying to learn LINQ and have a question on querying XML using VB.
My XML:
<Procedure-Text>
<A ID="marker1"></A>Do This Procedure
</Procedure-Text>
<Procedure-Text>
<A ID="marker2"></A>Do That Procedure
</Procedure-Text>
How can I specify my query to get only the procedure text that has the ID attribute marker2? In other words, I would like a resulting string that says Do That Procedure.

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.net - Update 2 Table Values In One Query In LINQ?

Apr 26, 2010

I have 2 tables Table1 with columns [BId,Name,Amount] Table2 with columns [CId,BId, ExpenseType,Expense]. BId Is the foreign key in Table2. The Amount field in Table1 is always higher than Expense in Table2. I need to update the values of Amount (increase or decrease) based on value of Expense and I want to do it in single query in LINQ. Eg If the Expense has to be updated with 200, I would decrease(negate) Amount value with 200. If Expense is reduce to 100 then the Amount is increased by a value of 100.

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Linq Query Handling Null Values?

Nov 12, 2011

From r In ReceiptLines
Where
r.RECEIPT.RECEIPTDATE >= _reportStartDate
And r.RECEIPT.RECEIPTDATE <= _reportEndDate

[Code].....

I am fetching all departments and their sales, average, count from the ReceiptLine, Receipt, ReceiptDiscount tables. The problem i am facing is, if i remove where discount > 0, I am getting null exception. But if I include that, then I only get sales that has discount. How would I write query that bring all sales less discount (if it has one).

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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.

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LINQ To XML Syntax For XML Element With Attributes?

May 13, 2009

I'm a bit of a LINQ newbie and I was having some trouble with the following. I'm trying to perform a query using LINQ on an XML file and store the results in a list of DataClass objects that match the XML.I've got an XML file that is defined like this:

<NewDataSet>
<NewDataTable>
<Field>Accepted ASNs</Field>
<Val>59</Val>[code]....

I have created a Data class to support this XML format. What I would like to do is create a LINQ Query to grab these 3 records and store them into a List of my DataClass. In order to support multiple Order elements, I have my class defined with a generic list of "Order" structs... It looks like this:

Public Class ASNData
Private _field As String
Private _value As String[code].....

how to grab the 3 order elements and store them into my list of Order structs.

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.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

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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?

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Readxml Using Attributes As Column Names And Values?

Mar 30, 2012

Is it possible to read in an xml string and use the attributes for column naming?

For example using the following xml.
<root>
<CategoryInfo>

[code].....

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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]....

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Parsing XML Attributes Into A Listbox And Filtering To Chosen Values

Jan 26, 2010

I use VB 2008, and have "moderate" programming skills.I've constructed an xml file:[code]

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Using Anonymous Types And Assigning Values To Controls Or Attributes

Jul 26, 2010

I'm trying to create a web site that users can log into and self serve their user information ie name, address etc. I've set up a SQL server DB with a couple of table holding the data and accessing those using Linq. I'm selecting specific data from my datacontext then trying to assign it to a label, ideally I want to assign the value to a class attribute so I can use the users details on multiple pages.

I've simplified the code (removing WHERE statement etc for the purposes of this question):

Using CurrentUserDataContext
As
New UserDataDataContext()

[Code].....

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Using Array / Collection Values In Control-names / Attributes (in VB)

Mar 5, 2012

I am working on my first VB application and have run into a problem. I am trying to loop through some data and displaying them in labels. I am using a for-each loop but end up with different row with the same labelname. What I would like to do, is to assign a number to the labelname (mylabel1, mylabel2,...), but I canīt figure out how, and I cant find anything online that will work. Here are some of the code that I have made, where I could use a solution to my problem...

[Code]...

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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."

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"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]....

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Xml - Mix Values From Local Data With Values Returned From Database While Using LINQ To SQL?

Oct 27, 2010

I am creating an xml file with LINQ as follows...

Public Sub CreateXml()
Dim db As New MDataContext
Dim Customers = <gallery columns="3" rows="3">

[code]....

Could i mix local values with the ones returned from the LINQ query...Something like the following?

Public Sub CreateXml(ByVal **Col** As String, ByVal **Row** As String)
Dim db As New MDataContext
Dim Customers = <gallery columns="& **Col** &" rows="& **Row** &">

[code]...

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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.

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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"

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.net - Should Use LINQ For This Query

Sep 4, 2009

I've been reading a fair bit about the performance of using LINQ rather than using a for each loop and from what I understand using a LINQ query would be a little bit slower but generally worth it for convenience and expressiveness. However I am a bit confused about how much slower it is if you were to use the results of the query in a for loop.

Let's say that I have a set called 'Locations' and a set of objects called 'Items'. Each 'item' can only belong to one 'location'. I want to link items that are under the same location to each other. If I were to do this using a normal 'For Each' loop it would be something like this:

For Each it as Item in Items
If it.Location.equals(Me.Location)
Me.LinkedItems.Add(it)
End If
Next

However if i was to use LINQ it would instead be this:

For Each it as Item in Items.Where(Function(i) i.Location.equals(Me.Location))
Me.LinkedItems.Add(it)
Next

is the second (LINQ) option going to loop once through the entire 'Items' set to complete the query, then loop through the results to add them to the list, resulting in essentially two loops, or will it do the one loop like the first (For Each) option?

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Can Do A LINQ Query Of A LINQ Query?

Mar 24, 2012

Is it possible to do the following? [code] Basically I have one Load_Gridview function that is called on all postbacks, and rather than creating a bunch of different cases.I want the filters to stack.My actual code has more filters set up (4 or 5 of the).It all compiles ok but when I run and try to execute with active checked, or a department selected I get the following error. [code]

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Linq Query In .net?

May 5, 2009

I have below XML file

<?
xml version="1.0" encoding="utf-8" ?><
PageFlow>
<
attributegroup name="Search"><
attributes>

[Code]...

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Put A Sum() In Linq Query?

Apr 18, 2012

I am looking to sum the "Status" field.

Dim _detailRecords As New DataTable
_detailRecords.Columns.Add("y")
_detailRecords.Columns.Add("z")

[Code]....

I'm also wanting to keep this as an IEnumerable of DataRow because I will be creating a datatable from it with

Dim yyyyy As DataTable = query8.CopyToDataTable

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Query With Linq To Xm?

Aug 13, 2010

I am Fairly new to Linq and I am trying to write a simple query to return the error messages within my xml file.

<?xml version="1.0" encoding="utf-8"?>
<Error xmlns="urn:xxxxx">
The following errors were detected:

[code].....

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Why The Sql Query Is Different On That Linq Query When Run On C# And On .net

Aug 26, 2009

if I run this under c#

from p in Addresses where p.Address2 == null select p.AddressID

it generate this query

SELECT [t0].[AddressID]
FROM [dbo].[Address] AS [t0]
WHERE [t0].[Address2] IS NULL

if I run this under vb.net

from p in Addresses where p.Address2 = nothing select p.AddressID

it generate this query

SELECT [t0].[AddressID]
FROM [dbo].[Address] AS [t0]
WHERE [t0].[Address2] = ''

p.Address2 is a varchar field that accept null value

why vb.net is "wrong" ?

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Database Table Attributes - Query A List Of Table Names In The Database Ordered By Date Created

Jan 22, 2011

[Code] my issue is that now i need two cases, first i need a query that will return the date created and modified of the table and i also need to know if its possible to query a list of table names in the database ordered by date created but that have a certain thing in their names. for example the database contains the following tables: [Code] and what i need the query to return is the tables that contain "Data", settings and employees are for the other functions of the program. so the query should return the 4 data tables in order of date created. but i have no idea how to go about doing that in the query, does anyone know how this is done?

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.net - Converting Linq To XML Query From C# To .Net?

Dec 1, 2009

I'm converting the Linq query below from C# to VB.Net. Can you spot my error? The query joins 3 XML datasets. C# - This one works great.

List<Course> courses =
(from course in CourseXML.Descendants(ns + "row")
join coursecategory in CourseCategoryXML.Descendants("Table") on (string)course.Attribute("code") equals (string)coursecategory.Element("DATA")

[code]....

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.net - Dynamic Linq Query?

Mar 14, 2011

I have been trying the following but it returns unexpected results:

Dim xd As XDocument = _
<?xml version="1.0" encoding="utf-8"?>
<root>

[code].....

The above result returns both 'element' nodes however it should only return the first where element/subelement@id=1/subsubelement@id=3 However if results.Ancestors. is used it returns the correct 'subelement' and if that line is not included it returns a single 'subsubelement' whih is also correct I don't understand why when mvoing to the 'element' it returns both (I realise both have a subelement with id=1 but I thought each further query would filter out the presvious results)?

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.net - LINQ C# Query In VB - Getting An Error

Feb 22, 2012

I have a List of Price Objects (Price contains Date, High, Low) and am trying to extract monthly averages via LINQ. I have this working in C# but we have a few legacy applications that need it in VB.Net and I can't quite seem to figure out the conversion. I've even tried breaking it into two queries to no avail.

[Code]...

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.net - Linq Query If Statement?

Jun 24, 2011

Ok im trying to do a if statement in Linq and was wondering if it was possible to do something like:

Dim loadFriends = From p In db.UserRelationships Where p.aspnet_User.UserName = User.Identity.Name _
Or p.aspnet_User1.UserName = User.Identity.Name And p.Type = 1 _
Select New With {if p.aspnet_user1.user = "a certan username" then .username = _
p.aspnet_user.username else .username = p.aspnet_user1.Username}

[Code]...

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.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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