Asp.net - The Specified LINQ Expression Contains References To Queries That Are Associated With Different Contexts?
Apr 5, 2011
I know there are similar questions on stackoverflow - and I looked through them and think my issue is somewhat similar, but haven't been able to find a solution by looking at any of these other questions/answers.I'm getting the error when attempting to execute the following code:
Private Sub btnReserve_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnReserve.Click
' Check that the room is still available.
Dim dbCheckOccupants As New pbu_housingEntities
Dim hall As String = CStr(Session("hall"))
[code]....
It is catching an error on this line:
Dim myID As String = GetID.First.id.ToString
As far as I can tell I'm not using multiple contexts?
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Oct 14, 2011
I've build a large program with many references. F.e.:
System.Data.DataSetExtensions
System.Linq.Dynamic
I've to write a Dynamic Linq Expression: [URL]
In my case: Dim query As IEnumerable = ds.Sales.Where(strWhere)
But with System.Data.DataSetExtensions Where is misinterpreted. The compiler expects (Datarow, Integer, Boolean). If I delete System.Data.DataSetExtensions everything is ok with this expression, but I get many other errors, so I need this reference. What can I do that the Where is interpreted correctly?
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May 31, 2012
I am calling this function when a button is CLICKED and received the error; The name "The" is not permitted in this context. Valid expression are constants, constants expression, and (in some contexts) variables. Column names are not permitted. Unclosed quotation mark after the character string 'True)'.
The function is as follows;
Private Sub Save()
Dim conn As SqlConnection = GetDbConnection()
Dim query As String
Dim cmd As New SqlCommand
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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?
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Feb 17, 2012
I have a program that is accessing many similar tables using a linq to sql datacontext. Do linq to sql tables implement a common interface? I would like to write methods that could work with any of the similar tables, so it would be great to do something like
Dim myTable as ILinqDataTable
If switch = "TableA" then myTable=myDataContext.TableA Else myTable=myDataContext.TableB
[Code]...
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Aug 24, 2011
I have a basic grid of Linq2Sql entities (frmList). I have a separate form for editing (frmEdit). frmEdit has its own DataContext (as that appears to be the recommended way). How can I tell when my detail form has saved changes?
I don't see a built-in method. I am considering raising an event on the detail form when I save the datacontex, but not sure how I consume this event on frmList, and I have a feeling these events are already created for me somewhere?
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Oct 11, 2010
Let's say I have 3 tables: carts, baskets and eggs where a basket can contain many eggs and where carts contain many baskets. Each basket has a foreign key that maps to a cart and each egg has a foreign key that maps to a basket.I need to return a table that contains these 3 columns:Cart Name | Count of Baskets in Cart | Count of Eggs in Cart.Each table is an EF and I'm using linq with VB.So far, I have 2 queries: one that returns the columns Cart Name and Count of Basket and another one that returns Cart Name and Count of Eggs. How can I combine these two result tables so that I get the results in one table?
Dim query1 = (From cart In myEntities.Carts
Where cart.UserID = TheUserID
Join baskets In myEntities.Baskets On baskets.CartID Equals cart.CartID
[code]...
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Nov 4, 2010
I have never used LINQ before, and I am getting an error in an application that does use it. This is a VB.NET (.NET 2.0) project in Visual Studio 2008.
Here is the offending code:
Dim orderedRows = From r In resultRows Order By r.FIELDNAME Select r
And here is the error (names changed to something generic, but otherwise accurate):
Expression of type '1-dimensional array of
Company.OurLibrary.FunctionalArea.Library.StoredProcStuff.USP_MYPROC.ResultRow'
is not queryable. Make sure you are not missing an assembly
reference and/or namespace import for the LINQ provider.
C:projectfilename.vb
So I recognize that I need to import LINQ libraries. This link led me to add "Imports System.Linq" to the file, but that is an unresolved reference. Based on the same link, I figured I needed to add a reference to "System.Core" to my project, but it is not listed as an available option when I try to add a reference (nor is it already checked).
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Mar 13, 2012
I have a function used to filter a list of options to return only those that are lot traced, and, when applicable, also only show items matching a specified pattern:
Private Shared Function FilterResultsLot(ByVal source As IQueryable(Of Item), _
ByVal itemCode As String) As IQueryable(Of Item)
If HasFilter(itemCode, True) Then
[Code].....
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Mar 17, 2009
I have 2 tables that are related. Each app can relate to many apps. ie, office can be related to word, excel.[code]I would like to do the following query. I use vb.net but c# is ok.Query is to return all the apps that are not related to (1), so the result should be (4, quake) .
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Apr 7, 2009
I decided to iterate through the Data.DataTable and trimmed the values there.Utilizing SirDemon's post, I have updated the code a little bit:
[code]...
I know that on the DisplayMember line the .First.Item() part is wrong, I just wanted to show what row I am trying to designate as the DisplayMember.
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Feb 17, 2011
I use the following code to fill the Table1 dictionary with the information found within the LINQ query.
Dim DB As New DatabaseDataContext
Dim Table1 As New Dictionary(Of String, Integer)
Dim Table2 As New Dictionary(Of String, Integer)
[code].....
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Jul 6, 2010
I will start a new project, use the queries and dealing with databases using LINQ or SQl ,Which is better to start ???
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Jun 5, 2008
I've recently ported my website from 2005 to 2008, and I'm using LINQ Queries to implement a search. The issue is that none of the fields are mandatory, so I've had to implement a dynamic LINQ Query (sic?). Here's the relevant code -
Public Function searchQuery(ByVal titleType As String, ByVal titleName As String, _
ByVal configMgr As String, ByVal lifecycle As String, _
ByVal CIType As String, ByVal recordsPerPage As String) As IEnumerable(Of
[code].....
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Oct 22, 2009
This is really a continuation from my earlier post. I've never worked with this datatype/collection (system.collection.generic.Ienumerable) before so I'm struggling to declare the query globally so I can reference the results within other sub routines/functions. I also am struggling to convert it to other types.how I can convert the collection of xml elements/system.collection.generic.Ienumerable into an xmltextreader (I know I will have to change the query below as it select the value of the node and not the node itself) I imagine by converting the query result to system.IO.stream My first port of call was MSDN but I find the material very difficult to understand for this particular subject.
[Code]...
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Nov 17, 2009
convert this C# code to VB, tried couple of converters and they dont work properly.
[Code]...
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Mar 30, 2010
[QueryInterceptor("Somethings")]
public Expression<Func<Something, bool>> OnSomethings()
{
// Code here
}
I had a view guesses, looked on msdn, but there are no examples matching the way that that is used.
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Nov 18, 2010
I'm having a little trouble converting some LINQ to VB.[code]Online code translators are not helping, and my unfamiliarly with VB LINQ is not very good.
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Aug 6, 2011
THE CODE IS :
var query1 = ((from c in dt.AsEnumerable()
orderby c.Field<int>("1") descending
select c));
var query2 = (from c in query1.Take(10)
select c);
[Code]...
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Mar 9, 2011
I have Crystal Reports 2008 installed on my win7 laptop but when i go to insert references from my application settings the CrystalDecisions references are missing and im not able to find them. Note: they do exist in my "c:windowsassembly" folder.
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Jun 9, 2010
I have the same problem as stated in this question, but the accepted solution there was a "works on my machine" answer.
[Code]...
And I receive the error: BC30201: Expression expected.
Does anyone have a more detailed idea of what could cause this?
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Dec 15, 2011
How to Join the objects in a LINQ select in this sample (C# variants accepted as well):
Class Room
Public Area As Integer
End Class
Class RoomPair
[code]....
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Mar 10, 2009
I have the following C# LINQ query expression:
[code]...
how to convert this to VB.NET?
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Oct 28, 2011
1) I am begginner to dynamic Linq and having serious trouble creating expression tree after WHERE
say.: items.Category_ID=4
I tried to construct it like: Dim products = From items In mydatacontent.Products
Dim AA As ParameterExpression = Expression.Parameter(GetType(String), "items")
Dim left1 As Expression = Expression.Property(AA, GetType(String).GetProperty("Category_ID")) here is the error Dim right1 As Expression = Expression.Constant("4") Dim BB As Expression = Expression.Equal(left1, right1)
[Code]...
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Jan 25, 2012
What I have right now is this:
Dim users = From users In tempTable _
Distinct Select users.Item("s_userid")
Dim usersCount As Integer = users.Count
But I pretty sure I shouldn't have to do that. I should be able to get the count in/from that first linq query.
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May 21, 2010
I need to test a logical expression held in a string to see if it evaluate to TRUE or FALSE.(the strig is built dynamically)For example the resulting string may contain "'dog'<'cat' OR (1>4 AND 4<6)". There are no variables in the string, it will logically evaluate. It will only contain simple operators = > < >< >= <= and AND , OR and Open and Close Brackets, string constants and numbers. (converted to correct syntax && || etc.)
I currently acheive this by creating a jscipt function and compiling it into a .dll. I then reference the .dll in my VB.NET project.
class ExpressionEvaluator
{
function Evaluate(Expression : String)
{
return eval(Expression);
}
}
Is there a simpler method using built in .NET functions or Lamdba expressions.
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Feb 3, 2011
Where can I find complex LINQ examples made using VB.NET Lambda Expression syntax?During my searches I always found 101 LINQ Samples but they use the other notation and for me is not always clear how to transform that code into a lambda expression.
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May 4, 2012
[code]The LINQ query going into "result" is incomplete because I'm stumped at what is happening there. I expect FirstOrDefault to refer to refer to a single Child object at that point in the expression, but it refers to a collection of child objects. Why? What is the best way to get a list of parents that have no associated child or have a child fitting a particular condition? (My actual code will have one child max, so this sample code is not representative.)I just don't understand what the collection of FirstOrDefault could be referring to. It should really be just 1 value or nothing at all times.
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Nov 28, 2010
translation of the following C# Linq Expression (in VB.NET 2008):
syncContext.Send((obj) => eventToBeFired(this, new EventArgs()), null);
Is used in this subroutine:
private void FireEvent(EventHandler eventToBeFired)
{
if (eventToBeFired != null)
{
[code]....
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Aug 11, 2011
I would use the System.Linq.Dynamic. I added the specified Dynamic.vb file, that starts like this:
[Code]...
to my (VB.NET)solution. Now Visual Studio does not recognize anymore in the project files the System.XXX references, proposing me to change them to Global.System.XXX
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