"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) = _
I am using a modal form with a datagridview in order to populate textboxes on a parent form. The datagridview is bound to an anonymous type resulting from a linq query, which varies depending on the textbox control whose keypress event is called. I always want to display a key value in column 0 of the datagridview (along with a variable number of additional columns), and then use that key value once the user selects a row.
However, when setting an anonymous type from a linq query as the datasource for a datagridview control, the columns are indexed alphabetically rather than in the sequence selected in the query. This requires setting the displayindex as a workaround, and then keeping track of which column contains my key value. I read elsewhere that this was something fixed in VS2008 SP1, but I still encounter the behavior.
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
I have a method in a webservice that has parameter with which users can decide how they want to order their results. This is a List(Of String) with the names of the fields in the order they want to sort them. I know I can normally order on multiple columns by doing the following
Dim test = Bars.OrderBy(Function(x) x.Foo) _ .ThenBy(Function(x) x.Bar) _ .ThenBy(Function(x) x.Test)
However in this case this won't work since I can't chain the ThenBy function because I'm adding the sorting orders in a loop. To use ThenBy I need an IOrderedQueryable collection. This is how I would want it to work
Dim sortColumns = {"Foo", "Bar", "Test"} Dim query = From b in Bars For each column in sortColumns Select Case column Case "Foo" query = query.Orderby(Function(x) x.Foo) [Code] .....
How can I convert an object of type System.Data.Linq.DataQuery to System.Linq.IQueryable?I'm working with Visual Basic/Silverlight, and the source code of my query is as follows:
Public Function Get_Cli_Pag() As IQueryable(Of V_Cliente_Pagare) Dim Qry = From P In Me.Context.Pagares Join C In Me.Context.Codigos On C.Codigo
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.
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.
I'm a bit of a n0ob to all this and I'm having trouble finding good resources on the net.What I'm trying to do is define a one-to-many relationship between two entities. I'm using the GUI tool in Visual Studio - and have created the tables in Microsoft SQL Server Management Studio.Basically, I have two tables....a 'Users' table and a 'Sites' table. A single user can have many sites associated with it.Users has a primary key of 'UID' and the Sites table as a primary key of 'Site_ID'.Sites also has a column 'UID' that should indicate which user that site is associated with.Anyway - it sounded pretty simple; but no matter what I attempt to do, I can't seem to get it to work. Mostly, I get validation errors - sometimes run-time errors, or sometimes, no actual data even though there should sites that match the UID of the user.I am able to connect and write LINQ against my Users table/pull down User objects - but can't seem to get it to know that the Sites are associated with the user.In the GUI - if I go to 'Add Association' and create a 1 to many link between Accounts and Sites - and Validate - I get an error saying, "Error1Error 11008: Association 'AccountsSites' is not mapped."
It seems like, when I try to make an association, it wants to link the 'Keys' of each entity.But U_ID and SITE_ID are the keys and, obviously, shouldn't match.If I click on the line it created in the GUI and I go to 'Table Mapping' I can see that it is trying to match those keys. Since I want it to match user_ids my first thought is to just make the U_ID the entity Key in the Sites entity but, of course, that's wrong because it would no longer allow a 1 to many relationship.
I have a multi-client DB (multitennant) with several tables.Two of these tables are tblEmployees and tblTitles.Now I have a relationship from tblEmployees.empTitle to tblTitles.ttlID.That far everything is working.But now I have to make the application for multiple clients/tennants.So I added the fields tblEmployees.empClient and tblTitles.ttlClient and included them into the association.This works fine for reading and for setting the persons title as well.But if I try to remove the title (set it to NULL), SQL to Linq tries to modify both tblEmployees.empTitle and tblEmploy ees. empClient with is not allowed because tblEmployees.empClient is part of the primary key.And so I get the following error:[code]How can I tell SQL to Linq only to modify field tblEmployees.empTitle???
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."
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.
I get the Following Error: Cannot add or insert the item 'Cake' in more than one place. You must first remove it from its current location or clone it Parameter name: item.I am trying to copy all the items in one column of a ListView to another Listview.
Using VB.net and the following LINQ statement. I suspect the "Order by" does not work with Concat(). I want to list the current item the user has and then list more available items in asending order. So first i select the current item from the db and then select the next available items in order. LINQ is ignoring the order by statement and sorting by the PK (which is itemID) I examined the list immediately after executing the statement. When I break up the statement and do them separately they work as predicted.
(From items In myDatabase.ItemAssignments _ Where items.BuildingID = buildingID _ And items.ResidentID = ResidentID _
Same thing I am trying to do in the linq order by. It's not working.I have column that is defined in the data base as string (Varchar) and I need to cast/convert it to integer before I need to sort it.What should be my linq statement?
I have a Dictinary(Of String, Item) and I'm trying to sort it into alphabetical order by the item name. I don't want to use a sorted dictinary and without it, I've having zero luck. Linq is not my strong point.
How do I order by a passed string value on my list of objects? i need to do paging and sorting on my List(Of) objects the paging is no problem but I don;t know who to get the Order By to work.Here is what I am currently doing and it's working great:[code]
This works great and sorts on L_Name. But I am trying to allow the user to sort the gridview themselves so I am passing in the SortExpression as a string. But I don't know how to incorperate the SortExpression into the LINQ Query. I tried Order By c. & SortExpression but that did not work.
I have following code that creates Linq query. I've never used Linq until today and having problem with "Order By Clause"[code..]
If I run the code, I get following error.Name 'p' is either not declared or not in the current scope. How come p!Weight in "Select Clause" works but not in "Order By Clause"?
Dim gg = From gs In AllData_TableList Order By gs.Biology Descending, gs.ChemistryDescending, gs.English Descending, gs.Frensh DescendingAll I need is to make this Statement order Dynamically like this
Dim Variable1 as string=Biology Dim Variable2 as string=Chemistry Dim Variable3 as string=English
I have collections of 2 different types - let's call them Cars and Trucks. Both share base class Vehicle, which has property Passengers.I want to merge them into a single collection ordered by that property. E.g., merge Cars and Trucks and order by Passengers.
I am using linq to fill a gridview with the information from an xml from code behind. I would like to order my Grid according to one of my elements in the xml ("value element").
gvResourceEditor.DataSource = (From resElem In resourceElements.Elements("data") _ Select New With { _ .Key = resElem.Attribute("name").Value, _ .Value = HttpUtility.HtmlEncode(resElem.Element("value").Value), _ .Comment = If(resElem.Element("comment") IsNot Nothing, HttpUtility.HtmlEncode(resElem.Element("comment").Value), String.Empty) _ }).OrderBy(?????)
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)
I have a LINQ to sql statement that joins 2 tables. I would like to add a order by clause on one of the columns. However the order by clause does not seem to take effect at all. right syntax in VB.net to achieve order by in the following:
Dim query = From dtIt In dbsomecontext.mytable Join dtIl In dbsomecontext.anothertable On dtIt.ItemID Equals dtIl.ItemID Where dtIl.IsAvailable = True Order By dtIt.manufacturer
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
I have a database with about 180,000 records. I'm trying to attach a pdf file to each of those records. Each pdf is about 250 kb in size. However, after about a minute my program starts taking about about a GB of memory and I have to stop it. I tried doing it so the reference to each linq object is removed once it's updated but that doeow can I make it clear the reference?
Private Sub uploadPDFs(ByVal args() As String) Dim indexFiles = (From indexFile In dataContext.IndexFiles Where indexFile.PDFContent = Nothing
