How To Get Lamda In LINQ To Actually Filter For Dynamic Linq
Sep 10, 2009Example-I have a person class
Public Class Person
Private _fname As String
Public Property Fname() As String
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LINQ Query Using The Dynamic LINQ Library?
Mar 31, 2011Forgive 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."
Dynamic LINQ Query Based On Dynamic Number Of Comboboxes?
Feb 5, 2010I would like to bind a DataGridView to a different LINQ query every time (in order to reuse the same form/DGV for different queries), like this:
[Code]....
but the "Qry", and the number of comboboxes, and their field names would change every time.
Dynamic SQL To Dynamic LINQ In .NET With MS SQL Server 2008?
May 24, 2010I need to represent the following query using LINQ:
DECLARE @PurchasedInventoryItemID Int = 2
DECLARE @PurchasedInventorySectionID Int = 0
DECLARE @PurchasedInventoryItem_PurchasingCategoryID Int = 3
DECLARE @PurchasedInventorySection_PurchasingCategoryID Int = 0
[code]....
Now, I know that a query in .NET doesnt look like this, this is my test in the SQL Design Studio. Naturally VB.NET variables will be used in place of the SQL local variables.My problem is this: All of the conditions after "WHERE" are optional. In that a query might be made that uses one, some, all, or none of the conditions. V.PropertyID and V.Value can also appear any number of times.In VB.NET I can make this query easy enough by simply concatenating strings, and using a loop to append the "V.PropertyID/V.Value" conditions.I can also make a Stored Procedure in MS SQL, which is easy enough.However, I want to accomplish this using LINQ.
Filter A List With Linq?
May 3, 2011Public Sub adjectAllNormals()
Dim qry As LinkedList(Of CElement) = From elm In Elements
From id In SelectIDs()
Where elm.ID = id
Console.WriteLine(qry.Count)
End Sub
Linq To Sql Time Filter
Jul 12, 2011I'm trying to filter out the time which is greater than 8:00 am and store it in array . Can anyone give me some suggestion?[code]
View 1 RepliesDynamic Where In Linq To SQL?
Sep 14, 2010How would I get something like this to work so that I can dynamically alter the where-clause in this linq to sql query?
Dim AccountID = 1234
Dim AccountList
Select Case Types
[Code]....
With the above code I get this error:
Late binding operations cannot be converted to an expression tree
Filter Out Item From A Linq 2 Sql Query?
Oct 1, 2009I have a list(of t) and I got a iqueryable(of a)
I want to filter out any item from the iqueryable(of a) where a.id = t.myotherid
I'm not really sure how to write this query[code]...
Linq To Read And Filter Xml Files
Dec 11, 2008I am trying to grasp using Linq to read and filter xml files. I've been googling and trying all day long but still not successful.[code]
1. Firstly I want to select a contact with a certain node value, my code looks like this:[code]
2. The third level nodes have some same descedants child elements. Is it possible to sort the entries by <contactId>? How can I do that? For example I want to have a result like this:[code]
Send LINQ Filter As Parameter?
Oct 4, 2010Imagind I have the following in VB:
function doSomething()
From ou In ctxt.Users.Where(Function(p) p.UserName = username)
...
end function
how can I send the filter as parameter (something like below)?
function doSomething(filter as whatTypeHereAndHowToInstantiateInCallingFunction)
From ou In ctxt.Users.Where(filter)
...
end function
.net - Dynamic Linq Query?
Mar 14, 2011I 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)?
C# - Abstracting Dynamic Linq To SQL Where
Feb 24, 2012UPDATE: Groo's answer was marked correct as it would be a good alternative. I decided to stick with the select/switch statements to avoid the performance issues of using reflection. As far as I can tell there is no way to do what I want without using Dynamic LINQ (and reflection) or a decompiler (to manually code each LINQ statement, which I am already doing by hand). Note: to make this update DropDownList16 through DropDownList20 were removed (needed the characters).Is there a way to abstract the building of a dynamic Linq to SQL query?
I am trying to build a Linq to SQL query with a dynamic where clause, based on user supplied filters. The user needs to be able to filter strings, integers, and dates using advanced options (equal, not equal, contains, starts with, etc). The user needs to be able to use these filters with as many or few columns as desired.
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Dynamic Column In Linq?
Jan 5, 2010Dim query=Form f in BBSDb.Forms order by f.FormID Descending Select f where I want the f.FormID to be able to replace with a variable..What I mean is.. it doesn't have to f.FormID .. I may want to set f.FormName to be in descending for example using the code dynamically.. Is there anyway to achive?
View 2 RepliesDynamic Query Linq To Xml?
Mar 16, 2011I want to write a query that the "where" in the query is a string something like"
Dim query as string= "Name =xxxx and Date > 10 "
Dim t = from book in doc.Descendants("books") Select _
[Name] = book..value, [Date] = book..value....
Where (query)
I build the query string on run time
Using Dynamic LINQ In Vb 2008?
Oct 17, 2011This is an extension of my last question which was answered, so I am starting a new thread. I have a query in LINQ that I was given to trim down the columns of a datatable. This works well, however, I need to make the LINQ query dynamic. So the query below:
Dim qColumnsIWant = From row As DataRow In inDT.AsEnumerable() _
Select _
EPN = row.Field(Of Integer)("EPNID"), _
EPNID = row.Field(Of String)("EPNNumber"), _
Ingot = row.Field(Of String)("Ingot"), _
ShopOrder = row.Field(Of String)("ShopOrder")
Linq To Entities, Filter Using Where And A List Of Stings?
Nov 2, 2011I am trying to write a query for an existing database, I am using LINQ on EF3.5 inside VS2008 as that is the only environment available to me.I have a starter query that gives me a list of items so the user can select what they want.
"e.Result =
From c In MLDb.TBL_FeatureInfoSet
Order By c.INSP_ROUTINE_NM
Select c.INSP_ROUTINE_NM
Distinct"
The user can then select from the list one or several items they are intersted in and i want to use these as the filter in a further database call. It's not then difficult to have a where to filter on one string however, I would also like to be able to allow the user to select several items from the list box and the data for all of those to be returned.
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Pass Property To Create Filter Like LINQ?
Jan 6, 2011I`m looking for a way to parse a parameter name like linq does.I want to filter before i download the date from the database.With LINQ the data is already red into a dataset. I only want to select data from the database witch i need. how i can send a property name to a function without using the property name as string and without to use to mutch code inside the function and without creating an instance of the object, etc.
Module
Module1
Dim user
As user =
[code]....
VS 2008 How To Pass A LINQ Query To A Sub And Filter It
Feb 6, 2010I have a LINQ query:[code]How can I pass "MyField" to the Sub and make the LINQ "Where" clause work?
View 2 RepliesVS 2010 Using LINQ To Filter Data From A Datatable?
Sep 1, 2010I am wondering if it is possible to filter data from a datatable.Sample datatable
Quote:
Sno CatID Nos
1 XYZ 25
[code].....
(Linq To Datasets) Dynamic Querying In .net?
Jan 24, 2010I have been looking into dynamic querying of datasets and the use of copytodatatable() for a project. I have seen in alot of forums that the copytodatatable functionality is unusable as it was removed. have an example of a dynamic Linq query being loaded into a datatable.
View 1 RepliesAsp.net - Make A Dynamic Where Clause: Linq To Sql?
Jun 28, 2011I have the following linq query:
Dim q = From definition In definitionList _
Where definition.ValueDefName.Contains(criteria)[code]....
I have already looked into this answer: LINQ - dynamic WHERE clause?Unfortunately, it doesn't work for me using .net 4.0. When I attempt to pass the criteria string in it ask for a predicate. The end goal is to add any of these:
definition.ValueDefname.Contains(criteria)
definition.ValueDefDesc.Contains(criteria)
definition.Aliaslist.Contains(Criteria)
definition.StrategicInitiative.Contains(Criteria)
to be passed into the query depending on what checkboxes the user has selected. How can I create a dynamic where clause in linq to sql? Is there new syntax for passing in a where clause as a string?
Building A Dynamic LINQ Query
Mar 16, 2011I have a listbox which users can select from a list if Towns, I want to be able to build a LINQ query based on the selected items in the list e.g.
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C# - Linq Query With Dynamic Where Clause?
Apr 13, 2012I'm need to do the equivalent of a t-sql statement like this using LINQ:
SELECT * FROM mytable WHERE idnumber IN('1', '2', '3')
so in LINQ I have:
Dim _Values as String = "1, 2, 3"
Dim _Query = (From m In mytable Where idnumber = _Values Select m).ToList()
Not sure what to do with _Values to make idnumber evaluate each value in the string.
Dynamic Linq Expression Tree After Where
Oct 28, 20111) 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]...
Linq Dynamic Query Program?
Aug 9, 2010How do i great dynamic linq query in VB.net?
View 3 RepliesCannot Filter A Binding Source Based On A Linq Query
Feb 3, 2010I've got a datacontext and created a binding source using LINQ to sql but cannot filter said bindingsource. The supportsfilter of the bindingsource is set to false ? why ? I can't find any info to say that I cannot filter a binding source based on a linq query.[code]
View 3 RepliesLinq Inheritance And Subtypes (filter Out Base Type)
Nov 8, 2010OK I have a base query that is returning a list (ObjectQuery, actually but I don't think it matters) I have about 5 subtypes based on the main type and I need to filter them. Everything works fine until I want the results to be of the main type (not a subclass) Basically I have a query that includes everything, then I filter out the types that are not checked in a checkedbox list. (asp.net) Lets say I have an Entity named Task, and SubTask1 and SubTask2 that inherit from Task
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.net - LINQ Dynamic Method Call Using Expressions?
May 3, 2011I'm trying to implement multicolumn filtering using LINQ expressions in a class that extends BindingList(Of T). Here is the relevant code:
Public Function GetFilterPredicate() As Func(Of T, Boolean)
Dim expressionList As List(Of Expression) = New List(Of Expression)
For Each item as FilterInfo in _FilterList
[code]....
However, an exception is thrown at the Expression.Call statement. I can't quite figure out the right arguments to supply. As it is now, I am getting this error when I run the code:
InvalidOperationException was unhandled:No generic method 'Equal' on type 'System.Linq.Expressions.Expression' is compatible with the supplied type arguments and arguments. No type arguments should be provided if the method is non-generic.
Dynamic Linq .OrderBy In .Net Not Accepting Strings?
Jun 20, 2012I'm having a problem implementing Scott G's Dynamic.vb extension at [URL] in my vb solution. I've searched StackOverflow (80+ Q&As) and numerous other sites without much luck. I'm using VS 2010.I've included Dynamic.vb in a problem with no root namespace, and then added a reference to that project in my main one. I'm getting intellisense for 4 overloads (rather than 2) so I'm pretty certain that the extension is in scope.I was having a tough time with clauses, especially the OrderBy as Scott demonstrated. If I simply pass a string as Scott's VB example did I get the error "Overload resolution failed because no accessible 'OrderBy' can be called with these arguments."
The line of code is:
Dim FilteredComponentList = From Component As MX.Component In ComponentList.AsQueryable _
.OrderBy("Name")
So I found other references that stated to pass a Lambda expression. So I tried this and at least I get no error, even if the sort function still doesn't seem to work. Here is the code that compiles and executes.
Private Sub SortByColumn()
If Not cmbComponentFilter.SelectedItem.ToString = "All" Then
Dim FilteredComponentList = From Component As MX.Component In ComponentList.AsQueryable _
[code]....
When I interrogate the dgvComponents.Columns(e.ColumnIndex).Name it gives the objects property I wish to sort by, but the sort still isn't working. I'm concerned why I can't get Scott's implementation to work, but I've heard his keynotes and read his blogs, so I'm guessing the problem lies with my implementation.
I'd like either to work but need to understand why as well. Why doesn't passing a string work? Isn't the PARAMARRAY declared in the function optional?
Dynamic Property Setter With Linq Expressions?
Jan 5, 2011I want to create a simple function that does the following:
Sub SetValue(Of TInstance As Class, TProperty)(
ByVal instance As TInstance,
ByVal [property] As Expression(Of Func(Of TInstance, TProperty)),
[code].....