.net - Pass An Expression To Act On A Single Field In An Anonymous Type In LINQ?
Mar 27, 2012
I have the following Data Transfer Objects defined:
Public Class MemberWithAddressesDTO
Public Property Member_PK As Integer
Public Property Firstname As String
Public Property DefaultAddress As AddressDTO
Public Property Addresses As IQueryable(Of AddressDTO)
End Class
[Code]...
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Jul 9, 2009
I'm a Linq noobie, maybe someone can point me in the right direction. What's wrong here? These anonymous types seem to have the same signatures.
[Code]...
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Aug 1, 2011
After reading this post i realized that i cannot pass an anonymous type as a parameter to a function. So what other options do i have?
Perhaps, passing a Query.ToList as parameter would help, or am i re-inventing the wheel?
Update: I have the following query, which i would like to pass to a function:
Sub Test
Dim Query = (From c In DB Select New With { .ElementName = c.Name })
DoSomething(Query)
[Code].....
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Nov 12, 2009
Why did the anonymous type property "Points" still have the value "0"? [code]
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Oct 22, 2009
I'm out of my depth populating a windows form from an XML linq query (see code further down in post). The listbox is populated as intended, when a value is selected (row) I would like to populate the remaining form controls. The linq query I believe has created a new datatype "Anonymous Types". The query is only local to the load form subroutine but I'm not sure how to make it global.
When I define the query simply as an object the code in the selectedValueChanged event can't execute due to late databinding. how I can initially load the listbox from linq xml query and then populate the other controls when the value changes? Am I right in thinking even though the listbox is multi-columns (property) you can ONLY ever reference a row and NOT a column? I'm new to LINQ and Anonymous Types and the more I read the more confused I seem to get. On a less important note the order by is not functioning as intended (no errors) but data is always retrieved in xml file order and not by the node <text>. Also looked at using <text>.first to order the results without success.
[Code]...
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Feb 25, 2010
I'm trying to write a linq to object query in vb.net, here is the c# version of what I'm trying to achieve (I'm running this in linqpad):
void Main()
{
var items = GetArray(
[code].....
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Jan 5, 2012
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(?????)
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Dec 16, 2011
I'm learning LINQ and VB and just spent an hour trying to access the fields of an anonymous type defined in a linq query. The key (I learned) is to convert the query to a list before you try to iterate through it with a for loop. How to access property of anonymous type in C#?
This does not work: edit (this compiles, but intellisense does not recognize the type)[code]...
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Sep 29, 2011
So I'm writing a query as follows:
Dim assSummary = From a In db.Assignments
Join ur In db.UserRegions
On a.Origin.ID Equals ur.Region.ID
[code]....
In the controller I can return the data easily as follows:
For Each c In assSummary
MsgBox(c.Description & " " & c.AssCount)
Next
If I pass the object through to the view using Viewdata("assSummary") = assSummary, how do I display the data? Every method I've tried results in messages about 'VB$AnonymousType_7(Of Integer,String) and I don't know how to retrieve the data from the anonymous type.
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May 10, 2010
I got 2 classes in a form, and I would like to pass a value from a textbox to the other class, so I decided to use Deligate.
Below is the code.
Public Delegate Sub delPassSize(ByVal text As TextBox)
'To get size from Class Calculate(Class 2)
Public Sub GetSize(ByVal txtForm1 As TextBox)
[code]....
and the error message is 'cls.Getsize is a delegate type and requires a single 'addressof' expression as the only argument to the constructor.'
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May 3, 2012
I have a stored procedure (I cannot edit) that I am calling via linq.
The stored procedure returns values (more complex but important data below):
Customer Stock Item Date Price Priority Qty
--------------------------------------------------------
CUST1 TAP 01-04-2012 £30 30 1 - 30
CUST1 TAP 05-04-2012 £33 30 1 - 30
CUST1 TAP 01-04-2012 £29 20 31 - 99
CUST1 TAP 01-04-2012 £28 10 1 - 30
I am trying to limit this list to rows which have unique Dates and unique quantities in LINQ. I want to remove items with the HIGHER priority leaving rows with unique dates and qty's.
I have tried several group by's using Max and order by's but have not been able to get a result.
Is there any way to do this via linq?
EDIT:
Managed to convert brad-rem's answer into VB.net.
Syntax below if anyone needs it:
returnlist = (From p In returnlist
Order By p.Qty Ascending, p.Priority
Group By AllGrp = p.Date, p.Qty Into g = Group
Select g.First).ToList
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Jun 29, 2010
Ok, just needing a 2nd set of eyes looking at this to make sure the error isn't something else other than my LINQ code here. Here's the function class itself:
Public Function GetJacketByPolicyID(ByVal jacketID As Int32) As tblPolicy
Dim db As New DEVDataContext()
Dim j As tblPolicy = db.tblPolicies.Single(Function(p) p.policyNumber = jacketID)
Return j
End Function
and here is the code which calls this class function in the web control form itself:
Dim p As tblPolicy
Dim j As New Jackets()
p = j.GetJacketByPolicyID(3000050)
For some reason it's flagging the 2nd line in the GetJacketByPolicyID function saying the specified cast is not valid. So I'm guessing it's something I'm doing wrong. I'm sure the tblPolicy/tblPolicies class works right since I can create a new instance of a tblPolicy and set a few variables by hand and return it, so that's not it. I've also checked the datarow I'm fetching and there's no null values in the record, so that shouldn't be it either.
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Sep 24, 2011
I am sure i am doing something terribly wrong, but i should better ask the experts.
At the third line i get the error Value of type <anonymous type> cannot be converted to <anonymous type>
Dim Query = (From c In Db.web Select New With {.AA = c.AA}).ToList
Dim v = New With {.Amount = 108}
Query.Add(v)
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May 1, 2009
I need to set a field that i have dumped into a dictionary to a value that is always a string, (well, it came from an xmlElement, so the .value is a string)
Function setMembers(ByRef ClssObj As Object, ByRef nLinkObj as Object, ByRef xml As XElement) as integer
Dim fields As New Dictionary(Of String, FieldInfo)
[code].....
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Mar 3, 2010
I work with C# 99% of the time. However, I'm having to update some legacy VB.Net code and encountering an issue with VB.Net code syntax. The error that I get is "ByRef" is underlined and "Expected Expression" tag shows up when you hover over "ByRef". The "FooDetail.Load" function is written in C# and expects a List object passed as reference. Don't have any trouble using the same function in other C# classes. Can someone indicate what is wrong with below VB.Net code.
Dim FooDetail As New clsFooDetail()
FooDetail.FooID = FooID
Dim lstFooDetail As New List(Of clsFooDetail)
FooDetail.Load(ConnectionString, "Stored Procedure", ByRef lstFooDetail as System.Collection.List(Of(clsFooDetail))
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Mar 22, 2012
I want to pass an optional parameter to a function of type System.Drawing.Color. The problem I am having is that when I declare the function it says "Constant expression is required" but I have tried variations of the following, including integers, full qualified indentifiers, even old vbWhite constants to no avail.
[Code]...
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Feb 23, 2010
How would you convert this to VB (using .NET 4.0 / VS2010) ?
bw.DoWork += (o, args) =>
{
Code Here
};
I thought maybe like this:
AddHandler bw.DoWork,
Function(o, args)[code]....
But it says Function does not return a value on all code paths.
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Nov 24, 2010
I have a list of properties and values that i'd like to use to dynamically build an Expression(Of Func(Of MyClass,MyClass))
I can run through the list and create each Expression by itself, but the only way I know how to combine them would be to use Expression.And or Expression.AndAlso, but that returns a BinaryExpression rather than my original Expression(Of Func(Of MyClass,MyClass)).
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Aug 30, 2010
I've pieced together some information from other posts but I'm stuck. The first part works fine. Basically I query the database using LINQ and then I loop through the results generating a report.
[Code]...
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Mar 6, 2012
I'm trying to send some Ids via route values with my data in my ajax call and I'm having issues passing more than one.
This is what I'm having to do now... Then split it out into an array on the server.[code]...
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Jun 29, 2009
I have a problem using linq and anonymous types in an asp.net vb.net application.When I write the code above, I have 2 errors :
- "declarations of variable with Option Strinct On requires an As clause"
- "the name 'item' is not declared"
Public Sub MyFunc(ByVal xe As System.Xml.Linq.XElement)
Dim lstitems = From it In xe.Elements Select txt = it.@Text, value = it.@Value
For Each item In lstitems
Dim s As String = item.txt
Next
End Sub
Does it mean that is not possible to use Option Strict On and Option Explicit On ?Or I make a syntax error ?Or is it just a bad configuration of my application ?
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Mar 19, 2010
I would like to use reflection on an anonymous type resulting from a LINQ to SQL query. I know that reflection on anonymous types works in general. The following code successfully generates a propertyinfo array with two elements:
Dim MyObject = New With {.Col1 = 1, .Col2 = "Test"}
Dim t As Type = MyObject.GetType()
Dim pilist As PropertyInfo() = t.GetProperties
[Code].....
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May 28, 2010
I've long since built a way around this, but it still keeps bugging me... it doesnt help that my grasp of dynamic LINQ queries is still shakey.
For the example:
Parent has fields (ParentKey, ParentField)
Child has fields (ChildKey, ParentKey, ChildField)
Pet has fields (PetKey, ChildKey, PetField)
[Code].....
The above Join call doesnt work. I sort of understand why it doesnt work, but hopefully it'll show you how I tried to accomplish this task.
After all this was done I would have appended a Select to finish the job.
I tried it with the PredicateBuilder with little success. I might not know how to use it right but it felt like it wasnt gonna handle the joining.
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Jul 2, 2011
Supposing the referenced List below contains 2 elements:
Dim Countries = From c In List _
Select New With { .Country = c.Country, .CountryID = c.CountryID }
The code above returns
.Country=Spain .CountryID = 1
.Country=Spain .CountryID = 1
How can I get the distinct values? The Countries query should contain only
.Country=Spain .CountryID = 1
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Apr 3, 2012
I am stumped. I have a DTO object with duplicates patient address data. I need to get only the unique addresses.
[Code]...
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Mar 11, 2009
Any best approach to what I'm trying to achieve (linq to sql, returning list of data to show in a grid/list etc etc)... Its complaining about anonymous type conversion, and from what I'm reading, thats not elegant way of doing it.
Public Function GetHistory(ByVal historyId As Integer) As List(Of ?????????)
Using dc As New myDataContext(Application.GetConnection)
Return (From t In dc.ActionTypes, a In t.MyTable Where a.HistoryID = historyId Select a.ActionOn, a.ActionBy, t.Description, a.ImpactedItem, a.ActionDescription).ToList
End Using
End Function
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Oct 25, 2011
I am in the process of learning LINQ to Objects. I am querying an array of reference elements using LINQ. In the code below, which I have marked with asteriks and PROBLEM, I am having difficulty returning any values for and I suspect its because of the multiple Select arguments.
'Program name:Querying an Array of Invoice Objects
'Created/revised:
'Project description:To demonstrate the use of LINQ to query objects
[Code].....
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Jul 14, 2011
I was toying around with some of the linq samples that come with LINQPad. In the "C# 3.0 in a Nutshell" folder, under Chater 9 - Grouping, there is a sample query called "Grouping by Multiple Keys". It contains the following query:
from n in new[] { "Tom", "Dick", "Harry", "Mary", "Jay" }.AsQueryable()
group n by new
{
[Code].....
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Apr 24, 2012
I've got the below, where I'm grouping a collection by a propery, then wanting to access the properties of my group. Problem I have is with the anonymous typing. Because of option strict I have to give an explicit type but I can't work out what the type should be. The below doesn't compile because t.HeadAccountKey isn't a value (as t has a type of object). So either I need do some casting or my linq selector is wrong,
[Code]....
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Apr 24, 2012
The documentation has an example about grouping on multiple properties[code]...
Is it possible to rewrite the original query to just return IEnumerable(Of CustomerRegionGroup), or do I have to use the anonymous type, and run a second query on the result of the first?
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