Using A Lambda Expression With ByRef Argument Gives Incompatible Signature Error

Mar 9, 2011

Why does this:Private [Function] As Func(Of Double, String) = Function(ByRef z As Double) z.ToString

gives the following error:Nested function does not have a signature that is compatible with delegate String)'.

While this:Private [Function] As Func(Of Double, String) = Function(ByVal z As Double) z.ToString

Does not? (The difference is ByRef/ByVal)

Furthermore, how might I implement such a thing?

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Delegate 'System.Threading.ThreadStart' Requires An 'AddressOf' Expression Or Lambda Expression As The Only Argument To Its Constructor?

Jan 23, 2010

I got this Error. below is my code.

GenerateTheList is function.Need help
Private Sub buttGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttGenerate.Click
Dim thread1 As New Thread(New ThreadStart(GenerateTheList))
thread1.Start()
End Sub

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'ByRef' Parameter '<parametername>' Cannot Be Used In A Lambda Expression?

Feb 12, 2011

I'm using SharpZipLib to compress files. The library is wrapped in a plugin interface, in a separate DLL. I pass the plugin dll a ByRef parameter to keep track of the compression progress.SharpZipLib, while compressing, will periodically call a delegate sub passed when launching the compression. I can't figure out how to update the ByRef parameter when the delegate is called. If I try to assign the ByRef variable in the body of a lamba expression, I get a 'ByRef' parameter '<parametername>' cannot be used in a lambda expression error.

[code]...

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Method - Action(Of T) And Lambda - Error: 'Expression Does Not Procedure A Value'

Apr 22, 2009

Imports System.Reflection

Public Class Test

[CODE]......................

'This line indicates a compile error: 'Expression does not procedure a value':

[CODE]..................

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VS 2008 ERROR: Argument 'Expression' Is Not A Value Value

Feb 3, 2011

IM doing an assignment for college. ITs saving records to a file, and getting them back basically. So really not that hard.

The error is occuring around the following line of

[Code]...

basically all I've been doing so far, is formatting the output fields to show dates correctly. And I believe I'm getting this error. There is data in the form becasue i wrote it there to test it.I think im saving this right, but it seems ODD that its not working for me.

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Error: Expression Is Not An Array Or A Method And Cannot Have An Argument List

Aug 4, 2011

i have these 3 sets of code that are giving me INT() errors. Error: Expression is not an array or a method, and cannot have an argument list.

Code1:

Private Sub Form6_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim Browser As New WebBrowser

[code]....

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DateTimePicker Incompatible With Column Expression Is SQL Query?

Dec 12, 2011

I have DateTimePicker, and when I execute this procedure:

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Me.TextBox1.Text = Me.DateTimePicker1.Value
sqltest = "SELECT * FROM Table " & _
"WHERE TOT_DATE = '" & Me.DateTimePicker1.Text & "'"
datest = New OleDb.OleDbDataAdapter(sqltest, con)
datest.Fill(dstest, "datepickertab")
Me.DataGridView1.DataSource = dstest.Tables(0)
End Sub

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.net - ByRef Underlined With "Expression Expected" Error When Trying To Pass In A Object Of Type List(Of ClsFooDetail)?

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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Get The Error "VB 9.0 Does Not Support This Kind Of Lambda Expression"?

Nov 23, 2010

I just upgraded from Visual Studio 2005 to Visual Studio 2010 yesterday. I tried opening my site; it started the conversion wizard and seemed to work OK. However, I get the error "Visual Basic 9.0 does not support this kind of lambda expression." Here is my code:[code]....

The error is on the "Function()" line. I thought multi-line lambda functions were one of the new VS2010 features. Why am I getting a VB9.0 error in VS2010?

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AddressOf' Expression Or Lambda Expression

Feb 22, 2009

From this code

[Code]...

If I put New Action(AddressOf PrivateMesage), then I get the following error: Bounds can be specified only for the top-level array when initializing an array of arrays. on the following code

[Code]...

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VB2008 Calculator - Error "expression Is Not An Array Or Method And Cannot Have An Argument List"

Oct 28, 2009

I am getting two errors for "expression is not an array or method, and cannot have an argument list," When debugging, the formula works quite well. However I will lose points for blue squiggly lines. I am not allowed to use any built in functions like math.

[Code]...

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Lambda - Is This Grammar In .Net Allowed (Procedure As Argument)

Jan 16, 2012

Public Class ABC
Public Sub Foo()
AA.Bar(nothing, Sub()
End Sub)
End Sub
End Class

I feel confused at the second argument of function AA.Bar, this argument is specified as a Sub/End Sub procedure.What is the function AA.Bar's possible definition looks like?An event? Delegate? Pointer like?...Where can I find the latest VB.NET Grammar Specification?What are the new features in VB.NET 4?

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GetAnsyKey Error "PInvoke Signature Does Not Match The Unmanaged Target Signature"

Jul 11, 2010

I was trying to use a GetAsyncKeyState code but each time I run the program an error occers where

[Code]....

'A call to PInvoke function 'WindowsApplication1!WindowsApplication1.Form1::GetAsyncKeyState' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.' The full code is in timer with (1) time interval

[Code]...

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C# - Solve This Error "Cannot Convert Lambda Expression To Type 'string' Because It Is Not A Delegate Type"

Jun 12, 2010

. I get this error: "Cannot convert lambda expression to type 'string' because it is not a delegate type" - keyword select become underlined in blue

[Code]...

Above code should displays drop list of employees first name and last name in a combo box

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Is The Return Expression ByRef Or ByVal

Jun 9, 2011

If a function returns a private shared (static) string, or a string declared as a module level variable, is the returned a reference to the shared string's instance or a different string instance having the same value?

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C# - Lambda Expression: CS To .Net?

Aug 24, 2011

I am dumb founded at this statement....maybe its just too many hours/days of doing C# to VB.Net conversion but i am drawing a blank on this conversion.

List<string> sColors = new List<string>(this.CustomPaletteValues.Split(','));
try {
List<Color> colors = sColors.ConvertAll<Color>(s => (Color)(new ColorConverter().ConvertFromString(s)));

What i have so far:

Dim colors As List(Of Color) = sColors.ConvertAll(Of Color)(....)

As you can see its the content of the lambda that i am hitting a brick wall with.

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.net - Convert C# Lambda Expression To VB?

Mar 23, 2012

In looking at Fuzzy Date Time Picker Control in C# .NET? Piotr Czaapla's answer to that question is exactly what I need. unfortunately, I'm a VB.NET guy and I'm not that familiar with lambda expresions, so my attempts to convert the code have resulted in hours of misplaced parenthesis and banging my head with a brick.

Any chance some bi-lingual wizard could convert the C# code to VB.net for me?

[Code]...

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.Net Lambda Expression With No Intellisense?

Mar 9, 2011

Using lambda's in VB.Net results in no intellisense. Is this a bug with VS2010 or expected? Note that it works fine in C#

Return Array.TrueForAll(chequeColl, Function(x) x.Number <> "N") 'No intellisense Number does not appear
Return Array.TrueForAll(chequeColl, Function(x As MyClass) x.Number <> "N") 'Now casted intellisense appears

UPDATE: Here's an example

Public Class Cheque
Public Property Id As String
Public Property Status As Byte

[code]....

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Convert C# Lambda += Expression To VB?

Feb 15, 2011

How should the following C# code be converted to VB.Net? I have tried several code converters and none produce correct results.

[code]...

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Converting A C# Lambda Expression?

Dec 15, 2011

I will probably sound like a bad developer here, but I am attempting to convert some code from the following page from C# to VB.NET:The code I am having trouble converting is from Step 4 of "Joining a Multicast Group" on the page, and here is the code with the comment lines removed:

private void Join()
{
_receiveBuffer = new byte[MAX_MESSAGE_SIZE];

[code].....

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Extract The Lambda From An Expression?

Aug 9, 2010

I want to implement this function:

Public Function GetFunc(Of TSource, TResult) _
selector As Expression(Of Func(Of TSource, TResult)) _
As Func(Of TSource, TResult)

[code]....

UPDATE:I have the following issue, it's a part of a function:

Dim obj As Object = value
For Each exp In expressions
If obj Is Nothing Then Return [default]

[code]....

Exception Details:

ArgumentException:Object of type 'System.Linq.Expressions.Expression`1 [System.Func`3[System.Char,System.Char,System.Char]]'cannot be converted to type 'System.Func`3[System.Char,System.Char,System.Char]'.

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Lambda Expression Not Working?

Jun 12, 2012

If been try to convert some code I have from VB.net to C# but I just cannot get it working!first is the vb code I'm only interested in the line that has the Lambda Expression for the C#[code]......

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Lambda Expression Shorthand

Mar 30, 2010

Currently, I have code similar to this:

xxx, _
If(dr.Table.Columns.Contains("EnterpriseID"), dr.Field(Of Integer)("EnterpriseID"), -1), _
xxx

I would like to create a Lamdba expression something like the following (this doesn't work):

Dim xCol As Func(Of DataRow, String, Type, Object, Object) = _
Function(dr, x, t, dflt) _
If(dr.Table.Columns.Contains(x), dr.field(Of t)(x), dflt)

So that I can say something like:

xxx, _
xCol(dr, "EnterpriseID", GetType(System.Integer), -1), _
xxx

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Trick Lambda Expression In VB

May 8, 2009

I know in VB Lambda expressions must return a value and can only have one statement. But in my case I just need to execute a Sub that does not return a value. Is there a way to trick it by somehow returning a dummy value yet still call my Sub? If possible what would the syntax be like?

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Using The Vb Equivilant Of The MAX Lambda Expression

Apr 7, 2011

I am having an issue using the vb equivilant of the MAX lambda expression. at foos.Max(function(x) x.id) when I try to intellisense the property ID VS will not show it. But when i run the example it works. Is there something I am doing which is wrong, an i am just lucky it runs? [Code]

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VB Lambda Expression For Sub Delegate?

Nov 29, 2010

There is the code:

Private Sub InsertItemInCache(Of T)(ByVal item As CachedItem(Of T), ByVal dependency As AggregateCacheDependency, _
ByVal key As String, ByVal updateCallBack As CacheItemUpdateCallback)

[code].....

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C# - Using Iteration Variable In A Lambda Expression?

Feb 16, 2012

[URL]..Module Module1

[Code]...

It says the result will always be 5 namely the final value of i. How come?

They don't put the iteration variable in the "closure"?

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Creating A Lambda Expression With Delegate?

Jul 16, 2010

I am Creating a Lambda Expression, but it' not getting me the write Out put :

Public Class Form1
Delegate Function GetLastChar(ByVal S As String) As String
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

[code]....

I want Send a Name like "Arindam" and its return me "m", the last character.but in messagbox return value shows "fasle" I can't under stand why it's showing "False" instead of "m", the last character.

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Delegate Not Working Instead Of Lambda Expression

May 14, 2010

I am having a generic ListOf-collection holding the self-created User-object, I can filter for users by using lambda-expression like this:
Dim reviewers As List(Of User) = users.Where(Function(u) u.DvRoleID = 2).ToList

Instead of using the lambda expression I can also write the function and call it as argument like this:
Public Function GetReviewer1(ByVal u As User) As Boolean
If u.DvRoleID = 2 Then
Return True
[Code] .....

Now the question: why can't I create a delegate having the same signature as the GetReviewer1 function and use the delegate as argument inside the where-clause like this:
Delegate Function Criteria(ByVal u As User) As Boolean
Public Function GetReviewer1(ByVal u As User) As Boolean
If u.DvRoleID = 2 Then
[Code] .....
The compiler does not accept the crit delegate as argument.

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Getting Exports From Container In MEF (Lambda Expression)

Jun 22, 2012

I am trying to see if the controller class name is the name of the controller name passed in. I think my lambda expression is wrong and that is why it isn't working properly. I am passing in the correct controller names, but the export variable is always null.

Public Function CreateController(requestContext As System.Web.Routing.RequestContext,
controllerName As String)

[Code].....

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