VS 2010 Lambda Expression Confusion
Sep 21, 2011I've been wondering about lambda expressions for a while now.Consider the following code..[code]But in the lambda expression I have access to all Sub Main's variables.
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VS 2010 Struggling With OrderBy Lambda Expression?
Aug 24, 2011I'm getting my feet wet with Lambda expressions and it's rather overwhelming.I have a UserPrincipal object called SelectedUser. I wish to get a sorted list of the user's groups This is what I have so far but when I include that code my application's form flashes a few times and closes! Also, what is the significance of the "r" in the "Return From r" statement?
Dim SortedGroups As PrincipalSearchResult(Of Principal) = GetSortedGroups(Me.SelectedUser.GetGroups())
Private Function GetSortedGroups(ByVal psp As PrincipalSearchResult(Of Principal)) As PrincipalSearchResult(Of Principal)
Return From r In psp.OrderBy(Function(t) t.Name)
End Function
Delegate 'System.Threading.ThreadStart' Requires An 'AddressOf' Expression Or Lambda Expression As The Only Argument To Its Constructor?
Jan 23, 2010I 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
AddressOf' Expression Or Lambda Expression
Feb 22, 2009From 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]...
C# - Lambda Expression: CS To .Net?
Aug 24, 2011I 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.
.net - Convert C# Lambda Expression To VB?
Mar 23, 2012In 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]...
.Net Lambda Expression With No Intellisense?
Mar 9, 2011Using 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]....
Convert C# Lambda += Expression To VB?
Feb 15, 2011How should the following C# code be converted to VB.Net? I have tried several code converters and none produce correct results.
[code]...
Converting A C# Lambda Expression?
Dec 15, 2011I 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].....
Extract The Lambda From An Expression?
Aug 9, 2010I 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]'.
Lambda Expression Not Working?
Jun 12, 2012If 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]......
View 2 RepliesLambda Expression Shorthand
Mar 30, 2010Currently, 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
Trick Lambda Expression In VB
May 8, 2009I 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?
View 3 RepliesUsing The Vb Equivilant Of The MAX Lambda Expression
Apr 7, 2011I 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]
View 1 RepliesVB Lambda Expression For Sub Delegate?
Nov 29, 2010There 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].....
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"?
Creating A Lambda Expression With Delegate?
Jul 16, 2010I 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.
Delegate Not Working Instead Of Lambda Expression
May 14, 2010I 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.
Getting Exports From Container In MEF (Lambda Expression)
Jun 22, 2012I 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].....
Lambda Expression And Validity Of Delegates
May 6, 2010In MSDN documentation defination about lambda expression is "A lambda expression is a function or subroutine without a name that can be used wherever a delegate is valid ". Here validity of delegate is necessery only when we are passing lambda expression as an argument to a method.
[Code]...
Lambda Expression With Ternary Operator In VB?
Feb 26, 2010Lambda expression with ternary operator in VB?
View 15 RepliesLinq - Examples Of .NET Lambda Expression?
Feb 3, 2011Where 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.
View 1 RepliesMake Lambda Expression Dynamically?
Jul 13, 2011In Entity Framework I usually do something like:
modelBuilder.Entity(Of Model).HasKey(Function(item As Model) New With {item.PropertyA, item.PropertyB })
to map a composite primary key
I need to write a generic function like[code]....
Use A Function Both Directly And As A Lambda Expression?
Apr 24, 2012Should I be concerned about the performance of the Compile method here?[code]...
The reason I want the lambda expression is because I want that function to be able to get all the way through LINQ-to-SQL to be converted to SQL. The reason I want the direct version is because I have other code that I want to validate individual serial numbers before submitting changes. And I fear that GetValidSerialNumbers.Contains(serialNumber) will execute a more-complex-than-necesssary query.
Use Lambda Expression Within ASP.NET MVC View Using Program?
Oct 28, 2009With ASP.NET MVC 1.0, .NET 3.5 and C# you can easily pass a method a lambda expression that will do a "Response.Write" some content when it's executed within the method[code]...
View 1 RepliesVS 2008 - Convertion Of C# And Lambda Expression To .net
Feb 1, 2010is there any perfect tool of converting C# and lambda expressions into vb.net code.
View 9 RepliesC# - Convert This Anonymous Method / Lambda Expression Across?
Feb 23, 2010How 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.
'ByRef' Parameter '<parametername>' Cannot Be Used In A Lambda Expression?
Feb 12, 2011I'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]...
C# - Use A Method Instead Of Lambda Expression With Extra Parameters?
Jan 27, 2012I have an inline lambda expression that I would like to use throughout my application. I just can't seem to find a reference on how to do this with more parameters than the element being tested. Here is a quick example of what I currently have.
Private Sub Test()
Dim List As New List(Of String) From {"Joe", "Ken", "Bob", "John"}
Dim Search As String = "*Jo*"
[Code].....
C# - Wrap Code In A Lambda Expression Using A BackgroundWorker?
Jun 24, 2011Consider the following C# code:
private void SomeMethod()
{
IsBusy = true;
var bg = new BackgroundWorker();
bg.DoWork += (sender, e) =>
[code]....
However, I'd like to be able to implement a method like SomeMethod from the C# example in VB.net. Likely this means wrapping the Backgroundworker in another class (which is something I want to do for dependency injection and unit testing anyway).