byref

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. Here's my code: Using InputFile As New IO.FileStream

After some playing around F# member constraints feature and writing function like this: let inline parse< ^a when ^a : (static member Parse: string -> ^a) > s = (^a: (static member Parse: string -> ^a) s) That works perfectly fine: let xs = [ "123"; "456"; "999" ] |> List.map parse<int> I'm trying to write other func tryParse , that uses static method TryParse and wraps the parse result into 'a option type for better support in F#. Something like this doesn't compiles: let inline tryParse s = let mutable x = Unchecked.defaultof< ^a> if (^a: (static member TryParse: string * ^a byref -> bool)

If arrays are returned by reference, why doesn't the following work: 'Class1 class module Private v() As Double Public Property Get Vec() As Double() Vec = v() End Property Private Sub Class_Initialize() ReDim v(0 To 3) End Sub ' end class module Sub Test1() Dim c As Class1 Set c = New Class1 Debug.Print c.Vec()(1) ' prints 0 as expected c.Vec()(1) = 5.6 Debug.Print c.Vec()(1) ' still prints 0 End Sub In VBA, arrays are never returned by reference unless they are returned through a ByRef parameter. Furthermore, whenever you use = to assign an array to a variable, you've made a new copy of the

Well, I came to understand that F# is able to manage references (some sort of C++ like references). This enables the possibilities to change value of parameters passed in functions and also enables the programmer to return more than a single value. However here's what I need to know: Ref keyword: The keyword ref is used to create, from a value, a reference to that value of the inferred type. So let myref = ref 10 This means that F# will create an object of type Ref<int> putting there (in the mutable field) my int 10 . OK. So I assume that ref is used to create instances of the Ref<'a> type. Is

Is it really impossible to create an extension method in C# where the instance is passed as a reference? Here’s a sample VB.NET console app: Imports System.Runtime.CompilerServices Module Module1 Sub Main() Dim workDays As Weekdays workDays.Add(Weekdays.Monday) workDays.Add(Weekdays.Tuesday) Console.WriteLine("Tuesday is a workday: {0}", _ CBool(workDays And Weekdays.Tuesday)) Console.ReadKey() End Sub End Module <Flags()> _ Public Enum Weekdays Monday = 1 Tuesday = 2 Wednesday = 4 Thursday = 8 Friday = 16 Saturday = 32 Sunday = 64 End Enum Module Ext <Extension()> _ Public Sub Add(ByRef Value

I just installed Visual Studio 2010 Service pack (proposed on Windows Update), and I can see a new feature on the "intellisense" that means when I write a Function or Sub in VB.NET it doesn't auto-complete parameters with ByRef or ByVal ... 1) Is there anyway that I can configure this option back to how it was before? 2) If I don't specify ByX , which one is used by default? (it seems like it is always ByRef ) Jay Tim covered what you asked directly, but something else to keep in mind is that any reference type variable, like a user defined class even if passed by value will allow you to make

In VB.NET, which is faster to use for method arguments, ByVal or ByRef ? Also, which consumes more resources at runtime (RAM)? I read through this question , but the answers are not applicable or specific enough. user50612 Byval and ByRef arguments should be used based on requirements and knowledge of how they work not on speed. http://www.developer.com/net/vb/article.php/3669066 In response to a comment by Slough - Which consumes more resources at runtime? Parameters are passed on the stack. The stack is very fast, because its memory allocation is simply a pointer increment to reserve a new