Boxing and UnBoxing VB.NET vs C#

Andy Read

Dear all,

From the following examples. Can anyone please tell me why the C# IL
produces the unbox statement and the VB doesn't?

* Forgive me if the code isn't perfect, I don't have VS.NET on my internet
machine!

VB

Dim X as Integer
Dim Y as Object = X '** Box here.
X = CType(X,Integer) '** No Unbox here??
C#

int X;
Object Y = X; // Box here
X = (int) Y; // Unbox here

Many Thanks

Andy Read

Jul 19 '05 #1

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4941

Mattias Sjögren

Andy,

From the following examples. Can anyone please tell me why the C# IL
produces the unbox statement and the VB doesn't?

If you use the DirectCast operator intead of CType, you'll get an
unbox instruction. CType calls into the VB library to support
conversion in addition to casting and unboxing.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/
Please reply only to the newsgroup.

Jul 19 '05 #2

Andy Read

Thanks Mattias

"Mattias Sjögren" <ma********************@mvps.org> wrote in message
news:#M**************@TK2MSFTNGP10.phx.gbl...

Andy,
From the following examples. Can anyone please tell me why the C# IL
produces the unbox statement and the VB doesn't?

If you use the DirectCast operator intead of CType, you'll get an
unbox instruction. CType calls into the VB library to support
conversion in addition to casting and unboxing.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/
Please reply only to the newsgroup.

Jul 19 '05 #3

Andy Read

Thanks Mattias

"Mattias Sjögren" <ma********************@mvps.org> wrote in message
news:#M**************@TK2MSFTNGP10.phx.gbl...

Andy,
From the following examples. Can anyone please tell me why the C# IL
produces the unbox statement and the VB doesn't?

If you use the DirectCast operator intead of CType, you'll get an
unbox instruction. CType calls into the VB library to support
conversion in addition to casting and unboxing.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/
Please reply only to the newsgroup.

Jul 19 '05 #4

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