WinScard.dll and VB2008

[John Whitworth]

Hi,

I'm rewriting an old VB6 app of mine in VB2008. All has been going well with
calls to winscard.dll, until I needed to send an array of bytes as part of a
structure. When using a winscard trace, I can see that the bytes in the
array suddenly become nonsense, whereas I know that what I called the DLL
with was good.

I think I need to do something along the lines of MarshalAs, but I haven't
the first clue where to start. Any assistance would be greatly appreciated.
Snippets of code follow (the actual call causing trouble is on the
"lResult=" line).

Thanks

John

EMV_Fns.vb
==========

Public StructC3 As APDURec

..
..
..

Public Function Case3APDU(ByVal CLA As Int32, ByVal INS As Int32, ByVal
P1 As Int32, ByVal P2 As Int32, ByVal Lc As Int32, ByVal Data As String) As
ResponseStruct

Dim LoadByte As Integer

StructC3.bCLA = CLA
StructC3.bINS = INS
StructC3.bP1 = P1
StructC3.bP2 = P2
StructC3.bP3 = Lc
ReDim StructC3.Data(Lc - 1)

For LoadByte = 0 To (Len(Data) / 2) - 1
StructC3.Data(LoadByte) = Val("&H" + Mid(Data, 1 + (LoadByte *
2), 2))
Next LoadByte

SendBuffLen = &H5 + Lc
RcvBuffLen = &HFF

lResult = PCSC.SCardTransmit(hCard, 0, StructC3, SendBuffLen, 0,
ReceiveBuff(0), RcvBuffLen)

If lResult <SCARD_S_SUCCESS Then
DummyByte = PcscError("Case3-SCardTransmit", lResult)
End If

Case3APDU = ProcessResponse(ReceiveBuff, RcvBuffLen, True, 8, 16,
True)

End Function
PCSC_Fns.vb
===========

Public Structure APDURec
Dim bCLA As Byte
Dim bINS As Byte
Dim bP1 As Byte
Dim bP2 As Byte
Dim bP3 As Byte
Dim Data() As Byte
Dim IsSend As Boolean
End Structure

..
..
..

Declare Ansi Function SCardTransmit Lib "WinScard.dll" ( _
ByVal hCard As Int32, ByVal pioSendRequest As Int32, _
ByRef sendbuff As APDURec, ByVal SendBuffLen As Int32, _
ByVal pioRecvRequest As Int32, ByRef RecvBuff As Byte, _
ByRef RecvBuffLen As Int32) As Int32

[John Whitworth]

"John Whitworth" <se****@gEEEEEEEEEEEEEEEEmail.comwrote in message
news:Ol**************@TK2MSFTNGP03.phx.gbl...

Hi,

I'm rewriting an old VB6 app of mine in VB2008. All has been going well
with calls to winscard.dll, until I needed to send an array of bytes as
part of a structure. When using a winscard trace, I can see that the bytes
in the array suddenly become nonsense, whereas I know that what I called
the DLL with was good.

As suggested in an old message on another forum, I have tried using
System.Text.Stringbuilder for this, but it fails with an error saying that a
normal string might work. It doesn't! :-(

Thx

John

[John Whitworth]

"John Whitworth" <se****@gEEEEEEEEEEEEEEEEmail.comwrote in message
news:Ol**************@TK2MSFTNGP03.phx.gbl...

Hi,

I'm rewriting an old VB6 app of mine in VB2008. All has been going well
with calls to winscard.dll, until I needed to send an array of bytes as
part of a structure. When using a winscard trace, I can see that the bytes
in the array suddenly become nonsense, whereas I know that what I called
the DLL with was good.

I think I've gone some way to solving this now. I've set up a new ByteStream
function, which just copies everything that was in an APDUrec structure into
a Byte() field. This then seems to pass into the DLL OK.

Thanks

John