[VB.NET] Problema API Connessione USB

[leadergl]

Ciao ragazzi,
ho un problema nel convertire una mia applicazione da VB6 a VB.NET o meglio ho un problema con un mio driver che serve ad interfacciarsi con una periferica USB in quanto il VB.NET mi restituisce errore sulla chiamata alla API CreateFile(...) per la connessione con un determinato apparecchio, vi posto il codice che mi da errore ed il tipo di errore:

    Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, ByVal lpSecurityAttributes As SECURITY_ATTRIBUTES, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long
    Private Declare Function DeviceIoControl Lib "kernel32" (ByVal hDevice As Long, ByVal dwIoControlCode As Long, ByVal lpInBuffer As String, ByVal nInBufferSize As Long, ByVal lpOutBuffer As String, ByVal nOutBufferSize As Long, ByVal lpBytesReturned As Long, ByVal lpOverlapped As OVERLAPPED) As Long
    Private Declare Function ReadFile Lib "kernel32.dll" (ByVal hFile As Long, ByRef lpBuffer As String, ByVal nNumberOfBytesToRead As Long, ByRef lpNumberOfBytesRead As Long, ByRef lpOverlapped As OVERLAPPED) As Long
    Private Declare Function WriteFile Lib "kernel32.dll" (ByVal hFile As Long, ByRef lpBuffer As String, ByVal nNumberOfBytesToWrite As Long, ByRef lpNumberOfBytesWritten As Long, ByRef lpOverlapped As OVERLAPPED) As Long
    Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

    'Costanti delle WinAPI
    Private Const OPEN_EXISTING = 3
    Private Const GENERIC_READ = &H80000000
    Private Const GENERIC_WRITE = &H40000000
    Private Const FILE_SHARE_READ = &H1
    Private Const FILE_SHARE_WRITE = &H2

    'Attributi di Sicurezza per la comunicazione
    Private Structure SECURITY_ATTRIBUTES
        Dim nLength As Long
        Dim lpSecurityDescriptor As Long
        Dim bInheritHandle As Long
    End Structure

    'Gestisce la sincronia della comunicazione
    Private Structure OVERLAPPED
        Dim Ternal As Long
        Dim TernalHigh As Long
        Dim Offset As Long
        Dim OffsetHigh As Long
        Dim hEvent As Long
    End Structure


    'Passo dalla Modalità Modem a quella Normal
    Public Function SwitchToNormal(ByVal ModemGuID As String) As String
        Dim DeviceHandle As Integer
        Dim Sa As SECURITY_ATTRIBUTES
        Dim OV As OVERLAPPED
        Dim nShare As Integer
        Dim ReceivedData As Integer 'Dati Ricevuti da USB
        Dim Response As Integer
        Dim ResponseString As String

        nShare = FILE_SHARE_READ Or FILE_SHARE_WRITE

        LenghtReceivedBuffer = 261

        DeviceHandle = CreateFile("\\.\" & ModemGuID, GENERIC_WRITE, nShare, Sa, OPEN_EXISTING, 0, 0)

....
....

    End Function

nel punto dove mi sono fermato mi da errore...:

An arithmetic, casting, or conversion operation in a checked context results in a overflow

In VB6 ovviamente funzionava tutto bene....ma evidentemente in VB.NET deve essere cambiato qualcosa...qualcuno sa come aiutartmi?

[leadergl]

Ok trovati e corretti gli errori...

solo che sebbene durante il debug tutto vada correttamente la periferica nn fa ciò che dovrebbe...e non riesco a capire xkè...

ho anche confrontato i debug del codice VB.NET con quello del VB6 e sono identici..quindi tutto si svolge per bene, o almeno sembra, però i risultati non sono gli stessi...

non capisco dove e cosa sto sbagliando...