Trying to read a C dll and convert some code

[Bum]

Hello all,

I have a C dll I need to tap into and some C code to interpret to vb.net 2005, but am so far unsuccessful. I just get the generic "runtime has encountered a fatal error at XXXXXX memory". I think my prob is passing the variables. Also, I know the * refers to pointers, but not sure how to interpret them. Hope someone can help...

'Here is the C Code:

enum XXXXStatus {StatusUnknown = 0, 
          Processed, 
          NoSuchSession,
          NoSuchInfo, 
          ReadOnlyInfo,
          InvalidInfo,
          NotYetImplemented = -1};
 
enum DataEncoding {EncodingUnknown = 0, 
        NoValue,
        ZeroTerminatedString, 
        Short16, 
        Int32, 
        Double64, 
        Boolean8, 
        Char8, 
        BinaryByte8
                                };
 
#define XXXX_INFO_ID_LENGTH    32
 
struct XXXXSessionInfoParameter {
    char          InfoID[XXXX_INFO_ID_LENGTH];
    int    InfoValueLength;        /* Total bytes */
    enum        DataEncoding        InfoEncoding;
    int            InfoDataCount;    /* Number of values or elements */
    void         *InfoData;
};
 
 
struct XXXXSessionInfoResponse {
    enum XXXXStatus     Status;
    char    InfoID[XXXX_INFO_ID_LENGTH];
    int             InfoParameterCount;
    struct    XXXXSessionInfoParameter         *InfoParameterList;
};
 
 
struct XXXXSessionInfoResponse __declspec (dllexport) *XXXXGetSessionInfo (unsigned long SessionID,  char    *InfoID);

'here's the call in C:

Info = XXXXGetSessionI nfo (SessionID, “SystemInventor y”)


'now here's what I have sofar in VB.net:

Public Enum DataEncoding
        EncodingUnknown = 0
        NoValue
        ZeroTerminatedString
        Short16
        Int32
        Double64
        Boolean8
        Char8
        BinaryByte8
    End Enum
 
    Public Enum XXXXStatus
        StatusUnknown = 0
        Processed
        NoSuchSession
        NoSuchInfo
        ReadOnlyInfo
        InvalidInfo
        RequestComplete
        NotYetImplemented = -1
    End Enum
 
   <DllImport("XXXXapi.dll", EntryPoint:="XXXXGetSessionInfo", ExactSpelling:=False, CharSet:=CharSet.Unicode)> _
    Public Function XXXXGetSessionInfo(ByVal SessionID As ULong, ByRef InfoID As String) As XXXXSessionInfoResponse
    End Function
 
 Public Class XXXXSessionInfoParameter
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> Public InfoID As String
        Public InfoValueLength As Integer ' Total bytes 
        Public InfoEncoding As DataEncoding
        Public InfoDataCount As Integer ' Number of values or elements 
        Public InfoData As IntPtr
    End Class
 
Public Class XXXXSessionInfoResponse
        Public Status As XXXXStatus
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=32)> Public InfoID As String
        Public InfoParameterCount As Integer
        Public InfoParameterList As XXXXSessionInfoParameter
    End Class

'heres the call I use in vb.net:

dim Info As XXXXSessionInfoResponse
 
     'please note sessionID was given in earlier code not shown
     Info = XXXXGetSessionInfo(SessionID, "SystemInventory")

Thanks in advance! B