Need help to marshall Win32 DLL call to VB.net

  • Thread starter Thread starter Gilles Vollant \(MVP\)
  • Start date Start date
G

Gilles Vollant \(MVP\)

Hello

I've (in WinImage SDK http://www.winimage.com/wima_sdk.htm ) a function that
I need to use from a VB.Net apps

First, on the unmanaged Win32 DLL, I've a function which get the number of
item (function GetNbEntryCurDir)
after, I allocate an array and I call GetDirInfo to fill the array


// GetNbEntryCurDir : Get the number of entry of cur directory
DWORD WIMAAPI GetNbEntryCurDir(HIMA hIma);


#define MAXLFN 256

typedef struct
{
char nom[8];
char ext[3];
char szCompactName[13];
BYTE bAttr;

BYTE dir_CreateMSec;
WORD dir_CreateDate;
WORD DosTime;
WORD DosDate;

BOOL fIsSubDir;
BOOL fSel; // for private use of client app.
BOOL fLfnEntry;
DWORD dwSize;
UINT uiPosInDir;
DWORD dwLocalisation;
DWORD dwTrueSize;
char longname[MAXLFN];
WORD dir_CreateTime;
WORD dir_LastAccessDate;
} DIRINFO;


// GetDirInfo : Get info about the entry of cur directory
// LPDIRINFO : array of DIRINFO that will receive the info
// (use GetNbEntryCurDir for know the size needed)
// bSort : specify how the file must be sort
// (SORT_NONE, SORT_NAME, SORT_EXT, SORT_SIZE or SORT_DATE)
BOOL WIMAAPI GetDirInfo(HIMA hIma,LPDIRINFO lpdi,BYTE bSort);

on C++ unmanager, I do:
{
HIMA hIma; // filled by other function
DWORD dwNumber = GetNbEntryCurDir(hIma);
DIRINFO* pDirInfo = (DIRINFO*)malloc(sizeof(DIRINFO) * dwNumber );
GetDirInfo(hIma,pDirInfo,0);
DWORD i;
for (i=0;i<dwNumber;i++) printf("%s\n", (pDirInfo+i)->longname)
}

I want do the same work on VB.net

I had converted DIRINFO structure on VB.net

Public Const MAXLFN As Short = 256

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi, Pack:=1)> _

Public Structure DIRINFO

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=8)> Public nom As String

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=3)> Public ext As String

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=13)> Public szCompactName As
String

Public bAttr As Byte

Public dir_CreateMSec As Byte

Public dir_CreateDate As Short

Public DosTime As Short

Public DosDate As Short

Public fIsSubDir As Integer

Public fSel As Integer

Public fLfnEntry As Integer

Public dwSize As Integer

Public uiPosInDir As Integer

Public dwLocalisation As Integer

Public dwTrueSize As Integer

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAXLFN)> Public longname As
String

Public dir_CreateTime As Short

Public dir_LastAccessDate As Short

End Structure



I need help to convert VB Array to unmanaged C-Style array. I suppose I need
<MarshalAs(UnmanagedType.LPArray)> or <MarshalAs(UnmanagedType.ByValArray)>



I tried

Declare Function GetDirInfo Lib "wimadll.dll" (ByVal Ima As Integer,
<MarshalAs(UnmanagedType.LPArray)> ByRef dia As DIRINFO, ByVal bSort As
Byte) As Boolean



without success



Any help or tips will be a lot welcome !



regards

Gilles Vollant
 
I found a (bad) solution



<StructLayout(LayoutKind.Sequential)> _

Public Structure DirInfoArrayStruct

<MarshalAs(UnmanagedType.ByValArray, SizeConst:=32)> Public diItem As
DIRINFO()

End Structure





This solution is not very good :

- I must known how many item I'll have when I compile (here I put 32)

- when a high number of item, I've stack error
 
Hi,

Gilles Vollant (MVP) said:
Hello

I've (in WinImage SDK http://www.winimage.com/wima_sdk.htm ) a function
that I need to use from a VB.Net apps

First, on the unmanaged Win32 DLL, I've a function which get the number of
item (function GetNbEntryCurDir)
after, I allocate an array and I call GetDirInfo to fill the array


// GetNbEntryCurDir : Get the number of entry of cur directory
DWORD WIMAAPI GetNbEntryCurDir(HIMA hIma);


#define MAXLFN 256

typedef struct
{
char nom[8];
char ext[3];
char szCompactName[13];
BYTE bAttr;

BYTE dir_CreateMSec;
WORD dir_CreateDate;
WORD DosTime;
WORD DosDate;

BOOL fIsSubDir;
BOOL fSel; // for private use of client app.
BOOL fLfnEntry;
DWORD dwSize;
UINT uiPosInDir;
DWORD dwLocalisation;
DWORD dwTrueSize;
char longname[MAXLFN];
WORD dir_CreateTime;
WORD dir_LastAccessDate;
} DIRINFO;


// GetDirInfo : Get info about the entry of cur directory
// LPDIRINFO : array of DIRINFO that will receive the info
// (use GetNbEntryCurDir for know the size needed)
// bSort : specify how the file must be sort
// (SORT_NONE, SORT_NAME, SORT_EXT, SORT_SIZE or SORT_DATE)
BOOL WIMAAPI GetDirInfo(HIMA hIma,LPDIRINFO lpdi,BYTE bSort);

on C++ unmanager, I do:
{
HIMA hIma; // filled by other function
DWORD dwNumber = GetNbEntryCurDir(hIma);
DIRINFO* pDirInfo = (DIRINFO*)malloc(sizeof(DIRINFO) * dwNumber );
GetDirInfo(hIma,pDirInfo,0);
DWORD i;
for (i=0;i<dwNumber;i++) printf("%s\n", (pDirInfo+i)->longname)
}

I want do the same work on VB.net

I had converted DIRINFO structure on VB.net

Public Const MAXLFN As Short = 256

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi, Pack:=1)> _

Public Structure DIRINFO

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=8)> Public nom As String

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=3)> Public ext As String

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=13)> Public szCompactName
As String

Public bAttr As Byte

Public dir_CreateMSec As Byte

Public dir_CreateDate As Short

Public DosTime As Short

Public DosDate As Short

Public fIsSubDir As Integer

Public fSel As Integer

Public fLfnEntry As Integer

Public dwSize As Integer

Public uiPosInDir As Integer

Public dwLocalisation As Integer

Public dwTrueSize As Integer

<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAXLFN)> Public longname As
String

Public dir_CreateTime As Short

Public dir_LastAccessDate As Short

End Structure



I need help to convert VB Array to unmanaged C-Style array. I suppose I
need <MarshalAs(UnmanagedType.LPArray)> or
<MarshalAs(UnmanagedType.ByValArray)>



I tried

Declare Function GetDirInfo Lib "wimadll.dll" (ByVal Ima As Integer,
<MarshalAs(UnmanagedType.LPArray)> ByRef dia As DIRINFO, ByVal bSort As
Byte) As Boolean
Click to expand...

Can't say i tested something like this recently, but you could try something
like:

Imports System.Runtime.InteropServices

Declare Function GetDirInfo Lib "wimadll.dll" (ByVal Ima As Integer,
<[In](),Out()> ByVal dia() As DIRINFO, ByVal bSort As Byte) As Boolean

HTH,
Greetings
 
Back
Top