C++ Function Pointer to VB.Net

[banleong@gmail.com]

To all gurus,

I am currently converting some of C++ codes to VB.net

The C++ Codes is as follows :

=============== == C++ CODE =============== ===
typedef struct _tagBBCameraPar ameter
{
unsigned int preview_width;
unsigned int preview_height;
unsigned int preview_x;
unsigned int preview_y;
unsigned int preview_format;
unsigned int preview_zoom;

const TCHAR* capture_file_na me;

unsigned int contrast;
unsigned int saturation;
unsigned int brightness;

} BBCameraParamet er;

typedef LPVOID HBBCAMERA;

BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraPreview Stop(HBBCAMERA) ;

=============== == END C++ CODE =============== ===

I managed to convert most of the codes to VB.Net but when I try to fun
BBCameraPreview Start function, it gives error.

'============== ===Partial VB.Net Code


Public Shared Function BBCameraPreview Start(ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

Public Shared Function BBCameraPreview Stop(ByVal HBBCamera As IntPtr)
As Integer
End Function

'=========== END OF PARTIAL VB.NET CODES

This is how i pass the parameters;

Dim BBParam as BBCameraParamet er '// already declared but not shown
here
Dim HBBCamera as IntPtr '//Handle

'I have no problems getting handle but once i set the parameters for
BBParam and pass as follows, i get error (not much help from the
message).

BBCameraPreview Start(HBBCAMERA , BBParam)

How do I call function BBCameraPreview Start correctly? Did i do it
correctly?

Please advices.
Thanks

[Branco Medeiros]

Re: C++ Function Pointer to VB.Net

banleong wrote:
<snip>

I am currently converting some of C++ codes to VB.net

<snip>

BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraPreview Stop(HBBCAMERA) ;
>
=============== == END C++ CODE =============== ===
>
I managed to convert most of the codes to VB.Net but when I try to fun
BBCameraPreview Start function, it gives error.
>
'============== ===Partial VB.Net Code
>
Public Shared Function BBCameraPreview Start(ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function
>
Public Shared Function BBCameraPreview Stop(ByVal HBBCamera As IntPtr)
As Integer
End Function

<snip>

Don't those need to be Declares to external libraries instead of local
methods?

Something like:

Declare Function BBCameraPreview Start Lib "???" ( _
ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer


Declare Function BBCameraPreview Stop Lib "???" ( _
ByVal HBBCamera As IntPtr) As Integer


HTH.

Regards,

Branco.

[lord.zoltar@gmail.com]

Re: C++ Function Pointer to VB.Net

I think function pointers are replaced (at least functionally) by
delegates. I'm not entirely sure what you're trying to do her, so I
can't suggest any code easily, but maybe look into using delegates
instead of function pointers.

What kind of error are you getting?

[banleong@gmail.com]

Re: C++ Function Pointer to VB.Net

Branco,

Yes, it is external libraries.

Lord Zoltar,
Basically, when i tried to pass the parameter as follows in this
function, i got error:

BBCameraPreview Start(HBBCAMERA , BBParam)

where HBBCamera is the handler and BBParam is the struction
declaration of BBCameraParamet er.

I assume there is not problem getting the handler because I can call
other functions like getting camera info by passing the handler
(function not shown here).

So, I assume there could be the way I declare the structure or passing
parameters of BBParam that causes the error.

Perhaps i should break down by questions to:
1) Is my declaration correct for BBCameraPreview Start in VB.net code
based on the C++ codes?

BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);

to

Public Shared Function BBCameraPreview Start(ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

2) Did i pass the parameter correct when calling BBCameraPreview Start
function? Below are my procedure

Dim BBParam As BBCameraParamet er 'Declare variable to hold
BBCameraParamet er structure
With BBParam
.preview_width = 0
.preview_height = 100
.preview_format = 0
.ImageQuality = 5
.brightness = 5
.rotation = rotation_degree .rotate_0
.preview_x = 0
.preview_y = 0
.contrast = 200
.saturation = 200
.ef_mode = effect_mode.eff ect_none
.wb_mode = white_balance_m ode.wb_auto
Dim pbuffer() As Byte
ReDim pbuffer(.previe w_width * .preview_height * 2)
ReDim .reserved(20)
.p_app_buffer = pbuffer
.p_app_capture_ buffer = pbuffer

End With

'Call function
BBCameraPreview Start (Handler, BBParam)

Am i doing the right thing here?

Thanks and Regards

[Branco Medeiros]

Re: C++ Function Pointer to VB.Net

banleong wrote:
<snip>

Yes, it is external libraries.

<snip>

1) Is my declaration correct for BBCameraPreview Start in VB.net code
based on the C++ codes?
>
BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);
>
to
>
Public Shared Function BBCameraPreview Start(ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

<snip>

Nope. When you have to reference a method in an external library, you
need to indicate to VB which library is this (the .dll file), the
character type accepted by the method (ansi or unicode) and the method
signature, among other things.

Usually this is done using a Declare. Suppose, for instance, that the
method that you want to call is from, say, a dll called BBAPI.dll.
This would be the declaration of the function in VB:

Declare Ansi Function BBCameraPreview Start _
Lib "BBAPI.dll" ( _
ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer

Of course, this is just the declaration. To actually *call* the
method, it's no different from any other methods.

HTH.

Regards,

Branco.

[banleong@gmail.com]

Re: C++ Function Pointer to VB.Net

On Mar 15, 1:17 pm, "Branco Medeiros" <branco.medei.. .@gmail.com>
wrote:

banleong wrote:
>
<snip>Yes, it is external libraries.
<snip>

1) Is my declaration correct for BBCameraPreview Start in VB.net code
based on the C++ codes?

>

BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);

>

to

>

Public Shared Function BBCameraPreview Start(ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

>
<snip>
>
Nope. When you have to reference a method in an external library, you
need to indicate to VB which library is this (the .dll file), the
character type accepted by the method (ansi or unicode) and the method
signature, among other things.
>
Usually this is done using a Declare. Suppose, for instance, that the
method that you want to call is from, say, a dll called BBAPI.dll.
This would be the declaration of the function in VB:
>
Declare Ansi Function BBCameraPreview Start _
Lib "BBAPI.dll" ( _
ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
>
Of course, this is just the declaration. To actually *call* the
method, it's no different from any other methods.
>
HTH.
>
Regards,
>
Branco.

Branco,

Thanks for your reply.

Actually i already declare the external function as

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraPreview Start(ByVal HBBCamera As
IntPtr, ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

Sorry for the confusion because i didn't include the <DllImportpar t
on early post.
However, passing the parameters seem to failed.Guess have not choice
but go back to manufacturer, eh?

Regards

[susiedba@hotmail.com]

Re: C++ Function Pointer to VB.Net

hey C++ kid

go and play in a freeway

C++ is dead and so is VB


SERIOUSLY

it's about time that someone told you the truth-- MS had a full hand--
the worlds most popular programming language; and they FOLDED. THEY
GAVE UP AND KILLED THE LANGUAGE; BECAUSE THE KIDS IN REDMOND WERE
SCARED OF A TINY COMPANY FROM CALIFORNIA WITH A THREE BILLION DOLLAR
MARKET CAP.


C++ is dead.
Java is dead.
VB is dead.

PHP won the war.


I'm dead fucking serious


-Todos





On Mar 14, 2:13 am, banle...@gmail. com wrote:

To all gurus,
>
I am currently converting some of C++ codes to VB.net
>
The C++ Codes is as follows :
>
=============== == C++ CODE =============== ===
typedef struct _tagBBCameraPar ameter
{
unsigned int preview_width;
unsigned int preview_height;
unsigned int preview_x;
unsigned int preview_y;
unsigned int preview_format;
unsigned int preview_zoom;
>
const TCHAR* capture_file_na me;
>
unsigned int contrast;
unsigned int saturation;
unsigned int brightness;
>
} BBCameraParamet er;
>
typedef LPVOID HBBCAMERA;
>
BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraPreview Stop(HBBCAMERA) ;
>
=============== == END C++ CODE =============== ===
>
I managed to convert most of the codes to VB.Net but when I try to fun
BBCameraPreview Start function, it gives error.
>
'============== ===Partial VB.Net Code
>
Public Shared Function BBCameraPreview Start(ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function
>
Public Shared Function BBCameraPreview Stop(ByVal HBBCamera As IntPtr)
As Integer
End Function
>
'=========== END OF PARTIAL VB.NET CODES
>
This is how i pass the parameters;
>
Dim BBParam as BBCameraParamet er '// already declared but not shown
here
Dim HBBCamera as IntPtr '//Handle
>
'I have no problems getting handle but once i set the parameters for
BBParam and pass as follows, i get error (not much help from the
message).
>
BBCameraPreview Start(HBBCAMERA , BBParam)
>
How do I call function BBCameraPreview Start correctly? Did i do it
correctly?
>
Please advices.
Thanks

[Branco Medeiros]

Re: C++ Function Pointer to VB.Net

banleong wrote:
<snip>

Actually i already declare the external function as
>
<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraPreview Start(ByVal HBBCamera As

<snip>

I suggest you try to provide a more complete description of your
scenario. Having known that you had already declared the function with
DllImport would spare a couple a posts, don't you think? Also, in your
first post you say that you get an error message while calling the
function, but don't provide it for lack of relevancy in the message.
Well, maybe the message *is irrelevant*, but then, again, maybe not
(the "DllImport" wasn't irrelevant at all, you see?).

Also missing is an example of the original C++ code filling the
paramenters (sometimes thare's a gotcha that passes unnoticed).

Finally -- to give some purpose to this post -- I noticed that the
fields you show in the C++ declaration of the BBCameraParamet er struct
don't seem to match your usage of the parameter. It would help also if
you provided your actual VB declaration of the struct.

HTH.

Branco.

[Mudhead]

Re: C++ Function Pointer to VB.Net

HBBCAMERA is a typedef pointer, so you'll have to pass the first parameter
ByRef. If that doesn't work, try changing the IntPtr to an UInt32

Public Shared Function BBCameraPreview Start(ByRef HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

or

Dim HBBCamera as Unit32

Public Shared Function BBCameraPreview Start(ByRef HBBCamera As UInt32,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function



<banleong@gmail .comwrote in message
news:1173942127 .379021.128630@ e1g2000hsg.goog legroups.com...

On Mar 15, 1:17 pm, "Branco Medeiros" <branco.medei.. .@gmail.com>
wrote:

>banleong wrote:
>>
><snip>Yes, it is external libraries.
><snip>

1) Is my declaration correct for BBCameraPreview Start in VB.net code
based on the C++ codes?

>>

BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);

>>

to

>>

Public Shared Function BBCameraPreview Start(ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

>>
><snip>
>>
>Nope. When you have to reference a method in an external library, you
>need to indicate to VB which library is this (the .dll file), the
>character type accepted by the method (ansi or unicode) and the method
>signature, among other things.
>>
>Usually this is done using a Declare. Suppose, for instance, that the
>method that you want to call is from, say, a dll called BBAPI.dll.
>This would be the declaration of the function in VB:
>>
> Declare Ansi Function BBCameraPreview Start _
> Lib "BBAPI.dll" ( _
> ByVal HBBCamera As IntPtr,
> ByRef BBParam1 As BBCameraParamet er) As Integer
>>
>Of course, this is just the declaration. To actually *call* the
>method, it's no different from any other methods.
>>
>HTH.
>>
>Regards,
>>
>Branco.

>
Branco,
>
Thanks for your reply.
>
Actually i already declare the external function as
>
<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraPreview Start(ByVal HBBCamera As
IntPtr, ByRef BBParam1 As BBCameraParamet er) As Integer
End Function
>
Sorry for the confusion because i didn't include the <DllImportpar t
on early post.
However, passing the parameters seem to failed.Guess have not choice
but go back to manufacturer, eh?
>
Regards
>

[banleong@gmail.com]

Re: C++ Function Pointer to VB.Net

Branco,

Thanks for your comment and sorry about the mixed up and confusion.
Below is the complete source code in C++ and converted VB.Net source
code.

The C++ code (bbappapi.h) is provided by hardware manufacturer.
However, they don't have any samples available in .Net and their
technical support is unreachable most of the time.

I also include the VB.Net source codes that i converted from C++ codes
and a function to call the methods. The error message is
"NotSupportedEx ception" which i think it's useless, or is it?

I hope i didn't miss out other information here. By the way, it's for
Windows CE 5.0 device.

-------------------- Begin C++ Code (bbappapi.h)
------------------------------

/*
* camera
*/
#define WM_BBCAMERA_UPD ATE_FPS WM_USER+1000

#define BB_CAMERA_CODE_ SUCCESS 0
#define BB_CAMERA_CODE_ ERR_UNKNOWN 1
#define BB_CAMERA_CODE_ ERR_INVALID_HAN DLE 2
#define BB_CAMERA_CODE_ ERR_INVALID_PAR AMETER 3

typedef enum
{
wb_auto = 0,
wb_cloudy,
wb_daylight,
wb_fluorescent_ 1,
wb_fluorescent_ 2,
wb_light_bulb

} white_balance_m ode;

typedef enum
{
effect_none = 0,
effect_negative ,
effect_embossin g,
effect_black_n_ white,
effect_sketch,
effect_solariza tion,
effect_sephia,
effect_aqua,
effect_posteriz e,
effect_warm,
effect_cool,
effect_antique,
effect_moonligh t,
effect_fog,

} effect_mode;

typedef enum
{
flip_x = 1,
flip_y,
flip_x_y,
flip_origin


} flip_mode;

typedef enum
{
rate_auto = 1,
rate_day_manual ,
rate_night_manu al
} frame_rate_mode ;

typedef enum
{
auto_save = 0,
manual_save
} save_mode;

typedef enum
{
file_type_jpg = 0,
file_type_bmp
} save_image_type ;

typedef enum
{
rotate_default= 0,
rotate_0,
rotate_90,
rotate_180,
rotate_270

} rotation_degree ;

typedef enum
{
pixel_format_yc bcr = 0,
pixel_format_rg b_565, // output data °¡ bmp ÀÌ´Ù.
pixel_format_rg b_565_raw // output data °¡ 16bit rgb µ¥ÀÌÅÍ ÀÌ´Ù.

} pixel_format_se lect;


typedef struct _tagBBCameraPar ameter
{
unsigned int preview_width;
unsigned int preview_height;
unsigned int preview_x;
unsigned int preview_y;
unsigned int preview_format;
unsigned int preview_zoom;

const TCHAR* capture_file_na me;
unsigned int capture_width;
unsigned int capture_height;
pixel_format_se lect capture_format;
unsigned int capture_strobe_ on;

unsigned int contrast;
unsigned int saturation;
unsigned int brightness;
effect_mode ef_mode;
white_balance_m ode wb_mode;
flip_mode fp_mode;
frame_rate_mode fr_mode;

unsigned int reserved[20];
BYTE* p_app_buffer;
BYTE* p_app_capture_b uffer; //still image capture¿¡¼ µ¥ÀÌÅ͸¦ ¹Þ
±âÀ§ÇÑ Æ÷ÀÎÅÍ

save_mode stillimage_save mode;
save_image_type save_fileType;
unsigned int ImageQuality;

BOOL isSaveFile;
rotation_degree rotation;

} BBCameraParamet er;

typedef struct _tagBBCameraInf o
{
unsigned int preview_max_wid th;
unsigned int preview_max_hei ght;
unsigned int preview_min_wid th;
unsigned int preview_min_hei ght;
unsigned int image_max_width ;
unsigned int image_max_heigh t;

unsigned int reserved[20];

} BBCameraInfo;


typedef LPVOID HBBCAMERA;

BBAPI HBBCAMERA WINAPI BBCameraOpen(HW ND);
BBAPI DWORD WINAPI BBCameraClose(H BBCAMERA);

BBAPI DWORD WINAPI BBCameraPreview Start(HBBCAMERA ,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraPreview Stop(HBBCAMERA) ;
BBAPI DWORD WINAPI BBCameraPreview Pause(HBBCAMERA );
BBAPI DWORD WINAPI BBCameraPreview Resume(HBBCAMER A);
BBAPI DWORD WINAPI BBCameraPreview Zoom(HBBCAMERA, BBCameraParamet er*);

BBAPI DWORD WINAPI BBCameraGetRawD ataStart(HBBCAM ERA,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraGetRawD ataStop(HBBCAME RA);
BBAPI DWORD WINAPI BBCameraGetRawD ataPause(HBBCAM ERA);
BBAPI DWORD WINAPI BBCameraGetRawD ataResume(HBBCA MERA);
BBAPI DWORD WINAPI BBCameraGetRawD ataZoom(HBBCAME RA,
BBCameraParamet er*);

BBAPI DWORD WINAPI BBCameraCapture (HBBCAMERA, BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraStoreCa ptureImage(HBBC AMERA,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraRestart PreviewFromCapt ure(HBBCAMERA,
BBCameraParamet er*);

BBAPI DWORD WINAPI BBCameraSetWhit eBalance(HBBCAM ERA,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraSetCont rast(HBBCAMERA, BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraSetSatu ration(HBBCAMER A,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraSetBrig htness(HBBCAMER A,
BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraSetEffe ct(HBBCAMERA, BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraSetFlip (HBBCAMERA, BBCameraParamet er*);
BBAPI DWORD WINAPI BBCameraNightMo de(HBBCAMERA, BBCameraParamet er*);

BBAPI DWORD WINAPI BBCameraGetInfo (HBBCAMERA, BBCameraInfo*);
BBAPI DWORD WINAPI BBCameraDumpReg ister(HBBCAMERA );

------------------------------ END of C++ Code -----------------------

---------------------------- Declaration in VB.Net------------
#Region " BB CAMERA API DECLARATIONS "
Public Const BB_CAMERA_CODE_ SUCCESS = 0
Public Const BB_CAMERA_CODE_ ERR_UNKNOWN = 1
Public Const BB_CAMERA_CODE_ ERR_INVALID_HAN DLE = 2
Public Const BB_CAMERA_CODE_ ERR_INVALID_PAR AMETER = 3

Enum white_balance_m ode
wb_auto = 0
wb_cloudy
wb_daylight
wb_fluorescent_ 1
wb_fluorescent_ 2
wb_light_bulb
End Enum

Enum effect_mode
effect_none = 0
effect_negative
effect_embossin g
effect_black_n_ white
effect_sketch
effect_solariza tion
effect_sephia
effect_aqua
effect_posteriz e
effect_warm
effect_cool
effect_antique
effect_moonligh t
effect_fog
End Enum

Enum flip_mode
flip_x = 1
flip_y
flip_x_y
flip_origin
End Enum

Enum frame_rate_mode
rate_auto = 1
rate_day_manual
rate_night_manu al
End Enum

Enum save_mode
auto_save = 0
manual_save
End Enum

Enum save_image_type
file_type_jpg = 0
file_type_bmp
End Enum

Enum rotation_degree
rotate_default = 0
rotate_0
rotate_90
rotate_180
rotate_270
End Enum

Enum pixel_format_se lect
pixel_format_yc bcr = 0
pixel_format_rg b_565 ' // output data °¡ bmp ÀÌ´Ù.
pixel_format_rg b_565_raw ' // output data °¡ 16bit rgb µ¥ÀÌÅÍ
ÀÌ´Ù.
End Enum

Structure BBCameraInfo
Public preview_max_wid th As System.UInt16
Public preview_max_hei ght As System.UInt16
Public preview_min_wid th As System.UInt16
Public image_max_width As System.UInt16
Public image_max_heigh t As System.UInt16
End Structure


Structure BBCameraParamet er
Public preview_width As System.UInt16
Public preview_height As System.UInt16
Public preview_x As System.UInt16
Public preview_y As System.UInt16
Public preview_format As System.UInt16
Public preview_zoom As System.UInt16

Public capture_file_na me As String

Public capture_width As System.UInt16
Public capture_height As System.UInt16
Public capture_strobe_ on As System.UInt16

Public capture_format As pixel_format_se lect

Public contrast As System.UInt16
Public saturation As System.UInt16
Public brightness As System.UInt16


Public ef_mode As effect_mode
Public wb_mode As white_balance_m ode
Public fp_mode As flip_mode
Public fr_mode As frame_rate_mode

' unsigned int reserved[20];
Public reserved() As System.UInt16

Public p_app_buffer() As Byte
Public p_app_capture_b uffer() As Byte

Public stillimage_save mode As save_mode
Public save_fileType As save_image_type
Public ImageQuality As Integer

Public isSaveFile As Boolean

Public rotation As rotation_degree
End Structure
#End Region

#Region " VARIABLES DECLARATION "
Dim HBBCAMERA As IntPtr
Dim BBInfo As New BBCameraInfo
Dim BBParam As New BBCameraParamet er

#End Region

#Region " BB CAMERA API"
<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraOpen(By Val HWND As IntPtr)
As IntPtr
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraClose(B yVal HBBCamera As IntPtr)
As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraPreview Start(ByVal HBBCamera As
IntPtr, ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraPreview Stop(ByVal HBBCamera As IntPtr)
As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraPreview Pause(ByVal HBBCamera As IntPtr)
As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraPreview Zoom(ByVal HBBCamera As IntPtr)
As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraGetInfo (ByVal HBBCamera As IntPtr,
ByRef BBInfo As BBCameraInfo) As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraGetRawD ataStart(ByVal HBBCamera As
IntPtr, ByRef BBParam As BBCameraParamet er) As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraGetRawD ataStop(ByVal HBBCamera As
IntPtr) As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraGetRawD ataPause(ByVal HBBCamera As
IntPtr, ByRef BBParam1 As BBCameraParamet er) As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraGetRawD ataResume(ByVal HBBCamera As
IntPtr) As Integer
End Function

<DllImport("bba ppapi.dll")_
Public Shared Function BBCameraCapture (ByVal HBBCamera As IntPtr,
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function
#End Region


' So this is the method that i call to
'
Private Sub StartOperation( )

Dim BBParam As BBCameraParamet er
Dim StartCamera as boolean

Try
HBBCAMERA = BBCameraOpen(pi cCamera.Handle) 'Get the
handler
StartCamera = True
Catch ex As Exception
StartCamera = False
End Try

If StartCamera Then
' If camera started then assign some parameters
With BBParam
.preview_width = 0
.preview_height = 100
.preview_format = 0
.ImageQuality = 5
.brightness = 50
.rotation = rotation_degree .rotate_0
.preview_x = 0
.preview_y = 0
.contrast = 200
.saturation = 200
.ef_mode = effect_mode.eff ect_none
.wb_mode = white_balance_m ode.wb_auto
Dim pbuffer() As Byte
ReDim pbuffer(.previe w_width * .preview_height * 2)
ReDim .reserved(20)
.p_app_buffer = pbuffer
.p_app_capture_ buffer = pbuffer
End With


TextBox1.Text = "Get handle :" & HBBCAMERA.ToStr ing

'GET CAMERA INFO (No problem here, can get the info from
camera)
BBCameraGetInfo (HBBCAMERA, BBInfo)
TextBox1.Text += vbCrLf & "BBInfo.image_m ax_height:" &
BBInfo.image_ma x_height
TextBox1.Text += vbCrLf & "BBInfo.image_m ax_width:" &
BBInfo.image_ma x_width
TextBox1.Text += vbCrLf & "BBInfo.preview _max_height:" &
BBInfo.preview_ max_height
TextBox1.Text += vbCrLf & "BBInfo.preview _max_width:" &
BBInfo.preview_ max_width
TextBox1.Text += vbCrLf & "BBInfo.preview _min_width:" &
BBInfo.preview_ min_width

Try
'Preview camera image (ERROR OCCURS HERE)
Dim rst As Integer = BBCameraPreview Start(HBBCAMERA ,
BBParam)
TextBox1.Text += vbCrLf & "Preview OK"

Catch ex As Exception
TextBox1.Text += vbCrLf & "Preview Failed"

End Try

Else
TextBox1.Text += vbCrLf & "Cannot start camera"
End If
End Sub
----------------------------- 'END OF VB.Net
Codes---------------------

Hope to hear from you guys.

Thanks again!

[Branco Medeiros]

Re: C++ Function Pointer to VB.Net

banleong wrote:
<snipped due to sheer size>

Yikes, it seems Google groups didn't like my post. Here it goes again
(sorry if it gets duplicated...)

Yes, there were issues with you conversion of the structures: missing,
wrongly typed and out-of-order fields, as well as missing marshalling
information. This may be causing your code to fail.

Try the rewrites below, I hope they're somewhat more "correct" than
the ones you already have.

<code>
'At file level
Imports InterOp = System.Runtime. InteropServices

'Inside your class
Public Const RESERVED_FIELD_ MAX As integer = 19

<InterOp.Struct Layout( _
InterOp.LayoutK ind.Sequential, _
Charset:=InterO p.CharSet.Ansi) _
Structure BBCameraParamet er
Public preview_width As UInteger
Public preview_height As UInteger
Public preview_x As UInteger
Public preview_y As UInteger
Public preview_format As UInteger
Public preview_zoom As UInteger


<InterOp.Marsha lAs(InterOp.Unm anagedType.LPSt r)_
Public capture_file_na me As String

Public capture_width As UInteger
Public capture_height As UInteger
Public capture_format As pixel_format_se lect
Public capture_strobe_ on As UInteger


Public contrast As UInteger
Public saturation As UInteger
Public brightness As UInteger
Public ef_mode As effect_mode
Public wb_mode As white_balance_m ode
Public fp_mode As flip_mode
Public fr_mode As frame_rate_mode

'Must initialize explicitly
<VBFixedArray(R ESERVED_FIELD_M AX)_
Public reserved() As UInteger

<InterOp.Marsha lAs(InterOp.Unm anagedType.LPAr ray)_
Public p_app_buffer() As Byte
<InterOp.Marsha lAs(InterOp.Unm anagedType.LPAr ray)_
Public p_app_capture_b uffer() As Byte


Public stillimage_save mode As save_mode
Public save_fileType As save_image_type
Public ImageQuality As UInteger

Public isSaveFile As Boolean
Public rotation_degree As rotation_degree

End Structure

<InterOp.Struct Layout(InterOp. LayoutKind.Sequ ential)_
Structure BBCameraInfo
Public preview_max_wid th As UInteger
Public preview_max_hei ght As UInteger
Public preview_min_wid th As UInteger
Public preview_min_hei ght As UInteger
Public image_max_width As UInteger
Public image_max_heigh t As UInteger

'Must initialize explicitly
<VBFixedArray(R ESERVED_FIELD_M AX)_
Public reserved() As UInteger
End Structure

<InterOp.DllImp ort("bbappapi.d ll", Charset:=InterO p.CharSet.Ansi) _
Public Shared Function BBCameraPreview Start( _
ByVal HBBCamera As IntPtr, _
ByRef BBParam1 As BBCameraParamet er) As Integer
End Function
</code>

Just remember that when declaring instances of both BBCameraParamet e
and BBCamera info you need to explicitly dimmension the reserverd
field:

Dim Param As New BBCameraParamet er
ReDim Param.reserved( RESERVED_FIELD_ MAX)

Dim Info As New BBCameraInfo
ReDim Info.reserved(R ESERVED_FIELD_M AX)


HTH.

Regards,

Branco.