help with byte arrays and pointers

[Patrick]

I've search for hours on this problem and cannot find a solution :(

Heres the bit of code:
IntPtr pointer = getFrameDll(Fra meNumber);

The pointer points to a byte[] array that represents a bitmap.

I do not know the length of the array and Marshal.SizeOf( ) returns 4 bytes
(32 bit integer)

for the size of the pointer.

Could someone please teach me how to get byte arrays from memory using
pointers?

Gratefully,

Patrick

[Truong Hong Thi]

Re: help with byte arrays and pointers

>Heres the bit of code:[color=blue]
>IntPtr pointer = getFrameDll(Fra meNumber);
>Could someone please teach me how to get byte >arrays from memory using
>pointers?[/color]
I think it is imposible. The function should also outputs the array
length.

Thi

[Patrick]

Re: help with byte arrays and pointers

I was afraid of that. It's all a learning lesson :)
BTW, trying to convert this line from Delphi to C#
function getFrameDll(fra me: integer): PByteArray; cdecl; external
'vidframe.dll' name '?getFrame@@YAP AEH@Z';

Thanks for the quick reply. (about 4 minutes)




"Truong Hong Thi" <thi1981@gmail. com> wrote in message
news:1132289600 .463163.210770@ g49g2000cwa.goo glegroups.com.. .[color=blue][color=green]
> >Heres the bit of code:
>>IntPtr pointer = getFrameDll(Fra meNumber);
>>Could someone please teach me how to get byte >arrays from memory using
>>pointers?[/color]
> I think it is imposible. The function should also outputs the array
> length.
>
> Thi
>[/color]

[Truong Hong Thi]

Re: help with byte arrays and pointers

Did you try methods like System.Drawing. Image.FromHBitm ap?

[Truong Hong Thi]

Re: help with byte arrays and pointers

I just had a look at System.Drawing namespace documentation and see
that the Bitmap constructor also accepts IntPtr and additional params.
Hope it works!

[Patrick]

Re: help with byte arrays and pointers

I just tried it. "A generic error occurred in GDI+". Does csharp have
something similar to a PByteArray ? Or is there a way to say the equivelant:
public static extern byte[]* foo()?

"Truong Hong Thi" <thi1981@gmail. com> wrote in message
news:1132290521 .429952.51170@g 43g2000cwa.goog legroups.com...[color=blue]
> Did you try methods like System.Drawing. Image.FromHBitm ap?
>[/color]

[Patrick]

Re: help with byte arrays and pointers

Thanks for your time :) Best of luck
--Patrick
"Truong Hong Thi" <thi1981@gmail. com> wrote in message
news:1132291112 .742760.291160@ o13g2000cwo.goo glegroups.com.. .[color=blue]
>I just had a look at System.Drawing namespace documentation and see
> that the Bitmap constructor also accepts IntPtr and additional params.
> Hope it works!
>[/color]

[Willy Denoyette [MVP]]

Re: help with byte arrays and pointers


"Patrick" <patrick@hotmai l.com> wrote in message
news:O4GovBA7FH A.2628@TK2MSFTN GP11.phx.gbl...[color=blue]
>I just tried it. "A generic error occurred in GDI+". Does csharp have
>something similar to a PByteArray ? Or is there a way to say the
>equivelant: public static extern byte[]* foo()?
>
> "Truong Hong Thi" <thi1981@gmail. com> wrote in message
> news:1132290521 .429952.51170@g 43g2000cwa.goog legroups.com...[color=green]
>> Did you try methods like System.Drawing. Image.FromHBitm ap?
>>[/color]
>
>[/color]

Yes, it has it's the IntPtr retuned , but if you don't know the length of
the byte[] pointed to by the returned poiner, how are you going to handle
the array contents?
Isn't it possible that the frame has a fixed lentgh? How do you manage this
in Delphi?

Willy.