Converting native arrays to managed arrays

[Bob Altman]

Hi all,

I'm writing C++/CLI code (compiled with /clr) that accepts a native char array
(and its length) and calls a managed routine that expects an array of
System::Byte. I was just wondering if there is any magic that I'm missing that
easily marshals the native array into a managed array, or do I need to write my
own code to allocate the managed array<and loop through it copying the native
data into the managed array?

TIA - Bob

[Mark Salsbery [MVP]]

Re: Converting native arrays to managed arrays

"Bob Altman" <rda@nospam.nos pamwrote in message
news:ep2BOzXeIH A.4852@TK2MSFTN GP05.phx.gbl...

Hi all,
>
I'm writing C++/CLI code (compiled with /clr) that accepts a native char
array (and its length) and calls a managed routine that expects an array
of System::Byte. I was just wondering if there is any magic that I'm
missing that easily marshals the native array into a managed array, or do
I need to write my own code to allocate the managed array<and loop
through it copying the native data into the managed array?

You can use System::Runtime ::InteropServic es::Marshal::Co py(), which does
the "loop through it copying " part for you :)

Mark

--
Mark Salsbery
Microsoft MVP - Visual C++

>
TIA - Bob
>

[Bob Altman]

Re: Converting native arrays to managed arrays

You can use System::Runtime ::InteropServic es::Marshal::Co py(), which does the

"loop through it copying " part for you :)
>
Mark

Thanks Mark!

[Bob Altman]

Re: Converting native arrays to managed arrays

"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nosp amwrote in message
news:BD264A84-

You can use System::Runtime ::InteropServic es::Marshal::Co py(), which does the
"loop through it copying " part for you :)

I've tried several variations on the following code, but it complains that it
can't find an overload for Marshal::Copy that it likes. I suspect that it
doesn't like the boxed handle to an IntPtr that I think I'm trying to feed it
(by way of the gcnew IntPtr() code). How do I cast a char* to an IntPtr?

const char* value = <some array of bytes>
int size = 15;
array<unsigned char>^ myArray = gcnew array<unsigned char>(size);
Marshal::Copy(g cnew IntPtr((void*)v alue), myArray, 0, size);

[Mark Salsbery [MVP]]

Re: Converting native arrays to managed arrays

"Bob Altman" <rda@nospam.nos pamwrote in message
news:uRKAeeYeIH A.1164@TK2MSFTN GP02.phx.gbl...

"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nosp amwrote in
message news:BD264A84-
>

>You can use System::Runtime ::InteropServic es::Marshal::Co py(), which does
>the "loop through it copying " part for you :)

>
I've tried several variations on the following code, but it complains that
it can't find an overload for Marshal::Copy that it likes. I suspect that
it doesn't like the boxed handle to an IntPtr that I think I'm trying to
feed it (by way of the gcnew IntPtr() code). How do I cast a char* to an
IntPtr?
>
const char* value = <some array of bytes>
int size = 15;
array<unsigned char>^ myArray = gcnew array<unsigned char>(size);
Marshal::Copy(g cnew IntPtr((void*)v alue), myArray, 0, size);
>
>

Maybe try something like this:

const char *value = new char[100];
int size = 15;
array<unsigned char>^ myArray = gcnew array<unsigned char>(size);
Marshal::Copy(I ntPtr(const_cas t<void*>(static _cast<const void*>(value))) ,
myArray, 0, size);
delete[] value;

Mark

--
Mark Salsbery
Microsoft MVP - Visual C++

[Mark Salsbery [MVP]]

Re: Converting native arrays to managed arrays

Also note that in my code sample, it ends up using the

Marshal::.Copy Method (IntPtr, array<Byte>[]()[], Int32, Int32)

form of Marshall::Copy( ) since the array is a Byte (unsigned char) array.

Cheers,
Mark

--
Mark Salsbery
Microsoft MVP - Visual C++


"Bob Altman" <rda@nospam.nos pamwrote in message
news:uRKAeeYeIH A.1164@TK2MSFTN GP02.phx.gbl...

"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nosp amwrote in
message news:BD264A84-
>

>You can use System::Runtime ::InteropServic es::Marshal::Co py(), which does
>the "loop through it copying " part for you :)

>
I've tried several variations on the following code, but it complains that
it can't find an overload for Marshal::Copy that it likes. I suspect that
it doesn't like the boxed handle to an IntPtr that I think I'm trying to
feed it (by way of the gcnew IntPtr() code). How do I cast a char* to an
IntPtr?
>
const char* value = <some array of bytes>
int size = 15;
array<unsigned char>^ myArray = gcnew array<unsigned char>(size);
Marshal::Copy(g cnew IntPtr((void*)v alue), myArray, 0, size);
>
>