ImportRow Question - C# Discussion Boards

Re: A complex one.....

Jon Newman28-Apr-03 11:53

Jon Newman

28-Apr-03 11:53

Cheers that seems to have done the trick! I knew it would be simple Smile | :)

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Jonathan 'nonny' Newman
Homepage [www.nonny.com] [^]

Marshalling char**

leppie27-Apr-03 2:42

leppie

27-Apr-03 2:42

Hi all (and S.Rod. as you are most likely to answer this Smile | :)

)

Say I have a C function:

char** Foo(int* size);

Now in MC++ its pie and I can just go:

int size = 0;
char** buffer = Foo(&size);
String* results __gc[] = new String*[size];
for (int i = 0; i < size; i++)
{
  results[i] = new String(buffer[i]);
  free(buffer[i]);
}
free(buffer);

But how do I approach this from a Marshalling POV in C# given I have Foo as a DllImport defined as IntPtr Foo(out int size)? How do I access the individual char* and the finally free the returned IntPtr? My attempts has failed miserably Frown | :(

Thanks

I rated this article 2 by mistake. It deserves more. I wanted to get to the second page... - vjedlicka 3:33 25 Nov '02

Re: Marshalling char**

Stephane Rodriguez.27-Apr-03 7:25

Stephane Rodriguez.

27-Apr-03 7:25

Here is how I got it to work,

C implementation :

extern "C" __declspec(dllexport) char** foo(int *nSize);

// implementation
__declspec(dllexport) char** foo(int *nSize)
{
  *nSize = 2;
  ::MessageBox(NULL,"unmanaged foo call","message",MB_OK);

  char **lpstr = (char**) CoTaskMemAlloc( 2*sizeof(LPSTR) );
  lpstr[0] = (char*) CoTaskMemAlloc( 100 ) ;
  strcpy(lpstr[0], "string1");
  lpstr[1] = (char*) CoTaskMemAlloc( 100 ) ;
  strcpy(lpstr[1], "string2");

  return lpstr;
}

Now for the managed part,

// declaration
[DllImport(@"..\bin\foo.dll", CharSet=CharSet.Auto)]
static public extern IntPtr foo(ref int nSize); // 

// implementation
int nSize = 0;
IntPtr pData = foo(ref nSize);
for (int i=0; i<nSize; i++)
{
  IntPtr pString = Marshal.ReadIntPtr(pData, 4*i);
  MessageBox.Show( Marshal.PtrToStringAnsi(pString) );
}

Re: Marshalling char**

leppie27-Apr-03 7:59

leppie

27-Apr-03 7:59

.S.Rod. wrote:
Marshal.ReadIntPtr

Dope, how did I miss that one again (some bells ring)? PtrToStringAnsi frees the string, would FreeHGlobal(pData) at the end be right then?

Thanks for the reply Smile | :)

I rated this article 2 by mistake. It deserves more. I wanted to get to the second page... - vjedlicka 3:33 25 Nov '02

Re: Marshalling char**

Stephane Rodriguez.27-Apr-03 8:05

Stephane Rodriguez.

27-Apr-03 8:05

FreeCoTaskMem(pData);

Re: Marshalling char**

leppie27-Apr-03 8:42

leppie

27-Apr-03 8:42

Hmm, I allocated the unmanaged memory with calloc, is FreeHGlobal an alias for that or do i need to dllimport that?

I rated this article 2 by mistake. It deserves more. I wanted to get to the second page... - vjedlicka 3:33 25 Nov '02

Re: Marshalling char**

Stephane Rodriguez.27-Apr-03 9:00

Stephane Rodriguez.

27-Apr-03 9:00

calloc, malloc or even new are not good when you are crossing the managed boundaries. Indeed, the only way to make sure the allocated memory is NOT freed or moved when it's being marshaled is to allocate the memory block in a shared space, hence CoTaskMemAlloc (for allocations), and FreeCoTaskMem (for deallocations).

ImportRow Question

2sky27-Apr-03 1:50

2sky

27-Apr-03 1:50

I have this program where I'm supposed to copy a datarow into another databale. Herefore I use the ImportRow method. The problem is that this method does not return the newly created datarow. Can anyone tell me how to get the new datarow that is created after calling ImportRow? Or is there a better way to copy a datarow between tables?

Thanks in advance

Re: ImportRow Question

Andres Manggini27-Apr-03 17:44

Andres Manggini

27-Apr-03 17:44

Hi,

DataTable.LoadDataRow might work better for you.

Hope this helps.

Andres Manggini.
Buenos Aires - Argentina.

Re: ImportRow Question

2sky28-Apr-03 8:09

2sky

28-Apr-03 8:09

Woops, overlooked that one Blush | :O

Thanks Andres !!! Cool | :cool:

question about treeview control

Robin Vane26-Apr-03 20:53

Robin Vane

26-Apr-03 20:53

can anyone tell me when the treenodes are drawn,when the background is redraw and when the treeview is scrolled what event is raised?

Re: question about treeview control

Meysam Mahfouzi27-Apr-03 17:13

Meysam Mahfouzi

27-Apr-03 17:13

Use Spy++ to inspect fired events

Regards

IIS's FTP

paulwhygle26-Apr-03 16:21

paulwhygle

26-Apr-03 16:21

Hello,
In an application I am running I would like to be able to shutdown IIS's FTP
service if a given condition is met. Is there a way to access the FTP to be
able to shut it down without having to shutdown all of IIS (I have a couple
of websites I would like to keep running). I am using C#.

Thank you,
Paul

Re: IIS's FTP

Ray Cassick26-Apr-03 18:44

Ray Cassick

26-Apr-03 18:44

You should be able to just access the FTP service on the box by using the Service Control Manager APIs.

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George Carlin wrote:
"Don't sweat the petty things, and don't pet the sweaty things."
Jörgen Sigvardsson wrote:
If the physicists find a universal theory describing the laws of universe, I'm sure the a**hole constant will be an integral part of that theory.

ProgressBar -Simple????

gman4426-Apr-03 14:14

gman44

26-Apr-03 14:14

I'll be darned if I can find a simple code on the entire internet to implement a ProgressBar for a common File.Copy procedure. One that actually show real-time progress and not just a timer or
min-max settings. Help

File.Copy(txtAudioSourceDir.Text + txtAudioSourceFile.Text);

Re: ProgressBar -Simple????

Jon Newman27-Apr-03 6:23

Jon Newman

27-Apr-03 6:23

I don't think there is a framework way for you to track the progress of the copy. The only way I see you doing it is to read the bytes into abuffer and then write them again. From that you can get your progress values on the number of bytes read/written.

Jonathan 'nonny' Newman
Homepage [www.nonny.com] [^]

Re: ProgressBar -Simple????

Richard Deeming29-Apr-03 1:09

Richard Deeming

29-Apr-03 1:09

The simplest way is to P/Invoke the SHFileOperation API. Have a look at http://www.codeproject.com/csharp/csdoesshell2.asp[^] for an example.

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Continuous Stream of MouseMove Messages!!!

Waleed Eissa26-Apr-03 12:50

Waleed Eissa

26-Apr-03 12:50

Hi Codegurus,
I keep getting MouseMove messages without the mouse moving at all!! .. have anybody been in the same situation? Hopefully it's not a bug, I doubt that that behavior is intended by design. This's what is written about MouseMove in MSDN, "Occurs when the mouse pointer is moved over the control".

More info...
// Used Software
VS .NET 2002
Microsft .NET Framework 1 SP2
Windows 2000 SP2
IE 6, DirectX 9 SDK

Thanks,

(a.k.a. Wal2k)
www.wal2k.com

PaintDesktop()

Waleed Eissa26-Apr-03 12:42

Waleed Eissa

26-Apr-03 12:42

Do you know of any equivalent to the PaintDesktop() Win32 API function in the .NET framework?

Many thanks

(a.k.a. Wal2k)
www.wal2k.com

3rd party control

Kant26-Apr-03 6:08

Kant

26-Apr-03 6:08

I try to add a 3rd party control to my project. I added the reference to the DLL. (via Add Reference)

But I don't see the control in the toolbox.

What I'm missing? Confused | :confused:

[edit] It's not strong named assembly and the control works properly with the provided sample project. [edit]

Don't Beer | [beer]

and drive.

Re: 3rd party control

Torsch26-Apr-03 9:15

Torsch

26-Apr-03 9:15

Hi,

why don't you add it by customizing the toolbox or did I understood something wrong?

Greetz
Torge

Re: 3rd party control

Kant26-Apr-03 13:00

Kant

26-Apr-03 13:00

Torsch wrote:
customizing the toolbox

I did it and it worked.

Thx.

Don't Beer | [beer]

and drive.

Re: 3rd party control

Torsch27-Apr-03 16:43

Torsch

27-Apr-03 16:43

Huhu,

sure...customizing the toolbox is like giving a hore 1,000 € Wink | ;)

Greetz
Torsch

Re: 3rd party control

David Stone26-Apr-03 11:06

David Stone

26-Apr-03 11:06

Right click on the toolbox and go to Customize Toolbox. Add the reference to the DLL from there and you'll see the control in your toolbox. Smile | :)

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Re: 3rd party control

Kant26-Apr-03 12:58

Kant

26-Apr-03 12:58

David Stone wrote:
Add the reference to the DLL from there and you'll see the control in your toolbox.

Duah...It worked.

Earlier I thought the list in the "Customize Toolbox" dialog is generated when you add the reference to the project. I didn't saw "browse" button. Agh!!!

Learning something new everyday in this stupid .no^et world ...

Thx.

Don't Beer | [beer]

and drive.

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