Re: Passing string - COM Discussion Boards

1-Apr-04 22:12

Hi all

I have a com that uses MFC.
When I register the com in a machine with Visual Studio everything is fine. But when I try to register the com in a machine without MFC it shows a error "Not all components could be loaded". Is it because I dont have visual studio installed in the target machine. ?
What files should I deploy with MyCom.dll to make it run everywhere..?

Thanks in advance
Regards

Re: Com without MFC

Mil 101-Apr-04 23:52

Mil 10

1-Apr-04 23:52

use Dependency walker tool comes with visual studio to c the dependecies of ur com dll. if mfc4x.dlls are not there in the mechine , then u have to copy that...

rgds.. mil10.

Re: Com without MFC

shiraztk2-Apr-04 0:28

2-Apr-04 0:28

Hi
Thank you Mil
I will try it..

Regards
Shiraz

Passing string

shiraztk1-Apr-04 19:46

1-Apr-04 19:46

Hi all

In my com I want to accept a filename and open the specified file.
The client will call
mycom->open(char * filename)

How should be my com taking care of it. ?
Please Help me...am new to com..
Regards

Rory Solley1-Apr-04 20:19

Rory Solley

1-Apr-04 20:19

To pass a string into a COM method, use a BSTR type parameter:

e.g. HRESULT IMyComInterface::Open(BSTR Filename);

which would be called like this (error handling and COM object creation omitted for clarity):

BSTR Filename = ::SysAllocString(L"c:\\myfile.txt");
HRESULT hR = pIMyComInterface->Open(Filename);
::SysFreeString(Filename);

HTH

shiraztk1-Apr-04 20:23

1-Apr-04 20:23

Thank you for immeadiate response

But inside my com I want to get the string back without using MFC ie CString. How do i do it ?
ie char * filename = ( BSTR convertto string) BSTR file.

Regards

Rory Solley1-Apr-04 21:37

Rory Solley

1-Apr-04 21:37

I think I understand what you're asking, does this help?

_bstr_t Tmp(Filename);
char* pFileToOpen = Tmp.operator char*();

(where Filename is the incoming BSTR parameter)

shiraztk1-Apr-04 22:06

1-Apr-04 22:06

Hi
Thanks for your help Rory Solley.

In fact I tried this one, which I found in some previous message posts.
/*********************************
USES_CONVERSION;
const char *text = OLE2A(BSTRstring);
*********************************/
Thanks once again.

Regards

Mike Dimmick2-Apr-04 1:52

Mike Dimmick

2-Apr-04 1:52

A BSTR is internally a WCHAR* that points to the beginning of the string. The length of the string is placed before the first character in memory.

You can assign a BSTR to a CString simply by constructing the CString object:

CString s = CString( file );

Stability. What an interesting concept. -- Chris Maunder

Passing pointers to STL iterators as params to COM interface methods

vprashu5-Apr-04 8:20

vprashu

5-Apr-04 8:20

Rory Solley wrote:
::SysFreeString(Filename);

Are u sure you want to do this? Your client will crash on this line.

The Caller allocates a BSTR and the CALLEE(in this case the COM object) frees it on a method call.

The Caller need to allocate and free the BSTR on an Event Interface ONLY.

prashu

petrym1-Apr-04 16:12

petrym

1-Apr-04 16:12

I have an ATL COM class that will have to copy itself often.

The COM class holds data internally using an STL list.
Copying the data using a SAFEARRAY or even an intermediate buffer will be a performance issue.

Why not just cast STL iterators down to ULONGs

I have defined an interface method that has two parameters. This interface is implemented by the ATL COM class in question.

The IDL
<code>
HRESULT Copy([in] ULONG Begin, [in] ULONG End );
</code>

The ATL code
<code>
STDMETHOD(Copy)( ULONG Begin, ULONG End )
{
  std::list<type>::iterator it = *( (std::list<type>::iterator*) Begin );
  std::list<type>::iterator sentinel = *( (std::list<type>::iterator*) End );
  
  for( ; it != sentinel; ++it )
  {

 //copy data
  }
}
</code>

Calling the method
<code>
other->Copy( (ULONG)&m_list.begin(), (ULONG)&m_list.end() );
</code>

The ATL COM class in question is an inproc server. It probably does not need to marshall because everything runs in the same apartment. One concern is that the OS may create a surrogate process and this method may be marshalled. Will this cause problems?

Any thoughts and/or feedback appreciated!!

mike

Custom ActiveX control hosting another custom control?

Member 9789281-Apr-04 5:00

Member 978928

1-Apr-04 5:00

Hi Guys,

Has anyone run into the issue where two custom programmed activeX controls will not run in the same application? I have ran into this morethan once in my very short activeX experience. Anyone else? ANyone know of a solution? I have tried mulitple configurations, for instance creating the controls in the same project, or in different projects, neither works. I have tried some advanced options, windowless activtion etc, but havn't hit upo the right combination.

Any help? Please? Pretty Please?

Thank all,
Jonathan Brown

Tool to embed exe in OCX?

kaleid31-Mar-04 18:31

kaleid

31-Mar-04 18:31

I remember running into a commerical tool a while back that would let you take almost any windows program (the exe) and convert it to a ocx. That ocx control could then be placed in any usual activex container.

For example, you would run this on notepad.exe and get notepad.ocx that you might embed on a web page for example.

Ignoring for the sake of argument why I would want to do this, does anyone know of such a tool?

Thanks,

--Tim

How COM client call my COM object

_David_Lee_30-Mar-04 15:24

_David_Lee_

30-Mar-04 15:24

Dear All,
So far, I have build a COM server,1 DLL. Then I use

#import "..\bin\MyCOMServer.dll"

however, the compiler, Visual C++ 6.0 tell me that:
fatal error C1083: Cannot open type library file: '..\bin\MyCOMServer.dll': No such file or directory

Any comments?

Thank you
David Confused | :confused:

User 21559730-Mar-04 17:43

User 215597

30-Mar-04 17:43

Check your path where .tlb file and DLL exists...
Just a thought....
"is ur component registered?"

modified 21-Apr-21 21:01pm.

_David_Lee_30-Mar-04 20:41

_David_Lee_

30-Mar-04 20:41

I have register it by regsrv32.exe.
However, even I explicity use the path such as follows:

#import "F:\MyProgram\MyServer.dll"

The result is same.

Any further suggestion? Eek! | :eek:

Steve S1-Apr-04 1:09

Steve S

1-Apr-04 1:09

Have you either (a) explicitly registered the type library
or (b) included it as a resource in your server DLL?

If no to both of these, try #import and specify the .TLB file, not the DLL.

Steve S

RChin1-Apr-04 3:28

RChin

1-Apr-04 3:28

_David_Lee_ wrote:
#import "F:\MyProgram\MyServer.dll"

Just a thought, but shouldn't that be
#import "F:\\MyProgram\\MyServer.dll" ?

I Dream of Absolute Zero

Mike Dimmick1-Apr-04 1:16

Mike Dimmick

1-Apr-04 1:16

#import doesn't seem to support paths with dots in. It's usually OK if the file appears in the same directory.

Stability. What an interesting concept. -- Chris Maunder