Forward declaration error of ICallFactory - COM Discussion Boards

Kaleb Pederson26-Apr-04 7:09

26-Apr-04 7:09

I'm just starting to learn COM and have found quite a few decent tutorials. However, none of them explain the easiest way to get the IID, CLISID, and ProgID. In fact, they all generally assume that it is known.

I have a 3rd party DLL that I'm working with. I have done a #import "dllname.dll" and have the generated C++ wrapper to look at.

In order to find the ProgID, I opened up the OLE/COM Object viewer, and navigated to the library in question. Then I found the class names that I was interested in. After having the class names, I went to regedit and pulled up HKLM\Software\Classes\CLSID\<id> by doing a find on the class name, then looked at the ProgID entry.

At this point, I can call CLSIDFromProgID and then CoCreateInstance successfully using a CComPtr<IClassType>. But, if I still don't know how to get at the IID that I would need should I call CoCreateInstance directly without a CComPtr.

What's the best way to get at the IID? I also presume that there's a better way to get at the CLSID and ProgID?

Re: Easily find IID, CLSID, ProgID?

Prakash Nadar26-Apr-04 7:51

Prakash Nadar

26-Apr-04 7:51

IID generally follows this rule,

interface name IMyInterface so iid is IID_IMyInterface
CLSID_IMyInterface.

God is Real, unless declared Integer.

Re: Easily find IID, CLSID, ProgID?

Kaleb Pederson26-Apr-04 8:46

Kaleb Pederson

26-Apr-04 8:46

I had tried that as a that's the convention that many of the examples that I had found used, but when I looked through the .tlh and .tli files that were generated from the #import, there is no reference to either CLSID or IID anywhere in those two files, thus the compiler complains about an undeclared identifier. Is that something that would typically be defined in the dll so that a #import would pull it in?

Thanks again.

Re: Easily find IID, CLSID, ProgID?

Prakash Nadar26-Apr-04 18:01

Prakash Nadar

26-Apr-04 18:01

did you put named_guids in the #import statement ?

God is Real, unless declared Integer.

Re: Easily find IID, CLSID, ProgID?

Kaleb Pederson27-Apr-04 9:33

Kaleb Pederson

27-Apr-04 9:33

Thanks! I had missed that attribute. I noticed the namespace ones and some others, but didn't even see that one. That will make things much easier.

Thanks again.

--Kaleb

how to maintain relationship between parent and child activeX control

Abhi Lahare26-Apr-04 0:49

Abhi Lahare

26-Apr-04 0:49

Hi all,

I am working on this from last few days, but no success yet Cry | :((

.

I am creating two activeX control in SetClientsite of another activeX control. using AtlAxCreateControl() function.
The two inner controls are clearly visible me in IE( container for the outer activeX control).
My question is even if i am able to create these control. how can I control
these child ActiveX from Parent ActiveX. because the AtlAxCreateControl() does not return anything about the control which I can be keep as a refernce in the outer activeX. or in Simple term how the other component knows about the inner component.

2. How to resize the two child controls?

Can someone help me?
Thanks in advance,
Abhishake

Re: how to maintain relationship between parent and child activeX control

Jitendra gangwar27-Apr-04 20:20

Jitendra gangwar

27-Apr-04 20:20

MSDN -----> Article 'Write ActiveX Controls Using Custom Interfaces Provided by ATL 3.0, Part III'.

The above articale would expain you what is happening behind the scene or more simply you would use connection points for interaction between the control and container.

Jitendra

Forward declaration error of ICallFactory

shahzi25-Apr-04 20:34

shahzi

25-Apr-04 20:34

hi,
i m trying to make my COM server to handle asynchronous calls. But for i have an error while trying to update the idl file for this purpose.
While adding these lines
coclass FullServ
{
[default] interface IFullServ;
interface ICallFactory;
}
it throughs the following error

error MIDL2337 : unsatisfied forward declaration : ICallFactory [ Coclass 'FullServ' ]

It will be so kind of u if u can help me out.

Shahzad Ahmad

Re: Forward declaration error of ICallFactory

Mike Dimmick26-Apr-04 23:30

Mike Dimmick

26-Apr-04 23:30

It's telling you that it couldn't find a full declaration of ICallFactory.

Make sure you've imported ObjIdl.idl, where this interface is defined. This interface wasn't defined in the headers which shipped with Visual Studio 6; you'll need a newer version of the Platform SDK, which you can obtain from http://www.microsoft.com/msdownload/platformsdk/sdkupdate/[^].

Stability. What an interesting concept. -- Chris Maunder

Re: Forward declaration error of ICallFactory

shahzi29-Apr-04 20:19

shahzi

29-Apr-04 20:19

Thanks Mike.I have done this. But when i include the Plateform 2000 SDK files in Visul C++ setting i have other error of in

BEGIN_OBJECT_MAP(ObjectMap)
OBJECT_ENTRY(CLSID_TryAsync, CTryAsync)
END_OBJECT_MAP()

Error: Can not access private member

Now i tried to simply replace the objidl.idl file of Visual studio with that of SDK. After This i havenot get any error in IDL File But it gives the following error if i try to make my object class inherit from IClassFactory.

error C2504: 'ICallFactory' : base class undefined
Thirdly when i include
async_uuid(06896d00-fb66-4222-8991-eb85c11720f9),
in IDL and my declaration of Interface is this

interface ITryAsync : IUnknown
{
[id(1), helpstring("method Add")] HRESULT Add [in] int a, [out, retval] int* b);
};
It gives Followin error
error MIDL2021 : duplicate id : [ Procedure 'Finish_Add' ( Interface 'AsyncITryAsync' ) ]

It will be so kind of you if you can help me in this regard.
If u have some useful sample then Please send me or give me its link.

non-blocking Method Calling from COM Client

shahzi23-Apr-04 22:27

shahzi

23-Apr-04 22:27

hi,
i want to develop an application in which com client can call methds of COM Server asynchronously. For this i have gone through non-blocking method calls" article from microsoft. But there are some problems. i m getting error on adding this line to IDL file.
[
object,
uuid(637D4FFD-3DBB-4783-B2A3-196AC10FF804),
// async_uuid(6847c7fb-15fc-4638-b403-779d654d90e2),
dual,
helpstring("IAsync Interface"),
pointer_default(unique)
]
interface IAsync : IUnknown
{
[id(1), helpstring("method add")] HRESULT add([in] int a, [ out ] int * b);

It gives the following error

error MIDL2021 : duplicate id : [ Procedure 'Finish_add' ( Interface 'AsyncIAsync' ) ]

Secondly if i wnt to make it server for VB Client i made the following change to the code
coclass Async
{
[default] interface IAsync;
interface ICallFactory;

};
and it return following error

error MIDL2337 : unsatisfied forward declaration : ICallFactory [ Coclass 'Async' ]

it will be so kind of u if u can help me in this regard. By giving any link or help

Pass by Value or by Reference

normanordas22-Apr-04 21:15

normanordas

22-Apr-04 21:15

Using P/Invoke how would i know that i should be passing "by value" or "by reference" to the arguments of a method or function of the DLL?
2. Equivalent type in .Net of the used data type for each variable (e.g what's the equivalent type of BSTR in VB.Net/C#?
3. In the type library it says:
VARIANT_BOOL _stdcall NE_QueryElementByID(
[in] long net,
[in] ElementTypeEnum eltype,
[in, out] IDAttRec* id,
[in, out] HandleAttRec* h);

This is the way i called it in VB.Net...is this correct?
...
<dllimport("neteng.dll")> _
Public Shared Function NE_QueryElementByID(ByRef net As Long, ByRef eltype As ElementTypeEnum, ByRef id As IDAttRec, ByRef h As HandleAttRec) As Boolean
End Function
...

Dim h1 As HandleAttRec
hi.Handle = 0
Dim id1 As IDAttRec
Dim m_startid As Int32 = 4424

id1.UserID = 99
id1.LayerKey = 1
dim bol as Boolean = NE_QueryElementByID(net, ElementTypeEnum.NE_EDGE, id1, h1)

Tnx a lot!

Re: Pass by Value or by Reference

Mike Dimmick23-Apr-04 9:24

Mike Dimmick

23-Apr-04 9:24

COM's IDL follows C's convention: arguments are always copied (pass-by-value). Where it gets tricky is that the value copied might be a pointer, simulating pass-by-reference.

In this case, you'll want to pass net and eltype ByVal, while id and h should be passed ByRef.

However, if you have a type library, why aren't you using tlbimp?

Stability. What an interesting concept. -- Chris Maunder

Using ISyncMgrRegister

jparsons22-Apr-04 19:57

jparsons

22-Apr-04 19:57

I'm trying to write my own customer SyncMgr component. I'm having some trouble loading up the ISyncMgrRegister object. I'm a little new to COM so I'm probably missing osmething obvious here. This is MC++ code. Can someone point me in the correct direction.

<br />
#include "stdafx.h"<br />
#include "mobsync.h"<br />
#using <mscorlib.dll><br />
<br />
using namespace System;<br />
<br />
int _tmain()<br />
{<br />
    HRESULT hr = CoInitialize(NULL);<br />
<br />
    if ( FAILED(hr) )<br />
    {<br />
      Console::WriteLine(S"Cannot Initilaize com");<br />
      goto error;<br />
    }<br />
<br />
    ISyncMgrRegister *reg = NULL;<br />
<br />
    hr = CoCreateInstance(<br />
      CLSID_SyncMgr,<br />
      NULL,<br />
      CLSCTX_LOCAL_SERVER,<br />
      IID_ISyncMgrRegister,<br />
      reinterpret_cast<void**>(reg));<br />
    if ( FAILED(hr) )<br />
    {<br />
      Console::WriteLine(S"Could not create an instance of the Sync Mgr");<br />
      goto error;<br />
    }<br />
<br />
    reg->Release();<br />
<br />
    Console::WriteLine(S"Press Enter to Exit");<br />
    Console::ReadLine();<br />
	return 0;<br />
<br />
error:<br />
<br />
  Console::WriteLine(S"Press enter to exit");<br />
  Console::ReadLine();<br />
  return 1;<br />
}

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n

Re: Using ISyncMgrRegister

Mike Dimmick23-Apr-04 9:26

Mike Dimmick

23-Apr-04 9:26

reinterpret_cast<void**>(&reg)

The rest looks fine.

Stability. What an interesting concept. -- Chris Maunder

Re: Using ISyncMgrRegister

jparsons23-Apr-04 11:58

jparsons

23-Apr-04 11:58

Wow that was a stupid mistake. Thanks

Jared
jparsons@jparsons.org
www.prism.gatech.edu/~gte477n

Re: Using ISyncMgrRegister

MichaelPine17-Apr-05 22:07

MichaelPine

17-Apr-05 22:07

Hi Jared,

I saw your post and was looking for some help, I am trying to write a Sync Manager component as well and I am having great difficulty with this as I am fairly new to C++ mostly VB, but I really need to hook into this interface, I to start with just wanted to get a hook in working, i.e register for synchronization and that sort of thing, do you have good samples you could share or point me in the right direction ?

Cheers
Michael

error in loading .dll

Peter GW22-Apr-04 5:17

Peter GW

22-Apr-04 5:17

Hi guys. I am having trouble in using a ATL Component interface (Activex Server component created in VC++) with vbscript on a ASP page. I can successfully create the interface in the asp page and successfully set & retrieve property values and call some methods. However, when one particular method is called i get the following error "Error in loading .dll : " followed by the appropriate method name.
This method returns a Recordset and uses ADO to query a table in a SQL database. This method works fine when called from within vba,VB or C++, it only complains when being called in VBscript in an asp page. I have checked the permissions of the .dll and all seems ok. Does anyone have any ideas about what could be causing this? Any help is gratefully received.

Thanks,

Peter G Welch

COM+ Transaction err0r

versatile_me21-Apr-04 18:03

versatile_me

21-Apr-04 18:03

hi all i am facing a problem in Com+ transaction
i have 3 classes 1 main class , others classes are a, b.
all these classes are derived from servicedcomponent and have required transaction attribute.
in a method of main class i am calling fuctions of class a and class b.
i want these to be in transaction
when i am using contecxtutil.setComplete and setabort in main class method and also in class a and class b method i get error saying something like this
"Transaction explicitly or implicitly committed or aborted".
am i doing it in a right way or am i missing something.
i am bit new in com+ app.
please guide me in this problem

best regards and thanx
jignesh Smile | :)

Load COM from a remote location

Fabio Panzavolta21-Apr-04 3:47

Fabio Panzavolta

21-Apr-04 3:47

Hi guys,
an application we're developing load COM objects during its execution. These COMs can be found in any location (local PC or remote PC). Now my question is, there will be problems on doing that?
Should I add the linker option /SWAPRUN:NET when linking the COM project to allow Windows load the COM from the remote PC without paging?
Thanx for your reponses,

Fabio

CreateDispatch AccessDenied

shiraztk21-Apr-04 0:49

shiraztk

21-Apr-04 0:49

Hi all

I have created a ATL com which runs all the machines. but faisl on one which is a Windows 2003 server. But it functions on another 2003 server.

When I call CreateDispatch("name",NULL); its showing error access denied.

Dont know whats happening
Please help me

COM tutorials

Poorniselva21-Apr-04 0:41

Poorniselva

21-Apr-04 0:41

Hi all,
Can anybody suggest some online reference to start learning COM using MFC>

exposing a class library as a COM object

User 96257820-Apr-04 9:41

User 962578

20-Apr-04 9:41

How would i exposs a class library as a COM object. i look through the SDK Docs and still a little lost.

[ ...what to put in here? ]
public class MediaStatusSink : IMediaStatusSink
{....
}

I just need help setting up the class attributes,
here is what im trying to do:

A sink is a COM component that supports the IMediaStatusSink interface and is registered as a member of the CATID_MediaStatusSink {FCB0C2A3-9747-4C95-9D02-820AFEDEF13F} component category.

in the registry editor at
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Component Categories\{FCB0C2A3-9747-4c95-9d02-820AFEDEF13F} i have:

(default) REG_SZ (value not set)
409 REG_SZ Media Status Sink

modified 16-May-21 21:01pm.

Catching COM Events without using ATL

jerry0davis20-Apr-04 5:09

jerry0davis

20-Apr-04 5:09

I'm using a COM API for a VoIP Voice phone. I can interrogate it fine using the following code...

IVOIPDevice* pISL = NULL;<br />
HRESULT hr;<br />
	<br />
	hr = CoCreateInstance(<br />
		CLSID_VOIPDevice,		// CLSID of coclass<br />
		NULL,                   // not used - aggregation<br />
        CLSCTX_INPROC_SERVER,<br />
		IID_IVOIPDevice,        // IID of interface<br />
		(void**) &pISL);        // Pointer to our interface pointer<br />
	<br />
	if (SUCCEEDED(hr))<br />
	{<br />
        // Call methods using pISL here.<br />
		TRACE("SUCCEED!!!!\n");<br />
	}<br />
    else<br />
	{<br />
        // Couldn't create the COM object.  hr holds the error code.<br />
		TRACE("SUCCEED NOT!!!!\n");<br />
return;<br />
	}<br />
<br />
pISL->etc etc etc

The interface for the events is _IVOIPDeviceEvents. How can I act on these events? I'd rather not use ATL if at all possible.

I feel like I'm diagonally parked in a parallel universe

Jerry Davis
http://www.astad.org
http://www.jvf.co.uk

Re: Catching COM Events without using ATL

Mike Dimmick20-Apr-04 5:54

Mike Dimmick

20-Apr-04 5:54

You'll need to implement _IVOIPDeviceEvents as a dispatch interface by implementing IDispatch. If you create a dual interface, you can get the OS to implement IDispatch for you by calling CreateStdDispatch.

You then need to give your dispatch pointer to the object by asking it for the appropriate connection point - an object that implements IConnectionPoint. First you QueryInterface for IConnectionPointContainer, then use that interface's FindConnectionPoint method to get the IConnectionPoint. You can then call Advise, passing in your dispatch interface pointer. Remember the returned cookie, so that you can later call Unadvise to clean up.

Stability. What an interesting concept. -- Chris Maunder

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.