Re: preparing DISPPARAMS for a method?? - COM Discussion Boards

zx2c426-Mar-05 6:35

26-Mar-05 6:35

This is what I have currently:

HRESULT hres;
DWORD d;
IConnectionPoint * icp;
IConnectionPointContainer * icpc;
hres = iITunes->QueryInterface(IID_IConnectionPointContainer,(PVOID *)&icpc);
hres = icpc->FindConnectionPoint(DIID__IiTunesEvents,&icp);
eventSink = new ITunesEventSink();
hres = icp->Advise((IUnknown*)&eventSink,&d);

and then
class ITunesEventSink:public _IiTunesEvents
{
public:
HRESULT OnAboutToPromptUserToQuitEvent();
};

The only problem is that "error C2259: 'ITunesEventSink' : cannot instantiate abstract class" Well duh, I need to impliment all of the virtual functions, but does that mean looking at the header files containing IDispatch and IUnknown and then copying in all of those function names and then giving functionality to them? If so, what is the best way to go about implimenting the functions?

Re: iTunes COM SDK

zx2c426-Mar-05 16:27

zx2c4

26-Mar-05 16:27

alright. i implimented the ITunesEventSink and now i have OnAboutToPromptUserToQuitEvent being called; however, it calls it on the wrong thread. Is there way that i can call a function from a different thread?

Is MDAC new Version backwork compatible?

netboy202025-Mar-05 8:04

netboy2020

25-Mar-05 8:04

Hello,

I have created one ActiveX Dll using VB and I am using Data Access Components 2.5.

After deploying this COM components I could access it through ASP Pages.

Everything goes well in development environment but in Production Environment we are installing MDAC 2.7.
And components are not working.

So I would like to confirm whether MDAC 2.7 installtion program includes MDAC 2.5. And my ActiveX dll having reference to the "Activex Data Access component 2.5" is suppose to work or not.

Thanks
Mitesh

Re: Is MDAC new Version backwork compatible?

John M. Drescher25-Mar-05 8:35

John M. Drescher

25-Mar-05 8:35

MDAC 2.7 is definitly not new, I have been using it for at least a year, probably 2 or 3. I have not noticed any kind of problem with backward compatibility.

[EDIT]
MDAC 2.8 is the latest version. It was first introduced in 8/4/2003 so I guess I have an old version...
[/EDIT]

John

Custom ActiveX control?

foxyspy24-Mar-05 20:23

foxyspy

24-Mar-05 20:23

How to fix (custom ActiveX)control size in design time.

I am using MFC ActiveX ControlWizard.

Please help me.

Thanks

David Park

preparing DISPPARAMS for a method??

Muhammad Azam24-Mar-05 19:00

Muhammad Azam

24-Mar-05 19:00

hi
I am writing an IDispatch client. i want to call this method

void SomeMethod(
[in, out] BSTR* strFile,
[in, out] BSTR* strMiscFile,
[in, out, optional, defaultvalue("Some Default value")] BSTR* strValue
);

using IDispatch::Invoke. I have got DISPID of this method using GetIDsOfNames, the problem is in making DISPPARAMS for this method that can be passed to Invoke.

does any one know how do we prepare DISPPARAMS for such type of methods as mentioned above.

Thanks in anticipation

Azam

Re: preparing DISPPARAMS for a method??

Vi227-Mar-05 22:30

Vi2

27-Mar-05 22:30

CComBSTR strFile, strMiscFile, strValue;

VARIANTARG* rgvarg = new VARIANTARG[3];

V_VT(&rgvarg[2]) = VT_BSTR | VT_BYREF;
V_BSTRREF(&rgvarg[2]) = &strFile;

V_VT(&rgvarg[1]) = VT_BSTR | VT_BYREF;
V_BSTRREF(&rgvarg[1]) = &strMiscFile;

V_VT(&rgvarg[0]) = VT_BSTR | VT_BYREF;
V_BSTRREF(&rgvarg[0]) = &strValue;

DISPPARAMS dispparams = { rgvarg, NULL, 3, 0 };

With best wishes,
Vita

Re: preparing DISPPARAMS for a method??

Muhammad Azam27-Mar-05 22:47

Muhammad Azam

27-Mar-05 22:47

hi Vita

Thank you very much for solving my problem. One thing i would also like to ask if you donot mind, how do we pass named parametrs to a function. lets say if the function is same as mentioned in my previous question i.e

void SomeMethod(
[in, out] BSTR* strFile,
[in, out] BSTR* strMiscFile,
[in, out, optional, defaultvalue("Some Default value")] BSTR* strValue
);

then how do v prepare DISPPARAMS for this function using named arguments?

thanks in anticipation

Azam

Re: preparing DISPPARAMS for a method??

Vi227-Mar-05 23:01

Vi2

27-Mar-05 23:01

Look at Automation: Passing Parameters[^]
But I don't recommend you to use the named arguments.

With best wishes,
Vita

Re: preparing DISPPARAMS for a method??

Muhammad Azam27-Mar-05 23:06

Muhammad Azam

27-Mar-05 23:06

Thanks once again. i will read this article. may i distrub u if i need some help in between Smile | :)

regards

Azam

Open excel woorbook in office xp 2002 with c#

24-Mar-05 6:16

Hello, I`ve got a problem with opening excel woorbook using this code.
I`ve got office xp 2002 with sp3.
On one computer i dont have this problem, but on the other one appears exception.

object mis = System.Reflection.Missing.Value;
Excel.Application excel = new Excel.ApplicationClass();
Excel._Workbook wkb = excel.Workbooks.Add(mis);
Excel._Worksheet sht = (Excel._Worksheet)wkb.Sheets[1];

I did add reference to excel 10. TypeLib version 1.4

This is the exception i`ve receive.
An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in SqlToExcel.exe

Additional information: Old libary or incorect form.
(Biblioteka w starym formacie lub nieprawidłowy typ biblioteki).

I dont now what to change in the code.

Please, help meeee. Frown | :(

Using COM dll in C

Monty²23-Mar-05 23:54

Monty²

23-Mar-05 23:54

i remember reading an article but i can't remeber where now, how can i use a COM dll in C (not create a COM object in C, just be able to call some functions)
thanks

C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do, it blows away your whole leg

Re: Using COM dll in C

Jörgen Sigvardsson24-Mar-05 2:52

Jörgen Sigvardsson

24-Mar-05 2:52

A COM DLL is a regular DLL with some restrictions on it: It must export the 5 functions DllMain, DllCanUnloadNow, DllGetClassObject, DllRegisterServer and DllUnregisterServer. Technically, the last function isn't really needed to run COM stuff, but if you want to uninstall the COM DLL, it's nice to be able to remove references to it in the registry.

To load a DLL:

HMODULE hDLL = LoadLibrary(_T("the.dll"));
if(!hDLL) exit(-1); // Error!

To acquire a function pointer to a function inside the DLL:

void (*function)();
function = (void (*)())GetProcAddress(hDLL, "TheNameOfFunction");
if(!function) exit(-1); // Error!
function(); // Call it

And finally, if you are done with the DLL, and you wish to unload it, call

FreeLibrary(hDLL);

There's also LoadLibraryEx which might be interesting to have a look at.

Did I answer your question? The MSDN Library has all the information you need to manuall load and use DLLs.

--
My name in Katakana is ヨルゲン.
My name in German is Jörgen.
My name in Mandarin/Kanji is 乔尔根西格瓦德森.
My name in Korean is 요르겐.

I blog too now[^]

Re: Using COM dll in C

Monty²24-Mar-05 5:20

Monty²

24-Mar-05 5:20

yes by using the above stuff i can create an object

how will i call the interface methods and all the vtbl stuff

thanks for such a neat reply very well explained thanks Big Grin | :-D

C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do, it blows away your whole leg

Re: Using COM dll in C

Jörgen Sigvardsson24-Mar-05 9:54

Jörgen Sigvardsson

24-Mar-05 9:54

Ah, you meant COM object methods, and not functions exported by the DLL. I see. In that case: what Mike said. Smile | :)

--
My name in Katakana is ヨルゲン.
My name in German is Jörgen.
My name in Mandarin/Kanji is 乔尔根西格瓦德森.
My name in Korean is 요르겐.

I blog too now[^]

Re: Using COM dll in C

Mike Dimmick24-Mar-05 5:43

Mike Dimmick

24-Mar-05 5:43

You use CoCreateInstance as before. To call an instance method, you need the header file generated from the source IDL by midl. Instead of writing, for example

p->GoForward()

you would write

IWebBrowser_GoForward(p)

That is, you prefix the call with the name of the interface and pass the object as the first parameter of the call. IWebBrowser_GoForward is actually a macro that masks the explicit dereference:

p->lpVtbl->GoForward(p)

I'd seriously query why you're using it from C, though - it's perfectly possible to make a hybrid C/C++ app where some modules are compiled as C and others as C++.

[EDIT:] On re-reading the ExDisp.h header file (just an example, it contains the IWebBrowser interface I referred to earlier) it looks like you only get the interface_method macros if you define COBJMACROS. [/EDIT]

Stability. What an interesting concept. -- Chris Maunder

Re: Using COM dll in C

Monty²24-Mar-05 7:22

Monty²

24-Mar-05 7:22

thanks that's a good insight

i agree the c/c++ hybrid application is the best way to go about it, i just want to have enough info on the subject before i start convincing them Big Grin | :-D

that it is a bad and time consuming idea

thanks for reply

C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do, it blows away your whole leg

QueryInterface calls

GizzoF23-Mar-05 0:41

GizzoF

23-Mar-05 0:41

Hi!

I have observed that when a COM object is created its QI method is called for the following interfaces:

1. IUnknown
2. IMarshal x2
3. {0000001B-0000-0000-C000-000000000046} (IdentityUnmarshal ??)
4. IUnknown
5. ISdtMarshalInfo
6. IExternalConnection
7. {4C1E39E1-E3E3-4296-AA86-3C938D896E92} WTF | :WTF:

8. IManagedObject
9. IConnectionPointContainer x2
10.{1C73A30-2A1C-11CE-ADE5-00AA0044773D} Sigh | :sigh:

11. IFeed (this is my interface)
12. {1C73A30-2A1C-11CE-ADE5-00AA0044773D}
13. IFeed

Could any of you explain where these calls come from?
Could be SCM doing his things? Proxy/Stub related? Confused | :confused:

Thanks in advance
Gizzo

Re: QueryInterface calls

ThatsAlok23-Mar-05 1:58

ThatsAlok

23-Mar-05 1:58

Simple OOPS concept of Construction and Destruction

Ifeed Derived From IConnectionPointContainer which from IManagedObject from IExternalConnection from iSdtMarshalInfo with Super One IUnknown

[Vote One Here, Complete my Survey....]

Alok Gupta
visit me at http://www.thisisalok.tk

"I ~~Think~~ Believe this Will Help"

Re: QueryInterface calls

GizzoF23-Mar-05 4:23

GizzoF

23-Mar-05 4:23

Hi again,

IFeed is my interface and it is derived from IDispatch. The class that implements IFeed is CFeedCOM... i think i'm going to post it...

class CFeedCOM : 	public CReferenceCountedObject, <br />
						public IFeed,<br />
						public ISupportErrorInfo,<br />
						public IConnectionPointContainerImpl<CFeedCOM>,<br />
						public CProxy_IFeedEvents<CFeedCOM>

CReferenceCountedObject is taken from Lim Bio Liong (this guy have saved my life with his articles).

The reason I wanted to know what happens under the hood of an object creation is:
When a client fails (sometimes, not always) the next client trying to connect to the server doesn't follow the same steps that the previous one. Instead of querying all the interfaces posted in my previous message, my object is asked for:

1. IUnknown
2. IMarshal x2
3. {0000001B-0000-0000-C000-000000000046}
4. IID_IUnknown

And now, something happens, and my object is released until m_cRef goes to zero. Then, QI is called for IManagedObject, m_cRef is incremented to 2, and again released until zero. This causes the destruction of my object of course what I'm trying to avoid.

I don't know if I explained the problem. I only want to know what is happening there.

Thanks for answering.

Best regards,
Gizzo.

DCOM Server using in service

Member 28664122-Mar-05 17:39

Member 286641

22-Mar-05 17:39

Hi,
I have made a DOCOM Server which is running as service in different machine and i want to use that server it in other machine within a service.how it can be possible plz help me out..
ajay

How to make an ActiveX control can be copied and pasted in a Richedit control

gxulg22-Mar-05 17:30

gxulg

22-Mar-05 17:30

I have written an ActiveX control, which can display static and dynamic image. So I can use it in an IM app like MSN to show some interesting expression. To test the control, I have written a subclass of richedit control, I can insert my control into the richedit now, and I have implemented some methods of IRichEditOleCallback so that can copy and paste the controls inserted in the richedit, it can save/load the controls and text in the richedit into/from a RTF file, too. But the test result made me sad, I can copy and paste a standard OLE object like a POWERPOINT file in the richedit, if I copy the control written by me, it failed, it seems my control had been copied and pasted successfully, because the richedit control remained a blank rectangle for my control in the position where it should be pasted to, but only a blank rect, no image was display.
From the test result, my conclusion is, my richedit is a good one, what should I modify is my ActiveX control, but I don't know what to do exactly to achieve my goal. I hope someone can help me, anyone who has the experience can contact me with MSN, my MSN ID is:gxulg@hotmail.com Thanks.

learn to be still.

Get text on screen

levgiang22-Mar-05 0:31

levgiang

22-Mar-05 0:31

How can i write a program can get text on screen at position of mouse cursor.

le van giang

How to make ICopyHook work ?

khan++21-Mar-05 0:43

khan++

21-Mar-05 0:43

I am writing a program which does not let the user copy a specific folder in windows explorer. The way to do this is to implement ICopyHook interface.
The dll has been registered at:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Directory\shellex\CopyHookHandlers\MyHook

I have tried code like this:
class ATL_NO_VTABLE CMyHook :
public ICopyHook
{

BEGIN_COM_MAP(CMyHook)
COM_INTERFACE_ENTRY_IID(IID_IShellCopyHook , CMyHook)
END_COM_MAP()

STDMETHOD_(UINT,CopyCallback) (THIS_ HWND hwnd, UINT wFunc, UINT wFlags, LPCSTR pszSrcFile, DWORD dwSrcAttribs, LPCSTR pszDestFile, DWORD dwDestAttribs);

};

This function never gets called. Instead when I try to copy a folder, I get the following message:
Cannot copy (foldername): Invalid MS-DOS function.
What to do?

Please F1 !

Re: How to make ICopyHook work ?

khan++21-Mar-05 23:01

khan++

21-Mar-05 23:01

I understood my own code finally.
Create a ATLCom Appwizard.
Insert a simple atl object.
Then add one line: public ICopyHook to the parent list.
Comment the other as shown.
To the COM_MAP, add one line, comment the others:
COM_INTERFACE_ENTRY_IID(IID_IShellCopyHook, CMyHook)

class ATL_NO_VTABLE CMyHook :
public CComObjectRootEx<CComSingleThreadModel>,
public CComCoClass<CMyHook, &CLSID_MyHook>,
public ICopyHook
// public IDispatchImpl<IMyHook, &IID_IMyHook, &LIBID_MYHOOKLib>
{
public:
CMyHook()
{
}

DECLARE_REGISTRY_RESOURCEID(IDR_MYHOOK)

DECLARE_PROTECT_FINAL_CONSTRUCT()

BEGIN_COM_MAP(CMyHook)
// COM_INTERFACE_ENTRY(IMyHook)
// COM_INTERFACE_ENTRY(IDispatch)
COM_INTERFACE_ENTRY_IID(IID_IShellCopyHook, CMyHook)
END_COM_MAP()

STDMETHOD_(UINT,CopyCallback) (THIS_ HWND hwnd, UINT wFunc, UINT wFlags, LPCSTR pszSrcFile, DWORD dwSrcAttribs,
LPCSTR pszDestFile, DWORD dwDestAttribs);

// IMyHook
public:
};

The above code works and in the function CopyCallback, you can handle the folder copy event. Of course the registry key also has to be set.

Thanks for reading. Hope it works for all.

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