Using VB Ole Server methods from VC

Shilpa Vyapari -- shini@highway.or.jp
Sunday, March 30, 1997

Environment: VC++ 4.0, Windows 95

I have a VB OLE Server object which is to be invoked both from VB as
well as VC. With VB applization it works fine. But when I try to call a
method of that object from VC, it fails. I can't get the dispid. I use
following function to convert name to dispid.

DISPID CLayoutView::NameToID( COleDispatchDriver &pDisp, TCHAR *pszName
)
{
    DISPID      dispid = 0;
    HRESULT     hr;
    TCHAR       szMsg[80];

    hr = pDisp.m_lpDispatch->GetIDsOfNames( IID_NULL, (OLECHAR FAR*
FAR*)&pszName, 1, 
		m_lcid, &dispid );

    if ( FAILED( hr ) )
    {
        wsprintf( szMsg,TEXT( "GetIDsOfNames on '%s' failed with 0x%lX"
), pszName, hr );
        AfxMessageBox( szMsg );
    }
    return dispid;
}

and call it through COleDispatchDriver interface :

	COleDispatchDriver dispDriver;

	dispDriver.CreateDispatch( "OLEServer.Screen2" );

	DISPID dispID = NameToID( dispDriver, "Display" ); // always falis and
displays error box

	if ( dispID != -1 )
	{
		int iret;
		dispDriver.InvokeHelper( dispID, DISPATCH_METHOD, VT_BOOL, &iret,
			NULL, NULL );
	}


Can anyone figure out what's going wrong? 

- Shilpa

---------------------------------
Shilpa Vyapari
Phone/Fax : 81 (0)3-3745-0040
mailto:shini@highway.or.jp
---------------------------------

---

Alberto Massari -- alby@belva.infomus.dist.unige.it
Tuesday, April 01, 1997

At 07:06 PM 30/3/97 +0900, you wrote:
>Environment: VC++ 4.0, Windows 95
>
>I have a VB OLE Server object which is to be invoked both from VB as
>well as VC. With VB applization it works fine. But when I try to call a
>method of that object from VC, it fails. I can't get the dispid. I use
>following function to convert name to dispid.
>
>DISPID CLayoutView::NameToID( COleDispatchDriver &pDisp, TCHAR *pszName
>)
>{
>    DISPID      dispid = 0;
>    HRESULT     hr;
>    TCHAR       szMsg[80];
>
>    hr = pDisp.m_lpDispatch->GetIDsOfNames( IID_NULL, (OLECHAR FAR*
>FAR*)&pszName, 1, 
>		m_lcid, &dispid );
>
>    if ( FAILED( hr ) )
>    {
>        wsprintf( szMsg,TEXT( "GetIDsOfNames on '%s' failed with 0x%lX"
>), pszName, hr );
>        AfxMessageBox( szMsg );
>    }
>    return dispid;
>}
>
>and call it through COleDispatchDriver interface :
>
>	COleDispatchDriver dispDriver;
>
>	dispDriver.CreateDispatch( "OLEServer.Screen2" );
>
>	DISPID dispID = NameToID( dispDriver, "Display" ); // always falis and
>displays error box
>
>	if ( dispID != -1 )
>	{
>		int iret;
>		dispDriver.InvokeHelper( dispID, DISPATCH_METHOD, VT_BOOL, &iret,
>			NULL, NULL );
>	}
>
>
>Can anyone figure out what's going wrong? 

Last year I wrote a piece of code like your, and it worked.
One week ago I recompiled it, and I found that GetIDsOfNames failed in
looking for an exported method.

I found out that GetIDsOfNames wants OLECHAR, and the only way to make it
works is:

#include 

DISPID CLayoutView::NameToID( COleDispatchDriver &pDisp, const char*pszName)
{
>>>>>>>>>>>>>>>>>>>>>>>>>>>> begin modified
	USES_CONVERSION;
>>>>>>>>>>>>>>>>>>>>>>>>>>>> end modified

	DISPID      dispid = 0;
	HRESULT     hr;
	TCHAR       szMsg[80];

>>>>>>>>>>>>>>>>>>>>>>>>>>>> begin modified
	OLECHAR* unicodeName=T2OLE(pszName);
	hr = pDisp.m_lpDispatch->GetIDsOfNames( IID_NULL, &unnicodeName, 1,
m_lcid, &dispid );
>>>>>>>>>>>>>>>>>>>>>>>>>>>> end modified

	if ( FAILED( hr ) )
	{
		wsprintf( szMsg,TEXT( "GetIDsOfNames on '%s' failed with 0x%lX"),
pszName, hr );
		AfxMessageBox( szMsg );
	}
	return dispid;
}


Ciao,

Alberto

			----------------------------
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alby@musart.dist.unige.it is: 	Alberto Massari

Universita' di Genova
Facolta' di Ingegneria Elettronica
Laboratorio di Informatica Musicale
Viale F. Causa 13
I-16100 Genova, Italia		http://musart.dist.unige.it/alby
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