Re: Problem with ATL/COM

"Brian Muth" <>
Wed, 10 Dec 2008 11:31:33 -0800
Tony, you have painted yourself into a corner with a really bad design. The best advice is to abandon this altogether.

OLE DB drivers already supports session pooling, so your effort to try to keep a session open for the duration of the C# program
accomplishes little, other than to give you a big coding headache. It's quite all right to open late, close early. Read more about
it here:


"Tony Johansson" <> wrote in message news:%23zjTx7RWJHA.5520@TK2MSFTNGP03.phx.gbl...


I use a C# webbapplication which call different COM object using the
defined COM interface for each concrete C++ class.
So at the bottom I have OpenDS method located in the concrete C++ class
This method is also define at the IHandle_DS COM interface.
Here is the sequence for the code.
1. I create a concrete C++ class from C# like this
   CHande_DS handle_ds = new Handle_DS();
2. I call OpenDS like this
3. I pass this concrete C++ object into a method called InitRules2 which is
defined in the COM interface ISyntaxObj
You can see below I have listed a piece of InitRules2.
4. I store the passed pointer to IHandle_DS in another class called
5. The first method to be called from InitRules2 is DBInitCommandTemplate
6. If you now look at method DBInitCommandTemplate below you can see that I
use the local Session and local DS in the previous code in several places
but in the new code I can't use the local Session because of the new
I must in some way use the CSession object that is stored in the concrete
C++ class CHandle_DS but that is not easy because of the COM interface

The reason for storing this CDataSource and CSession in CHandel_DS is to
keep the database open until I close it at the end of C# So I have to drag this
CHandle_DS object from C# into the InitRules2 because of keeping
the status of my connection to the database.

So can you give me some piece of advice how to modify or create a new interface so I
can access the object Session in method DBInitCommandTemplate see below and
LoadProcedureRules below.

Note in especially that I only use the object Session in both DBInitCommandTemplate and

STDMETHODIMP CSyntaxObj::InitRules2(IHandle_DS* handle_ds, BSTR Provider,
BSTR DataSource, BSTR UserId, BSTR Password, BSTR ProductID, BSTR Revision,
           BSTR ApplicationID, BSTR ApplicationRev, BSTR SubfileID,
  m_pAltObj = new CAlterObj;
  m_pAltObj->m_handle_DS = handle_ds;
  m_pAltObj->DBInitCommandTemplate(some parameter here)))

HRESULT CAlterObj::DBInitCommandTemplate(some parameter here)
CCommand<CAccessor<CSetRole> > sqlRole;
//CSession Session; // old code
//CDataSource DS; // old code
//hr = DS.Open(); // old code
//hr = Session.Open(DS); // old code
  hr = sqlRole.Open(Session);
  hr = LoadProcedureRules(&Session,&dbPropSet,ProductID, Revision,

   hr = DS.Open("OraOLEDB.Oracle","IDTHU1","CCR_DTH_USER","P55534552");
   hr = Session.Open(DS);
   return hr;

HRESULT CAlterObj::LoadProcedureRules(CSession *pSession, CDBPropSet *pDbPropSet, BSTR ProductId, BSTR Revision, BSTR SubfileID)
   CCommand<CAccessor<CDbProcedureRulesGet> > sqlItems;
   hr = sqlItems.Open(*pSession, NULL, pDbPropSet);


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