ConnectionPoint Events

ConnectionPoint events allow a COM object to receive events from SQL-DMO objects. ConnectionPoint point events are available only to C++ applications.

To implement the event methods of a SQL-DMO object named Object that supports ConnectionPoint events, a COM object (typically named ObjectSink) must follow these requirements:

• Inherit from the ISQLOLEObjectSink interface to get the correct VTBL.
• Implement all event methods for the SQL-DMO object that is included in the ISQLOLEObjectSink interface.
• Respond to the IID_ISQLOLEObjectSink interface ID.

    To use events of a SQL-DMO object named Object that supports ConnectionPoint events

1. Call the IUnknown::QueryInterface method of the SQL-DMO object that supports ConnectionPoint events. Pass IID_IConnectionPointContainer as the riid parameter, and pass the address of a pointer to a ConnectionPointContainer object as the ppvObj parameter.

   QueryInterface will set ppvObj to point to a ConnectionPointContainer object.

2. Call the IConnectionPointContainer::FindConnectionPoint method of the ConnectionPointContainer object. Pass the event sink interface ID of the SQL-DMO object as the first (xxx) parameter, and pass the address of a pointer to a ConnectionPoint object as the second (yyy) parameter.

   FindConnectionPoint will set yyy to point to a ConnectionPoint object.

3. Create an ObjectSink object.
4. Call the ISQLOLEObjectSink::Advise method of the ConnectionPoint object. Pass a pointer to the ObjectSink object as the pAdvSink parameter, and pass the address of a token as the pdwConnection parameter.

   Advise will set pdwConnection to an advisement identifier, or "cookie," that is used when calling ISQLOLEObjectSink::Unadvise.

5. Use the SQL-DMO object. When a SQL-DMO event for that object is fired, SQL-DMO will call the appropriate event method of the ObjectSink object.
6. Call the ISQLOLEObjectSink::Unadvise method of the ConnectionPoint object. Pass the "cookie" advisement identifier as the dwConnection parameter.

   SQL-DMO will no longer call the ObjectSink object when SQL-DMO events are fired.

7. Call the IUnknown::Release method of the ConnectionPoint object.
8. Call the IUnknown::Release method of the ConnectionPointContainer object.

The following table lists the SQL-DMO objects that support ConnectionPoint events and the event sink interfaces and interface IDs for each of them.

For more information about COM events, see the Microsoft OLE Control Developer's Kit and the Microsoft Win32 SDK.