This method enables a control to notify its sink when a form closes the control.
HRESULT HandleClose( IDispatch *pdispControl );
NOERROR indicates that the sink handled the message to close the control. S_FALSE indicates that the sink did not handle the message to close the control. If an error occurs, the appropriate HRESULT value is returned.
A control invokes this method when its own IASControl::Close method is invoked. This takes place when a form shuts down a control. Processing subsequently stops and any needed shutdown procedures are performed.
IASControl::Close, IASClassMsgSink::HandleStart