Fundamentals of ATL COM Objects

The following illustration depicts the relationship among the various classes and interfaces used in defining an ATL COM object.

ATL implements IUnknown in two phases:

• CComObject, CComAggObject, or CComPolyObject implements the IUnknown methods.

• CComObjectRoot or CComObjectRootEx manages the reference count and outer pointers of IUnknown.

Other aspects of your ATL COM object are handled by other classes:

• CComCoClass defines the object's default class factory and aggregation model.

• IDispatchImpl provides a default implementation of the IDispatch Interface portion of any dual interfaces on the object.

• ISupportErrorInfoImpl implements the ISupportErrorInfo interface that ensures error information can be propagated up the call chain correctly.

In This Section

• Implementing CComObjectRootEx
  Show example COM map entries for implementing CComObjectRootEx.

• Implementing CComObject, CComAggObject, and CComPolyObject
  Discusses how the DECLARE_*_AGGREGATABLE macros affect the use of CComObject, CComAggObject, and CComPolyObject.

• Supporting IDispatch and IErrorInfo
  Lists the ATL implementation classes to use for supporting the IDispatch and IErrorInfo interfaces.

• Supporting IDispEventImpl
  Discusses the steps to implement a connection point for your class.

• Changing the Default Class Factory and Aggregation Model
  Show what macros to use to change the default class factory and aggregation model.

• Creating an Aggregated Object
  Lists the steps for creating an aggregated object.

Related Sections

• Creating an ATL Project
  Provides information about creating an ATL COM object.

• ATL
  Provides links to conceptual topics on how to program using the Active Template Library.

См. также

Основные понятия

ATL Concepts