Add a REQUIRED_CATEGORY macro to your component's category map to specify that it should be registered as requiring the category identified by the catID parameter.
The component categories listed in the map will be registered automatically when the module is registered if the class has an associated OBJECT_ENTRY_AUTO or OBJECT_ENTRY_NON_CREATEABLE_EX_AUTO macro.
Clients can use the category information registered for the class to determine its capabilities and requirements without having to create an instance of it. For example, a control may require that a container support data binding. The container can find out if it has the capabilities necessary to host the control by querying the category manager for the categories required by that control. If the container does not support a required feature, it can refuse to host the COM object.
For more information about component categories, including a sample list, see What are Component Categories and how do they work? in the Windows SDK.
Safe For Scripting
Safe For Initialization
Simple Frame Site Containment
Simple Data Binding
Advanced Data Binding
See Internet Aware Objects in the Windows SDK for a sample list.