ICatInformation:IUnknown

Article
06/30/2006

This interface provides methods for obtaining information about the categories implemented or required by a certain class, as well as information about the categories registered on a given machine.

When to Implement

There is no need to implement this interface. The Component Category Manager, a system-provided COM object that can be instantiated by using the CoCreateInstance function, implements ICatInformation.

When to Use

Call the methods of ICatInformation to obtain a listing of available categories, enumerate classes that belong to a particular category, and determine if a class belongs to a specific category.

Information on using component categories can be found in Component Categories Manager Implementation.

Methods

The following table shows the methods for this interface in the order that the compiler calls the methods. Like all COM interfaces, this interface inherits the methods for the IUnknown interface.

IUnknown method	Description
QueryInterface	Returns pointers to supported interfaces.
AddRef	Increments reference count.
Release	Decrements reference count.

ICatInformation method	Description
EnumCategories	Returns an enumerator for the component categories registered on the system.
GetCategoryDesc	Retrieves the localized description string for a specific category identifier.
EnumClassesOfCategories	Returns an enumerator over the classes that implement/require a certain set of categories.
IsClassOfCategories	Determines if a class implements/requires the specified categories.
EnumImplCategoriesOfClass	Returns an enumerator over the CATIDs implemented by the specified class.
EnumReqCategoriesOfClass	Returns an enumerator over the CATIDs required by the specified class.

Remarks

To determine whether the platform supports this interface, see Determining Supported COM APIs.

Requirements

OS Versions: Windows CE 3.0 and later.
Header: Comcat.h, Comcat.idl.
Link Library: Ole32.lib, Uuid.lib.

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