Property Set Implementations in COM

While the potential for uses of persistent property sets is not fully tapped, there are currently two primary uses:

  • Storing summary information with an object such as a document
  • Transferring property data between objects

COM property sets were designed to store data that is suited to representation as a moderately sized collection of fine-grained values. Data sets that are too large for this to be feasible should be broken into separate streams, storages, and/or property sets. The COM property set data format was not meant to provide a substitute for a database of many tiny objects.

COM provides implementations of the property set interfaces for various objects, along with three helper functions. The following section describes some performance characteristics of these implementations. For more information on specific interfaces and how to get a pointer to these interfaces, refer to the following in the COM reference section:

In addition, there are four helper functions, designed to aid in dealing with properties that have been read from a property set into memory (into a PROPVARIANT structure):

The following sections discuss property set implementations in COM in greater detail:



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