Adding Application-specific Information to the Data
Application developers can add custom information to the client dataset's Data property. Because this information is bundled with the data packet, it is included when you save the data to a file or stream. It is copied when you copy the data to another dataset. Optionally, it can be included with the Delta property so that a provider can read this information when it receives updates from the client dataset.
To save application-specific information with the Data property, use the SetOptionalParam method. This method lets you store an OleVariant that contains the data under a specific name.
To retrieve this application-specific information, use the GetOptionalParam method, passing in the name that was used when the information was stored.