About Writing a Custom Handler

The CML/LitCrit application uses the default RDS handler. A custom handler could have been written instead.

A custom RDS handler object must support the IDatafactoryHandler interface, which is also supported by the default handler, MSDFMAP.HANDLER. To add this support, if you are writing this handler as a Microsoft Visual Basic project, do the following:

1. Add the following as project references: the ActiveX Data Objects (ADO) library and the RDS customization handler type library, MSDFHTL.TLD.
2. Include the following statement in the Visual Basic project's declarations section:

   Implements IDatafactoryHandler
    

This provides support for the IDatafactoryHandler interface, and with it support for its GetRecordset and Reconnect methods.

You can add new functionality such as your own data validation object. To do this, you can support ADO events by adding new methods or new properties for these events.