True DBList supports a row-based unbound mode that does not rely upon either the Visual Basic Data control or the ComponentOne XArrayDB object. Instead, unbound mode events fire whenever the list needs to retrieve a group of adjacent rows or update, add, or delete an individual row. Unlike application mode, an intermediate RowBuffer object serves as the liaison between the list and your data source.
There are actually two row-based unbound modes: DataMode 1 - Unbound, is the original unbound mode of DBList; DataMode 2 - Unbound Extended, uses a slightly different event syntax that simplifies coding and is more efficient. Therefore, if you are writing a new application, you should use mode 2. Mode 1 is included for backward compatibility with DBList.
To use the newer row-based unbound mode, set the DataMode property of the list to 2 - Unbound Extended at design time. In code, write a handler for the UnboundReadDataEx event. If you are converting an application that uses DataMode 1, you can improve its performance dramatically by writing a handler for the UnboundGetRelativeBookmark event.
Regardless of whether you use mode 1 or 2, all of the list's bookmark-related properties, methods, and events (Bookmark, FirstRow, GetBookmark, FetchCellStyle, and others) work the same in the row-based unbound modes as they do in any other DataMode, either bound or unbound.
Unbound mode is only used for populating a control with data. If you are using True DBList to update another data source, you must set the DataSource property to the name of a bound data control at design time.