A DataStore is a nonvisual DataWindow control. DataStores act just like DataWindow controls except that many of the visual properties associated with DataWindow controls do not apply to DataStores. Because you can print DataStores, PowerBuilder provides some events and functions for DataStores that pertain to the visual presentation of the data.
However, graph functions such as CategoryCount, CategoryName, GetData, SeriesCount, and so forth depend on the visual graph control, which is not created for a DataStore object. These functions return an error value or an empty string when used with DataStores.