Most XML display groups contain controls that represent database information. TDataGrid and TFieldGroup represent the fields from a dataset. By default, TQueryFieldGroup represents the parameter values for a query or stored procedure or field values that filter a table. If the database information comes from the dataset represented by an XML broker's data packet, XMLDataSetField is an empty string and the XMLBroker property fully describes the dataset. However, if the database information comes from a nested detail set, XMLDataSetField indicates what detail dataset to use from the data packet associated with XMLBroker. 

Specify the name of the dataset field as the value of XMLDataSetField. If the XML display group is bound to the detail set of a detail set, you can use periods to qualify dataset field names. Thus, for example, if XMLBroker represents a customer dataset with a nested Orders dataset field that has its own nested LineItems field, you can bind the XML display group to the LineItems dataset by setting XMLDataSetField to

Orders.LineItems

XMLBroker 

VisibleFields 

Setting Web Item Properties