IDataReaderExtension IDataReaderExtension IDataReaderExtension Interface


Provides a means of reading one or more forward-only streams of result sets obtained by executing a command at a data source, and is used by SQL Server Reporting Services to retrieve aggregation-specific information about a result set.

public interface class IDataReaderExtension : IDisposable, Microsoft::ReportingServices::DataProcessing::IDataReader
public interface IDataReaderExtension : IDisposable, Microsoft.ReportingServices.DataProcessing.IDataReader
Public Interface IDataReaderExtension
Implements IDataReader, IDisposable


The IDataReaderExtension interface enables you to implement an extension of the IDataReader interface, which you can use to provide a report server with aggregation information about your result set. For more information about DataReader classes, see Implementing a DataReader Class for a Data Processing Extension.

An application does not create an instance of the IDataReaderExtension interface directly, but creates an instance of a class that implements IDataReaderExtension.

Classes that implement IDataReaderExtension must also implement the required members, and typically define additional members to add provider-specific functionality. Because IDataReaderExtension inherits from IDataReaderExtension, you must also implement all of the IDataReaderExtension members as part of your DataReader class.

Changes made to a result set by another process or thread while data is being read may be visible to the user of a class that implements an IDataReaderExtension. However, the precise behavior is both provider and timing dependent.

Users do not create an instance of a DataReader class directly. Instead, they obtain the DataReader through the ExecuteReader method of the Command object. Therefore, you should mark DataReader constructors as internal.


AggregationFieldCount AggregationFieldCount AggregationFieldCount

Gets the number of fields by which the data is aggregated.

IsAggregateRow IsAggregateRow IsAggregateRow

Indicates whether the current row contains aggregate data.


IsAggregationField(Int32) IsAggregationField(Int32) IsAggregationField(Int32)

Indicates whether the data is aggregated by the field with the given index.

Applies to