• Artigo

Interface IDataReaderExtension

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.

Namespace:  Microsoft.ReportingServices.DataProcessing
Assemblies:   Microsoft.ReportingServices.SharePoint.UI.WebParts (em Microsoft.ReportingServices.SharePoint.UI.WebParts.dll)
  Microsoft.ReportingServices.Interfaces (em Microsoft.ReportingServices.Interfaces.dll)

Sintaxe

'Declaração
Public Interface IDataReaderExtension _
    Inherits IDataReader, IDisposable
'Uso
Dim instance As IDataReaderExtension

public interface IDataReaderExtension : IDataReader, 
    IDisposable

public interface class IDataReaderExtension : IDataReader, 
    IDisposable

type IDataReaderExtension =  
    interface
        interface IDataReader
        interface IDisposable
    end

public interface IDataReaderExtension extends IDataReader, IDisposable

O tipo IDataReaderExtension expõe os membros a seguir.

Propriedades

  Nome Descrição
Propriedade pública AggregationFieldCount Gets the number of fields by which the data is aggregated.
Propriedade pública FieldCount Gets the number of fields in the data reader. (Herdado de IDataReader.)
Propriedade pública IsAggregateRow Indicates whether the current row contains aggregate data.

Início

Métodos

  Nome Descrição
Método público Dispose (Herdado de IDisposable.)
Método público GetFieldType Gets the Type information corresponding to the type of object that is returned from GetValue. (Herdado de IDataReader.)
Método público GetName Gets the name of the field to find. (Herdado de IDataReader.)
Método público GetOrdinal Return the index of the named field. (Herdado de IDataReader.)
Método público GetValue Return the value of the specified field. (Herdado de IDataReader.)
Método público IsAggregationField Indicates whether the data is aggregated by the field with the given index.
Método público Read Advances the IDataReader to the next record. (Herdado de IDataReader.)

Início

Comentários

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 Implementando uma classe DataReader para uma extensão de processamento de dados.

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.