IDataReaderExtension 接口

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.

命名空间：  Microsoft.ReportingServices.DataProcessing
程序集：   Microsoft.ReportingServices.SharePoint.UI.WebParts（在 Microsoft.ReportingServices.SharePoint.UI.WebParts.dll 中）
  Microsoft.ReportingServices.Interfaces（在 Microsoft.ReportingServices.Interfaces.dll 中）

语法

声明
Public Interface IDataReaderExtension _
    Inherits IDataReader, IDisposable
用法
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

IDataReaderExtension 类型公开以下成员。

属性

	名称	说明
	AggregationFieldCount	Gets the number of fields by which the data is aggregated.
	FieldCount	Gets the number of fields in the data reader. （从 IDataReader 继承。）
	IsAggregateRow	Indicates whether the current row contains aggregate data.

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方法

	名称	说明
	Dispose	（从 IDisposable 继承。）
	GetFieldType	Gets the Type information corresponding to the type of object that is returned from GetValue. （从 IDataReader 继承。）
	GetName	Gets the name of the field to find. （从 IDataReader 继承。）
	GetOrdinal	Return the index of the named field. （从 IDataReader 继承。）
	GetValue	Return the value of the specified field. （从 IDataReader 继承。）
	IsAggregationField	Indicates whether the data is aggregated by the field with the given index.
	Read	Advances the IDataReader to the next record. （从 IDataReader 继承。）

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注释

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 为数据处理扩展插件实现 DataReader 类.

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.

请参阅

参考

Microsoft.ReportingServices.DataProcessing 命名空间