IDataRecord Interface

Definition

Namespace:

System.Data

Assembly:

System.Data.Common.dll

Provides access to the column values within each row for a DataReader, and is implemented by .NET data providers that access relational databases.

public interface class IDataRecord

public interface IDataRecord

type IDataRecord = interface

Public Interface IDataRecord

Derived

System.Data.Common.DbDataReader

System.Data.Common.DbDataRecord

System.Data.EntityClient.EntityDataReader

System.Data.IDataReader

System.Data.IExtendedDataRecord

System.Data.Objects.DbUpdatableDataRecord

Examples

The following example creates instances of the derived classes, SqlConnection, SqlCommand, and SqlDataReader. The example reads through the data, writing it out to the console. Finally, the example closes the SqlDataReader, and then the SqlConnection.

private static void ReadOrderData(string connectionString)
{
    string queryString =
        "SELECT OrderID, CustomerID FROM dbo.Orders;";

    using (SqlConnection connection =
               new SqlConnection(connectionString))
    {
        SqlCommand command =
            new SqlCommand(queryString, connection);
        connection.Open();

        SqlDataReader reader = command.ExecuteReader();

        // Call Read before accessing data.
        while (reader.Read())
        {
            ReadSingleRow((IDataRecord)reader);
        }

        // Call Close when done reading.
        reader.Close();
    }
}

private static void ReadSingleRow(IDataRecord dataRecord)
{
    Console.WriteLine(String.Format("{0}, {1}", dataRecord[0], dataRecord[1]));
}

Private Sub ReadOrderData(ByVal connectionString As String)
    Dim queryString As String = _
        "SELECT OrderID, CustomerID FROM dbo.Orders;"

    Using connection As New SqlConnection(connectionString)
        Dim command As New SqlCommand(queryString, connection)
        connection.Open()

        Dim reader As SqlDataReader = command.ExecuteReader()

        ' Call Read before accessing data.
        While reader.Read()
            ReadSingleRow(CType(reader, IDataRecord))
        End While

        ' Call Close when done reading.
        reader.Close()
    End Using
End Sub

Private Sub ReadSingleRow(ByVal record As IDataRecord)
   Console.WriteLine(String.Format("{0}, {1}", record(0), record(1)))
End Sub

Remarks

The IDataReader and IDataRecord interfaces enable an inheriting class to implement a DataReader class. This provides a way of reading one or more forward-only streams of result sets. For more information about DataReader classes, see Retrieving Data Using a DataReader.

An application does not create an instance of the IDataRecord interface directly, but creates an instance of a class that inherits IDataRecord. Typically, you do this by obtaining a DataReader through the ExecuteReader method of the Command object.

Classes that inherit IDataRecord must implement all inherited members, and typically define additional members to add provider-specific functionality.

Providers implementing a DataReader are required to expose data in common language runtime (CLR) types. Type coercion is defined for some types not included in the CLR. These values may be accessed as alternative types that comply with CLR types. As an example, the following table lists suggested mappings from OLE DB data types to CLR types, with alternative types in parentheses.

OLE DB type	CLR type
DBTYPE_BOOL	Int16
DBTYPE_BSTR	string
DBTYPE_BYTES	byte[]
DBTYPE_CY	Decimal
DBTYPE_DATE	DateTime
DBTYPE_DBDATE	DateTime
DBTYPE_DBTIME	DateTime
DBTYPE_DBTIMESTAMP	DateTime
DBTYPE_DECIMAL	Decimal
DBTYPE_EMPTY	null
DBTYPE_ERROR	ExternalException
DBTYPE_FILETIME	DateTime
DBTYPE_GUID	Guid
DBTYPE_HCHAPTER	not supported
DBTYPE_I1	SByte
DBTYPE_I2	Int16
DBTYPE_I4	Int32
DBTYPE_I8	Int64
DBTYPE_IDISPATCH	object
DBTYPE_IUNKNOWN	object
DBTYPE_NULL	DBNull.Value
DBTYPE_NUMERIC	Decimal
DBTYPE_PROPVARIANT	object
DBTYPE_R4	Single
DBTYPE_R8	Double
DBTYPE_STR	string
DBTYPE_UDT	not supported
DBTYPE_UI1	byte (Int16)
DBTYPE_UI2	UInt16 (Int32)
DBTYPE_UI4	UInt32 (Int64)
DBTYPE_UI8	UInt64 (Decimal)
DBTYPE_VARIANT	object
DBTYPE_VARNUMERIC	not supported
DBTYPE_WSTR	string

Properties

FieldCount	Gets the number of columns in the current row.
Item[Int32]	Gets the column located at the specified index.
Item[String]	Gets the column with the specified name.

Methods

GetBoolean(Int32)	Gets the value of the specified column as a Boolean.
GetByte(Int32)	Gets the 8-bit unsigned integer value of the specified column.
GetBytes(Int32, Int64, Byte[], Int32, Int32)	Reads a stream of bytes from the specified column offset into the buffer as an array, starting at the given buffer offset.
GetChar(Int32)	Gets the character value of the specified column.
GetChars(Int32, Int64, Char[], Int32, Int32)	Reads a stream of characters from the specified column offset into the buffer as an array, starting at the given buffer offset.
GetData(Int32)	Returns an IDataReader for the specified column ordinal.
GetDataTypeName(Int32)	Gets the data type information for the specified field.
GetDateTime(Int32)	Gets the date and time data value of the specified field.
GetDecimal(Int32)	Gets the fixed-position numeric value of the specified field.
GetDouble(Int32)	Gets the double-precision floating point number of the specified field.
GetFieldType(Int32)	Gets the Type information corresponding to the type of Object that would be returned from GetValue(Int32).
GetFloat(Int32)	Gets the single-precision floating point number of the specified field.
GetGuid(Int32)	Returns the GUID value of the specified field.
GetInt16(Int32)	Gets the 16-bit signed integer value of the specified field.
GetInt32(Int32)	Gets the 32-bit signed integer value of the specified field.
GetInt64(Int32)	Gets the 64-bit signed integer value of the specified field.
GetName(Int32)	Gets the name for the field to find.
GetOrdinal(String)	Return the index of the named field.
GetString(Int32)	Gets the string value of the specified field.
GetValue(Int32)	Return the value of the specified field.
GetValues(Object[])	Populates an array of objects with the column values of the current record.
IsDBNull(Int32)	Return whether the specified field is set to null.