ExecutePageReader Method (DbCommandBase)

In This Topic

Syntax
Remarks
Example
Requirements
See Also

Returns a specific subset of rows when paging through the results of a query.

Syntax

Visual Basic
C#

public DbDataReader ExecutePageReader( 
   CommandBehavior behavior,
   int startRecord,
   int maxRecords
)

'Declaration
 
Public Function ExecutePageReader( _
   ByVal behavior As CommandBehavior, _
   ByVal startRecord As Integer, _
   ByVal maxRecords As Integer _
) As DbDataReader

Parameters

behavior: One of the System.Data.CommandBehavior values.
startRecord: Zero-based ordinal of row that result set starts with.
maxRecords: Quantity of rows in result set.

Return Value

A DbDataReaderBase object.

Remarks

Use method ExecutePageReader when you want to retrieve not the whole dataset but some part of it that begins with given row number and has certain quantity of rows. This is especially useful when working with large amounts of data.

If you want to retrieve all data in a dataset, use System.Data.Common.DbCommandBase.ExecuteReader() instead.

Example

The example below shows how to retrieve a part of a table. If this function is called with parameters startRecord=2 and maxRecords=3, it returns 3 rows: second, third, and fourth.

csharp

public void ExecutePaged(PgSqlConnection pgConnection, int StartRow, int PageLength)
{
  PgSqlCommand pgCommand = new PgSqlCommand("SELECT DeptNo, DName, Loc FROM Test.Dept", pgConnection);
  pgConnection.Open();
  PgSqlDataReader pgReader = pgCommand.ExecutePageReader(System.Data.CommandBehavior.Default,StartRow,PageLength);
  try
  {
    while (pgReader.Read())
    {
        Console.WriteLine(pgReader.GetInt32(0).ToString() + ", " + pgReader.GetString(1) + ", " + pgReader.GetString(2));
    }
  }
  finally
  {
    pgReader.Close();
    pgConnection.Close();
  }
}

Visual Basic

Public Sub ExecutePaged(ByVal pgConnection As PgSqlConnection, ByVal StartRow As Integer, ByVal PageLength As Integer)
  Dim pgCommand As New PgSqlCommand("SELECT DeptNo, DName, Loc FROM Test.Dept", pgConnection)
  pgConnection.Open()
  Dim pgReader As PgSqlDataReader = pgCommand.ExecutePageReader(System.Data.CommandBehavior.Default, StartRow, PageLength)
  Try
    While pgReader.Read()
      Console.WriteLine(pgReader.GetInt32(0).ToString() + ", " _
      + pgReader.GetString(1) + ", " _
      + pgReader.GetString(2))
    End While
  Finally
    pgReader.Close()
    pgConnection.Close()
  End Try
End Sub

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

DbCommandBase Class
DbCommandBase Members

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