ExecutePageReader Method (PgSqlCommand)

In This Topic

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

Syntax

Visual Basic
C#

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

public new PgSqlDataReader ExecutePageReader( 
   CommandBehavior behavior,
   int startRecord,
   int maxRecords
)

Parameters

behavior: One of the System.Data.CommandBehavior values.
startRecord: Specifies the number of starting record of the set of records to be returned.
maxRecords: Specifies total number of records to retrieve.

Return Value

A PgSqlDataReader object with requested records.

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 ExecuteReader() instead.

Note: This method is not supported in .NET Standard 1.3 compatible assembly. It is available only in the assembly for full .NET Framework and .NET Standard 2.0 compatible assembly.

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 * 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) + ", " + 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 * 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

PgSqlCommand Class
PgSqlCommand Members
ExecuteReader() Method

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