ExecutePageReader Method (DbCommandBase)

In This Topic

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

Syntax

Visual Basic
C#

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

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

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(SqlConnection myConnection, int StartRow, int PageLength)
{
  SqlCommand myCommand = new SqlCommand("SELECT DeptNo, DName, Loc FROM Test.Dept", myConnection);
  myConnection.Open();
  SqlDataReader myReader = myCommand.ExecutePageReader(System.Data.CommandBehavior.Default,StartRow,PageLength);
  try
  {
    while (myReader.Read())
    {
        Console.WriteLine(myReader.GetInt32(0).ToString() + ", " + myReader.GetString(1) + ", " + myReader.GetString(2));
    }
  }
  finally
  {
    myReader.Close();
    myConnection.Close();
  }
}

Visual Basic

Public Sub ExecutePaged(ByVal myConnection As SqlConnection, ByVal StartRow As Integer, ByVal PageLength As Integer)
  Dim myCommand As New SqlCommand("SELECT DeptNo, DName, Loc FROM Test.Dept", myConnection)
  myConnection.Open()
  Dim myReader As SqlDataReader = myCommand.ExecutePageReader(System.Data.CommandBehavior.Default, StartRow, PageLength)
  Try
    While myReader.Read()
      Console.WriteLine(myReader.GetInt32(0).ToString() + ", " _
      + myReader.GetString(1) + ", " _
      + myReader.GetString(2))
    End While
  Finally
    myReader.Close()
    myConnection.Close()
  End Try
End Sub

Reference

DbCommandBase Class
DbCommandBase Members

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