ExecutePageReader Method

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

[Visual Basic]
Public Function ExecutePageReader( _
   ByVal behavior As CommandBehavior, _
   ByVal startRecord As Integer, _
   ByVal maxRecords As Integer _
) As DbDataReader

[C#]
public DbDataReader ExecutePageReader( 
   CommandBehavior behavior,
   int startRecord,
   int maxRecords
);

Parameters

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

Return Type

A DbDataReader 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 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.

[C#]

public void ExecutePaged(MySqlConnection myConnection, int StartRow, int PageLength) 
{ 
  MySqlCommand myCommand = new MySqlCommand("SELECT * FROM Test.Dept", myConnection); 
  myConnection.Open(); 
  MySqlDataReader myReader = myCommand.ExecutePageReader(System.Data.CommandBehavior.Default,StartRow,PageLength); 
  try 
  { 
    while (myReader.Read()) 
    { 
      Console.WriteLine(myReader.GetInt32(0) + ", " + myReader.GetString(1) + ", " + myReader.GetString(2)); 
    } 
  } 
  finally 
  { 
    myReader.Close(); 
    myConnection.Close(); 
  } 
}

[Visual Basic]

Public Sub ExecutePaged(ByVal myConnection As MySqlConnection, ByVal StartRow As Integer, ByVal PageLength As Integer)
   Dim myCommand As New MySqlCommand("SELECT * FROM Test.Dept", myConnection)
   myConnection.Open()
   Dim myReader As MySqlDataReader = 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

See Also

Language