Data Access in Client and Middle-Tier Programming
How to: Iterate through Records in a DataReader (Visual Basic)

This example iterates through a data reader created using a data adapter's select command as well as maintaining a count of records read.

Example

Visual Basic
Dim reader As SqlClient.SqlDataReader
Dim recordData As String = ""
Dim recordCount As Integer = 0
Dim i As Integer = 0

sqlConnection1.Open()

reader = sqlDataAdapter1.SelectCommand.ExecuteReader()

While reader.Read()

    For i = 0 To reader.FieldCount - 1
        recordData &= reader(i).ToString()
        recordData &= "-"
    Next

    recordData &= ControlChars.CrLf
    recordCount += 1
End While

sqlConnection1.Close()
MessageBox.Show("Records processed: " & recordCount)
MessageBox.Show("Data:" & ControlChars.CrLf & recordData)

This code example is also available as an IntelliSense code snippet. In the code snippet picker, it is located in Data - Designer features and ADO.NET. For more information, see How to: Insert Snippets Into Your Code (Visual Basic).

Compiling the Code

This example requires:

  • A project reference to System.data.dll.

  • Access to the members of the System.Data namespace. Add an Imports statement if you are not fully qualifying member names in your code. For more information, see Imports Statement (.NET Namespace and Type).

  • A data connection named sqlConnection1.

  • A SQLDataAdapter object named sqlDataAdapter1.

Robust Programming

The following conditions may cause an exception:

See Also

Concepts

Reference

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