Display data in msgbox from database

Imports System.Data
Imports System.Data.OleDb
Public Class Form1
    Dim ConnectionString As String = System.Configuration.ConfigurationSettings.AppSettings("dsn")
    Dim con As OleDbConnection = New OleDbConnection(ConnectionString)
    Dim com As OleDbCommand
    Dim oledbda As OleDbDataAdapter
    Dim ds As DataSet
    Dim dt As DataTable
    Dim str, sname As String

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        con.Open()
        str = "select * from student"
        com = New OleDbCommand(str, con)
        Dim reader As OleDbDataReader = com.ExecuteReader
        While reader.Read()
            sname += reader(1) + vbCrLf
        End While
        MessageBox.Show(sname)
        reader.Close()
        con.Close()
    End Sub
End Class