Leitura e manipulação arquivo TXT

Imports System.IO
Imports System.Text
Public Class Form3
    Public texto As String
    Public parte_texto As String
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim tamanho As String 'variavel tamannho da string
        Dim file_name As String = "c:\xml\TESTE.txt"
        Dim TEXTline As String
        If System.IO.File.Exists(file_name) = True Then
            Dim objReader As New System.IO.StreamReader(file_name, Encoding.UTF8)
            Do While objReader.Peek() <> -1
              
                texto = objReader.ReadLine
                parte_texto = texto.Substring(0, 9)

                MessageBox.Show(parte_texto)

            Loop

            'TextBox1.Text = TEXTline
          
        Else
            MessageBox.Show("Arquivo não encontrado")

        End If