Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button1.Click
 
        RichTextBox1.Clear()
        RichTextBox1.Text = My.Computer.FileSystem.ReadAllText("D:\...")
 
 
 
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
        BackgroundWorker1.RunWorkerAsync()
 
        ListBox1.Items.Clear()
 
    End Sub