Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        aiotxb.Text = txb1.Text & txb2.Text & txb3.Text
    End Sub
 
 
    Private Sub aiotxb_TextChanged(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles aiotxb.TextChanged
        Line1 = txb1
        Line2 = txb2
        Line3 = txb3
    End Sub