Public Class Form1

    Private Sub btnconvert_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnconvert.Click
        Dim celsius As integer = -40
        Dim farenheit As integer

        Dim fmtstr As String = "{0,-10} {1,10}"
        Do While celsius <= 40

            farenheit = (9 / 5) * celsius + 32

            With lstdegree.Items


                .Add(String.Format(fmtstr, "Celsius", "Fahrenheit"))
                .Add(String.Format(fmtstr, "", ""))
                .Add(String.Format(fmtstr, celsius, farenheit))

            End With
            celsius += 5
        Loop

    End Sub
End Class