Visual Basic

Private Sub Button1_Click(ByVal sender As System.Object, _<br />
      ByVal e As System.EventArgs) Handles Button1.Click

Public Class SoundClass
    .
    . yada yada yada
    .
End Class
 
Public Class Form1
    .
    . yada yada yada
    .
    Private Sub Button1_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click
        Dim SoundInst As New SoundClass()
        SoundInst.PlaySoundFile("C:\ringout.wav")
    End Sub
End Class

Private Sub txtTitleLevel_KeyPress(ByVal sender As Object, _
ByVal e As System.Windows.Forms.KeyPressEventArgs) _
Handles txtTitleLevel.KeyPress

    If (e.KeyChar >= "0" And e.KeyChar <= "9") Or _
    e.KeyChar = Chr(8) Then
        ' Chr(8) mean backspace.
        e.Handled = False ' Allow user to input numeric value.
    Else
        e.Handled = True ' Do not allow user to type character.
    End If

End Sub