Control de volumen por código en Compact Framework C#

public class ControlVolumen
{
//Estas constantes contienen los niveles de volumen de la PDA
const int OFF = 1;
const int VERY_LOW = 858993459;
const int LOW = 1717986918;
const int NORMAL = -1717986919;
const int HIGH = -858993460;
const int VERY_HIGH = -1;

[DllImport("coredll.dll")]
private static extern int waveOutSetVolume(IntPtr hwo, int dwVolume);
[DllImport("coredll.dll")]
private static extern int waveOutGetVolume(IntPtr hwo, ref int dwVolume);

public static void Apagado()
{
waveOutSetVolume(IntPtr.Zero, OFF);
}

public static void MuyBajo()
{
waveOutSetVolume(IntPtr.Zero, VERY_LOW);
}

public static void Bajo()
{
waveOutSetVolume(IntPtr.Zero, LOW);
}

public static void Normal()
{
waveOutSetVolume(IntPtr.Zero, NORMAL);
}

public static void Alto()
{
waveOutSetVolume(IntPtr.Zero, HIGH);
}

public static void MuyAlto()
{
waveOutSetVolume(IntPtr.Zero, VERY_HIGH);
}

public static void SubirVolumen()
{
int vol = 0;
waveOutGetVolume(IntPtr.Zero, ref vol);
switch (vol)
{
case (OFF):
MuyBajo();
break;

case (VERY_LOW):
Bajo();
break;

case (LOW):
Normal();
break;

case (NORMAL):
Alto();
break;

case (HIGH):
MuyAlto();
break;

case (VERY_HIGH):
MessageBox.Show("Volumen a tope");
break;
}
}

public static void BajarVolumen()
{
int vol = 0;
waveOutGetVolume(IntPtr.Zero, ref vol);
switch (vol)
{
case (OFF):
MessageBox.Show("Sin sonido");
break;

case (VERY_LOW):
Apagado();
break;

case (LOW):
MuyBajo();
break;

case (NORMAL):
Bajo();
break;

case (HIGH):
Normal();
break;

case (VERY_HIGH):
Alto();
break;
}
}
}