/// <summary>
/// Increments or decrements the current volume level by the <see cref="stepAmount"/>.
/// </summary>
/// <param name="stepAmount">Value between -100 and 100 indicating the desired step amount. Use negative numbers to decrease
/// the volume and positive numbers to increase it.</param>
/// <returns>the new volume level assigned</returns>
public static float StepMasterVolume(float stepAmount)
{
IAudioEndpointVolume masterVol = null;
try
{
masterVol = GetMasterVolumeObject();
if (masterVol == null)
{
return(-1);
}
float stepAmountScaled = stepAmount / 100;
// Get the level
float volumeLevel;
masterVol.GetMasterVolumeLevelScalar(out volumeLevel);
// Calculate the new level
float newLevel = volumeLevel + stepAmountScaled;
newLevel = Math.Min(1, newLevel);
newLevel = Math.Max(0, newLevel);
masterVol.SetMasterVolumeLevelScalar(newLevel, Guid.Empty);
// Return the new volume level that was set
return(newLevel * 100);
}
finally
{
if (masterVol != null)
{
Marshal.ReleaseComObject(masterVol);
}
}
}
/// <summary>
/// Get the current system volume, if an error is encountered return the default 100.
/// </summary>
/// <returns></returns>
private static int GetVolumeWindowsVista()
{
object enumerator = null;
Guid devEnumeratorGuid = new Guid("BCDE0395-E52F-467C-8E3D-C4579291692E");
Guid idevEnumeratorGuid = new Guid("00000000-0000-0000-C000-000000000046");
int CLSCTX_INPROC_SERVER = 1;
CoInitialize(null);
int result = CoCreateInstance(ref devEnumeratorGuid, null,
CLSCTX_INPROC_SERVER, ref idevEnumeratorGuid,
out enumerator);
if (result != 0 || enumerator == null)
{
return(100);
}
IMMDeviceEnumerator devEnum = enumerator as IMMDeviceEnumerator;
if (devEnum == null)
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(devEnum);
return(100);
}
IntPtr devicePtr = IntPtr.Zero;
int eRender = 0; int eConsole = 0;
int ret = devEnum.GetDefaultAudioEndpoint(eRender, eConsole, ref devicePtr);
if (ret != 0)
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(devEnum);
return(100);
}
object obj = System.Runtime.InteropServices.Marshal.GetObjectForIUnknown(devicePtr);
IMMDevice device = obj as IMMDevice;
if (device == null)
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(devEnum);
System.Runtime.InteropServices.Marshal.ReleaseComObject(device);
}
Guid iAudioEndPointVolGuid = new Guid("5CDF2C82-841E-4546-9722-0CF74078229A");
uint context = (uint)0x17;
IntPtr activationParams = IntPtr.Zero;
IntPtr endPoint = IntPtr.Zero;
ret = device.Activate(ref iAudioEndPointVolGuid, context,
activationParams, ref endPoint);
if (ret != 0)
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(devEnum);
System.Runtime.InteropServices.Marshal.ReleaseComObject(device);
return(100);
}
obj = System.Runtime.InteropServices.Marshal.GetObjectForIUnknown(endPoint);
IAudioEndpointVolume audioEndpoint = obj as IAudioEndpointVolume;
if (audioEndpoint == null)
{
System.Runtime.InteropServices.Marshal.ReleaseComObject(devEnum);
System.Runtime.InteropServices.Marshal.ReleaseComObject(device);
return(100);
}
float volume = 0.0f;
audioEndpoint.GetMasterVolumeLevelScalar(ref volume);
System.Runtime.InteropServices.Marshal.ReleaseComObject(audioEndpoint);
System.Runtime.InteropServices.Marshal.ReleaseComObject(device);
System.Runtime.InteropServices.Marshal.ReleaseComObject(devEnum);
return((int)(volume * 100f));
}