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Windows API - Win32
A core set of Windows application programming interfaces (APIs) for desktop and server applications. Previously known as Win32 API.
2,523 questions
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With this test, I could change the volume of a device which is not selected on my PC
I hardcoded the test with "Mixage stéréo (Realtek High Definition Audio)", returned from friendly name, to be changed (in french here...)
HRESULT hr = HRESULT.E_FAIL;
Guid CLSID_MMDeviceEnumerator = new Guid("{BCDE0395-E52F-467C-8E3D-C4579291692E}");
Type MMDeviceEnumeratorType = Type.GetTypeFromCLSID(CLSID_MMDeviceEnumerator, true);
object MMDeviceEnumerator = Activator.CreateInstance(MMDeviceEnumeratorType);
IMMDeviceEnumerator pMMDeviceEnumerator = (IMMDeviceEnumerator)MMDeviceEnumerator;
if (pMMDeviceEnumerator != null)
{
IMMDeviceCollection pDeviceCollection = null;
hr = pMMDeviceEnumerator.EnumAudioEndpoints(EDataFlow.eAll, DEVICE_STATE_ACTIVE | DEVICE_STATE_UNPLUGGED, out pDeviceCollection);
if (hr == HRESULT.S_OK)
{
uint nDevices = 0;
hr = pDeviceCollection.GetCount(out nDevices);
for (uint i = 0; i < nDevices; i++)
{
IMMDevice pDevice = null;
hr = pDeviceCollection.Item(i, out pDevice);
if (hr == HRESULT.S_OK)
{
IPropertyStore pPropertyStore = null;
hr = pDevice.OpenPropertyStore(STGM_READ, out pPropertyStore);
if (hr == HRESULT.S_OK)
{
string sFriendlyName = null;
string sDesc = null;
PROPVARIANT pv = new PROPVARIANT();
hr = pPropertyStore.GetValue(ref PKEY_Device_FriendlyName, out pv);
if (hr == HRESULT.S_OK)
{
sFriendlyName = Marshal.PtrToStringUni(pv.pwszVal);
}
hr = pPropertyStore.GetValue(ref PKEY_Device_DeviceDesc, out pv);
if (hr == HRESULT.S_OK)
{
sDesc = Marshal.PtrToStringUni(pv.pwszVal);
}
Console.WriteLine("Device: {0}", sFriendlyName);
IntPtr hGlobal = Marshal.AllocHGlobal(260);
hr = pDevice.GetId(out hGlobal);
string sId = Marshal.PtrToStringUni(hGlobal);
Marshal.FreeHGlobal(hGlobal);
IntPtr pAudioEndpointVolumePtr = IntPtr.Zero;
PROPVARIANT pvActivate = new PROPVARIANT();
hr = pDevice.Activate(typeof(IAudioEndpointVolume).GUID, 0, ref pvActivate, out pAudioEndpointVolumePtr);
if (hr == HRESULT.S_OK)
{
IAudioEndpointVolume pAudioEndpointVolume = Marshal.GetObjectForIUnknown(pAudioEndpointVolumePtr) as IAudioEndpointVolume;
float nVolume = 0;
hr = pAudioEndpointVolume.GetMasterVolumeLevelScalar(out nVolume);
System.Diagnostics.Trace.WriteLine("\tMaster Volume : " + nVolume.ToString());
if (sFriendlyName == "Mixage stéréo (Realtek High Definition Audio)")
{
hr = pAudioEndpointVolume.SetMasterVolumeLevelScalar(0.5f, Guid.Empty);
hr = pAudioEndpointVolume.GetMasterVolumeLevelScalar(out nVolume);
System.Diagnostics.Trace.WriteLine("\tNew Master Volume : " + nVolume.ToString());
}
Marshal.ReleaseComObject(pAudioEndpointVolume);
}
IMMEndpoint pEndpoint = null;
pEndpoint = (IMMEndpoint)pDevice;
EDataFlow eDirection = EDataFlow.eAll;
hr = pEndpoint.GetDataFlow(out eDirection);
System.Diagnostics.Trace.WriteLine("\tDirection : " + eDirection.ToString());
Marshal.ReleaseComObject(pPropertyStore);
}
Marshal.ReleaseComObject(pDevice);
}
}
}
Marshal.ReleaseComObject(pDeviceCollection);
}
Declarations :
public enum HRESULT : int
{
S_OK = 0,
S_FALSE = 1,
E_NOINTERFACE = unchecked((int)0x80004002),
E_NOTIMPL = unchecked((int)0x80004001),
E_FAIL = unchecked((int)0x80004005)
}
[ComImport, Guid("886D8EEB-8CF2-4446-8D02-CDBA1DBDCF99"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IPropertyStore
{
HRESULT GetCount([Out] out uint propertyCount);
HRESULT GetAt([In] uint propertyIndex, [Out, MarshalAs(UnmanagedType.Struct)] out PROPERTYKEY key);
HRESULT GetValue([In, MarshalAs(UnmanagedType.Struct)] ref PROPERTYKEY key, [Out, MarshalAs(UnmanagedType.Struct)] out PROPVARIANT pv);
HRESULT SetValue([In, MarshalAs(UnmanagedType.Struct)] ref PROPERTYKEY key, [In, MarshalAs(UnmanagedType.Struct)] ref PROPVARIANT pv);
HRESULT Commit();
}
public const int STGM_READ = 0x00000000;
public const int STGM_WRITE = 0x00000001;
public const int STGM_READWRITE = 0x00000002;
public enum EDataFlow
{
eRender = 0,
eCapture = (eRender + 1),
eAll = (eCapture + 1),
EDataFlow_enum_count = (eAll + 1)
}
public enum ERole
{
eConsole = 0,
eMultimedia = (eConsole + 1),
eCommunications = (eMultimedia + 1),
ERole_enum_count = (eCommunications + 1)
}
[ComImport]
[Guid("A95664D2-9614-4F35-A746-DE8DB63617E6")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IMMDeviceEnumerator
{
HRESULT EnumAudioEndpoints(EDataFlow dataFlow, int dwStateMask, out IMMDeviceCollection ppDevices);
HRESULT GetDefaultAudioEndpoint(EDataFlow dataFlow, ERole role, out IMMDevice ppEndpoint);
HRESULT GetDevice(string pwstrId,out IMMDevice ppDevice);
HRESULT RegisterEndpointNotificationCallback(IMMNotificationClient pClient);
HRESULT UnregisterEndpointNotificationCallback(IMMNotificationClient pClient);
}
public const int DEVICE_STATE_ACTIVE = 0x00000001;
public const int DEVICE_STATE_DISABLED = 0x00000002;
public const int DEVICE_STATE_NOTPRESENT = 0x00000004;
public const int DEVICE_STATE_UNPLUGGED = 0x00000008;
public const int DEVICE_STATEMASK_ALL = 0x0000000f;
[ComImport]
[Guid("0BD7A1BE-7A1A-44DB-8397-CC5392387B5E")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IMMDeviceCollection
{
HRESULT GetCount(out uint pcDevices);
HRESULT Item(uint nDevice, out IMMDevice ppDevice);
}
[ComImport]
[Guid("D666063F-1587-4E43-81F1-B948E807363F")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IMMDevice
{
[PreserveSig]
HRESULT Activate(ref Guid iid, int dwClsCtx, ref PROPVARIANT pActivationParams, out IntPtr ppInterface);
//HRESULT Activate(ref Guid iid, int dwClsCtx, IntPtr pActivationParams, out IntPtr ppInterface);
HRESULT OpenPropertyStore(int stgmAccess, out IPropertyStore ppProperties);
//HRESULT GetId(StringBuilder ppstrId);
HRESULT GetId(out IntPtr ppstrId);
HRESULT GetState(out int pdwState);
}
[ComImport]
[Guid("7991EEC9-7E89-4D85-8390-6C703CEC60C0")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IMMNotificationClient
{
HRESULT OnDeviceStateChanged(string pwstrDeviceId, int dwNewState);
HRESULT OnDeviceAdded(string pwstrDeviceId);
HRESULT OnDeviceRemoved(string pwstrDeviceId);
HRESULT OnDefaultDeviceChanged(EDataFlow flow, ERole role, string pwstrDefaultDeviceId);
HRESULT OnPropertyValueChanged(string pwstrDeviceId, ref PROPERTYKEY key);
}
[ComImport]
[Guid("1BE09788-6894-4089-8586-9A2A6C265AC5")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IMMEndpoint
{
HRESULT GetDataFlow(out EDataFlow pDataFlow);
}
public struct PROPERTYKEY
{
public PROPERTYKEY(Guid InputId, UInt32 InputPid)
{
fmtid = InputId;
pid = InputPid;
}
Guid fmtid;
uint pid;
};
[StructLayout(LayoutKind.Sequential)]
public struct PROPARRAY
{
public UInt32 cElems;
public IntPtr pElems;
}
[StructLayout(LayoutKind.Explicit, Pack = 1)]
public struct PROPVARIANT
{
[FieldOffset(0)]
public ushort varType;
[FieldOffset(2)]
public ushort wReserved1;
[FieldOffset(4)]
public ushort wReserved2;
[FieldOffset(6)]
public ushort wReserved3;
[FieldOffset(8)]
public byte bVal;
[FieldOffset(8)]
public sbyte cVal;
[FieldOffset(8)]
public ushort uiVal;
[FieldOffset(8)]
public short iVal;
[FieldOffset(8)]
public UInt32 uintVal;
[FieldOffset(8)]
public Int32 intVal;
[FieldOffset(8)]
public UInt64 ulVal;
[FieldOffset(8)]
public Int64 lVal;
[FieldOffset(8)]
public float fltVal;
[FieldOffset(8)]
public double dblVal;
[FieldOffset(8)]
public short boolVal;
[FieldOffset(8)]
public IntPtr pclsidVal; // GUID ID pointer
[FieldOffset(8)]
public IntPtr pszVal; // Ansi string pointer
[FieldOffset(8)]
public IntPtr pwszVal; // Unicode string pointer
[FieldOffset(8)]
public IntPtr punkVal; // punkVal (interface pointer)
[FieldOffset(8)]
public PROPARRAY ca;
[FieldOffset(8)]
public System.Runtime.InteropServices.ComTypes.FILETIME filetime;
}
[ComImport]
[Guid("5CDF2C82-841E-4546-9722-0CF74078229A")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IAudioEndpointVolume
{
HRESULT RegisterControlChangeNotify(IAudioEndpointVolumeCallback pNotify);
HRESULT UnregisterControlChangeNotify(IAudioEndpointVolumeCallback pNotify);
HRESULT GetChannelCount(out uint pnChannelCount);
HRESULT SetMasterVolumeLevel(float fLevelDB, ref Guid pguidEventContext);
HRESULT SetMasterVolumeLevelScalar(float fLevel, ref Guid pguidEventContext);
HRESULT GetMasterVolumeLevel(out float pfLevelDB);
HRESULT GetMasterVolumeLevelScalar(out float pfLevel);
HRESULT SetChannelVolumeLevel(uint nChannel, float fLevelDB, ref Guid pguidEventContext);
HRESULT SetChannelVolumeLevelScalar(uint nChannel, float fLevel, ref Guid pguidEventContext);
HRESULT GetChannelVolumeLevel(uint nChannel, out float pfLevelDB);
HRESULT GetChannelVolumeLevelScalar(uint nChannel, out float pfLevel);
HRESULT SetMute(bool bMute, ref Guid pguidEventContext);
HRESULT GetMute(out bool pbMute);
HRESULT GetVolumeStepInfo(out uint pnStep,out uint pnStepCount);
HRESULT VolumeStepUp(ref Guid pguidEventContext);
HRESULT VolumeStepDown(ref Guid pguidEventContext);
HRESULT QueryHardwareSupport(out int pdwHardwareSupportMask);
HRESULT GetVolumeRange(out float pflVolumeMindB, out float pflVolumeMaxdB, out float pflVolumeIncrementdB);
}
[ComImport]
[Guid("657804FA-D6AD-4496-8A60-352752AF4F89")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IAudioEndpointVolumeCallback
{
HRESULT OnNotify(IntPtr pNotify);
}