如何查看系统音频是否静音？
How to check if the system audio is muted?
我发现 this answer which recommends using the "core audio.dll" API 的代码如下：
private function getmute() as boolean
Dim devenum As New MMDeviceEnumerator
Dim device As MMDevice = devenum.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia)
If device.AudioEndpointVolume.Mute = True Then
Return True
Else
Return False
End If
End Function
我试过那个代码，但它不起作用，我无法对另一个问题发表评论。
当我尝试上面的代码时，以下行抛出异常：
If device.AudioEndpointVolume.Mute = True Then
这是异常消息：
AudioEndpointVolume is not a member of device.
我已经导入了CoreAudioAPI，还有什么问题吗？
我正在寻找 VB.NET 或 C# 解决方案。
使用 C/C++ 并了解一些 directshow 的知识非常简单，但是对于 C#，您需要某种包装器来进行调用。老实说，我不使用托管语言来使用低级库，但我可能找到了适合您的情况的代码：
private int IsMuted() {
IAudioEndpointVolume masterVol = null;
try {
masterVol = GetMasterVolumeObject();
if( masterVol == null )
return -1; //error
bool isMuted;
masterVol.GetMute( out isMuted );
return Convert.ToInt32( isMuted );
}
finally {
if( masterVol != null )
Marshal.ReleaseComObject( masterVol );
}
}
private IAudioEndpointVolume GetMasterVolumeObject() {
IMMDeviceEnumerator deviceEnumerator = null;
IMMDevice speakers = null;
try {
deviceEnumerator = (IMMDeviceEnumerator)( new MMDeviceEnumerator() );
deviceEnumerator.GetDefaultAudioEndpoint( EDataFlow.eRender, ERole.eMultimedia, out speakers );
Guid IID_IAudioEndpointVolume = typeof( IAudioEndpointVolume ).GUID;
object o;
speakers.Activate( ref IID_IAudioEndpointVolume, 0, IntPtr.Zero, out o );
IAudioEndpointVolume masterVol = (IAudioEndpointVolume)o;
return masterVol;
}
finally {
if( speakers != null ) Marshal.ReleaseComObject( speakers );
if( deviceEnumerator != null ) Marshal.ReleaseComObject( deviceEnumerator );
}
}
COM 接口来自 Windows CoreAudio API:
[ComImport]
[Guid( "BCDE0395-E52F-467C-8E3D-C4579291692E" )]
internal class MMDeviceEnumerator {
}
internal enum EDataFlow {
eRender,
eCapture,
eAll,
EDataFlow_enum_count
}
internal enum ERole {
eConsole,
eMultimedia,
eCommunications,
ERole_enum_count
}
[Guid( "A95664D2-9614-4F35-A746-DE8DB63617E6" ), InterfaceType( ComInterfaceType.InterfaceIsIUnknown )]
internal interface IMMDeviceEnumerator {
int NotImpl1();
[PreserveSig]
int GetDefaultAudioEndpoint( EDataFlow dataFlow, ERole role, out IMMDevice ppDevice );
// the rest is not implemented
}
[Guid( "D666063F-1587-4E43-81F1-B948E807363F" ), InterfaceType( ComInterfaceType.InterfaceIsIUnknown )]
internal interface IMMDevice {
[PreserveSig]
int Activate( ref Guid iid, int dwClsCtx, IntPtr pActivationParams, [MarshalAs( UnmanagedType.IUnknown )] out object ppInterface );
// the rest is not implemented
}
// http://netcoreaudio.codeplex.com/SourceControl/latest#trunk/Code/CoreAudio/Interfaces/IAudioEndpointVolume.cs
[Guid( "5CDF2C82-841E-4546-9722-0CF74078229A" ), InterfaceType( ComInterfaceType.InterfaceIsIUnknown )]
public interface IAudioEndpointVolume {
[PreserveSig]
int NotImpl1();
[PreserveSig]
int NotImpl2();
/// <summary>
/// Gets a count of the channels in the audio stream.
/// </summary>
/// <param name="channelCount">The number of channels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetChannelCount(
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 channelCount );
/// <summary>
/// Sets the master volume level of the audio stream, in decibels.
/// </summary>
/// <param name="level">The new master volume level in decibels.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetMasterVolumeLevel(
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Sets the master volume level, expressed as a normalized, audio-tapered value.
/// </summary>
/// <param name="level">The new master volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetMasterVolumeLevelScalar(
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Gets the master volume level of the audio stream, in decibels.
/// </summary>
/// <param name="level">The volume level in decibels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetMasterVolumeLevel(
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Gets the master volume level, expressed as a normalized, audio-tapered value.
/// </summary>
/// <param name="level">The volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetMasterVolumeLevelScalar(
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Sets the volume level, in decibels, of the specified channel of the audio stream.
/// </summary>
/// <param name="channelNumber">The channel number.</param>
/// <param name="level">The new volume level in decibels.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetChannelVolumeLevel(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Sets the normalized, audio-tapered volume level of the specified channel in the audio stream.
/// </summary>
/// <param name="channelNumber">The channel number.</param>
/// <param name="level">The new master volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetChannelVolumeLevelScalar(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Gets the volume level, in decibels, of the specified channel in the audio stream.
/// </summary>
/// <param name="channelNumber">The zero-based channel number.</param>
/// <param name="level">The volume level in decibels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetChannelVolumeLevel(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Gets the normalized, audio-tapered volume level of the specified channel of the audio stream.
/// </summary>
/// <param name="channelNumber">The zero-based channel number.</param>
/// <param name="level">The volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetChannelVolumeLevelScalar(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Sets the muting state of the audio stream.
/// </summary>
/// <param name="isMuted">True to mute the stream, or false to unmute the stream.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetMute(
[In] [MarshalAs( UnmanagedType.Bool )] Boolean isMuted,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Gets the muting state of the audio stream.
/// </summary>
/// <param name="isMuted">The muting state. True if the stream is muted, false otherwise.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetMute(
[Out] [MarshalAs( UnmanagedType.Bool )] out Boolean isMuted );
/// <summary>
/// Gets information about the current step in the volume range.
/// </summary>
/// <param name="step">The current zero-based step index.</param>
/// <param name="stepCount">The total number of steps in the volume range.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetVolumeStepInfo(
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 step,
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 stepCount );
/// <summary>
/// Increases the volume level by one step.
/// </summary>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int VolumeStepUp(
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Decreases the volume level by one step.
/// </summary>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int VolumeStepDown(
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Queries the audio endpoint device for its hardware-supported functions.
/// </summary>
/// <param name="hardwareSupportMask">A hardware support mask that indicates the capabilities of the endpoint.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int QueryHardwareSupport(
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 hardwareSupportMask );
/// <summary>
/// Gets the volume range of the audio stream, in decibels.
/// </summary>
/// <param name="volumeMin">The minimum volume level in decibels.</param>
/// <param name="volumeMax">The maximum volume level in decibels.</param>
/// <param name="volumeStep">The volume increment level in decibels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetVolumeRange(
[Out] [MarshalAs( UnmanagedType.R4 )] out float volumeMin,
[Out] [MarshalAs( UnmanagedType.R4 )] out float volumeMax,
[Out] [MarshalAs( UnmanagedType.R4 )] out float volumeStep );
}
VB.Net CoreAudio API 实现的重写（+ 奖励） 已发布。
代码封装在 Class (CoreAudio) 中，包括原始的 IsMuted() 方法，以及我即时实现的其他方法（因为，为什么不呢）。
有关 MSDN 上 Windows CoreAudio APIs 的更多信息。
GitHub NAudio CoreAudioApi 实施 (C#).
实现的方法：
IsMuted() As Integer
Return默认音频设备的静音状态。
SetMute(Boolean)
设置默认音频设备 (True/False) 的静音状态。
GetVolume() As Integer
获取默认音频设备的音量状态。值范围从 0 to 100.
SetVolume(Integer)
将默认音频设备的音量状态设置为 0 to 100 范围内的值。
VolumeUp()
将默认音频设备的音量增加一级（通常为 2 个单位）。
VolumeDown()
将默认音频设备的音量降低一级。
用法：
Public AudioDevice As CoreAudio = New CoreAudio()
'0=False, 1=True, -1=Error
Dim IsMuted As Integer = AudioDevice.IsMuted()
'True=Mutes the Audio, False=Un-Mutes (?) it
AudioDevice.SetMute(True)
Dim Volume As Integer = AudioDevice.GetVolume()
'Sets the Audio level to 50%
AudioDevice.SetVolume(50)
'Increases the Audio level by 1 Step
AudioDevice.VolumeUp()
'Decreases the Audio level by 1 Step
AudioDevice.VolumeDown()
声明：
Imports System
Imports System.Runtime.InteropServices
Public Class CoreAudio
Friend Enum EDataFlow
eRender
eCapture
eAll
EDataFlow_enum_count
End Enum
Friend Enum ERole
eConsole
eMultimedia
eCommunications
ERole_enum_count
End Enum
<Flags>
Friend Enum CLSCTX As UInteger
CLSCTX_INPROC_SERVER = &H1
CLSCTX_INPROC_HANDLER = &H2
CLSCTX_LOCAL_SERVER = &H4
CLSCTX_INPROC_SERVER16 = &H8
CLSCTX_REMOTE_SERVER = &H10
CLSCTX_INPROC_HANDLER16 = &H20
CLSCTX_RESERVED1 = &H40
CLSCTX_RESERVED2 = &H80
CLSCTX_RESERVED3 = &H100
CLSCTX_RESERVED4 = &H200
CLSCTX_NO_CODE_DOWNLOAD = &H400
CLSCTX_RESERVED5 = &H800
CLSCTX_NO_CUSTOM_MARSHAL = &H1000
CLSCTX_ENABLE_CODE_DOWNLOAD = &H2000
CLSCTX_NO_FAILURE_LOG = &H4000
CLSCTX_DISABLE_AAA = &H8000
CLSCTX_ENABLE_AAA = &H10000
CLSCTX_FROM_DEFAULT_CONTEXT = &H20000
CLSCTX_ACTIVATE_32_BIT_SERVER = &H40000
CLSCTX_ACTIVATE_64_BIT_SERVER = &H80000
CLSCTX_INPROC = CLSCTX_INPROC_SERVER Or CLSCTX_INPROC_HANDLER
CLSCTX_SERVER = CLSCTX_INPROC_SERVER Or CLSCTX_LOCAL_SERVER Or CLSCTX_REMOTE_SERVER
CLSCTX_ALL = CLSCTX_SERVER Or CLSCTX_INPROC_HANDLER
End Enum
<ComImport, Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")>
Friend Class MMDeviceEnumeratorComObject
End Class
<ComImport, Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)>
Friend Interface IMMDeviceEnumerator
Function NotImpl1() As Integer
Function GetDefaultAudioEndpoint(dataFlow As EDataFlow, role As ERole, ByRef ppDevice As IMMDevice) As Integer
End Interface
<ComImport, Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)>
Friend Interface IMMDevice
Function Activate(ByRef iid As Guid, dwClsCtx As CLSCTX, pActivationParams As IntPtr, <Out> ByRef ppInterface As IAudioEndpointVolume) As Integer
End Interface
<ComImport, Guid("5CDF2C82-841E-4546-9722-0CF74078229A"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)>
Friend Interface IAudioEndpointVolume
Function RegisterControlChangeNotify() As Integer
Function UnregisterControlChangeNotify() As Integer
Function GetChannelCount(ByRef channelCount As Integer) As Integer
Function SetMasterVolumeLevel() As Integer
Function SetMasterVolumeLevelScalar(level As Single, eventContext As Guid) As Integer
Function GetMasterVolumeLevel(<Out> ByRef level As Single) As Integer
Function GetMasterVolumeLevelScalar(<Out> ByRef level As Single) As Integer
Function SetChannelVolumeLevel(channelNumber As Integer, level As Single, eventContext As Guid) As Integer
Function SetChannelVolumeLevelScalar(channelNumber As Integer, level As Single, eventContext As Guid) As Integer
Function GetChannelVolumeLevel(channelNumber As Integer, <Out> ByRef level As Single) As Integer
Function GetChannelVolumeLevelScalar(channelNumber As Integer, <Out> ByRef level As Single) As Integer
Function SetMute(<MarshalAs(UnmanagedType.Bool)> isMuted As Boolean, eventContext As Guid) As Integer
Function GetMute(<Out> ByRef isMuted As Boolean) As Integer
Function GetVolumeStepInfo(<Out> ByRef pnStep As Integer, ByRef pnStepCount As Integer) As Integer
Function VolumeStepUp(eventContext As Guid) As Integer
Function VolumeStepDown(eventContext As Guid) As Integer
Function QueryHardwareSupport(<Out> ByRef hardwareSupportMask As Integer) As Integer
Function GetVolumeRange(<Out> ByRef volumeMin As Single, <Out> ByRef volumeMax As Single, <Out> ByRef volumeStep As Single) As Integer
End Interface
Public Function IsMuted() As Integer
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
If masterVol Is Nothing Then
Return -1
End If
Dim isAudioMuted As Boolean
masterVol.GetMute(isAudioMuted)
Return Convert.ToInt32(isAudioMuted)
Finally
If masterVol IsNot Nothing Then
Marshal.ReleaseComObject(masterVol)
End If
End Try
End Function
Public Sub SetMute(IsMute As Boolean)
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.SetMute(IsMute, Guid.Empty)
Finally
If masterVol IsNot Nothing Then
Marshal.ReleaseComObject(masterVol)
End If
End Try
End Sub
Public Function GetVolume() As Integer
Dim fVolume As Single
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.GetMasterVolumeLevelScalar(fVolume)
Return CType(fVolume * 100, Integer)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Function
Public Sub SetVolume(Volume As Integer)
Volume = Math.Max(Math.Min(Volume, 100), 0)
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.SetMasterVolumeLevelScalar((CType(Volume, Single) / 100), Guid.Empty)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Sub
Public Sub VolumeUp()
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.VolumeStepUp(Guid.Empty)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Sub
Public Sub VolumeDown()
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.VolumeStepDown(Guid.Empty)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Sub
Friend Function GetMasterVolumeObject() As IAudioEndpointVolume
Dim deviceEnumerator As IMMDeviceEnumerator = Nothing
Dim MediaDevice As IMMDevice = Nothing
Try
deviceEnumerator = TryCast(New MMDeviceEnumeratorComObject(), IMMDeviceEnumerator)
deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, MediaDevice)
Dim EndPointVolID As Guid = GetType(IAudioEndpointVolume).GUID
Dim ppEndpoint As IAudioEndpointVolume = Nothing
MediaDevice.Activate(EndPointVolID, CLSCTX.CLSCTX_ALL, IntPtr.Zero, ppEndpoint)
Return ppEndpoint
Finally
Marshal.ReleaseComObject(deviceEnumerator)
Marshal.ReleaseComObject(MediaDevice)
End Try
End Function
End Class
我发现 this answer which recommends using the "core audio.dll" API 的代码如下：
private function getmute() as boolean
Dim devenum As New MMDeviceEnumerator
Dim device As MMDevice = devenum.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia)
If device.AudioEndpointVolume.Mute = True Then
Return True
Else
Return False
End If
End Function
我试过那个代码，但它不起作用，我无法对另一个问题发表评论。
当我尝试上面的代码时，以下行抛出异常：
If device.AudioEndpointVolume.Mute = True Then
这是异常消息：
AudioEndpointVolume is not a member of device.
我已经导入了CoreAudioAPI，还有什么问题吗？
我正在寻找 VB.NET 或 C# 解决方案。
使用 C/C++ 并了解一些 directshow 的知识非常简单，但是对于 C#，您需要某种包装器来进行调用。老实说，我不使用托管语言来使用低级库，但我可能找到了适合您的情况的代码：
private int IsMuted() {
IAudioEndpointVolume masterVol = null;
try {
masterVol = GetMasterVolumeObject();
if( masterVol == null )
return -1; //error
bool isMuted;
masterVol.GetMute( out isMuted );
return Convert.ToInt32( isMuted );
}
finally {
if( masterVol != null )
Marshal.ReleaseComObject( masterVol );
}
}
private IAudioEndpointVolume GetMasterVolumeObject() {
IMMDeviceEnumerator deviceEnumerator = null;
IMMDevice speakers = null;
try {
deviceEnumerator = (IMMDeviceEnumerator)( new MMDeviceEnumerator() );
deviceEnumerator.GetDefaultAudioEndpoint( EDataFlow.eRender, ERole.eMultimedia, out speakers );
Guid IID_IAudioEndpointVolume = typeof( IAudioEndpointVolume ).GUID;
object o;
speakers.Activate( ref IID_IAudioEndpointVolume, 0, IntPtr.Zero, out o );
IAudioEndpointVolume masterVol = (IAudioEndpointVolume)o;
return masterVol;
}
finally {
if( speakers != null ) Marshal.ReleaseComObject( speakers );
if( deviceEnumerator != null ) Marshal.ReleaseComObject( deviceEnumerator );
}
}
COM 接口来自 Windows CoreAudio API:
[ComImport]
[Guid( "BCDE0395-E52F-467C-8E3D-C4579291692E" )]
internal class MMDeviceEnumerator {
}
internal enum EDataFlow {
eRender,
eCapture,
eAll,
EDataFlow_enum_count
}
internal enum ERole {
eConsole,
eMultimedia,
eCommunications,
ERole_enum_count
}
[Guid( "A95664D2-9614-4F35-A746-DE8DB63617E6" ), InterfaceType( ComInterfaceType.InterfaceIsIUnknown )]
internal interface IMMDeviceEnumerator {
int NotImpl1();
[PreserveSig]
int GetDefaultAudioEndpoint( EDataFlow dataFlow, ERole role, out IMMDevice ppDevice );
// the rest is not implemented
}
[Guid( "D666063F-1587-4E43-81F1-B948E807363F" ), InterfaceType( ComInterfaceType.InterfaceIsIUnknown )]
internal interface IMMDevice {
[PreserveSig]
int Activate( ref Guid iid, int dwClsCtx, IntPtr pActivationParams, [MarshalAs( UnmanagedType.IUnknown )] out object ppInterface );
// the rest is not implemented
}
// http://netcoreaudio.codeplex.com/SourceControl/latest#trunk/Code/CoreAudio/Interfaces/IAudioEndpointVolume.cs
[Guid( "5CDF2C82-841E-4546-9722-0CF74078229A" ), InterfaceType( ComInterfaceType.InterfaceIsIUnknown )]
public interface IAudioEndpointVolume {
[PreserveSig]
int NotImpl1();
[PreserveSig]
int NotImpl2();
/// <summary>
/// Gets a count of the channels in the audio stream.
/// </summary>
/// <param name="channelCount">The number of channels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetChannelCount(
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 channelCount );
/// <summary>
/// Sets the master volume level of the audio stream, in decibels.
/// </summary>
/// <param name="level">The new master volume level in decibels.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetMasterVolumeLevel(
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Sets the master volume level, expressed as a normalized, audio-tapered value.
/// </summary>
/// <param name="level">The new master volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetMasterVolumeLevelScalar(
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Gets the master volume level of the audio stream, in decibels.
/// </summary>
/// <param name="level">The volume level in decibels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetMasterVolumeLevel(
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Gets the master volume level, expressed as a normalized, audio-tapered value.
/// </summary>
/// <param name="level">The volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetMasterVolumeLevelScalar(
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Sets the volume level, in decibels, of the specified channel of the audio stream.
/// </summary>
/// <param name="channelNumber">The channel number.</param>
/// <param name="level">The new volume level in decibels.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetChannelVolumeLevel(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Sets the normalized, audio-tapered volume level of the specified channel in the audio stream.
/// </summary>
/// <param name="channelNumber">The channel number.</param>
/// <param name="level">The new master volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetChannelVolumeLevelScalar(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[In] [MarshalAs( UnmanagedType.R4 )] float level,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Gets the volume level, in decibels, of the specified channel in the audio stream.
/// </summary>
/// <param name="channelNumber">The zero-based channel number.</param>
/// <param name="level">The volume level in decibels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetChannelVolumeLevel(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Gets the normalized, audio-tapered volume level of the specified channel of the audio stream.
/// </summary>
/// <param name="channelNumber">The zero-based channel number.</param>
/// <param name="level">The volume level expressed as a normalized value between 0.0 and 1.0.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetChannelVolumeLevelScalar(
[In] [MarshalAs( UnmanagedType.U4 )] UInt32 channelNumber,
[Out] [MarshalAs( UnmanagedType.R4 )] out float level );
/// <summary>
/// Sets the muting state of the audio stream.
/// </summary>
/// <param name="isMuted">True to mute the stream, or false to unmute the stream.</param>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int SetMute(
[In] [MarshalAs( UnmanagedType.Bool )] Boolean isMuted,
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Gets the muting state of the audio stream.
/// </summary>
/// <param name="isMuted">The muting state. True if the stream is muted, false otherwise.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetMute(
[Out] [MarshalAs( UnmanagedType.Bool )] out Boolean isMuted );
/// <summary>
/// Gets information about the current step in the volume range.
/// </summary>
/// <param name="step">The current zero-based step index.</param>
/// <param name="stepCount">The total number of steps in the volume range.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetVolumeStepInfo(
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 step,
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 stepCount );
/// <summary>
/// Increases the volume level by one step.
/// </summary>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int VolumeStepUp(
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Decreases the volume level by one step.
/// </summary>
/// <param name="eventContext">A user context value that is passed to the notification callback.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int VolumeStepDown(
[In] [MarshalAs( UnmanagedType.LPStruct )] Guid eventContext );
/// <summary>
/// Queries the audio endpoint device for its hardware-supported functions.
/// </summary>
/// <param name="hardwareSupportMask">A hardware support mask that indicates the capabilities of the endpoint.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int QueryHardwareSupport(
[Out] [MarshalAs( UnmanagedType.U4 )] out UInt32 hardwareSupportMask );
/// <summary>
/// Gets the volume range of the audio stream, in decibels.
/// </summary>
/// <param name="volumeMin">The minimum volume level in decibels.</param>
/// <param name="volumeMax">The maximum volume level in decibels.</param>
/// <param name="volumeStep">The volume increment level in decibels.</param>
/// <returns>An HRESULT code indicating whether the operation passed of failed.</returns>
[PreserveSig]
int GetVolumeRange(
[Out] [MarshalAs( UnmanagedType.R4 )] out float volumeMin,
[Out] [MarshalAs( UnmanagedType.R4 )] out float volumeMax,
[Out] [MarshalAs( UnmanagedType.R4 )] out float volumeStep );
}
VB.Net CoreAudio API 实现的重写（+ 奖励）
代码封装在 Class (CoreAudio) 中，包括原始的 IsMuted() 方法，以及我即时实现的其他方法（因为，为什么不呢）。
有关 MSDN 上 Windows CoreAudio APIs 的更多信息。
GitHub NAudio CoreAudioApi 实施 (C#).
实现的方法：
IsMuted() As Integer
Return默认音频设备的静音状态。
SetMute(Boolean)
设置默认音频设备 (True/False) 的静音状态。
GetVolume() As Integer
获取默认音频设备的音量状态。值范围从 0 to 100.
SetVolume(Integer)
将默认音频设备的音量状态设置为 0 to 100 范围内的值。
VolumeUp()
将默认音频设备的音量增加一级（通常为 2 个单位）。
VolumeDown()
将默认音频设备的音量降低一级。
用法：
Public AudioDevice As CoreAudio = New CoreAudio()
'0=False, 1=True, -1=Error
Dim IsMuted As Integer = AudioDevice.IsMuted()
'True=Mutes the Audio, False=Un-Mutes (?) it
AudioDevice.SetMute(True)
Dim Volume As Integer = AudioDevice.GetVolume()
'Sets the Audio level to 50%
AudioDevice.SetVolume(50)
'Increases the Audio level by 1 Step
AudioDevice.VolumeUp()
'Decreases the Audio level by 1 Step
AudioDevice.VolumeDown()
声明：
Imports System
Imports System.Runtime.InteropServices
Public Class CoreAudio
Friend Enum EDataFlow
eRender
eCapture
eAll
EDataFlow_enum_count
End Enum
Friend Enum ERole
eConsole
eMultimedia
eCommunications
ERole_enum_count
End Enum
<Flags>
Friend Enum CLSCTX As UInteger
CLSCTX_INPROC_SERVER = &H1
CLSCTX_INPROC_HANDLER = &H2
CLSCTX_LOCAL_SERVER = &H4
CLSCTX_INPROC_SERVER16 = &H8
CLSCTX_REMOTE_SERVER = &H10
CLSCTX_INPROC_HANDLER16 = &H20
CLSCTX_RESERVED1 = &H40
CLSCTX_RESERVED2 = &H80
CLSCTX_RESERVED3 = &H100
CLSCTX_RESERVED4 = &H200
CLSCTX_NO_CODE_DOWNLOAD = &H400
CLSCTX_RESERVED5 = &H800
CLSCTX_NO_CUSTOM_MARSHAL = &H1000
CLSCTX_ENABLE_CODE_DOWNLOAD = &H2000
CLSCTX_NO_FAILURE_LOG = &H4000
CLSCTX_DISABLE_AAA = &H8000
CLSCTX_ENABLE_AAA = &H10000
CLSCTX_FROM_DEFAULT_CONTEXT = &H20000
CLSCTX_ACTIVATE_32_BIT_SERVER = &H40000
CLSCTX_ACTIVATE_64_BIT_SERVER = &H80000
CLSCTX_INPROC = CLSCTX_INPROC_SERVER Or CLSCTX_INPROC_HANDLER
CLSCTX_SERVER = CLSCTX_INPROC_SERVER Or CLSCTX_LOCAL_SERVER Or CLSCTX_REMOTE_SERVER
CLSCTX_ALL = CLSCTX_SERVER Or CLSCTX_INPROC_HANDLER
End Enum
<ComImport, Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")>
Friend Class MMDeviceEnumeratorComObject
End Class
<ComImport, Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)>
Friend Interface IMMDeviceEnumerator
Function NotImpl1() As Integer
Function GetDefaultAudioEndpoint(dataFlow As EDataFlow, role As ERole, ByRef ppDevice As IMMDevice) As Integer
End Interface
<ComImport, Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)>
Friend Interface IMMDevice
Function Activate(ByRef iid As Guid, dwClsCtx As CLSCTX, pActivationParams As IntPtr, <Out> ByRef ppInterface As IAudioEndpointVolume) As Integer
End Interface
<ComImport, Guid("5CDF2C82-841E-4546-9722-0CF74078229A"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)>
Friend Interface IAudioEndpointVolume
Function RegisterControlChangeNotify() As Integer
Function UnregisterControlChangeNotify() As Integer
Function GetChannelCount(ByRef channelCount As Integer) As Integer
Function SetMasterVolumeLevel() As Integer
Function SetMasterVolumeLevelScalar(level As Single, eventContext As Guid) As Integer
Function GetMasterVolumeLevel(<Out> ByRef level As Single) As Integer
Function GetMasterVolumeLevelScalar(<Out> ByRef level As Single) As Integer
Function SetChannelVolumeLevel(channelNumber As Integer, level As Single, eventContext As Guid) As Integer
Function SetChannelVolumeLevelScalar(channelNumber As Integer, level As Single, eventContext As Guid) As Integer
Function GetChannelVolumeLevel(channelNumber As Integer, <Out> ByRef level As Single) As Integer
Function GetChannelVolumeLevelScalar(channelNumber As Integer, <Out> ByRef level As Single) As Integer
Function SetMute(<MarshalAs(UnmanagedType.Bool)> isMuted As Boolean, eventContext As Guid) As Integer
Function GetMute(<Out> ByRef isMuted As Boolean) As Integer
Function GetVolumeStepInfo(<Out> ByRef pnStep As Integer, ByRef pnStepCount As Integer) As Integer
Function VolumeStepUp(eventContext As Guid) As Integer
Function VolumeStepDown(eventContext As Guid) As Integer
Function QueryHardwareSupport(<Out> ByRef hardwareSupportMask As Integer) As Integer
Function GetVolumeRange(<Out> ByRef volumeMin As Single, <Out> ByRef volumeMax As Single, <Out> ByRef volumeStep As Single) As Integer
End Interface
Public Function IsMuted() As Integer
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
If masterVol Is Nothing Then
Return -1
End If
Dim isAudioMuted As Boolean
masterVol.GetMute(isAudioMuted)
Return Convert.ToInt32(isAudioMuted)
Finally
If masterVol IsNot Nothing Then
Marshal.ReleaseComObject(masterVol)
End If
End Try
End Function
Public Sub SetMute(IsMute As Boolean)
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.SetMute(IsMute, Guid.Empty)
Finally
If masterVol IsNot Nothing Then
Marshal.ReleaseComObject(masterVol)
End If
End Try
End Sub
Public Function GetVolume() As Integer
Dim fVolume As Single
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.GetMasterVolumeLevelScalar(fVolume)
Return CType(fVolume * 100, Integer)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Function
Public Sub SetVolume(Volume As Integer)
Volume = Math.Max(Math.Min(Volume, 100), 0)
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.SetMasterVolumeLevelScalar((CType(Volume, Single) / 100), Guid.Empty)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Sub
Public Sub VolumeUp()
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.VolumeStepUp(Guid.Empty)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Sub
Public Sub VolumeDown()
Dim masterVol As IAudioEndpointVolume = Nothing
Try
masterVol = GetMasterVolumeObject()
masterVol.VolumeStepDown(Guid.Empty)
Finally
Marshal.ReleaseComObject(masterVol)
End Try
End Sub
Friend Function GetMasterVolumeObject() As IAudioEndpointVolume
Dim deviceEnumerator As IMMDeviceEnumerator = Nothing
Dim MediaDevice As IMMDevice = Nothing
Try
deviceEnumerator = TryCast(New MMDeviceEnumeratorComObject(), IMMDeviceEnumerator)
deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, MediaDevice)
Dim EndPointVolID As Guid = GetType(IAudioEndpointVolume).GUID
Dim ppEndpoint As IAudioEndpointVolume = Nothing
MediaDevice.Activate(EndPointVolID, CLSCTX.CLSCTX_ALL, IntPtr.Zero, ppEndpoint)
Return ppEndpoint
Finally
Marshal.ReleaseComObject(deviceEnumerator)
Marshal.ReleaseComObject(MediaDevice)
End Try
End Function
End Class