Hey,
As part of my cleaning up of various test projects and half baked ideas - I came across this little class the other day. Basically, it can mute and/or set the Master Volume of the computer using the 'mixerSetControlDetails' API and its various cousins.
I originally converted the code over from this (http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q178456) VB6 support document and as part of the conversion process I wrote this FAQ @ VBCity (http://www.vbcity.com/forums/faq.asp?tid=47436) and amended it to perform the mute function as well.
The only two methods you'll be interested in are the 'SetSound' and 'SetVolume' method, the former takes a boolean parameter to mute the sound - the latter an integer to represent the volume level as a percentage, although you're more than welcome to improve this...
Have fun - M
Imports System.Runtime.InteropServices
Public Class Sound
#Region "Comments"
' This class is responisble for all interactions for muting and controlling the master volume level
' There is no warranty associated with this code - if you use this and it blows up you machine.
' Well, that will teach you to write you own code in future, won't it ;-)
' Mark Dryden (aka Drydo@vbcity.com)
#End Region
#Region "Constants"
Private Const MMSYSERR_NOERROR As Integer = 0
Private Const MAXPNAMELEN As Integer = 32
Private Const MIXER_LONG_NAME_CHARS As Integer = 64
Private Const MIXER_SHORT_NAME_CHARS As Integer = 16
Private Const MIXERCONTROL_CT_CLASS_FADER As Integer = &H50000000
Private Const MIXERCONTROL_CT_UNITS_UNSIGNED As Integer = &H30000
Private Const MIXERCONTROL_CT_UNITS_BOOLEAN As Integer = &H10000
Private Const MIXERCONTROL_CT_CLASS_SWITCH As Integer = &H20000000
Private Const MIXERLINE_COMPONENTTYPE_DST_FIRST As Integer = &H0&
Private Const MIXERLINE_COMPONENTTYPE_DST_SPEAKERS As Integer = (MIXERLINE_COMPONENTTYPE_DST_FIRST + 4)
Private Const MIXERCONTROL_CONTROLTYPE_FADER As Integer = (MIXERCONTROL_CT_CLASS_FADER Or MIXERCONTROL_CT_UNITS_UNSIGNED)
Private Const MIXERCONTROL_CONTROLTYPE_VOLUME As Integer = (MIXERCONTROL_CONTROLTYPE_FADER + 1)
Private Const MIXER_GETLINEINFOF_COMPONENTTYPE As Integer = &H3&
Private Const MIXER_GETLINECONTROLSF_ONEBYTYPE As Integer = &H2
Private Const MIXERCONTROL_CONTROLTYPE_BASS As Integer = (MIXERCONTROL_CONTROLTYPE_FADER + 2)
Private Const MIXERCONTROL_CONTROLTYPE_TREBLE As Integer = (MIXERCONTROL_CONTROLTYPE_FADER + 3)
Private Const MIXERCONTROL_CONTROLTYPE_EQUALIZER As Integer = (MIXERCONTROL_CONTROLTYPE_FADER + 4)
Private Const MIXERCONTROL_CONTROLTYPE_BOOLEAN As Integer = (MIXERCONTROL_CT_CLASS_SWITCH Or MIXERCONTROL_CT_UNITS_BOOLEAN)
Private Const MIXERCONTROL_CONTROLTYPE_MUTE As Integer = (MIXERCONTROL_CONTROLTYPE_BOOLEAN + 2)
#End Region
#Region "Structs"
<StructLayout(LayoutKind.Sequential)> _
Private Structure MIXERCONTROL
<FieldOffset(0)> Public cbStruct As Integer ' size in Byte of MIXERCONTROL
<FieldOffset(4)> Public dwControlID As Integer ' unique control id for mixer device
<FieldOffset(8)> Public dwControlType As Integer ' MIXERCONTROL_CONTROLTYPE_xxx
<FieldOffset(12)> Public fdwControl As Integer ' MIXERCONTROL_CONTROLF_xxx
<FieldOffset(16)> Public cMultipleItems As Integer ' if MIXERCONTROL_CONTROLF_MULTIPLE set
<FieldOffset(20), MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=MIXER_SHORT_NAME_CHARS)> Public szShortName As String ' * MIXER_SHORT_NAME_CHARS ' short name of control
<FieldOffset(36), MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=MIXER_LONG_NAME_CHARS)> Public szName As String ' * MIXER_LONG_NAME_CHARS ' Integer name of control
<FieldOffset(100)> Public lMinimum As Integer ' Minimum value
<FieldOffset(104)> Public lMaximum As Integer ' Maximum value
<FieldOffset(108), MarshalAs(UnmanagedType.ByValArray, SizeConst:=11, ArraySubType:=UnmanagedType.AsAny)> Public reserved() As Integer ' reserved structure space
End Structure
<StructLayout(LayoutKind.Sequential)> _
Private Structure MIXERCONTROLDETAILS
<FieldOffset(0)> Public cbStruct As Integer ' size in Byte of MIXERCONTROLDETAILS
<FieldOffset(4)> Public dwControlID As Integer ' control id to get/set details on
<FieldOffset(8)> Public cChannels As Integer ' number of channels in paDetails array
<FieldOffset(12)> Public item As Integer ' hwndOwner or cMultipleItems
<FieldOffset(16)> Public cbDetails As Integer ' size of _one_ details_XX struct
<FieldOffset(20)> Public paDetails As IntPtr ' pointer to array of details_XX structs
End Structure
<StructLayout(LayoutKind.Sequential)> _
Private Structure MIXERCONTROLDETAILS_UNSIGNED
<FieldOffset(0)> Public dwValue As Integer ' value of the control
End Structure
<StructLayout(LayoutKind.Sequential)> _
Private Structure MIXERLINECONTROLS
<FieldOffset(0)> Public cbStruct As Integer ' size in Byte of MIXERLINECONTROLS
<FieldOffset(4)> Public dwLineID As Integer ' line id (from MIXERLINE.dwLineID)
<FieldOffset(8)> Public dwControl As Integer ' MIXER_GETLINECONTROLSF_ONEBYTYPE
<FieldOffset(12)> Public cControls As Integer ' count of controls pmxctrl points to
<FieldOffset(16)> Public cbmxctrl As Integer ' size in Byte of _one_ MIXERCONTROL
<FieldOffset(20)> Public pamxctrl As IntPtr ' pointer to first MIXERCONTROL array
End Structure
<StructLayout(LayoutKind.Sequential)> _
Private Structure MIXERLINE
<FieldOffset(0)> Public cbStruct As Integer ' size of MIXERLINE structure
<FieldOffset(4)> Public dwDestination As Integer ' zero based destination index
<FieldOffset(8)> Public dwSource As Integer ' zero based source index (if source)
<FieldOffset(12)> Public dwLineID As Integer ' unique line id for mixer device
<FieldOffset(16)> Public fdwLine As Integer ' state/information about line
<FieldOffset(20)> Public dwUser As Integer ' driver specific information
<FieldOffset(24)> Public dwComponentType As Integer ' component type line connects to
<FieldOffset(28)> Public cChannels As Integer ' number of channels line supports
<FieldOffset(32)> Public cConnections As Integer ' number of connections (possible)
<FieldOffset(36)> Public cControls As Integer ' number of controls at this line
<FieldOffset(40), MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=MIXER_SHORT_NAME_CHARS)> Public szShortName As String ' * MIXER_SHORT_NAME_CHARS
<FieldOffset(56), MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=MIXER_LONG_NAME_CHARS)> Public szName As String ' * MIXER_LONG_NAME_CHARS
<FieldOffset(120)> Public dwType As Integer
<FieldOffset(124)> Public dwDeviceID As Integer
<FieldOffset(128)> Public wMid As Integer
<FieldOffset(132)> Public wPid As Integer
<FieldOffset(136)> Public vDriverVersion As Integer
<FieldOffset(168), MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=MAXPNAMELEN)> Public szPname As String ' * MAXPNAMELEN
End Structure
#End Region
#Region "API Declarations"
Private Declare Function mixerOpen Lib "winmm.dll" _
(ByRef phmx As Integer, <MarshalAs(UnmanagedType.U4)> ByVal uMxId As Integer, ByVal dwCallback As Integer, ByVal dwInstance As Integer, ByVal fdwOpen As Integer) As Integer
Private Declare Function mixerGetLineInfo Lib "winmm.dll" Alias "mixerGetLineInfoA" _
(<MarshalAs(UnmanagedType.I4)> ByVal hmxobj As Integer, ByRef pmxl As MIXERLINE, ByVal fdwInfo As Integer) As Integer
Private Declare Function mixerGetLineControls Lib "winmm.dll" Alias "mixerGetLineControlsA" _
(<MarshalAs(UnmanagedType.I4)> ByVal hmxobj As Integer, ByRef pmxlc As MIXERLINECONTROLS, ByVal fdwControls As Integer) As Integer
Private Declare Function mixerSetControlDetails Lib "winmm.dll" (<MarshalAs(UnmanagedType.I4)> ByVal hmxobj As Integer, _
ByRef pmxcd As MIXERCONTROLDETAILS, ByVal fdwDetails As Integer) As Integer
#End Region
Public Sub SetVolume(ByVal Level As Integer)
' Sets the volume to a specific percentage as passed through
Dim hmixer As Integer
Dim volCtrl As New MIXERCONTROL
Dim lngReturn As Integer
Dim lngVolSetting As Integer
' Obtain the hmixer struct
lngReturn = mixerOpen(hmixer, 0, 0, 0, 0)
' Error check
If lngReturn <> 0 Then Exit Sub
' Obtain the volumne control object
Call GetVolumeControl(hmixer, MIXERLINE_COMPONENTTYPE_DST_SPEAKERS, _
MIXERCONTROL_CONTROLTYPE_VOLUME, volCtrl)
' Then determine the value of the volume
lngVolSetting = CType(volCtrl.lMaximum * (Level / 100), Integer)
' Then set the volume
SetVolumeControl(hmixer, volCtrl, lngVolSetting)
End Sub
Public Sub SetSound(ByVal boolMute As Boolean)
' This routine sets the volume setting of the current unit depending on the value passed through
Dim hmixer As Integer
Dim volCtrl As New MIXERCONTROL
Dim lngReturn As Integer
Dim lngVolSetting As Integer
' Obtain the hmixer struct
lngReturn = mixerOpen(hmixer, 0, 0, 0, 0)
' Error check
If lngReturn <> 0 Then Exit Sub
' Obtain the volumne control object
Call GetVolumeControl(hmixer, MIXERLINE_COMPONENTTYPE_DST_SPEAKERS, _
MIXERCONTROL_CONTROLTYPE_MUTE, volCtrl)
' Then determine the value of the volume
If boolMute Then
' Mute
lngVolSetting = 1
Else
' Turn the sound on
lngVolSetting = 0
End If
' Then set the volume
SetVolumeControl(hmixer, volCtrl, lngVolSetting)
End Sub
Private Function GetVolumeControl(ByVal hmixer As Integer, ByVal componentType As Integer, ByVal ctrlType As Integer, _
ByRef mxc As MIXERCONTROL) As Boolean
' Obtains an appropriate pointer and info for the volume control
' [Note: original source taken from MSDN http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q178456&]
' This function attempts to obtain a mixer control. Returns True if successful.
Dim mxlc As New MIXERLINECONTROLS
Dim mxl As New MIXERLINE
Dim rc As Integer, pmem As IntPtr
mxl.cbStruct = Marshal.SizeOf(mxl)
mxl.dwComponentType = componentType
' Obtain a line corresponding to the component type
rc = mixerGetLineInfo(hmixer, mxl, MIXER_GETLINEINFOF_COMPONENTTYPE)
If (MMSYSERR_NOERROR = rc) Then
mxlc.cbStruct = Marshal.SizeOf(mxlc)
mxlc.dwLineID = mxl.dwLineID
mxlc.dwControl = ctrlType
mxlc.cControls = 1
mxlc.cbmxctrl = Marshal.SizeOf(mxc)
' Allocate a buffer for the control
pmem = Marshal.AllocHGlobal(Marshal.SizeOf(mxc))
mxlc.pamxctrl = pmem
mxc.cbStruct = Marshal.SizeOf(mxc)
' Get the control
rc = mixerGetLineControls(hmixer, _
mxlc, _
MIXER_GETLINECONTROLSF_ONEBYTYPE)
If (MMSYSERR_NOERROR = rc) Then
mxc = CType(Marshal.PtrToStructure(mxlc.pamxctrl, GetType(MIXERCONTROL)), MIXERCONTROL)
Marshal.FreeHGlobal(pmem)
Return True
End If
Marshal.FreeHGlobal(pmem)
Exit Function
End If
Return False
End Function
Private Function SetVolumeControl(ByVal hmixer As Integer, _
ByVal mxc As MIXERCONTROL, _
ByVal volume As Integer) As Boolean
' Sets the volumne from the pointer of the object passed through
' [Note: original source taken from MSDN http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q178456&]
'This function sets the value for a volume control. Returns True if successful
Dim mxcd As MIXERCONTROLDETAILS
Dim vol As MIXERCONTROLDETAILS_UNSIGNED
Dim rc As Integer
Dim hptr As IntPtr
mxcd.item = 0
mxcd.dwControlID = mxc.dwControlID
mxcd.cbStruct = Marshal.SizeOf(mxcd)
mxcd.cbDetails = Marshal.SizeOf(vol)
hptr = Marshal.AllocHGlobal(Marshal.SizeOf(vol))
' Allocate a buffer for the control value buffer
mxcd.paDetails = hptr
mxcd.cChannels = 1
vol.dwValue = volume
Marshal.StructureToPtr(vol, hptr, False)
' Set the control value
rc = mixerSetControlDetails(hmixer, _
mxcd, _
0)
Marshal.FreeHGlobal(hptr)
If (MMSYSERR_NOERROR = rc) Then
Return True
Else
Return False
End If
End Function
End Class
. . .