handling volume control in C#

handling volume control in C#

• Kiavash

  Hello Brenda,

  I found a sample code to control the system volume. You can ask our buddy to try it.

  using System;

  using System.Runtime.InteropServices;

  
  namespace PhidgetTest

  {

  public class AudioMixerHelper

  {

  public const int MMSYSERR_NOERROR = 0;

  public const int MAXPNAMELEN = 32;

  public const int MIXER_LONG_NAME_CHARS = 64;

  public const int MIXER_SHORT_NAME_CHARS = 16;

  public const int MIXER_GETLINEINFOF_COMPONENTTYPE = 0x3;

  public const int MIXER_GETCONTROLDETAILSF_VALUE = 0x0;

  public const int MIXER_GETLINECONTROLSF_ONEBYTYPE = 0x2;

  public const int MIXER_SETCONTROLDETAILSF_VALUE = 0x0;

  public const int MIXERLINE_COMPONENTTYPE_DST_FIRST = 0x0;

  public const int MIXERLINE_COMPONENTTYPE_SRC_FIRST = 0x1000;

  public const int MIXERLINE_COMPONENTTYPE_DST_SPEAKERS =

  (MIXERLINE_COMPONENTTYPE_DST_FIRST + 4);

  public const int MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE =

  (MIXERLINE_COMPONENTTYPE_SRC_FIRST + 3);

  public const int MIXERLINE_COMPONENTTYPE_SRC_LINE =

  (MIXERLINE_COMPONENTTYPE_SRC_FIRST + 2);

  public const int MIXERCONTROL_CT_CLASS_FADER = 0x50000000;

  public const int MIXERCONTROL_CT_UNITS_UNSIGNED = 0x30000;

  public const int MIXERCONTROL_CONTROLTYPE_FADER =

  (MIXERCONTROL_CT_CLASS_FADER | MIXERCONTROL_CT_UNITS_UNSIGNED);

  public const int MIXERCONTROL_CONTROLTYPE_VOLUME =

  (MIXERCONTROL_CONTROLTYPE_FADER + 1);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerClose(int hmx);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerGetControlDetailsA(int hmxobj, ref

  MIXERCONTROLDETAILS pmxcd, int fdwDetails);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerGetDevCapsA(int uMxId, MIXERCAPS

  pmxcaps, int cbmxcaps);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerGetID(int hmxobj, int pumxID, int

  fdwId);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerGetLineControlsA(int hmxobj, ref

  MIXERLINECONTROLS pmxlc, int fdwControls);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerGetLineInfoA(int hmxobj, ref

  MIXERLINE pmxl, int fdwInfo);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerGetNumDevs();

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerMessage(int hmx, int uMsg, int

  dwParam1, int dwParam2);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerOpen(out int phmx, int uMxId,

  int dwCallback, int dwInstance, int fdwOpen);

  [DllImport("winmm.dll", CharSet = CharSet.Ansi)]

  private static extern int mixerSetControlDetails(int hmxobj, ref

  MIXERCONTROLDETAILS pmxcd, int fdwDetails);

  public struct MIXERCAPS

  {

  public int wMid;

  public int wPid;

  public int vDriverVersion;

  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAXPNAMELEN)]

  public string szPname;

  public int fdwSupport;

  public int cDestinations;

  }

  public struct MIXERCONTROL

  {

  public int cbStruct;

  public int dwControlID;

  public int dwControlType;

  public int fdwControl;

  public int cMultipleItems;

  [MarshalAs(UnmanagedType.ByValTStr,

  SizeConst = MIXER_SHORT_NAME_CHARS)]

  public string szShortName;

  [MarshalAs(UnmanagedType.ByValTStr,

  SizeConst = MIXER_LONG_NAME_CHARS)]

  public string szName;

  public int lMinimum;

  public int lMaximum;

  [MarshalAs(UnmanagedType.U4, SizeConst = 10)]

  public int reserved;

  }

  public struct MIXERCONTROLDETAILS

  {

  public int cbStruct;

  public int dwControlID;

  public int cChannels;

  public int item;

  public int cbDetails;

  public IntPtr paDetails;

  }

  public struct MIXERCONTROLDETAILS_UNSIGNED

  {

  public int dwValue;

  }

  public struct MIXERLINE

  {

  public int cbStruct;

  public int dwDestination;

  public int dwSource;

  public int dwLineID;

  public int fdwLine;

  public int dwUser;

  public int dwComponentType;

  public int cChannels;

  public int cConnections;

  public int cControls;

  [MarshalAs(UnmanagedType.ByValTStr,

  SizeConst = MIXER_SHORT_NAME_CHARS)]

  public string szShortName;

  [MarshalAs(UnmanagedType.ByValTStr,

  SizeConst = MIXER_LONG_NAME_CHARS)]

  public string szName;

  public int dwType;

  public int dwDeviceID;

  public int wMid;

  public int wPid;

  public int vDriverVersion;

  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAXPNAMELEN)]

  public string szPname;

  }

  public struct MIXERLINECONTROLS

  {

  public int cbStruct;

  public int dwLineID;

  public int dwControl;

  public int cControls;

  public int cbmxctrl;

  public IntPtr pamxctrl;

  }

  private static bool GetVolumeControl(int hmixer, int componentType,

  int ctrlType, out MIXERCONTROL mxc, out int vCurrentVol)

  {

  // This function attempts to obtain a mixer control.

  // Returns True if successful.

  MIXERLINECONTROLS mxlc = new MIXERLINECONTROLS();

  MIXERLINE mxl = new MIXERLINE();

  MIXERCONTROLDETAILS pmxcd = new MIXERCONTROLDETAILS();

  MIXERCONTROLDETAILS_UNSIGNED du = new

  MIXERCONTROLDETAILS_UNSIGNED();

  mxc = new MIXERCONTROL();

  int rc;

  bool retValue;

  vCurrentVol = -1;

  mxl.cbStruct = Marshal.SizeOf(mxl);

  mxl.dwComponentType = componentType;

  rc = mixerGetLineInfoA(hmixer, ref mxl,

  MIXER_GETLINEINFOF_COMPONENTTYPE);

  if (MMSYSERR_NOERROR == rc)

  {

  int sizeofMIXERCONTROL = 152;

  int ctrl = Marshal.SizeOf(typeof(MIXERCONTROL));

  mxlc.pamxctrl = Marshal.AllocCoTaskMem(sizeofMIXERCONTROL);

  mxlc.cbStruct = Marshal.SizeOf(mxlc);

  mxlc.dwLineID = mxl.dwLineID;

  mxlc.dwControl = ctrlType;

  mxlc.cControls = 1;

  mxlc.cbmxctrl = sizeofMIXERCONTROL;

  // Allocate a buffer for the control

  mxc.cbStruct = sizeofMIXERCONTROL;

  // Get the control

  rc = mixerGetLineControlsA(hmixer, ref mxlc,

  MIXER_GETLINECONTROLSF_ONEBYTYPE);

  if (MMSYSERR_NOERROR == rc)

  {

  retValue = true;

  // Copy the control into the destination structure

  mxc = (MIXERCONTROL)Marshal.PtrToStructure(

  mxlc.pamxctrl, typeof(MIXERCONTROL));

  }

  else

  {

  retValue = false;

  }

  int sizeofMIXERCONTROLDETAILS =

  Marshal.SizeOf(typeof(MIXERCONTROLDETAILS));

  int sizeofMIXERCONTROLDETAILS_UNSIGNED =

  Marshal.SizeOf(typeof(MIXERCONTROLDETAILS_UNSIGNED));

  pmxcd.cbStruct = sizeofMIXERCONTROLDETAILS;

  pmxcd.dwControlID = mxc.dwControlID;

  pmxcd.paDetails =

  Marshal.AllocCoTaskMem(sizeofMIXERCONTROLDETAILS_UNSIGNED);

  pmxcd.cChannels = 1;

  pmxcd.item = 0;

  pmxcd.cbDetails = sizeofMIXERCONTROLDETAILS_UNSIGNED;

  rc = mixerGetControlDetailsA(hmixer, ref pmxcd,

  MIXER_GETCONTROLDETAILSF_VALUE);

  du = (MIXERCONTROLDETAILS_UNSIGNED)Marshal.PtrToStructure(

  pmxcd.paDetails, typeof(MIXERCONTROLDETAILS_UNSIGNED));

  vCurrentVol = du.dwValue;

  return retValue;

  }

  retValue = false;

  return retValue;

  }

  private static bool SetVolumeControl(int hmixer, MIXERCONTROL mxc,

  int volume)

  {

  // This function sets the value for a volume control.

  // Returns True if successful

  bool retValue;

  int rc;

  MIXERCONTROLDETAILS mxcd = new MIXERCONTROLDETAILS();

  MIXERCONTROLDETAILS_UNSIGNED vol = new

  MIXERCONTROLDETAILS_UNSIGNED();

  mxcd.item = 0;

  mxcd.dwControlID = mxc.dwControlID;

  mxcd.cbStruct = Marshal.SizeOf(mxcd);

  mxcd.cbDetails = Marshal.SizeOf(vol);

  // Allocate a buffer for the control value buffer

  mxcd.cChannels = 1;

  vol.dwValue = volume;

  // Copy the data into the control value buffer

  mxcd.paDetails = Marshal.AllocCoTaskMem(Marshal.SizeOf(

  typeof(MIXERCONTROLDETAILS_UNSIGNED)));

  Marshal.StructureToPtr(vol, mxcd.paDetails, false);

  // Set the control value

  rc = mixerSetControlDetails(hmixer, ref mxcd,

  MIXER_SETCONTROLDETAILSF_VALUE);

  if (MMSYSERR_NOERROR == rc)

  {

  retValue = true;

  }

  else

  {

  retValue = false;

  } return retValue;

  }

  public static int GetVolume()

  {

  int mixer;

  MIXERCONTROL volCtrl = new MIXERCONTROL();

  int currentVol;

  mixerOpen(out mixer, 0, 0, 0, 0);

  int type = MIXERCONTROL_CONTROLTYPE_VOLUME;

  GetVolumeControl(mixer,

  MIXERLINE_COMPONENTTYPE_DST_SPEAKERS, type, out volCtrl, out

  currentVol);

  mixerClose(mixer);

  return currentVol;

  }

  public static void SetVolume(int vVolume)

  {

  int mixer;

  MIXERCONTROL volCtrl = new MIXERCONTROL();

  int currentVol;

  mixerOpen(out mixer, 0, 0, 0, 0);

  int type = MIXERCONTROL_CONTROLTYPE_VOLUME;

  GetVolumeControl(mixer,

  MIXERLINE_COMPONENTTYPE_DST_SPEAKERS, type, out volCtrl, out

  currentVol);

  if (vVolume > volCtrl.lMaximum) vVolume = volCtrl.lMaximum;

  if (vVolume < volCtrl.lMinimum) vVolume = volCtrl.lMinimum;

  SetVolumeControl(mixer, volCtrl, vVolume);

  GetVolumeControl(mixer,

  MIXERLINE_COMPONENTTYPE_DST_SPEAKERS, type, out volCtrl, out

  currentVol);

  if (vVolume != currentVol)

  {

  throw new Exception("Cannot Set Volume");

  }

  mixerClose(mixer);

  }

  }

  }

  
  ====

  Thanks.
  Best Regards, Tian Qiang

  -brenda (ISV Buddy Team)
  

  
  
  

• hbuchal_dotnet

  HI! Im new in C# and so, Im kind of consufed where to put this code. i would like to request for a .sln file for this so that I could study it. Because I simply copied and paste all the code in my main form and gets a lot of errors. Hehehehe. Im really lost hehehe. Please. Thanks!!!

  
  
  
• handling volume control in C#