C# Definition:

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 2)]
public struct MIXERLINETARGET
{
     private UInt32 dwType;
     private UInt32 dwDeviceID;
     private UInt16 wMid;
     private UInt16 wPid;
     private UInt32 vDriverVersion;
     [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MixerXPNative.MAXPNAMELEN)]
     private string szPname;

     #region Properties

     /// <summary>MIXERLINE_TARGETTYPE_xxxx</summary>
     public MIXERLINE_TARGETTYPE Type
     {
        get { return (MIXERLINE_TARGETTYPE)this.dwType; }
        set { this.dwType = (UInt32)value; }
     }
     /// <summary>target device ID of device type</summary>
     public UInt32 DeviceID
     {
        get { return this.dwDeviceID; }
        set { this.dwDeviceID = value; }
     }
     /// <summary>of target device</summary>
     public UInt16 ManufacturerID
     {
        get { return this.wMid; }
        set { this.wMid = value; }
     }
     /// <summary></summary>
     public UInt16 ProductID
     {
        get { return this.wPid; }
        set { this.wPid = value; }
     }
     /// <summary></summary>
     public UInt32 DriverVersion
     {
        get { return this.vDriverVersion; }
        set { this.vDriverVersion = value; }
     }
     /// <summary></summary>
     public string PName
     {
        get { return this.szPname; }
        set { this.szPname = value; }
     }

     #endregion
}

VB Definition:

Structure MIXERLINETARGET
  Dim dwType As AudioLineType
  Dim dwDeviceId As UInteger
  Dim wMid As UShort
  Dim wPid As UShort
  Dim vDriverVersion As UInteger
  <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAXPNAMELEN)> Dim szPName As String
End Structure

User-Defined Field Types:

AudioLineType

public enum MIXERLINE_TARGETTYPE : uint
{
     UNDEFINED      = 0,
     WAVEOUT    = 1,
     WAVEIN     = 2,
     MIDIOUT    = 3,
     MIDIIN     = 4,
     AUX        = 5,
}
public enum MIXERLINE_LINEF : uint
{
     ACTIVE          = 0x00000001u,
     DISCONNECTED    = 0x00008000u,
     SOURCE          = 0x80000000u,
}
public enum MIXERLINE_COMPONENTTYPE : uint
{
     DST_FIRST       = 0x00000000u,
     DST_UNDEFINED   = (DST_FIRST + 0),
     DST_DIGITAL     = (DST_FIRST + 1),
     DST_LINE    = (DST_FIRST + 2),
     DST_MONITOR     = (DST_FIRST + 3),
     DST_SPEAKERS    = (DST_FIRST + 4),
     DST_HEADPHONES  = (DST_FIRST + 5),
     DST_TELEPHONE   = (DST_FIRST + 6),
     DST_WAVEIN      = (DST_FIRST + 7),
     DST_VOICEIN     = (DST_FIRST + 8),
     DST_LAST    = (DST_FIRST + 8),
     SRC_FIRST       = 0x00001000u,
     SRC_UNDEFINED   = (SRC_FIRST + 0),
     SRC_DIGITAL     = (SRC_FIRST + 1),
     SRC_LINE    = (SRC_FIRST + 2),
     SRC_MICROPHONE  = (SRC_FIRST + 3),
     SRC_SYNTHESIZER = (SRC_FIRST + 4),
     SRC_COMPACTDISC = (SRC_FIRST + 5),
     SRC_TELEPHONE   = (SRC_FIRST + 6),
     SRC_PCSPEAKER   = (SRC_FIRST + 7),
     SRC_WAVEOUT     = (SRC_FIRST + 8),
     SRC_AUXILIARY   = (SRC_FIRST + 9),
     SRC_ANALOG      = (SRC_FIRST + 10),
     SRC_LAST    = (SRC_FIRST + 10),
}

Notes:

None.