public void OnNotify(IntPtr notifyData)
        {
            //Since AUDIO_VOLUME_NOTIFICATION_DATA is dynamic in length based on the
            //number of audio channels available we cannot just call PtrToStructure
            //to get all data, thats why it is split up into two steps, first the static
            //data is marshalled into the data structure, then with some IntPtr math the
            //remaining floats are read from memory.
            //
            var data = (AudioVolumeNotificationDataStruct)Marshal.PtrToStructure(notifyData, typeof(AudioVolumeNotificationDataStruct));

            //Determine offset in structure of the first float
            var offset = Marshal.OffsetOf(typeof(AudioVolumeNotificationDataStruct), "ChannelVolume");
            //Determine offset in memory of the first float
            var firstFloatPtr = (IntPtr)((long)notifyData + (long)offset);

            var voldata = new float[data.nChannels];

            //Read all floats from memory.
            for (int i = 0; i < data.nChannels; i++)
            {
                voldata[i] = (float)Marshal.PtrToStructure(firstFloatPtr, typeof(float));
            }

            //Create combined structure and Fire Event in parent class.
            var notificationData = new AudioVolumeNotificationData(data.guidEventContext, data.bMuted, data.fMasterVolume, voldata);
            parent.FireNotification(notificationData);
        }
 internal void FireNotification(AudioVolumeNotificationData notificationData)
 {
     AudioEndpointVolumeNotificationDelegate del = OnVolumeNotification;
     if (del != null)
     {
         del(notificationData);
     }
 }