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);
}
}