Extracting PRINTER_NOTIFY_INFO_DATA Problem

[ehabhassan]

Hi,
i'm trying to catch the printer notification using the winspool.drv, my problem is how can i extract the PRINTER_NOTIFY_INFO_DATA from the resulting PRINTER_NOTIFY_INFO, by the way the count of the PRINTER_NOTIFY_INFO is (70015864140) and the Flags is (30399774226120704):

//--------------------------
[DllImport("winspool.drv", EntryPoint = "OpenPrinterA",
    SetLastError = true, CharSet = CharSet.Ansi,
    ExactSpelling = true,
    CallingConvention = CallingConvention.StdCall)]
        public static extern bool OpenPrinter(String pPrinterName,
        out IntPtr phPrinter,
        Int32 pDefault);


        [DllImport("winspool.drv", EntryPoint = "ClosePrinter",
            SetLastError = true,
            ExactSpelling = true,
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool ClosePrinter
        (Int32 hPrinter);

        [DllImport("winspool.drv",
        EntryPoint = "FindFirstPrinterChangeNotification",
        SetLastError = true, CharSet = CharSet.Ansi,
        ExactSpelling = true,
        CallingConvention = CallingConvention.StdCall)]
        public static extern IntPtr FindFirstPrinterChangeNotification
    ([InAttribute()] IntPtr hPrinter,
    [InAttribute()] Int32 fwFlags,
    [InAttribute()] Int32 fwOptions,
    [InAttribute(), MarshalAs(UnmanagedType.LPStruct)] PRINTER_NOTIFY_OPTIONS pPrinterNotifyOptions)
    ;

        [DllImport("winspool.drv", EntryPoint = "FindNextPrinterChangeNotification",
        SetLastError = true, CharSet = CharSet.Ansi,
        ExactSpelling = false,
        CallingConvention = CallingConvention.StdCall)]
        public static extern bool FindNextPrinterChangeNotification
                            ([InAttribute()] IntPtr hChangeObject,
                             [OutAttribute()] out Int32 pdwChange,
                             [InAttribute(), MarshalAs(UnmanagedType.LPStruct)] PRINTER_NOTIFY_OPTIONS pPrinterNotifyOptions,
                            [OutAttribute()] out IntPtr lppPrinterNotifyInfo
                                 )
   ;
//---------------------------------------------
int phand;
IntPtr whand ;

RegisteredWaitHandle rwh ;
ManualResetEvent wh;

const int PRINTER_NOTIFY_OPTIONS_REFRESH = 1;
//---------------------------------------------
private void Form1_Load(object sender, EventArgs e)
        {
        wh = new ManualResetEvent(false);

        IntPtr phand ;
        
        int pValue = 0;
        OpenPrinter("HPLaserJet4050SeriesPCL6", out phand, pValue);
        int pdwChange = 0;
        PRINTER_NOTIFY_OPTIONS  notifyOptions = new PRINTER_NOTIFY_OPTIONS();
        notifyOptions.Count = 0;
        notifyOptions.dwFlags = PRINTER_NOTIFY_OPTIONS_REFRESH;
        notifyOptions.dwVersion = 2;
        IntPtr ptr = IntPtr.Zero;
        
        whand = FindFirstPrinterChangeNotification(phand, (int)Printer_Change_Notification_General_Flags.PRINTER_CHANGE_JOB, 0, notifyOptions);
        wh.Handle = whand;

        rwh = ThreadPool.RegisterWaitForSingleObject(wh, 
           new WaitOrTimerCallback(PrinterNotifyWaitCallback), 
           wh, -1, true);
        }

//-----------------------------------------------
public void PrinterNotifyWaitCallback( 
    Object state , 
    bool timedOut )
        {
        Console.WriteLine("IN");
        int pdwChange = 0;
        IntPtr ptr = IntPtr.Zero;
        PRINTER_NOTIFY_OPTIONS  notifyOptions = new PRINTER_NOTIFY_OPTIONS();
        notifyOptions.Count = 1;
        notifyOptions.dwFlags = PRINTER_NOTIFY_OPTIONS_REFRESH;
        notifyOptions.dwVersion = 2;
            
        

        bool nxt = FindNextPrinterChangeNotification(whand, out pdwChange, notifyOptions, out ptr);
        PRINTER_NOTIFY_INFO pni = (PRINTER_NOTIFY_INFO)Marshal.PtrToStructure(ptr, typeof(PRINTER_NOTIFY_INFO));
        
        wh.Reset();
        rwh = ThreadPool.RegisterWaitForSingleObject(wh, new WaitOrTimerCallback(PrinterNotifyWaitCallback), wh, -1, true);
        
        }
//------------------------------------------
[StructLayout(LayoutKind.Sequential)]
    public class PRINTER_NOTIFY_OPTIONS
    {
        public int dwVersion;
        public int dwFlags;
        public int Count;
        public IntPtr lpTypes;
        public PRINTER_NOTIFY_OPTIONS_TYPE pTypes;
    }
   [StructLayout(LayoutKind.Sequential)]
public class PRINTER_NOTIFY_OPTIONS_TYPE
   {
    public Int16 wType;
    public Int16 wReserved0 ;
    public Int32 dwReserved1 ;
    public Int32 dwReserved2 ;
    public Int32 FieldCount;
    public IntPtr pFields ;

}
//---------------------------------------------
public enum Printer_Change_Notification_General_Flags
{
        PRINTER_CHANGE_JOB = 0x0000ff00
 }


struct PRINTER_NOTIFY_INFO
{
    public long Version;
    public long Flags;
    public long Count;
}
struct PRINTER_NOTIFY_INFO_DATA
{
    public int Type;
    public int Field;
    public long Reserved;
    public long Id;
} 
--------------------------------