public void Start()
{
if (!WinSpool.OpenPrinter(printerName, out hPrinter, IntPtr.Zero))
{
var errorCode = Marshal.GetLastWin32Error();
throw new SpoolWatcherException($"Error in OpenPrinter: {errorCode}");
}
var printerNotifyOptions = new PrinterNotifyOptions();
printerNotifyOptions.Version = 2;
var optionsType = CreateOptionsType();
printerNotifyOptions.Count = (uint)optionsType.Count();
var pNotifyOptionsSz = Marshal.SizeOf <PrinterNotifyOptions>();
printerNotifyOptions.pTypes = Marshal.AllocHGlobal(pNotifyOptionsSz * optionsType.Count());
for (int i = 0; i < optionsType.Count(); i++)
{
var ptr = IntPtr.Add(printerNotifyOptions.pTypes, i * pNotifyOptionsSz);
Marshal.StructureToPtr(optionsType.ElementAt(i), ptr, false);
}
notificationHandle = WinSpool.FindFirstPrinterChangeNotification(hPrinter, PrinterChange, (uint)printerNotifyCategory, ref printerNotifyOptions);
foreach (var optionType in optionsType)
{
Marshal.FreeHGlobal(optionType.pFields);
}
Marshal.FreeHGlobal(printerNotifyOptions.pTypes);
if (notificationHandle.IsInvalid)
{
var errorCode = Marshal.GetLastWin32Error();
throw new SpoolWatcherException($"Error in FindFirstPrinterChangeNotification: {errorCode}");
}
stopEvent.Reset();
tNotifications = new Thread(() => WaitForNotifications());
tNotifications.Start();
}
private static extern bool FindNextChangeNotification(SafeNotificationHandle hChangeHandle);
public static unsafe extern CONFIGRET CM_Register_Notification(
[Friendly(FriendlyFlags.In)] CM_NOTIFY_FILTER *pFilter,
void *pContext,
CM_NOTIFY_CALLBACK pCallback,
out SafeNotificationHandle pNotifyContext);
internal static extern bool FindNextPrinterChangeNotification(SafeNotificationHandle hChange, out PrinterChange pdwChange, PrinterNotifyOptions printerNotifyOptions, out SafePrinterNotifyInfo pPrinterNotifyInfo);
