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 void WaitForNotifications()
{
var handles = new WaitHandle[] { notificationHandle, stopEvent.WaitHandle };
while (WaitHandle.WaitAny(handles) == 0)
{
if (WinSpool.FindNextPrinterChangeNotification(notificationHandle, out var change, IntPtr.Zero, out SafePrinterNotifyInfo pNotifyInfo))
{
PrinterNotifyInfo printerNotifyInfo = pNotifyInfo;
while ((printerNotifyInfo.Flags & PRINTER_NOTIFY_INFO_DISCARDED) == PRINTER_NOTIFY_INFO_DISCARDED)
{
pNotifyInfo.Close();
var notifyOptions = new PrinterNotifyOptions
{
Flags = PRINTER_NOTIFY_OPTIONS_REFRESH
};
var nextRet = WinSpool.FindNextPrinterChangeNotification(notificationHandle, out change, notifyOptions, out pNotifyInfo);
printerNotifyInfo = pNotifyInfo;
if (!nextRet)
{
break;
}
}
if (SpoolerNotificationReached != null)
{
var datas = new List <NotificationInfo>();
for (uint i = 0; i < printerNotifyInfo.Count; i++)
{
var notificationInfo = new NotificationInfo();
notificationInfo.Id = printerNotifyInfo.aData[i].Id;
switch (printerNotifyInfo.aData[i].Type)
{
case NotifyType.Job:
notificationInfo.Type = NotifyType.Job;
notificationInfo.InfoData = DataFieldParser.GetJobTypeData(printerNotifyInfo.aData[i]);
break;
case NotifyType.Printer:
notificationInfo.Type = NotifyType.Printer;
notificationInfo.InfoData = DataFieldParser.GetPrinterTypeData(printerNotifyInfo.aData[i]);
break;
default:
break;
}
datas.Add(notificationInfo);
}
var evArgs = new SpoolNotificationEventArgs
{
PrinterChange = change,
NotificationInfos = datas.ToArray()
};
SpoolerNotificationReached(this, evArgs);
}
pNotifyInfo.Close();
}
}
}