PrintJob的实际总页数（Win32_PrintJob）

我每次使用ManagementEventWatcher进行更改时都会查询Win32_PrintJob WMI类，我获取了有关它的数据，例如：Document，HostPrintQueue，JobId，JobStatus，TotalPages等 . But TotalPages is not representing the real number of page to print ，似乎此刻获取这些数据仍然是printjob还没有完成处理和转换大量页面进行打印，但实际总数是其他数字，如何在完成处理后获得打印作业的实际数量？这是我的代码：

ManagementEventWatcher createPrintJobWatcher;
        String strComputerName = ".";
        // Create event query to be notified within 1 milli second of a change in a service
        WqlEventQuery createPrintJobQuery = new WqlEventQuery("SELECT * FROM __InstanceCreationEvent WITHIN 0.001 WHERE TargetInstance ISA \"Win32_PrintJob\"");

        createPrintJobWatcher = new ManagementEventWatcher();
        createPrintJobWatcher.Scope = new ManagementScope("\\\\" + strComputerName + "\\root\\CIMV2");
        createPrintJobWatcher.Query = createPrintJobQuery;
        // times out watcher.WaitForNextEvent in 1 seconds
        createPrintJobWatcher.Options.Timeout = new TimeSpan(0, 0, 1);
        //set the print event handler
        createPrintJobWatcher.EventArrived += new EventArrivedEventHandler(createPrintJobListener);

        createPrintJobWatcher.Start();

        Console.WriteLine("Listening...");

        Console.ReadLine();

createPrintJobListener方法：

static void createPrintJobListener(object sender, EventArrivedEventArgs e)
    {

        SelectQuery query = new SelectQuery("Win32_PrintJob");
        using (ManagementObjectSearcher searcher = new ManagementObjectSearcher(query))
        using (ManagementObjectCollection printJobs = searcher.Get())
            foreach (ManagementObject printJob in printJobs)
            {
                Console.WriteLine("c1:", printJob);
                Console.WriteLine("ID: {0}", printJob.GetPropertyValue("JobId").ToString());
                Console.WriteLine("name: {0}", printJob.GetPropertyValue("name").ToString());
                Console.WriteLine("status: {0}", printJob.GetPropertyValue("status").ToString());
                if (printJob.GetPropertyValue("JobStatus") != null)
                {
                    Console.WriteLine("JobStatus: {0}", printJob.GetPropertyValue("JobStatus").ToString());
                }
                else
                {
                    Console.WriteLine("JobStatus: NULLLLLL");
                }

                Console.WriteLine("PC: {0}", printJob.GetPropertyValue("HostPrintQueue").ToString());
                Console.WriteLine("TOTOAL PAGES: {0}", printJob.GetPropertyValue("TotalPages").ToString());                    
            }
    }