printer job monitoring problem

[sengkok]

hi,

i have written a printer job monitoring program as the code shown below , a
timer is used to call this function every second . i have a network printer
tat attached to my pc. i facing a problems that some time the program can
detect the print job but some how most of the time it cant detect any printer
job while actually the printing some documents .
any one has facing this problem before ? or any suggestion for me.
(i find out that most of the time when i print document from the internet
explorer , my program cant detect any print job)
beside using WMI , what others methods i can use to detect the print job ?

public void GetPrintJobsCol lection()
{
string f_SearchQuery = "SELECT * FROM Win32_PrintJob" ;
ManagementObjec tSearcher f_SearchPrintJo bs =
new ManagementObjec tSearcher(f_Sea rchQuery);
ManagementObjec tCollection f_PrntJobCollec tion = f_SearchPrintJo bs.Get();
foreach(Managem entObject f_PrntJob in f_PrntJobCollec tion)
{
MessageBox.Show ("Your Document(s) are Printing now") ;
m_JobID = f_PrntJob.Prope rties["JobId"].Value.ToString () ;
m_DocName = f_PrntJob.Prope rties["Document"].Value.ToString () ;
m_TotalPages = f_PrntJob.Prope rties["TotalPages "].Value.ToString () ;
m_PrinterQueue[m_PrintQCount] = m_JobID ;
if (Convert.ToDoub le (m_TotalPages) <= 0)
m_TotalPages = "1" ;
DeductPrintingV alue (Convert.ToInt1 6(m_TotalPages) ) ;
}