WMI to detect printer online/offline

Hi,

Sorry for this long preamble, but it will help with my question....

I'm developing a dedicated XP Embedded application.

If the user prints fom the application, but no printer is available, a
typical "printer offline" dialog will appear (Printer dependent, in my case
a Canon i550). This is undesirable, the customer wants it just to ignore the
print request, and no dialog ever be visible.

For this reason, I want to detect if the printer is Online/offline BEFORE
attempting to print. If offline, I can then abort the print, and won't see
the dialog.

The Win32 API's "OpenPrinter" etc. seem to work on the spooler queue, rather
than the printer itself, and will only report the printer offline AFTER a
dcoument is sent, whichis too late, because I will then see the dialog.

It seems that I could use WMI. I've tried using
GetObject(sPrinter).InstancesOf("win32_Printer")

and then looking at Printer.PrinterStatus, but the same effect is seen as
with Win32 API.



So, the question is, how can I tell if a printer is offline/online without
sending a print to it?

I think I have to use WMI extensions to the printer WDM driver?

Any pointers, advice recieved with thanks!

Andy Foster

You would need to force a port status update to set the printer status.
This is assuming that the Port is a Standard TC/IP Port with SNMP enabled.

--
Alan Morris
Windows Printing Team
Search the Microsoft Knowledge Base here:
http://support.microsoft.com/default.aspx?scid=fh;[ln];kbhowto

This posting is provided "AS IS" with no warranties, and confers no rights.

"Andy Foster" <nospam@nospam.com> wrote in message
news:uoAQaJwhEHA.4092@TK2MSFTNGP10.phx.gbl...
> Hi,
>
> Sorry for this long preamble, but it will help with my question....
>
> I'm developing a dedicated XP Embedded application.
>
> If the user prints fom the application, but no printer is available, a
> typical "printer offline" dialog will appear (Printer dependent, in my
case
> a Canon i550). This is undesirable, the customer wants it just to ignore
the
> print request, and no dialog ever be visible.
>
> For this reason, I want to detect if the printer is Online/offline BEFORE
> attempting to print. If offline, I can then abort the print, and won't see
> the dialog.
>
> The Win32 API's "OpenPrinter" etc. seem to work on the spooler queue,
rather
> than the printer itself, and will only report the printer offline AFTER a
> dcoument is sent, whichis too late, because I will then see the dialog.
>
> It seems that I could use WMI. I've tried using
> GetObject(sPrinter).InstancesOf("win32_Printer")
>
> and then looking at Printer.PrinterStatus, but the same effect is seen as
> with Win32 API.
>
>
>
> So, the question is, how can I tell if a printer is offline/online without
> sending a print to it?
>
> I think I have to use WMI extensions to the printer WDM driver?
>
> Any pointers, advice recieved with thanks!
>
> Andy Foster
>
>
>