Is Printer Online

**GremlinSA** · November 19th, 2008, 05:42 AM

I've come across a very wierd issue with Vista..

If my USB receipt printer is not Plugged in when a print job is sent, the job is sent out into the unknown ... and lost forever .... with out any sort of error....

A little testing and playing around i found that if i manually set the "Use Printer Offline" Check .. all print jobs are queued, and wait for the printer to come back online.. If i clear the Check while the printer is still not available, Again all the jobs are sent out into the unknown...

NOW .... The decision is to check if the Printer is Available, and if not to prompt the user to make it available or cancel the print ...

However digging through all the printer object's i'm still to find the correct property's to check this..

Help !!! where do i check if a specified printer is available... (IE. Plugged in and switched on)..

Thanks

Gremmy...

**HairyMonkeyMan** · November 19th, 2008, 06:26 AM

Maybe you can use a WMI object like this guy:
http://bytes.com/forum/thread347497.html

**HanneSThEGreaT** · November 19th, 2008, 06:56 AM

Great find Hairy!

You could also use the OpenPrinter API along with the PRINTER_INFO_2 structure to determine if a printer is available or not

**GremlinSA** · November 19th, 2008, 07:53 AM

Thanks..

However this returns does not realy return correct info, Acctualy I get strange results with it..

Originally Posted by Results from Codesnip

Send To OneNote 2007: waiting (idle)
Microsoft XPS Document Writer: waiting (idle)
EPSON TM-T88IV Receipt: unknown state
\\MARTIN\HP DeskJet 840C/841C/842C/843C: waiting (idle)
\\RICHARD\HP LaserJet 5: waiting (idle)
\\SYNCFIREWALL1\Brother MFC9600/9870 Series: waiting (idle)

I have 3 printers setup according to what network i'm attached to ..
Brother = Office Network
HP LaserJet = Home Network
HP DeskJet = Clients Network

And the Epson is the USB One. (above result = USB cable out)..

However, of the three printers that are connected to 3 Very different Networks, it shows that all three are available to print too.. With the reciept printer i cant take the chance that the receipt printer might be networked (two (or more) units sharing a Printer), and this code snip Fails when it comes to Networked printers..

Surprisingly this code snip is Found 19 times in google, on different forums, even on a thread asking about networked printer status..

I need to be able to get info like what the control panel has IE..

Here you can see that 3 printer objects are "Ready", One is "Not Avail" , and two are essentially unknown ..

After plugging in the USB printer is becomes ready..

I'm still looking into the WMI code to see if i can find something else that will return correct results, however WMI.PrinterStatus is not quite good enough..

Thanks

Gremmy..

**HairyMonkeyMan** · November 19th, 2008, 08:18 AM

I think Hannes' call of using the API could be a good avenue for you:
http://www.codeproject.com/KB/printi...atchvbnet.aspx

**HanneSThEGreaT** · November 19th, 2008, 08:27 AM

Have you tried the Api I suggested ¿

The following is a list of APIs Structures and constants needed :
APIs :

Code:

OpenPrinter
FindFirstPrinterChangeNotification
FindNextPrinterChangeNotification

Structures :

Code:

PRINTER_NOTIFY_INFO 
PRINTER_NOTIFY_INFO_2

Constants :

Code:

    JOB_NOTIFY_FIELD_PRINTER_NAME = &H0 
    JOB_NOTIFY_FIELD_MACHINE_NAME = &H1 
    JOB_NOTIFY_FIELD_PORT_NAME = &H2 
    JOB_NOTIFY_FIELD_USER_NAME = &H3 
    JOB_NOTIFY_FIELD_NOTIFY_NAME = &H4 
    JOB_NOTIFY_FIELD_DATATYPE = &H5 
    JOB_NOTIFY_FIELD_PRINT_PROCESSOR = &H6 
    JOB_NOTIFY_FIELD_PARAMETERS = &H7 
    JOB_NOTIFY_FIELD_DRIVER_NAME = &H8 
    JOB_NOTIFY_FIELD_DEVMODE = &H9 
    JOB_NOTIFY_FIELD_STATUS = &HA 
    JOB_NOTIFY_FIELD_STATUS_STRING = &HB 
    JOB_NOTIFY_FIELD_SECURITY_DESCRIPTOR = &HC 
    JOB_NOTIFY_FIELD_DOCUMENT = &HD 
    JOB_NOTIFY_FIELD_PRIORITY = &HE 
    JOB_NOTIFY_FIELD_POSITION = &HF 
    JOB_NOTIFY_FIELD_SUBMITTED = &H10 
    JOB_NOTIFY_FIELD_START_TIME = &H11 
    JOB_NOTIFY_FIELD_UNTIL_TIME = &H12 
    JOB_NOTIFY_FIELD_TIME = &H13 
    JOB_NOTIFY_FIELD_TOTAL_PAGES = &H14 
    JOB_NOTIFY_FIELD_PAGES_PRINTED = &H15 
    JOB_NOTIFY_FIELD_TOTAL_BYTES = &H16 
    JOB_NOTIFY_FIELD_BYTES_PRINTED = &H17

    PRINTER_CHANGE_ADD_FORM = &H10000 
    PRINTER_CHANGE_SET_FORM = &H20000 
    PRINTER_CHANGE_DELETE_FORM = &H40000 
    PRINTER_CHANGE_FORM = &H70000 
    PRINTER_CHANGE_PORT = &H700000 
    PRINTER_CHANGE_JOB = &HFF00 
    PRINTER_CHANGE_PRINTER = &HFF 
    PRINTER_CHANGE_PRINT_PROCESSOR = &H7000000 
    PRINTER_CHANGE_PRINTER_DRIVER = &H70000000
    PRINTER_CHANGE_ADD_PORT = &H100000 
    PRINTER_CHANGE_CONFIGURE_PORT = &H200000 
    PRINTER_CHANGE_DELETE_PORT = &H400000 
    PRINTER_CHANGE_ADD_JOB = &H100 
    PRINTER_CHANGE_SET_JOB = &H200 
    PRINTER_CHANGE_DELETE_JOB = &H400 
    PRINTER_CHANGE_WRITE_JOB = &H800 
    PRINTER_CHANGE_ADD_PRINTER = &H1 
    PRINTER_CHANGE_SET_PRINTER = &H2 
    PRINTER_CHANGE_DELETE_PRINTER = &H4 
    PRINTER_CHANGE_FAILED_CONNECTION_PRINTER = &H8 
    PRINTER_CHANGE_ADD_PRINT_PROCESSOR = &H1000000 
    PRINTER_CHANGE_DELETE_PRINT_PROCESSOR = &H4000000
    PRINTER_CHANGE_ADD_PRINTER_DRIVER = &H10000000 
    PRINTER_CHANGE_SET_PRINTER_DRIVER = &H20000000 
    PRINTER_CHANGE_DELETE_PRINTER_DRIVER = &H40000000

    PRINTER_NOTIFY_FIELD_SERVER_NAME = &H0
    PRINTER_NOTIFY_FIELD_PRINTER_NAME = &H1
    PRINTER_NOTIFY_FIELD_SHARE_NAME = &H2
    PRINTER_NOTIFY_FIELD_PORT_NAME = &H3
    PRINTER_NOTIFY_FIELD_DRIVER_NAME = &H4
    PRINTER_NOTIFY_FIELD_COMMENT = &H5
    PRINTER_NOTIFY_FIELD_LOCATION = &H6
    PRINTER_NOTIFY_FIELD_DEVMODE = &H7
    PRINTER_NOTIFY_FIELD_SEPFILE = &H8
    PRINTER_NOTIFY_FIELD_PRINT_PROCESSOR = &H9
    PRINTER_NOTIFY_FIELD_PARAMETERS = &HA
    PRINTER_NOTIFY_FIELD_DATATYPE = &HB
    PRINTER_NOTIFY_FIELD_SECURITY_DESCRIPTOR = &HC
    PRINTER_NOTIFY_FIELD_ATTRIBUTES = &HD
    PRINTER_NOTIFY_FIELD_PRIORITY = &HE
    PRINTER_NOTIFY_FIELD_DEFAULT_PRIORITY = &HF
    PRINTER_NOTIFY_FIELD_START_TIME = &H10
    PRINTER_NOTIFY_FIELD_UNTIL_TIME = &H11
    PRINTER_NOTIFY_FIELD_STATUS = &H12
    PRINTER_NOTIFY_FIELD_STATUS_STRING = &H13
    PRINTER_NOTIFY_FIELD_CJOBS = &H14
    PRINTER_NOTIFY_FIELD_AVERAGE_PPM = &H15
    PRINTER_NOTIFY_FIELD_TOTAL_PAGES = &H16
    PRINTER_NOTIFY_FIELD_PAGES_PRINTED = &H17
    PRINTER_NOTIFY_FIELD_TOTAL_BYTES = &H18
    PRINTER_NOTIFY_FIELD_BYTES_PRINTED = &H19
    PRINTER_NOTIFY_FIELD_OBJECT_GUID = &H1A

I googled ( just for the sake of googling ) for OpenPrinter :
http://www.google.co.uk/search?hl=en...r+vb.net&meta=

Then, for FindFirstPrinterChangeNotification :
http://www.google.co.uk/search?hl=en...G=Search&meta=

Then, for FindNextPrinterChangeNotification :
http://www.google.co.uk/search?hl=en...G=Search&meta=

I eventually run into this article :
http://www.codeproject.com/KB/printi...atchvbnet.aspx

I hope it helps

EDIT: I Didn't see your latest reply Hairy, I was so busy typing

**TheCPUWizard** · November 19th, 2008, 09:04 AM

Two quick comments/observations:

1) There are definately issues with any networked printer, and even after years of searching I have not found any approach that is universally reliable.

2) Even if you can detect with 100% reliability the ability of a printer to accept a print job, this does NOT mean that a (usable) printout will be generated. The best you can get is a "probability".

For critical items (eg reciepts), this has caused me to generate a sub-system that does pre-printer queuing and caching. This was definately non-trivial as it requires a means of storing the information necessary to generate the prinout, but the benfits were amazing.