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Error getting INF file using WMI commads

samelamin used Ask the Experts™
Hey all

I am trying to retreive the INF file for a installed printer driver

The aim is to uise it to instal clones of the same printer, however I am getting an error and i dont know why because it gives me the name of the printer

the error:
Object reference not set to an instance of an object.
string printerName, printerDriver, portName; bool sharedPrinter;
            string path="not working";
            string infname = "";
            portName = null;

            chosen = comboBox1.SelectedItem.ToString();

            ObjectQuery objectQuery = new ObjectQuery("SELECT * FROM Win32_PrinterDriver WHERE NAME='"+chosen+"'");
            ManagementObjectSearcher searcher =
            new ManagementObjectSearcher(objectQuery);

            foreach (ManagementObject mo in searcher.Get())
                    infname = mo["InfName"].ToString();


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Meir RivkinFull stack Software Engineer

which line throws the error?
Meir RivkinFull stack Software Engineer

it's possible that mo["InfName"] returns null and then u call ToString() which ultimately trigger the exception.
other than that u should debug it to see what code throw the exception


Thats right thats what triggers the error

So if its null does that mean that the INF is ntprint.inf?

I thought its supposed to return it regardless?

how should i resolve this?
Meir RivkinFull stack Software Engineer

according to Microsoft Windows Printing Team the InfName field is IN only, used for installing a driver. You cannot retrieve it. (http://www.pcreview.co.uk/forums/thread-531326.php)


Wow ok that clears things up.

So is there any way to add a new printer using the drivers already installed in code ?
Full stack Software Engineer
you should use rundll32 printui.dll,PrintUIEntry
check http://support.microsoft.com/kb/189105


ALright I see where my mistake is

I am trying to add a printer but at the same time i want that printer to use a driver thats already installed

So installing the print driver was a mistake the aim is to add a printer then allocate it adriver thats already been installed

I dont think i can do that using print ui


solved it thanks