C# – Printing by executing a process in a Windows Service

cnetprintingwindows-services

I have a Windows Service that needs to start a process to send a file to the printer (I found that solution there https://stackoverflow.com/a/4875755/1228738) . I do this using the Process.Start().
My problem is that nothing happens.

The service is actually installed on my developer machine (win7, x64). I tried installing it as LOCAL SYSTEM, NETWORK SERVICE, LOCAL SERVICE with the same result every time.

I tried those way of starting my process :

Process p = new  Process();
p.StartInfo.FileName = "C:\\Program Files (x86)\\Foxit Software\\Foxit Reader\\Foxit Reader.exe";
p.StartInfo.Arguments = "-p myFile.pdf";
p.Start();

and

Process.Start("C:\\Program Files (x86)\\Foxit Software\\Foxit Reader\\Foxit Reader.exe", "-p myFile.pdf");

and also

ProcessStartInfo startInfo = new ProcessStartInfo();
startInfo.FileName = "C:\\Program Files (x86)\\Foxit Software\\Foxit Reader\\Foxit Reader.exe";
startInfo.Arguments = "-p myFile.pdf";

Process.Start(startInfo);

When I execute the same code in a winform application, everything works fine, the file is sent to the printer. But in the Windows Service, nothing happens.

I saw that post https://stackoverflow.com/a/6271309/1228738, which explains why I would not see the UI, that's fine I don't have any UI anyway. But as said in the comment section, a process with no user input should be OK. The process that I start don't need any user input.

The only thing I can think of right now, is that because of session isolation (https://stackoverflow.com/a/5063750/1228738), the service can't find any installed printers… Can that be the case ? If so, any suggestion how to work around that ? And if not, any idea of what's wrong ?

Thanks!

EDIT #1

I tried running the service with my user account, and it's working, so I guess my fears are confirmed… the users LOCAL SYSTEM and NETWORK SERVICE have no installed printers.

So I'll refine my question a little bit. Is there a way for those account to access printers installed on the computer ?

EDIT #2

We finally decided that a user will be created for running that service and in that user accounts we'll install the printer on which to print.

I guess this question can be closed now.
Thank you all for your help.

Best Answer

I had this issue too, this trick solved it

Go to services ---> Double click the required service ---> proceed to logon tab

Supply the Log-in credentials from which printer was installed.

Run your service, then check the printer queue.

Reason: Local system account does not have those printer installed !

See screen shot below. enter image description here

Related Solutions

Windows – How to uninstall a Windows service if the files do not exist anymore

You have at least three options. I have presented them in order of usage preference.

Method 1 - You can use the SC tool (Sc.exe) included in the Resource Kit. (included with Windows 7/8)

Open a Command Prompt and enter

sc delete <service-name>

Tool help snippet follows:

DESCRIPTION:
        SC is a command line program used for communicating with the
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delete----------Deletes a service (from the registry).

Method 2 - use delserv

Download and use delserv command line utility. This is a legacy tool developed for Windows 2000. In current Window XP boxes this was superseded by sc described in method 1.

Method 3 - manually delete registry entries (Note that this backfires in Windows 7/8)

Windows services are registered under the following registry key.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services

Search for the sub-key with the service name under referred key and delete it. (and you might need to restart to remove completely the service from the Services list)

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When you launch a new process using ProcessStartInfo the process is started in the same window station and desktop as the launching process. If you are using different credentials then the user will, in general, not have sufficient rights to run in that desktop. The failure to initialize errors are caused when user32.dll attempts to initialize in the new process and can't.

To get around this you must first retrieve the security descriptors associated with the window station and desktop and add the appropriate permissions to the DACL for your user, then launch your process under the new credentials.

EDIT: A detailed description on how to do this and sample code was a little long for here so I put together an article with code.

        //The following security adjustments are necessary to give the new 
        //process sufficient permission to run in the service's window station
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        IntPtr hWinSta = GetProcessWindowStation();
        WindowStationSecurity ws = new WindowStationSecurity(hWinSta,
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        ws.AddAccessRule(new WindowStationAccessRule("LaunchProcessUser",
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        ws.AcceptChanges();

        IntPtr hDesk = GetThreadDesktop(GetCurrentThreadId());
        DesktopSecurity ds = new DesktopSecurity(hDesk,
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        EventLog.WriteEntry("Launching application.", EventLogEntryType.Information);

        using (Process process = Process.Start(psi))
        {
        }

Best Answer

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