How to print PDF document from Windows Service

Question

I have windows service that must periodically print PDF document from server. My function is

private void PrintFormPdfData(byte[] formPdfData)
{
    string tempFile;

    tempFile = Path.GetTempFileName();

    using (FileStream fs = new FileStream(tempFile, FileMode.Create))
    {
        fs.Write(formPdfData, 0, formPdfData.Length);
        fs.Flush();
    }

    string pdfArguments = string.Format("/p /h\"{0}\"", tempFile);

    string pdfPrinterLocation = @"C:\Program Files (x86)\Adobe\Reader 9.0\Reader\AcroRd32.exe";


    ProcessStartInfo newProcess = new ProcessStartInfo(pdfPrinterLocation, pdfArguments);
    newProcess.CreateNoWindow = true;
    newProcess.RedirectStandardOutput = true;
    newProcess.UseShellExecute = false;
    newProcess.RedirectStandardError = true;

    Process pdfProcess = new Process();
    pdfProcess.StartInfo = newProcess;
    pdfProcess.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
    pdfProcess.Start();
    pdfProcess.WaitForExit();
}

When I implement this in Windows Application it works, but when I implement in Windows service it does not work.

Can you help me?

Answer 1

I solved this problem with the registry edits found in this article: https://support.microsoft.com/en-us/kb/184291.

Printing from Windows services (and also IIS) uses the SYSTEM account as I understand it. This account does not have access to the printer but these registry edits gives that SYSTEM account printing privileges.

Here is a summary:

1. export 3 keys ("folders within regedit.exe") to .reg files:
   • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\Current Version\Devices
   • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\Current Version\PrinterPorts
   • HKEY_CURRENT_USER\Software\Microsoft\Windows NT\Current Version\Windows
2. edit your 3 newly created reg files and change "HKEY_CURRENT_USER" to "HKEY_USERS\.DEFAULT"
3. run your 3 reg files by double clicking them in explorer (this adds them to the registry)

That's all it takes. This helped me to print pdf files to a printer from PHP in IIS 7. My php script would work just fine so long as the server happened to have the Administrator logged in when the script was run. Now no one needs to be logged in and the script still works :)

I hope this saves someone as much searching and tinkering as I put in to find it.