Access Denied trying to purge printqueue in C#

Question

I'm trying to make a method in C# that empties all items in a print queue. Below is my code:

LocalPrintServer localPrintServer = new LocalPrintServer(PrintSystemDesiredAccess.AdministratePrinter); 
PrintQueue printQueue = localPrintServer.GetPrintQueue(printerName);

if (printQueue.NumberOfJobs > 0)
{
    printQueue.Purge();
}

When this code runs, on the localPrintServer constructor, the app throws this error: "An exception occurred while creating the PrintServer object. Win32 error: Access is denied."

That constructor has a few overloads (including sending no parameters). Trying any of those, I get past that line, but when I get to the printQueue.Purge() call, I get the same access denied message as listed above.

Looking for suggestions of how / what I can do to get around this. I can manually delete the print jobs from my computer. I'm not sure if the app runs with the same access I have nor how to check that.

Solution 1

This problem is caused by the GetPrintQueue method being slightly evil, since it does not allow you to pass in the desired access level. With your code as it is, you are connecting to the print server with AdministratePrinter rights (which is meaningless), and connecting to the print queue with default user rights. Thus, the operation will fail, even if Everyone has admin rights on the print queue.

To fix this, use the constructor for PrintQueue instead to specify the correct access level:

using (PrintServer ps = new PrintServer()) {
    using (PrintQueue pq = new PrintQueue(ps, printerName,
          PrintSystemDesiredAccess.AdministratePrinter)) {
        pq.Purge();
    }
}

This may still cause permission errors if you're not running in the context of a member of the Administrators group (or not running with elevated permissions), so surrounding this with a try/catch block is a good idea for production code.

Solution 2

Are you running your website as 4.0? I ran into issues when we upgraded our website from 3.5 to 4.0 Framework. The Print Purging functionality stopped working in the 4.0 Framework. Ultimately I ended up creating a web service that used the 3.5 framework and had the 4.0 website communicate the printer it wanted to purge to the 3.5 web service.

(Sorry to revive this thread, this was one of the threads I stumbled onto when I was looking for an answer. Figured I'd post this if it helps someone that runs into the same situation)

Solution 3

I tried using @mdb solution but it didn't work (Access denied using Framework .NET 4.6.1). So I ended up using the following solution:

void CleanPrinterQueue(string printerName)         
{   
   using (var ps = new PrintServer())
   {
      using (var pq = new PrintQueue(ps, printerName, PrintSystemDesiredAccess.UsePrinter))
      {
         foreach (var job in pq.GetPrintJobInfoCollection())
            job.Cancel();
      }
   }
}

Comments

[HiTech]

this well very helpful. I was also trying to make changes using the GetPrintQueue() method. +1

[James Tan]

Seriously nice insight on the fact that the PrintServer requested permissions are not inherited by PrintQueue's retrieved through it!