Batch printing exception - vb.net

Question

I get this error while printing multiple .xps documents to a physical printer
Dim defaultPrintQueue As PrintQueue = GetForwardPrintQueue(My.Settings.SelectedPrinter)
Dim xpsPrintJob As PrintSystemJobInfo
xpsPrintJob = defaultPrintQueue.AddJob(JobName, Document, False)
Documents are spooled succesfully till, a print job exception occurs
The InnerException is Insufficient memory to continue the execution of the program.
The source is PresentationCore.dll
Where should i start searching?

Answer 1

When attempting to perform tasks that may fail due to temporary or permanent restrictions on some resource, I tend to use a back-off strategy. This strategy has been followed on things as diverse as message queuing and socket opens.
The general process for such a strategy is as follows.
set maxdelay to 16 # maximum time period between attempts
set maxtries to 10 # maximum attempts
set delay to 0
set tries to 0
while more actions needed:
if delay is not 0:
sleep delay
attempt action
if action failed:
add 1 to tries
if tries is greater than maxtries:
exit with permanent error
if delay is 0:
set delay to 1
else:
double delay
if delay is greater than maxdelay:
set delay to maxdelay
else:
set delay to 0
set tries to 0
This allows the process to run at full speed in the vast majority of cases but backs off when errors start occurring, hopefully giving the resource provider time to recover. The gradual increase in delays allows for more serious resource restrictions to recover and the maximum tries catches what you would term permanent errors (or errors that are taking too long to recover).
I actually prefer this try-it-and-catch-failure approach to the check-if-okay-then-try one since the latter can still often fail if something changes between the check and the try. This is called the "better to seek forgiveness than ask permission" method, which also works quite well with bosses most of the time, and wives a little less often :-)
One particularly useful case was a program which opened a separate TCP session for each short-lived transaction. On older hardware, the closed sockets (those in TCP WAIT state) eventually disappeared before they were needed again.
But, as the hardware got faster, we found that we could open sessions and do work much quicker and Windows was running out of TCP handles (even when increased to the max).
Rather than having to re-engineer the communications protocol to maintain sessions, this strategy was implemented to allow graceful recovery in the event handles were starved.
Granted it's a bit of a kludge but this was legacy software approaching end-of-life, where bug fixes are often just enough to get it working and it wasn't deemed strategic enough to warrant spending a lot of money in fixing it properly.
Update: It may be that there's a (more permanent) problem with PresentationCore. This KB article states that there's a memory leak in WPF within .NET 3.5SP1 (of which your print driver may be a client).
If the backoff strategy doesn't fix your problem (it may not if it's a leak in a long lived process), you might want to try applying the hotfix. Me, I'd replicate the problem in a virtual machine and then patch that to test it (but I'm an extreme paranoid).
It was found by googling PresentationCore Insufficient memory to continue the execution of the program and checking the first link here. Search for the string "hotfix that relates to this issue" on that page.

Answer 2

Before adding a new job to the queue you should check the queue state. More info on PrintQueue.IsOutOfMemory property and related properties that can be queried to verify that the queue is not in an error state.
Of course pax' hint to use a defensive strategy when accessing resources like printers is best practice. For starter you may want to put the line adding the job into a try block.

Answer 3

You might want to consider launching a new process to handle the printing of each document, the overhead should be low compared to the effort of printing the documents.