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How to: Diagnose Problematic Print Job	03/30/2017	csharp vb cpp	troubleshooting print job problems [WPF] print jobs [WPF], troubleshooting print jobs [WPF], diagnosing problems	b081a170-84c6-48f9-a487-5766a8d58a82

How to: Diagnose Problematic Print Job

Network administrators often field complaints from users about print jobs that do not print or print slowly. The rich set of print job properties exposed in the APIs of Microsoft .NET Framework provide a means for performing a rapid remote diagnosis of print jobs.

Example

The major steps for creating this kind of utility are as follows.

1. Identify the print job that the user is complaining about. Users often cannot do this precisely. They may not know the names of the print servers or printers. They may describe the location of the printer in different terminology than was used in setting its xref:System.Printing.PrintQueue.Location%2A property. Accordingly, it is a good idea to generate a list of the user's currently submitted jobs. If there is more than one, then communication between the user and the print system administrator can be used to pinpoint the job that is having problems. The substeps are as follows.

   1. Obtain a list of all print servers.

   2. Loop through the servers to query their print queues.

   3. Within each pass of the server loop, loop through all the server's queues to query their jobs

   4. Within each pass of the queue loop, loop through its jobs and gather identifying information about those that were submitted by the complaining user.

2. When the problematic print job has been identified, examine relevant properties to see what might be the problem. For example, is job in an error state or did the printer servicing the queue go offline before the job could print?

The code below is series of code examples. The first code example contains the loop through the print queues. (Step 1c above.) The variable myPrintQueues is the xref:System.Printing.PrintQueueCollection object for the current print server.

The code example begins by refreshing the current print queue object with xref:System.Printing.PrintQueue.Refresh%2A?displayProperty=nameWithType. This ensures that the object's properties accurately represent the state of the physical printer that it represents. Then the application gets the collection of print jobs currently in the print queue by using xref:System.Printing.PrintQueue.GetPrintJobInfoCollection%2A.

Next the application loops through the xref:System.Printing.PrintSystemJobInfo collection and compares each xref:System.Printing.PrintSystemJobInfo.Submitter%2A property with the alias of the complaining user. If they match, the application adds identifying information about the job to the string that will be presented. (The userName and jobList variables are initialized earlier in the application.)

[!code-cppDiagnoseProblematicPrintJob#EnumerateJobsInQueues] [!code-csharpDiagnoseProblematicPrintJob#EnumerateJobsInQueues] [!code-vbDiagnoseProblematicPrintJob#EnumerateJobsInQueues]

The next code example picks up the application at Step 2. (See above.) The problematic job has been identified and the application prompts for the information that will identify it. From this information it creates xref:System.Printing.PrintServer, xref:System.Printing.PrintQueue, and xref:System.Printing.PrintSystemJobInfo objects.

At this point the application contains a branching structure corresponding to the two ways of checking a print job's status:

• You can read the flags of the xref:System.Printing.PrintSystemJobInfo.JobStatus%2A property which is of type xref:System.Printing.PrintJobStatus.

• You can read each relevant property such as xref:System.Printing.PrintSystemJobInfo.IsBlocked%2A and xref:System.Printing.PrintSystemJobInfo.IsInError%2A.

This example demonstrates both methods, so the user was previously prompted as to which method to use and responded with "Y" if they wanted to use the flags of the xref:System.Printing.PrintSystemJobInfo.JobStatus%2A property. See below for the details of the two methods. Finally, the application uses a method called ReportQueueAndJobAvailability to report on whether the job can be printed at this time of day. This method is discussed in Discover Whether a Print Job Can Be Printed At This Time of Day.

[!code-cppDiagnoseProblematicPrintJob#IdentifyAndDiagnoseProblematicJob] [!code-csharpDiagnoseProblematicPrintJob#IdentifyAndDiagnoseProblematicJob] [!code-vbDiagnoseProblematicPrintJob#IdentifyAndDiagnoseProblematicJob]

To check print job status using the flags of the xref:System.Printing.PrintSystemJobInfo.JobStatus%2A property, you check each relevant flag to see if it is set. The standard way to see if one bit is set in a set of bit flags is to perform a logical AND operation with the set of flags as one operand and the flag itself as the other. Since the flag itself has only one bit set, the result of the logical AND is that, at most, that same bit is set. To find out whether it is or not, just compare the result of the logical AND with the flag itself. For more information, see xref:System.Printing.PrintJobStatus, the & Operator (C# Reference), and xref:System.FlagsAttribute.

For each attribute whose bit is set, the code reports this to the console screen and sometimes suggests a way to respond. (The HandlePausedJob method that is called if the job or queue is paused is discussed below.)

[!code-cppDiagnoseProblematicPrintJob#SpotTroubleUsingJobAttributes] [!code-csharpDiagnoseProblematicPrintJob#SpotTroubleUsingJobAttributes] [!code-vbDiagnoseProblematicPrintJob#SpotTroubleUsingJobAttributes]

To check print job status using separate properties, you simply read each property and, if the property is true, report to the console screen and possibly suggest a way to respond. (The HandlePausedJob method that is called if the job or queue is paused is discussed below.)

[!code-cppDiagnoseProblematicPrintJob#SpotTroubleUsingJobProperties] [!code-csharpDiagnoseProblematicPrintJob#SpotTroubleUsingJobProperties] [!code-vbDiagnoseProblematicPrintJob#SpotTroubleUsingJobProperties]

The HandlePausedJob method enables the application's user to remotely resume paused jobs. Because there might be a good reason why the print queue was paused, the method begins by prompting for a user decision about whether to resume it. If the answer is "Y", then the xref:System.Printing.PrintQueue.Resume%2A?displayProperty=nameWithType method is called.

Next the user is prompted to decide if the job itself should be resumed, just in case it is paused independently of the print queue. (Compare xref:System.Printing.PrintQueue.IsPaused%2A?displayProperty=nameWithType and xref:System.Printing.PrintSystemJobInfo.IsPaused%2A?displayProperty=nameWithType.) If the answer is "Y", then xref:System.Printing.PrintSystemJobInfo.Resume%2A?displayProperty=nameWithType is called; otherwise xref:System.Printing.PrintSystemJobInfo.Cancel%2A is called.

[!code-cppDiagnoseProblematicPrintJob#HandlePausedJob] [!code-csharpDiagnoseProblematicPrintJob#HandlePausedJob] [!code-vbDiagnoseProblematicPrintJob#HandlePausedJob]

See also

• xref:System.Printing.PrintJobStatus
• xref:System.Printing.PrintSystemJobInfo
• xref:System.FlagsAttribute
• xref:System.Printing.PrintQueue
• & Operator (C# Reference)
• Documents in WPF
• Printing Overview