Develop Reference

How to contentiously loop through in order to get printer Status

I have coded a simple console application that checks the status of a printer. When status of a printer changes to a "printing status" the console app simply writes out a message saying "The Printer is now Printing".
Now what i'm having difficulties with is making this program keep checking the status of printer .. I'm not so sure what loop i have to use and how i can apply it. Please see below for more information:
public static void getPrintJob()
{
string printerName = "Some Printer Name";
string query = string.Format("SELECT * from Win32_Printer WHERE Name LIKE '%{0}'", printerName);
ManagementObjectSearcher searcher = new ManagementObjectSearcher(query);
ManagementObjectCollection coll = searcher.Get();
foreach (ManagementObject printer in coll)
{
if (Convert.ToInt32(printer.Properties["PrinterStatus"].Value) == 4)
{
Console.Write("Printer is Printing");
}
What kind of loop could i put above for this program to continuously keep on checking the the printer status? and whenever the status changes to 4 (printing status on the printer i'm targeting ).

If you want this to run forever, a while loop will work:
public static void getPrintJob()
{
string printerName = "Some Printer Name";
string query = string.Format("SELECT * from Win32_Printer WHERE Name LIKE '%{0}'", printerName);
ManagementObjectSearcher searcher = new ManagementObjectSearcher(query);
while(true)
{
ManagementObjectCollection coll = searcher.Get();
var alreadyPrinting = false;
foreach (ManagementObject printer in coll)
{
if (Convert.ToInt32(printer.Properties["PrinterStatus"].Value) == 4 && !alreadyPrinting)
{
Console.Write("Printer is Printing");
alreadyPrinting = true;
}
else
{
alreadyPrinting = false;
}
}
Thread.Sleep(1000);
}
}
As RB pointed out in the comments, Thread.Sleep(1000) will pause the loop for 1 second and stop it consuming all the CPU resource.
EDIT:
updated after comments.
Added a bool to track if the printer was already printing. This stops the code writing to the console for as long as the printer is printing. Multiple printers can start and will write to the console. But only once per print job.
Moved the coll variable assignment inside the while loop.

Job Results From LocalPrintServer GetPrintQueue Are In Wrong Order

I use the following routine to get my printer queue jobs. For some reason they seem to be in the wrong order...
Routine To Get List Of Printer Jobs:
private List<string> GetPrinterQueueJobs(string targetPrinterName)
{
List<string> jobs = new List<string>();
string unc = null;
string printerName = targetPrinterName;
if (printerName.Contains("\\"))
{
string[] printerNameParts = printerName.Split('\\');
unc = printerNameParts[0];
printerName = printerNameParts[1];
}
PrintQueue printQue = null;
if (unc == null)
{
//local printer
printQue = new LocalPrintServer().GetPrintQueue(printerName);
}
else
{
//remote printer
printQue = new PrintServer(unc).GetPrintQueue(printerName);
}
foreach (PrintSystemJobInfo queItem in printQue.GetPrintJobInfoCollection())
{
jobs.Insert(queItem.PositionInPrintQueue - 1, queItem.Name);
}
return jobs;
}
Usage Of Routine:
private void cbPrinters_SelectedIndexChanged(object sender, EventArgs e)
{
List<string> printers = GetListOfPrinters();
ComboBox cb = (ComboBox)sender;
string printerName = cb.Text;
if (printers.Contains(printerName))
{
List<string> printerQue = GetPrinterQueueJobs(printerName);
foreach (string queItem in printerQue)
{
ListViewItem lvi = new ListViewItem(queItem);
lvPrintQueue.Items.Add(lvi);
}
}
}
This is what the Windows Print Queue looks like:
This is what my results look like:
As you can see in this case they are inverted. The crazy thing is, when stepping through the routine I also check the "PositionInPrintQueue" property and it seems to think the jobs are actually in the order shown in my returned results.
Why is this happening? Does anyone have any ideas on how I can get them to be returned in the correct order?
Thanks!

It turns out that the Windows Printer Queue was not showing the items in order! By default it does not show you the order of the jobs! There is no type of "Queue Id", "Queue Index" or "Job Order" column in the Windows Printer Queue. When looking at the jobs, you can sort by job name, status, owner, pages, size, port, and submitted.
If you sort by submitted they should all match the results returned in the GetPrintJobInfoCollection() method. But in the end, don't trust the Windows Printer Queue for job order, trust the order returned in the GetPrintJobInfoCollection() method.

Performance Counter Instance Name vs. Process Name

I am connecting to various performance counters in the Process category. I am using the following c# method to determine the instance name to use when acquiring the counters:
private const string _categoryName = "Process";
private const string _processIdCounter = "ID Process";
public static bool TryGetInstanceName(Process process, out string instanceName)
{
PerformanceCounterCategory processCategory = new PerformanceCounterCategory(_categoryName);
string[] instanceNames = processCategory.GetInstanceNames();
foreach (string name in instanceNames)
{
using (PerformanceCounter processIdCounter = new PerformanceCounter(_categoryName, _processIdCounter, name, true))
{
if (process.Id == (int)processIdCounter.RawValue)
{
instanceName = name;
return true;
}
}
}
instanceName = null;
return false;
}
Now, I have noticed that the instance name returned usually matches the value of Process.ProcessName.
How are the instance name and process name related?
I ask because I want to simplify the foreach loop in the routine so that I do not have to acquire the ID Process counter for instances that cannot match the current process. I envision a final method that might look like this:
public static bool TryGetInstanceName(Process process, out string instanceName)
{
PerformanceCounterCategory processCategory = new PerformanceCounterCategory(_categoryName);
string[] instanceNames = processCategory.GetInstanceNames();
foreach (string name in instanceNames)
{
if (name /* more or less matches */ process.ProcessName)
{
using (PerformanceCounter processIdCounter = new PerformanceCounter(_categoryName, _processIdCounter, name, true))
{
// ...
}
}
}
instanceName = null;
return false;
}

Seeing that an answer was not forthcoming, I did some more trial and error testing and observed the following behaviour:
Regular Processes
It appears that, for the first regular process with a given name, the process name matches the instance name. For subsequent processes with the same name, the instance name is modified by appending #1, #2, ...
Alarmingly, it also appears to be possible for the instance name associated with the process to change. This appears to happen when processes earlier in the numeric sequence end. There is a race-condition between determining the instance name and acquiring the relevant counters!
Service Processes
Windows NT Services running under the Service Control Manager appear to behave in the same way that regular processes behave. The instance name also appears to change if you end a service-process earlier in the numeric sequence.
ASP.NET Applications
The same assumptions work for applications hosted under IIS except that the process name is w3wp. Different app. pools definitely get different processes and, by starting and stopping app. pools, I ascertained that the instance name changes in the same way, under the same circumstances as above.
Conclusion
My conclusion is that the instance name always starts with the process name and the method can be modified as follows:
public static bool TryGetInstanceName(Process process, out string instanceName)
{
PerformanceCounterCategory processCategory = new PerformanceCounterCategory(_categoryName);
string[] instanceNames = processCategory.GetInstanceNames();
foreach (string name in instanceNames)
{
if (name.StartsWith(process.ProcessName))
{
using (PerformanceCounter processIdCounter = new PerformanceCounter(_categoryName, _processIdCounter, name, true))
{
if (process.Id == (int)processIdCounter.RawValue)
{
instanceName = name;
return true;
}
}
}
}
instanceName = null;
return false;
}
Additionally, it is vitally important that one acknowledges the presence of the race-condition mentioned above when using the instance name returned.
(In the absence of further input, I will accept this as an answer. Feel free to correct me.)

Also note that if you are monitoring muliple instances of the same process then the instance naming isn't consistent across different categories. So the solution given above only works if you are pulling counters from the same category that the pid was was pulled from. I did find the pid was in some other categores - but not all - and not with consistent naming.

Wouldn't this solution be a little bit faster:
public static bool TryGetInstanceName(Process process, out string instanceName)
{
PerformanceCounterCategory processCategory = new PerformanceCounterCategory(_categoryName);
string processName = Path.GetFileNameWithoutExtension(process.ProcessName);
string[] instanceNames = processCategory.GetInstanceNames()
.Where(inst => inst.StartsWith(processName))
.ToArray();
foreach (string name in instanceNames)
{
using (PerformanceCounter processIdCounter = new PerformanceCounter(_categoryName, _processIdCounter, name, true))
{
if (process.Id == (int)processIdCounter.RawValue)
{
instanceName = name;
return true;
}
}
}
instanceName = null;
return false;
}
(Copied from Rick Strahl's blog and modified a bit).
Nevertheless, you need to take care: If there a multiple processes with the same name and one of them exits, the naming of all of them changes:
One thing to mention related to windows process instance names is that they change dynamically when one of the processes exits.
For example if chrome#8 exits, chrome#9 will become chrome#8 and chrome#10 >will become chrome#9. At this point getting the value of the counter >previously created for chrome#10 will throw an exception. This
is really annoying if you want to to monitor multiple instances of
multiple processes as it gets down to monitoring process exits and
recreating all the counters (really ugly).
One way would be to change the way process instance names are generated >(see http://support.microsoft.com/kb/281884) but this has
the potential of affecting other apps using the perfmon api.

Is it possible to check if a Mutex is created by using wildcards?

For example my application creates mutex's like so:
MyApplication\\{UserName}
and then my updater program (that updates this application) needs to check whether this has been created or not but it doesn't know the username.
I have the code:
string mutexString = "MyApplication\\User1"
bool isNew;
var mutex = new Mutex(true, mutexString , out isNew);
if(isNew)
{
//Run my program
}
This works fine if I know the username but I would like to know if it is possible for this to work with wildcards?

So from the comments I get the sense that this is impossible so a better solution might be to check the running processes which I achieved like so:
foreach (var process in Process.GetProcesses())
{
if (process.MainWindowTitle.IndexOf("MyApp",StringComparison.InvariantCultureIgnoreCase) >= 0)
{
isNew = false;
}
}

Is there a way to check if a printing process was successful?

I have an application where I need to print a ticket. Each ticket must be unique. The application is windows forms and written entirely in c#. For our application we're using Samsung ML- 2525 laser monochromatic printers.
The flow is basically the following, the operator picks a product/ticket (which is unique) and then it presses a button that does 2 things:
Connects to a database and updates the product as used
Prints the ticket (this is done using System.Drawing and GDI+)
For some reason, every once in a while, the image that needs to be printed is not sent to the printer. It's a rare case, but it happens.
I tried to connect to the printer using Win32_Printer ( http://msdn.microsoft.com/en-us/library/Aa394363 ) but I can't get to get the current printer's state (online, offline, low toner, paper jam, etc). I can only check if the printer exists and that the paper size is installed correctly. I tried code similar to the following but it didn't work
private string MonitorPrintJobWmi()
{
var jobMessage = String.Empty;
var scope = new ManagementScope(ManagementPath.DefaultPath);
scope.Connect();
var selectQuery = new SelectQuery { QueryString = #"select * from Win32_PrintJob" };
var objSearcher = new ManagementObjectSearcher(scope, selectQuery);
var objCollection = objSearcher.Get();
foreach (var job in objCollection)
{
if (job != null)
{
jobMessage += String.Format("{0} \r\n", job["Name"].ToString());
jobMessage += String.Format("{0} \r\n", job["JobId"].ToString());
_jobId = Convert.ToInt32(job["JobId"]);
jobMessage += String.Format("{0} \r\n", job["JobStatus"].ToString());
jobMessage += String.Format("{0} \r\n", job["Status"].ToString());
}
}
return jobMessage;
}
I tried to get an API for the printer but I couldn't get a hold of it. By the way, the printer's software do indicate different errors in the windows toolbar.
My question is if anyone can lead me in the right direction as to how to connect to a printer and check if printing was successful.
Also, it would be helpful if someone know of some other specific printer in which I may accomplish this ie, changing hardware.
Thanks,

To get a list of print queues on the local machine, try PrintServer's GetPrintQueues method.
Once you have an instance of the PrintQueue object associated with the relevant printer, you can use it to access the printer's status (IsOffline, IsPaperOut, etc.). Also, you can use it to get a list of the jobs in the given queue (GetPrintJobInfoCollection) which then will allow you to get job-specific status information (IsInError, IsCompleted, IsBlocked, etc.).
Hope this helps!

After try to print your PrintDocument (System.Drawing.Printing), try to check status of printjobs.
First step: Initialize your printDocument.
Second step: Get your printer Name From System.Drawing.Printing.PrinterSettings.InstalledPrinters.Cast<string>();
And copy it into your printerDocument.PrinterSettings.PrinterName
Third step: Try to print and dispose.
printerDocument.Print();
printerDocument.Dispose();
Last step: Run the check in a Task (do NOT block UI thread).
Task.Run(()=>{
if (!IsPrinterOk(printerDocument.PrinterSettings.PrinterName,checkTimeInMillisec))
{
// failed printing, do something...
}
});
Here is the implementation:
private bool IsPrinterOk(string name,int checkTimeInMillisec)
{
System.Collections.IList value = null;
do
{
//checkTimeInMillisec should be between 2000 and 5000
System.Threading.Thread.Sleep(checkTimeInMillisec);
// or use Timer with Threading.Monitor instead of thread sleep
using (System.Management.ManagementObjectSearcher searcher = new System.Management.ManagementObjectSearcher("SELECT * FROM Win32_PrintJob WHERE Name like '%" + name + "%'"))
{
value = null;
if (searcher.Get().Count == 0) // Number of pending document.
return true; // return because we haven't got any pending document.
else
{
foreach (System.Management.ManagementObject printer in searcher.Get())
{
value = printer.Properties.Cast<System.Management.PropertyData>().Where(p => p.Name.Equals("Status")).Select(p => p.Value).ToList();
break;
}
}
}
}
while (value.Contains("Printing") || value.Contains("UNKNOWN") || value.Contains("OK"));
return value.Contains("Error") ? false : true;
}
Good luck.