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I am working on a project right now that involves receiving a message from another application, formatting the contents of that message, and sending it to a printer. The technology of choice is C# windows service. The output could be called a report, I suppose, but a reporting engine is not necessary. A simple templating engine, like StringTemplate, or even XSLT outputting HTML would be fine. The problem I'm having is finding a free way to print this kind of output from a service. Since it seems that it will work, I'm working on a prototype using Microsoft's RDLC, populating a local report and then rendering it as an image to a memory stream, which I will then print. Issues with that are:
Multi-page printing will be a big headache.
Still have to use PrintDocument to print the memory stream, which is unsupported in a Windows Service (though it may work - haven't gotten that far with the prototype yet)
If the data coming across changes, I have to change the dataset and the class that the data is being deserialized into. bad bad bad.
Has anyone had to do anything remotely like this? Any advice? I already posted a question about printing HTML without user input, and after wasting about 3 days on that, I have come to the conclusion that it cannot be done, at least not with any freely available tool.
All help is appreciated.
EDIT: We are on version 2.0 of the .NET framework.
Trust me, you will spend more money trying to search/develop a solution for this as compared to buying a third party component. Do not reinvent the wheel and go for the paid solution.
Printing is a complex problem and I would love to see the day when better framework support is added for this.
Printing from a Windows service is really painful. It seems to work... sometimes... but finally it craches or throws an exception from time to time, without any clear reason. It's really hopeless. Officially, it's even not supported, without any explanation, nor any proposal for an alternate solution.
Recently, I have been confronted to the problem and after several unsuccessful trials and experimentations, I came finally with two viable solutions:
Write your own printing DLL using the Win32 API (in C/C++ for instance), then use it from your service with P/Invoke (works fine)
Write your own printing COM+ component, then uses it from your service. I have chosen this solution with success recently (but it was third party COM+ component, not own written) It works absolutely fine too.
I've done it. It's a pain in the A*s. The problem is that printing requires that GDI engine to be in place, which normally means that you have to have the desktop, which only loads when you're logged in. If you're attempting to do this from a Service on a Server, then you normally aren't logged in.
So first you can't run as the normal service user, but instead as a real user that has interactive login rights. Then you have to tweak the service registry entries (I forget how at the moment, would have to find the code which I can do tonight if you're really interested). Finally, you have to pray.
Your biggest long term headache will be with print drivers. If you are running as a service without a logged in user, some print drivers like to pop up dialogs from time to time. What happens when your printer is out of toner? Or out of paper? The driver may pop up a dialog that will never be seen, and hold up the printer queue because nobody is logged in!
To answer your first question, this can be fairly straight forward depending on the data. We have a variety of Service-based applications that do exactly what you are asking. Typically, we parse the incoming file and wrap our own Postscript or PCL around it. If you layout is fairly simple, then there are some very basic PCL codes you can wrap it with to provide the font/print layup you want (I'd be more then happy to give you some guidance here offline).
One you have a print ready file you can send it to a UNC printer that is shared, directly to a locally installed printer, or even to the IP of the device (RAW or LPR type data).
If, however, you are going down the PDF path, the simplest method is to send the PDF output to a printer that supports direct PDF printing (many do now). In this case you just send the PDF to the device and away it prints.
The other option is to launch Ghostscript which should be free for your needs (check the licensing as they have a few different version, some GNU, some GPL etc.) and either use it's built in print function or simply convert to Postscript and send to the device. I've used Ghostscript many times in Service apps but not a huge fan as you will basically be shelling out and executing a command line app to do the conversion. That being said, it's a stable app that does tend to fail gracefully
Printing from a service is a bad idea. Network printers are connected "per-user". You can mark the service to be run as a particular user, but I'd consider that a bad security practice. You might be able to connect to a local printer, but I'd still hesitate before going this route.
The best option is to have the service store the data and have a user-launched application do the printing by asking the service for the data. Or a common location that the data is stored, like a database.
If you need to have the data printed as regular intervals, setup a Task event thru the Task Scheduler. Launching a process from a service will require knowing the user name and password, which again is bad security practice.
As for the printing itself, use a third-party tool to generate the report will be the easiest.
This may not be what you're looking for, but if I needed to do this quick&dirty, I would:
Create a separate WPF application (so I could use the built-in document handling)
Give the service the ability to interact with the desktop (note that you don't actually have to show anything on the desktop, or be logged in for this to work)
Have the service run the application, and give it the data to print.
You could probably also jigger this to print from a web browser that you run from the service (though I'd recommend building your own shell IE, rather than using a full browser).
For a more detailed (also free) solution, your best bet is probably to manually format the document yourself (using GDI+ to do the layout for you). This is tedious, error prone, time consuming, and wastes a lot of paper during development, but also gives you the most control over what's going to the printer.
If you can output to post script some printers will print anything that gets FTPed to a certain directory on them.
We used this to get past the print credits that our university exposed on us, but if your service outputs to a ps then you can just ftp the ps file to the printer.
We are using DevExpress' XtraReports to print from a service without any problems. Their report model is similar to that of Windows Forms, so you could dynamically insert text elements and then issue the print command.
I think we are going to go the third party route. I like the XSL -> HTML -> PDF -> Printer flow... Winnovative's HTML to PDF looks good for the first part, but I'm running into a block finding a good PDF printing solution... any suggestions? Ideally the license would be on a developer basis, not on a deployed runtime basis.
In answer to your question about PDF printing, I have not found an elegant solution. I was "shell" ing out to Adobe which was unreliable and required a user to be logged in at all times. To fix this specific problem, I requested that the files we process (invoices) be formatted as multi-page Tiff files instead which can be split apart and printed using native .NET printing functions. Adobe's position seems to be "get the user to view the file in Adobe Reader and they can click print". Useless.
I am still keen to find a good way of producing quality reports which can be output from the web server...
Printing using System.Drawing.Printing is not supported by MS, as per Yann Trevin's response. However, you might be able to use the new, WPF-based, System.Printing (I think)
Related
I'm looking for the best way to achieve the following workflow.
Ask a series of questions
Captured the responses
Use the answers captured to either hide or show certain aspects of word document.
Save the complete word document to a location (TBD).
I'm not a developer, so will need to source one who could pick this up, but before I do I wanted to know the best approach to this workflow.
Appreciate any feedback you can offer.
Cheers
There are several libraries for interacting with Word (.docx) documents in C#, such as NPOI and DocX, and it is not theoretically complicated to programatically populate a document based on user input and some decision tree and then save it somewhere locally or expose it for download via a web interface. But, keep in mind, that's only part of the solution -- apps have to be hosted, secured, monitored, etc., and that's where the "hard" part is likely to be.
If you are looking to accomplish this within an enterprise environment that uses Microsoft Office 365, you may not need a developer at all. Microsoft Flow / Microsoft PowerAutomate allows you to produce complex workflows such as the one you described. There's a very similar one listed here:
https://flow.microsoft.com/en-us/galleries/public/templates/3c651e28cded46aab2ba40a2c3116f30/create-word-and-pdf-documents-from-microsoft-forms/
I have some code that prints a document using the System.Drawing.Printing namespace. This now needs to be moved into a windows service. The documentation states that this is not possible, which would support my findings so far (in that it doesn't work). I'm working under the assumption that I can get this to work by using the System.Printing namespace instead.
Here is the code that I have so far:
private Metafile myDoc;
myDoc = GetEmfDoc();
PrintServer ps = new PrintServer("\\server1\printer1");
EnumeratedPrintQueueTypes[] flags = { EnumeratedPrintQueueTypes.Local };
PrintQueueCollection queues = ps.GetPrintQueues(flags);
PrintQueue pq = queues.First<PrintQueue>();
pq.AddJob("JobName", ?);
So I want to pass myDoc to pq.AddJob(), but this doesn't seem to be possible. Using System.Drawing.Printing it was possible to simply render this on a page by page basis in the PrintDocument.PrintPage event.
Is what I'm trying to do possible, and if so, could someone point me in the right direction?
Classes within the System.Drawing.Printing namespace are not supported for use within a Windows service or ASP.NET application or service. Attempting to use these classes from within one of these application types may produce unexpected problems, such as diminished service performance and run-time exceptions.
It is important to understand what "not supported" means in this context. It literally means what it says, it you try to print from a service and discover a problem then you cannot call Microsoft Support and ask for help.
This is not a problem that's induced by System.Drawing, it is a generic problem with printer drivers. Chunks of code that are supplied by the printer manufacturer, not Microsoft. A significant problem with them is that they are invariably designed to be used from a desktop program. Word, Acrobat, etcetera. They readily take advantage of that, they often pop up a window to let you know that they are Working On It. Not in the least to spam the manufacturer name and reminding you that the toner cartridge is half empty. These drivers are likely to misbehave in a service. The "runtime exceptions" phrase mentioned in the note.
The worst problem with them is that they use a popup window to let you know that there's a problem. These windows are not visible when you use the printer driver from a service. So you'll have to deal with print jobs that for no discernible reason refuse to print. The "diminished service performance" phrase in the note. That's very difficult to deal with, IT staff is just powerless to have a shot at fixing the problem when they can't see any diagnostic.
Your approach doesn't solve that fundamental problem. If you really want to pursue this then contact the printer manufacturer and ask for specific advise. Don't get your hopes up, getting good answers out of hardware companies is pretty difficult.
This is a combination of permission issues and Session 0 isolation...
The following might solve the problem you face although I do NOT recommend it:
IF you really want/need to make this work you will need to make a logon (beforehand!) to the remote server (in your example server1) from inside Session 0 (NOT from the "normal" user session) - either interactively (you can switch to the session 0 desktop via rundll32 winsta.dll,WinStationSwitchToServicesSession) OR via some calls (for example using WNetAddConnection2 with the proper credentials to the remote machine, unfortunately this is usable from .NET only via p/invoke or COM using WScript.Network). The credentials used for this logon need to have full permissions regarding printing on the remote machine.
Are you running your service in an account that has the necessary rights to use the printer? More details in the Windows Services FAQ.
I want to find a decent solution to track URLs and html content that users are visiting and provide more information to user. The solution should bring minimum impacts to end users.
I don't want to write plugins for different browsers. It's hard to maintain.
I don't accept proxy method, since I don't want to change any of user's proxy settings.
My application is writen in C# and targeting to Windows. It's best if the solution can support other OS as well.
Based on my research, I found following methods that looks working for me, but all of them have their drawbacks, I can't determine which one is the best.
Use WinPcap
WinPcap sniffers all TCP packets without changing any of user settings but only requires to install the WinPcap setup, which is acceptable to me. But I have two questions:
a. how to convert TCP packet into URL and HTML
b. Does it really impact the performance? I don't know if sniffer all TCP traffic is overhead for this requirment.
Find history files for different browsers
This way looks like the easist one, but I wonder if the solution is stable. I am not sure if the browser will stably write the history and when it writes to. My application will popup information before the user leave the current page. The solution won't work for me if browser writes to history file when user close the browser.
Use FindWindow or accessiblity object or COM interface to find the UI element which contains the URL
I find this way is not complete, for example, Chrome will only show the active tab's URL but not all of them.
Another drawback is that I have to request the URL another time to get its HTML content.
Any comment or suggestion is welcome.
BTW, I am not doing any spyware. The application is trying to find all RSS feeds from web page and show them to end users. I can easily do that in a browser plugin but I really want to support multiple broswers with single UI. Thanks.
Though this is very old post, I thought to just give an input.
Approach 1 of WinPcap is the best one. This will work for any browser, even builtin browser of any other installed application. The approach will be less resource consuming too.
There is a library Pcap.Net that has HTTP parser. You can construct http stream and use its httpresponsedatagram to parse the body that can be consumed by your application.
This link helped giving more insight to me -
Tcp Session Reconstruction with Winpcap
I was wondering if there is another way to spell check a Windows app instead what I've been of using: "Microsoft.Office.Interop.Word". I can't buy a spell checking add-on. I also cannot use open source and would like the spell check to be dynamic..any suggestions?
EDIT:
I have seen several similar questions, the problem is they all suggest using open source applications (which I would love) or Microsoft Word.
I am currently using Word to spell check and it slows my current application down and causes several glitches in my application. Word is not a clean solution so I'm really wanting to find some other way.. Is my only other option to recreate my app as a WPF app so I can take advantage of the SpellCheck Class?
If I were you I would download the data from the English Wiktionary and parse it to obtain a list of all English words (for instance). Then you could rather easily write at least a primitive spell-checker yourself. In fact, I use a parsed version of the English Wiktionary in my own mathematical application AlgoSim. If you'd like, I could send you the data file.
Update
I have now published a parsed word list at english.zip (942 kB, 383735 entries, zip). The data originates from the English Wiktionary, and as such, is licensed under the Creative Commons Attribution/Share-Alike License.
To obtain a list like this, you can either download all articles on Wiktionary as a huge XML file containing all Wiki- and HTML-formatted articles. This is then more or less trivial to parse. Alternatively, you can run a bot on the site. I got help to obtain a parsed file from a user at Wiktionary (I seem to have forgotten his name, though...), and this file (english.txt in english.zip) is a further processed version of the file I got.
http://msdn.microsoft.com/en-us/library/system.windows.controls.spellcheck.aspx
I use Aspell-win32, it's old but it's open source, and works as well or better than the Word spell check. Came here looking for a built in solution.
Is it possible to have an application built using the .NET speech recognition classes and pass in a WAV file for it to go through and create a text representation of it. For example, this what I'm trying to do:
We have a QA department at my office and they have to listen to hundreds of calls a day which is quite impossible, and there's not enough people listening to everything to keep up. What I want to do is have the audio file uploaded to our server and have the server parse it and create a transcript of it. It doesn't matter if it's not perfect, but just a base which would be easier to skim through a couple of dozen lines of text than listen to a 2 hour recording.
Based on a saved transcript I can implement full-text search in the database and also run checks against the transcript if someone is saying something that's a misrepresentation.
So, is it possible to create an application using the .NET speech recognition classes and just pass the WAV file to it and it spit out a rough transcript?
I've dug around MSDN on the Speech classes briefly while thinking up the idea, so I don't have that much knowledge if it's possible to be done.
If possible, I would appreciate any examples in C#. Topic 1055347 is similar to the question I'm having, and was provided links, the most specific of which is in C++. I'm not a C++ developer, nor have I ever went to school for programming, I'm all self though C#, so I would like to stay in the language that I know.
Thanks in advance!
This sounds like you've got a call center type of application. Microsoft Speech Server has a SR engine optimized for telephony (8000 Hz sample rate), which will generate much better recognitions than the desktop SR engine. However, the engine isn't really designed for transcription (although it can do it), and the transcriptions definitely need to be reviewed before further processing occurs. Microsoft Exchange Unified Communications uses the SR engine to generate transcripts of voice mail, and while it's better than nothing, it often generates amusing nonsense.
With areas like speech recognition you are likely to either find a stand alone EXE or an API in c/c++.
For the links in the other topic, you can use a tool like P Interop Assistant to generate C# code. The C# code acts like a wrapper around the unmanaged dll, so you can call it from c#.
This is likely to be the best way to get the functionality you are looking for.
Yes.
I did such an application a few years ago on the Tablet PC; you can read about it at http://web.archive.org/web/20060615192119/www.devx.com/TabletPC/Article/30761 (At the time, I spoke of using Interop to access the libraries, but I believe that the programming model has remained the same, just with a managed wrapper.)
At the time, the results were very poor, but maybe for your use-case better than nothing.
How about route the calls to Google Voice? I'm sure there are similar services. I have been amazed at its accuracy so far, plus you can click and listen to it if required. Google Voice will forward voice calls to SMS or email.
UPDATE: On reread, maybe since you are recording calls it won't work as I yous the voice message left.