I apologize for the length of the question, but I believe it is difficult to understand the “why” without the background.
Background: I have two applications running in a Windows Embedded Standard 7 environment. They should be the only two applications running on the machine. One, called “Controller”, is written in C++ the other, “DBconnector”, is written in c#. This is not new code. It has been in active use and development for almost 20 years.
The purpose of the software is to run a manufacturing machine for producing parts. These machines are big and dangerous if the program crashes. Long ago, I discovered that if the network went down for some reason, all the threads in the application would stall – not just the network thread. This was disastrous since leaving the controller in a state with the wrong relays on in extremely rare circumstances could cause the machine to literally explode. Note: Several things have been added to the software and hardware to prevent this now. While this danger doesn’t really exist anymore, stability is still extremely important. I never want the operator to be stuck in a state where they can’t hit the reset button. My solution at the time was to move the networking tasks into a separate application. The OS was windows XP based at the time. I have no idea if the problem still exists in windows 10 since I really don’t want to rewrite hundreds of thousands of lines of code to try and merge the two programs now.
The development of the two programs diverged such that the one that controlled the machine, Controller, was designed for extreme stability and the other, DBconnector, was where dangerous things like networking and most file I/O happened. Communication between the two programs is facilitated using a memory mapped file that they both can access. I have no problem sharing window handles or process id’s or any other data that might be needed between the two programs.
Here is my question. How can I make the Controller application display the GUI of DBconnector? For example, I have started to add functionality to Controller that requires DBconnector to display the quality control sheets that are held on a web site on company servers. I want for an operator to be able to pull up the quality control sheet directly on the machine. The operator currently only interacts with the Controller application. I don’t want Controller to be able to access the network. Also, C# has some tools to make displaying a web page easy. It seems to me that the place to do this is DBconnector. The problem is that DBconnector runs in the background and cannot currently be seen or accessed by a user. So, the question is how to solve this.
First option I have tried is to tell DBconnector to come forward and put Controller in the background. Then, when the user is done, Controller comes back to the front. I have made this to work using some hacks, but it is inconsistent. The trick I used was to minimize and then maximize DBconnector which seems to bring it to the front most of the time and try to hold focus on one or the other. There still might be a way to do it this way, but it needs to be something that is consistent.
The second option is to run the DBconnector application inside of one of Controller’s windows. I have no idea how to do this. I thought about using ATL or COM, but I think these run as threads within Controllers process rather than as a separate application.
The third option I’ve considered is to create a window inside Controller that intercepts and passes all user input messages directly to Dbconnector using a windows message handle and takes a screenshot of DBconnector whenever the it is invalidated and passes it through the memory mapped file. Currently, this is what I am swaying towards.
Are there any suggestions on how to do the first and last option better, or how to do the second option at all, or another solution that I have missed? Keep in mind that our current hardware is running Windows Embedded Standard 7. The project is currently in visual studio 2015. The C++ window technology is MFC implemented using libraries originally from around 2003 I think. DBconnector is in .NET framework 4 in C#.
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I am a software engineer intern for a manufacturing company and they want me to develop an application for the company. They are leaning towards a web application however, I wish to know whether a desktop application would better fit the job. Therefore, I have been googling and looking through stackoverflow to find out what the pros and cons between desktop applications and web applications are. The following is essentially what I found:
Quick disclaimer, I have background in C# and WPF so I am a bit biased as it would be easier for me to develop a desktop application. I have no web experience so there is nothing I can really talk about in that area which is why I wish to know more about whether this application is better suited as a web application or desktop application. I am absolutely open to learning Php and web development to expand my abilities. I have started (a bit) looking into developing the web application using Php7 with Laravel framework.
Pros of desktop applications:
Typically faster than Web Applications (Assuming web application will perform complex queries, calculations, etc, and not just display markups)
Development of GUIs is faster
More secure as desktop applications are private by default.
There are more available controls allowing for a more rich and interactive experience for user (Or at least, these controls are easier/faster to implement on desktop based applcations compared to a web-based application)
Can take advantage of user hardware.
Cons of desktop applications:
Use/deployment is limited by system (However, this should not be a problem because all our systems are Windows based.)
Updates and installation must be manually implemented.
If every client desktop gets a database connection, scaling is not
good as database suffers from heavy load. (However, this probably
will not be the case since we won't have more than 500 users).
Pros of web application
Cross platform (No need to deal with different operating systems) so it is easily portable
Development is quick and easy
Deployment is easy as updates are automatic and server side.
Large community support and available frameworks.
Cons of web application
Larger overhead (Applications tend to be slower due to need to transmit data across the internet).
Need to deal with different browsers. Javascript most likely needs to be tweaked to be perfect on one web platform (Chrome, Firefox, etc) and will not be perfect on the others. (However, this is not that big of a deal).
Security is an issue since data will be public.
Please let me know if any of the above is outdated (most of the posts I found were from 2011 or prior) or wrong. Also, if there is any other pro/con to consider.
Moving on to the application description....
Background on the company: We build and process dozens of different parts every day. For each type of part, after X amount of the part is processed, a sample needs to be taken for inspection. So for example, part Y has 3 samples taken every 120 minutes to be inspected (Because the machine typically finishes processing X amounts in 120 minutes). The inspection results (measurement data) are then stored in the database (MySQL database).
General summary of the application's purpose:
View the schematics of all the parts we design (We store all the schematics as pdfs on a network drive, so this is simply just pulling up the specific pdf requested from the drive and displaying it onto the application).
View/update the status of all the machines in the company (What parts are they working on, are they online/offline, etc). A certain user (Inspector) will use this application to update machine status/information. Then another user (Operator) will use the application to view the statuses.
Monitor part inspections. So, for every machine and part being processed, there will be a timer to let a Operator user know when a certain part needs to be submitted for inspection. Upon part submission, an inspector will then receive a notification to inspect the part, and after letting the application know that they completed the inspection, the timer will restart to let the operator know whens the next time they need to submit a part.
The application will calculate statistical data (For example, Cpk values) from the part measurements obtained from inspection results and display the statistical data along with a graph/chart.
I hope I explained all of this clearly enough. Some other things to note, from my understanding, the users will not need remote access. This application will pretty much only be used on company site. Also, the original reason that the company wanted a web application was because operators will be using a tablet for the application and the tablets they acquired were original android based. However, they decided to switch to using Windows Surface tablets so WPF applications are now a possibility.
With all of this being said, I am really looking for input on what route people with more experience would recommend. I am still in college so please forgive my lack of knowledge/experience. What else should I be thinking about when deciding between a web application and desktop application?
Here are some of the pages I have seen while pondering this topic:
Advantages of web applications over desktop applications
https://www.quora.com/How-much-different-is-it-to-build-a-web-application-vs-a-desktop-application
https://www.quora.com/What-are-the-advantages-and-disadvantages-of-web-based-application-development-vs-desktop-application-development
There were more stackoverflow pages but the one listed above pretty much has everything that the other pages stated.
EDIT: Seems like web-application is winning so far (Not that I mind at all, I am actually excited to develop a web-application based off what I am hearing). Is there anyone who would rather do a desktop application? If so, why?
I'm inherently biased against web apps. They're difficult to get right due to browsers, they're typically insecure (by accident though). The platform sucks (JavaScript and the bazillion libraries from random people/orgs), "everything is a string". I could go on.
However it's undeniably the best platform for reaching a wide, public audience and allowing continual updates.
In a corporate environment the advantages do tend to go away, but not entirely. Updates, for example can be achieved generally by storing all your .exe & DLLs in a shared directory. As you say, you can build a much richer UI quicker and cheaper using the Windows platform.
With regards to your architecture, something that has worked for me in a similar situation is to have a Windows front end, but also have the guts of the business logic, data access (connection pooling) and processing off on a stateless web server (or two) accessed from the UI via Web Services (protocol of your choice - I prefer SOAP due to WCF and WSDL but plenty of folks won't).
This allows for centralised data access and a place to put your one-off batch jobs or calculations that can then be shared. It also has the advantage that if you need to do something really intensive, not every client machine has to have that capability.
Your situation seems to fit this model but without a lot of insider knowledge it's primarily opinion, but possibly one to consider.
Sounds like assembling or similar company work proccess monitoring to me.
If i have to build this application then first i will search and do some research if the function you want is possible and easy to develop with the programming language you will use
for example, if i choose to develop using web based then :
Larger overhead (Applications tend to be slower due to need to
transmit data across the internet).
you can use intranet and good spec server computer
Need to deal with different browsers. Javascript most likely needs to
be tweaked to be perfect on one web platform (Chrome, Firefox, etc)
and will not be perfect on the others. (However, this is not that big
of a deal).
then set the standard browser for working in your workplace
View the schematics of all the parts we design (We store all the
schematics as pdfs on a network drive, so this is simply just pulling
up the specific pdf requested from the drive and displaying it onto
the application).
you can upload pdf to server and view it within browser using pdf viewer plugin like pdfjs or similar plugin
View/update the status of all the machines in the company (What parts
are they working on, are they online/offline, etc). A certain user
(Inspector) will use this application to update machine
status/information. Then another user (Operator) will use the
application to view the statuses
is the machine have ip ?
can i use ping function to the machine to determine the machine is online or not to ease the task ?
if not then what is the schedule of the inspector to inspect the machine ?
of course the inspector can login to the system then update the machine status manually using web application
Monitor part inspections. So, for every machine and part being
processed, there will be a timer to let a Operator user know when a
certain part needs to be submitted for inspection. Upon part
submission, an inspector will then receive a notification to inspect
the part, and after letting the application know that they completed
the inspection, the timer will restart to let the operator know whens
the next time they need to submit a part.
this one sounds like scheduling mechanics to ensure the quality, you can make a timer with jquery and using ajax to send notification to the operator with specific data about certain part that need to be inspected
The application will calculate statistical data (For example, Cpk
values) from the part measurements obtained from inspection results
and display the statistical data along with a graph/chart.
this one is depends on your statistic formula, you can use highchart plugin for this one
the second one after you ensure your choosen programming language able to accomplish the task you want is to design the database structure
Quote by Linus Torvalds :
"Bad programmers worry about the code. Good programmers worry about data structures and their relationships."
Have a nice day, good luck with deciding after give it some good thinking to avoid development problem in the future
So this is a weird one.
I created a WPF application using MahApps for the GUI. So far my testing indicates that the app works fine on several different machines. Of course this is not the case on the client's machine.
The client makes use of Terminal Services and Windows Server 2008R2. Several users can be logged into their own version of the server at anytime. The app starts up fine once or twice, but after a day or so, it no longer opens up.
The app doesn't show up in the Application tab of Task Manager, but its process can be seen to be running in Processes Tab of Task Manager.
To be honest, I'm completely stumped. I had a look at the event manager log and couldn't find anything indicative of a problem. (Of course I might have missed something). I saw another SO question suggesting to disable hardware acceleration, but I'm not if that would help.
Any and all ideas would be greatly appreciated.
EDIT:
I thought I might mention the only thing that helps is if we restart the client machine.
EDIT:
I think I have isolated the issue to integration with Twain (should probably have mentioned that as another possible factor). I think the Twain library (unmanaged code) somehow stalls without sending back an error. Disabling it has "fixed" the issue.
This somehow relates to Twain and multi-session setups. I'm almost sure of it.
First you can analyze the wait chain in Windows Resource Monitor to check if there are any resources the process is waiting for. (You can find more information about the wait chain here or here.)
If you don't find any viable suspects there, you can create a memory dump of the hanging process and analyze the call stacks. If you don't know how to create one, you can read about it here. If you want to use Windows Task Manager and your OS is 64-bit then please be aware that you need to use the same bitness of Task Manager as the application.
That is: If your application is 64-bit then you have to use C:\Windows\System32\taskmgr.exe and if it's 32-bit you have to use C:\Windows\SysWOW64\taskmgr.exe. If you forget this important step you'll just get an unusable dump full of gibberish.
After you got the memory dump you can either load it into WinDbg (using the same bitness as the application) or Visual Studio (best to use 2015 or later) and analyze the call stacks of all running threads.
You can download WinDbg here and read about the necessary WinDbg configuration here. For the list of all threads you need to use this SOS command.
If you need help in loading memory dumps into Visual Studio you can find more information here.
After you've looked at the call stacks you most definitely find the answer what is waiting on what resources and is thus preventing the shutdown or startup of the application. It can either be a classic deadlock or an external resource like writing/reading of a file or some other waiting without a timeout like accessing a database or an URL that can't be reached at the moment. And of course it can also be just an infinite loop - if it doesn't consume much CPU then perhaps with some kind of DoEvents in between.
And last but very not least: If you are really interested what can be analyzed if an application hangs you can read about an example analysis done by the absolutely awesome great Mark Russinovich here.
So for work they have me writing a simple program for tracking employee efficiency within their workflow (things like using keyboard shortcuts, window locations, how often they need to look stuff up). Currently we want to track the 'F5' key (brings up next work item), 'Alt+Tab' (changes windows), 'Ctrl+V' (paste), but may be expanded as they find there are more shortcuts or things they want to track.
Note We are on windows 7, and using c# to write the tracking program.
In order to do this I wrote a low-level hooking library to capture the chosen keystrokes, send off the message down the hook chain and then add a note to a db that the key was used. The hooking library works great in All web browsers and most normal programs (except we don't actually care about browsers so we ignore everything done in them).
The issue is that the application that they use for managing their work (the program we actually care about tracking) some how stops our hooks from hooking and I do not know how. The application in question is TA2000 Desktop.
I know that with the way hooks work if an application fails to call callnexthook() within the LowLevelHooksTimeout period that the system kills the hook. So figuring maybe TA2000 was just taking to long or something I bumped up the timeout to 30 seconds (yes I know this is significantly more time than a hook should even need) but this had no effect.
The next thing I tried was implementing a tracking system based on the Raw Input API. And once again the tracking tracks on browsers, Microsoft office, notepad, and all the other programs I opened except it still is unable to track key press in TA2000. This really surprised me because according to MSDN
An application does not have to detect or open the input device.
An application gets the data directly from the device, and processes the data for its needs
An application can distinguish the source of the input even if it is from the same type of device. For example, two mouse devices.
So if I am getting the data directly from the device how is TA2000 preventing me from also getting the key press?
The last thing I could think of trying was using dll injection on TA2000 to inject a hook. However this method seems risky because It is something neither I nor any other developer here has any experience with and the application we want to track is operation critical so messing it up can not happen and injecting code into its memory space seems like a good way to mess things up.
If someone could explain how TA2000 could be stopping me from tracking keystrokes and how to beat it or point me in a good direction I would be very appreciative.
p.s. This felt questionable as an appropriate question for the SO format but it also feels specific enough to be a viable question. So sorry if this is not a good question but I am at my wits end with this.
This financial software package is secured to prevent snooping. Running the key logging software as Administrator appears to fix this specific problem. The security was identified initially using Sysinternals' Process Explorer, which is a great starting point for unexpected problems like this.
I have a large-ish Winforms application written in C# which is periodically unresponsive. The issue seems to occur once the application has been use for an hour or so. Exact timings are difficult to gather as users often go off to work on something selse, get back to it and find it has become unresponsive.
I think a memory leak can be ruled out as I'm not seeing excessive memory usage (I've asked users to send a screenshot of the task manager and memory usagage is the same as I would see when the application is runnning normally)
Similarly, CPU usage is normal (single digit %)
As I've so far been unable to recreate the issue on mydevelopment PC I am planning on sitting next to one of the affected users and mirror every action the user performs in order to recreate this. (I'll be setting up a laptop to RDP in to my main PC)
Recreating the issue is one thing, but I'll need to find out what is actually going on in the application.
Could anyone tell me if running in debug mode (through visual studio) will be sufficient or will I need to do something different?
I've searched through a few posts and I've seen mention of profiling software, however I'm not sure if this would only help with general performance issues or memory management issues.
Alternatively, if anyone has come across similar freezing issues then do you have any suggestions of the kind of causes for this?
Some technical details: Aplication is C#, compiled against .NET 3.5, winforms GUI. There are a few external libraries (most significant is ComponentFactory Krypton Suite). Data access is to a Microsoft SQL Server 2005 database. The solution contains 39 projects, I'm not sure if that might have something to do with it?
Any suggestions/pointers would be greatly appreciated.
The application is working much more reliably now, freezing issues still occur on occasion but nowhere near as often as before.
The issue appears to be related to the endpoint security (in this case, Cisco Security Agent) present in the environment I'm working in, application has been whitelisted and has has significantly rediced the instances of application hangs. The development system I work on does not have this endpoint security present, so it didn't show up in early stages of testing.
Thanks for all your feedback, I think there are still threading and garbage collection issues that need cleaning up, hopefully this should sort out the last few issues.
I would like to be able to do an "inplace" update with my program. Basically, I want to be able to login remotely where the software is deployed, install it while other users are still using it (in a thin client way), and it update their program.
Is this possible without too much of a hassle? I've looked into clickonce technology, but I don't think that's really what I'm looking for.
What about the way firefox does it's updates? Just waits for you to restart the program, and notifies you when it's been updated.
UPDATE: I'm not remoting into the users' PC. This program is ran on a server, and I remote in and update it, the users run it directly off the server through remote access.
ClickOnce won't work because it requires a webserver.
I had some example code that I can't find right now but you can do something similar to Firefox with the System.Deployment.Application namespace.
If you use the ApplicationDeployment class, you should be able to do what you want.
From MSDN, this class...
Supports updates of the current deployment programmatically, and handles on-demand downloading of files.
Consider the MS APIs with BITS, just using bitsadmin.exe in a script or the Windows Update Services.
Some questions:
Are the users running the software locally, but the files are located on a networked share on your server?
Are they remoting into the same server you want to remote into, and execute it there?
If 2. are they executing the files where they are placed on the server, or are they copying them down to a "private folder"?
If you cannot change the location of the files, and everyone is remoting in, and everyone is executing the files in-place, then you have a problem. As long as even 1 user is running the program, the files will be locked. You can only update the files once everyone is out.
If, on the other hand, the users are able to run their own private copy of the files, then I would set up a system where you have a central folder with the latest version of the files, and when a user starts his program, it checks if the central folder has newer versions than the user is about to execute. If it does, copy the new version down first.
Or, if that will take too long, and the user will get impatient (what, huh, users getting impatient?), then having the program check the versions after startup, and remind the user to exit would work instead. In this case, the program would set a flag that upon next startup would do the copying, only now the user is aware of it happening.
The copying part would easily be handled by either having a separate executable that does the actual copying, and executing that instead, or the program could copy itself temporarily to another location and run that copy with parameters that says "update the original files".
While you can design your code to modify itself (maybe not in C#?), this is generally a bad idea. This means that you must restart something to get the update. (In Linux you are able to replace files that are in use, however an update does not happen until the new data is loaded into memory i.e. application restart)
The strategy used by Firefox (never actually looked into it) is storing the updated executable in a different file which is checked for when program starts to load. This allows the program to overwrite the program with the update before the resource is locked by the OS. You can also design you program more modular so that portions of it can be "restarted" without requiring a restart of the entire program.
How you actually do this is probably provided by the links given by others.
Edit:: In light of a response given to Lasse V. Karlsen
You can have your main program looking for the latest version of the program to load (This program wouldn't be able to get updates without everyone out). You then can remove older versions once people are no longer using it. Depending on how frequent people restart their program you may end up with a number of older programs versions.
ClickOnce and Silverlight (Out of browser) both support your scenario, if we talk about upgrades. Remote login to your users machine? Nope. And no, Firefox doesn't do that either as far as I can tell..
Please double-check both methods and add them to your question, explaining why they might not do what you need. Otherwise it's hard to move on and suggest better alternatives.
Edit: This "I just updated, please restart" thing you seem to like is one method call for Silverlight applications running outside of the browser. At this point I'm fairly certain that this might be the way to go for you.
ClickOnce doesn't require a webserver, it will let you publish updates while users are running the software. You can code your app to check for new update every few minutes and prompt the user to restart the app if a new version is found which will then take them through the upgrade process.
Another option is a Silverlight OOB application, but this would be more work if your app is already built as WinForms/WPF client app.
Various deployment/update scenarios (for .NET applications) are discussed with there pros and cons in Microsoft's Smart Client Architecture and Design Guide. Though a little bit old I find that most still holds today, as it is describing rather the basic architectural principles than technical details. There is a PDF version, but you find it online as well:
Deploying and Updating Smart Client Applications
Is this possible without too much of a hassle?
Considering the concurrency issues with thin clients and the complexity of Windows installations, yes hot updates will be a hassel without doing it the way the system demands.