I have a windows mobile application
I have noticed that it properly terminate on exiting, they simply minimize and take up memory. I need to cehck whether any instance of the same application is running in the taskmanager.If exists, i need to kill the process.
I need to write small app that would loop through all open application processes and terminate the required one.
Does such an application exist? If not, which onecould I use to write my own app for it?
Typically this is not how you solve this problem.
You should hold a 'mutex' in your application, and when it launches a second time, you first check this mutex, and if it's taken, you know your app is already running.
Find an appropriate global mutex to hold, and then check for it (I'm not sure what sort you can use on whatever version of Windows Mobile you are targetting, but a trivial search should help you find the answer).
If your app shows an [X] in the corner that's a Minimize button. Change the MinimizeButton property of the form and it will become an [ok] button which will close it.
The CF under Windows Mobile already enforces application singleton behavior. If the app is already running, the CF will look for it, find it, and bring it to the fore for you. No extra work needed.
If you really want to find the process and terminate it, that's done with the toolhelp API set. You can P/Invoke it or use the classes in the Smart Device Framework.
Related
I am using the UI Automation COM-to-.NET Adapter to read the contents of the target Google Chrome browser that plays a FLASH content on Windows 7. It works.
I succeeded to get the content and elements. Everything works fine for some time but after few hours the elements become inaccessible.
The (AutomationElement).FindAll() returns 0 children.
Is there any internal undocumented Timeout used by UIAutomation ?
According to this IUIAutomation2 interface
There are 2 timeouts but they are not accessible from IUIAutomation interface.
IUIAutomation2 is supported only on Windows 8 (desktop apps only).
So I believe there is some timeout.
I made a workaround that restarts the searching and monitoring of elements from the beginning of the desktop tree but the elements are still not available.
After some time (not sure how much) the elements are available again.
My requirements are to read the values all the time as fast as possible but this behavior makes a damage to the whole architecture.
I read somewhere that there is some timeout of 3 minutes but not sure.
if there is a timeout, is it possible to change it ?
Is it possible to restart something or release/dispose something ?
I can't find anything on MSDN.
Does anybody have any idea what is happening and how to resolve ?
Thanks for this nicely put question. I have a similar issue with a much different setup. I'm on Win7, using UIAutomationCore.dll directly from C# to test our application-under-development. After running my sequence of actions & event subscriptions and all the other things, I intermittently observe that the UIA interface stops working (about 8-10min in my case, but I'm heavily using the UIA interface).
Many different things including dispatching the COM interface, sleeping at different places failed. The funny revelation was I managed to use the AccEvent.exe (part of SDK like inspect.exe) during the test and saw that events also stopped flowing to AccEvent, too. So it wasn't my client's interface that stopped, but it was rather the COM-server (or whatever the UIAutomationCore does) that stopped responding.
As a solution (that seems to work most of the time - or improve the situation a lot), I decided I should give the application-under-test some breathing point, since using the UIA puts additional load on it. This could be a smartly-put sleep points in your client, but instead of sleeping a set time, I'm monitoring the processor load of the application and waiting until it settles down.
One of the intermittent errors I receive when the problem manifests itself is "... was unable to call any of the subscribers..", and my search resulted in an msdn page saying they have improved things on CUIAutomation8 interface, but as this is Windows8 specific, I didn't have the chance to try that yet.
I should also add that I also reduced the number of calls to UIA by incorporating more ui caching (FindAllBuildCache), as the less the frequency of back-and-forth the better it is for the uia. Thanks to the answer of Guy in another question: UI Automation events stop being received after a while monitoring an application and then restart after some time
When we deactivate a WP app, it can be tombstoned and terminated later by the OS. I need to save some unsaved app data to a persistent storage when the process is terminated, but not before this. Obviously, the Deactivated event cannot be used for this purpose as it is raised immediately when an app is moved to the background; the Close event is also not the event we need as it si not raised when the app process is terminated by the OS. Is there a special Windows Phone app event for that, something like Application_Terminated?
The problem is that the operating system only tombstones your app when it is under severe resource pressure. At the time it is not practical to wake up the app and run app code because it might risk whatever is currently in the foreground. This limitation exists on all modern mobile operating systems (Android, IOS included). This is just the cost of operating in a battery/resource friendly environment.
Having said that, it sounds like your backing store does not disambiguate between data the user "saved" and data that is just being cached until the user can finish the transaction. It would be useful to build the idea in. Think of it the way some of the smarter web sites on the internet now work. You can navigate away while you were in the middle of entering data and when you come back the site presents you with the partially filled form. The site understands that you weren't "done" but it respects the fact that you had provided some of the information you'd need to get "done".
What I'm saying here is that the problem is easily fixed by understanding and accommodating the way your users are likely to use the app. Thinking of your app like a web site (at least in this context) helps out things into perspective. Sorry about the longish answer. I hope it helps :)
There is no such event. You should save your state on Deactivated so that if the application is removed from memory (tombstoned) you can set yourself up again upon reactivation. If your problem is figuring out whether or not you need to restore state on Activated, check out the ActivatedEventArgs.IsApplicationInstancePreserved flag (http://msdn.microsoft.com/en-us/library/windowsphone/develop/microsoft.phone.shell.activatedeventargs.isapplicationinstancepreserved(v=vs.105).aspx). This flag tells you whether your app was tombstoned. If it wasn't, you can throw away the old state or overwrite it the next time you are deactivated.
I have the following piece of code which gets the list of installed printers into a combobox:
For Each s As String In Printing.PrinterSettings.InstalledPrinters
edtPrinter.Items.Add(s)
Next
However I have a problem with a single client install, probably with the spool service, where this iteration hangs and locks up my app. I can trigger the same "hang" in explorer by clicking on "Devices and Printers" in Control Panel on that particular computer. Restarting Spool32 causes the app to free up until the iteration is hit again.
Rather than fix their spooler problem, how best to implement some kind of timeout or otherwise prevent this call from freezing my app if there is a spooler problem? I can't really call this on a separate thread without difficulty - is there a better way to call this property without exposing my app to the freeze?
One possibility: Sometimes Windows crashes when accessing Windows printing functions on a machine with no printers installed. Make sure your client has at least one printer installed.
I'm writing a small Mac application (in Obj-C) which runs the following command:
system("killall Finder");
I wanted to see what would happen if I sandbox the app (as sandboxing will be required on June 01), and the app wouldn't work. I got the following response:
killall: warning: kill -TERM 6524: Operation not permitted
Is there any way to get around that? As in a specific entitlement to add or another way to run the command?
Thanks in advance.
Your app completely goes against the spirit of the sandbox, so there's almost no chance that the MAS reviewers will accept it. Also, you may be surprised at what "defaults write com.apple.finder" does from inside your sandbox—basically, nothing useful. You'll have to use a temporary exception entitlement to home-relative /Library/Preferences/com.apple.finder.plist, use some non-sandbox-affected API to get the path to home (e.g., getpwent()->pw_dir), and load and save the plist directly. And then you'll discover that there is no way to call on a non-child process from a sandboxed app, period, no way around it—and if you try to system killall, it ends up running inside the same sandbox as you, and therefore has the same limitations.
However, you asked a specific question as to whether there's a way around that system killall failing, and there are at least three (not counting holes in the sandbox which have either been plugged by 10.7.4 or will surely be plugged soon):
You can create a helper app that isn't sandboxed, that does the killall for you. The only two App Store-approved ways to do this are XPC and SMLoginItemSetEnabled. And you're not allowed to enable the helper without the user explicitly telling you to do so.
You can send Finder an Apple Event asking it to quit, instead of signaling it. The easiest way to do this is to execute the Applescript 'tell app "Finder" to quit'. At least for 10.7.3 and earlier, you'll need a temporary exception entitlement to send Apple Events to com.apple.finder. (There may be different mechanisms for future OS versions, but nobody can discuss them outside the NDA forums.)
You can send an Apple Event to some other process—like System Events—to kill Finder on your behalf.
And so on.
If you have a good reason you can still kill applications like this:
How can I terminate my app in a helper app with sanboxing enabled?
I have an application that needs to "poll" a webservice to see if the user has any new messages waiting. I have no control over the webservice so I cannot switch to a "push" mechanism, I'm stuck making a request every X number of seconds to see what's available.
I am using a System.Threading.Timer to make the request every so often, but am encountering a few problems. The biggest is that it stops running when the phone is sent into "standby" mode (screen off, but still able to get calls and email/txt notifications).
I'd really like it to behave like other background applications. What can I do to make it work without being too big of a drain on the battery?
Hate to answer my own question, but I was pointed to this, which was able to perform even when the device is asleep. Looks like it's working perfectly.
There's nothing you can do, AFAIK. Standby mode is meant to suspend the processor to save power, and there's no way your code can execute if the processor isn't running. There are things your application can do to prevent the device from going into standby mode, but this really isn't advisable at all.
Yep. Similar to how MusiGenesis has answered, you won't be able to do much without keeping the device up and running. Similar to how some phones will notify that "Game/App Running" and thus your battery is being slapped around.
What about writing an interface from your phone to leverage text messaging (which still works) and get it to send a text message to the web service? Would that be possible? I'm guessing that sort of method might also stop running, but I figure it's a thought?
I'm not sure about compact framework, but in Win32 there is WaitableTimer that can wake up computer from standby. It takes some native calls though as there's no wrapper in .Net.
Although you can't modify the webservice, you might be able to add a second "shadow" webservice in between your clients and the original webservice. The shadow webservice could poll the original webservice and then "push" anything it finds out to the PDAs.
I think you might still have the same problem, though. I've never done "push" from a webservice, but I think it's basically implemented by having the client make an initial call to a webservice method that takes a delegate to a method in the client, which the webservice then hangs onto. When the webservice needs to push something, it calls that delegate. If the client has gone into standby mode in the meantime, the attempt to call the delegate from the server will fail.