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dotnet compact framework : HttpWebRequest file download and progress bar update kills main thread
What is in your main thread that dies after the first run? Are you using
WIndows Application model (main form that is instantiated via Application.Run) or did you put together something of your own? If the MSDN article that you refer to is this one[1], are you following the model I use in that article or do you have something quite different? 1. http://msdn.microsoft.com/library/en-us/dnnetcomp/html/AutoUpdater.asp -- Alex Feinman --- Visit http://www.opennetcf.org [quoted text, click to view] "George Chatzigeorgiou" <bandit@e-spark.gr> wrote in message
news:%23E2tp$TDFHA.1084@tk2msftngp13.phx.gbl... > Hi all. > > I'm having this problem: > > My app , reads an xml file through Http , parses it for file version > differences with the local files, and starts downloading newer files. > This propably takes some time, so I want to show some progress information > to the user before he starts pressing every available button on the > device. I wish, that is. Because trying every available configuration and > combination but to no avail. Let me explain. > > Option 1: Create an HttpWebRequest, an HttpWebResponse, and start reading > blocks of data. After every block , update the progress bar. > Result: Not only the progress bar doesn't update (repaint, refresh is > somewhat chocked by the Read method ), but after the first download > finished, the main thread exits. I take care to close everything after the > end of the download, but the problem persists. > > Option 2: Use asynchronous transfer, and Control.Invoke for updates. > (same as the MSDN sample). > Result: Progress bar updates, but after the first operation is > completeted, guess what: main thread dies. Moreover there is no way to > control the operation (I need to replace the old file, but I wouldn't know > when the async. operation has finished....so option 3). > > Option 3: Use asynchronous operations, and ManualResetEvent singaling to > control the operation. > Result: If I try to Invoke, everything dies. If I don't Invoke (for > progress bar update), after the first operation has finished, the main > thread dies. > > It seems, that somehow, someone wants to delete a thread , and because no > other than the main thread is available, the app exits. I tries a really > big delay (like Thread.Sleep(1000000)) to give time to the next > webResponse to fire, and it worked until the next progress bar update > crashed everything again. > > I'm sure I'm doing something terribly wrong, an RTFM somewhere in the last > page or whatever. > Any ideas? > > Thanks in advance.
When you say the thread dies do you mean your application exits or it hangs?
If you share some code that replicates this problem we may have better ideas... A couple of results on a quick search may be of help: http://groups-beta.google.com/group/microsoft.public.dotnet.framework.compactframework/search?group=microsoft.public.dotnet.framework.compactframework&q=httpwebrequest+thread&qt_g=1&searchnow=Search+this+group For your scenario, the BackgroundWorker may be suitable (usually is when a background operation needs to report progress to the UI): http://www.danielmoth.com/Blog/2004/12/backgroundworker-for-cf-10.html Cheers Daniel -- http://www.danielmoth.com/Blog/ [quoted text, click to view] "George Chatzigeorgiou" <bandit@e-spark.gr> wrote in message
news:%23E2tp$TDFHA.1084@tk2msftngp13.phx.gbl... > Hi all. > > I'm having this problem: > > My app , reads an xml file through Http , parses it for file version > differences with the local files, and starts downloading newer files. > This propably takes some time, so I want to show some progress information > to the user before he starts pressing every available button on the > device. I wish, that is. Because trying every available configuration and > combination but to no avail. Let me explain. > > Option 1: Create an HttpWebRequest, an HttpWebResponse, and start reading > blocks of data. After every block , update the progress bar. > Result: Not only the progress bar doesn't update (repaint, refresh is > somewhat chocked by the Read method ), but after the first download > finished, the main thread exits. I take care to close everything after the > end of the download, but the problem persists. > > Option 2: Use asynchronous transfer, and Control.Invoke for updates. > (same as the MSDN sample). > Result: Progress bar updates, but after the first operation is > completeted, guess what: main thread dies. Moreover there is no way to > control the operation (I need to replace the old file, but I wouldn't know > when the async. operation has finished....so option 3). > > Option 3: Use asynchronous operations, and ManualResetEvent singaling to > control the operation. > Result: If I try to Invoke, everything dies. If I don't Invoke (for > progress bar update), after the first operation has finished, the main > thread dies. > > It seems, that somehow, someone wants to delete a thread , and because no > other than the main thread is available, the app exits. I tries a really > big delay (like Thread.Sleep(1000000)) to give time to the next > webResponse to fire, and it worked until the next progress bar update > crashed everything again. > > I'm sure I'm doing something terribly wrong, an RTFM somewhere in the last > page or whatever. > Any ideas? > > Thanks in advance.
Hi all.
I'm having this problem: My app , reads an xml file through Http , parses it for file version differences with the local files, and starts downloading newer files. This propably takes some time, so I want to show some progress information to the user before he starts pressing every available button on the device. I wish, that is. Because trying every available configuration and combination but to no avail. Let me explain. Option 1: Create an HttpWebRequest, an HttpWebResponse, and start reading blocks of data. After every block , update the progress bar. Result: Not only the progress bar doesn't update (repaint, refresh is somewhat chocked by the Read method ), but after the first download finished, the main thread exits. I take care to close everything after the end of the download, but the problem persists. Option 2: Use asynchronous transfer, and Control.Invoke for updates. (same as the MSDN sample). Result: Progress bar updates, but after the first operation is completeted, guess what: main thread dies. Moreover there is no way to control the operation (I need to replace the old file, but I wouldn't know when the async. operation has finished....so option 3). Option 3: Use asynchronous operations, and ManualResetEvent singaling to control the operation. Result: If I try to Invoke, everything dies. If I don't Invoke (for progress bar update), after the first operation has finished, the main thread dies. It seems, that somehow, someone wants to delete a thread , and because no other than the main thread is available, the app exits. I tries a really big delay (like Thread.Sleep(1000000)) to give time to the next webResponse to fire, and it worked until the next progress bar update crashed everything again. I'm sure I'm doing something terribly wrong, an RTFM somewhere in the last page or whatever. Any ideas?
[quoted text, click to view]
Alex Feinman [MVP] wrote: > What is in your main thread that dies after the first run? Are you using > WIndows Application model (main form that is instantiated via > Application.Run) or did you put together something of your own? > > If the MSDN article that you refer to is this one[1], are you following > the model I use in that article or do you have something quite different? > > 1. http://msdn.microsoft.com/library/en-us/dnnetcomp/html/AutoUpdater.asp > Hi Alex. Thanks a lot for the quick response. Yes, the main thread that dies comes from Application.Run. And when I say die, I mean that is is killed. If the app is executed from withing the VS debugger, then I get a remote connection lost error, and if I'm just executing the app normally, it just vanishes (actually it is killed, it doesn't appear in the task manager). I've used a hybrid of the code the MSDN article uses, because I need to update a number of files and not just one. For a single file, everything works fine, but if you want to start a new download after the first has finished, you must have some sort of control over the operation. I used ManualResetEvent.WaitOne, and ManualResetEvent.Set when the last byte was recieved. But as I mentioned in the first post, this didn't work, as when I used the BegineRead function again, together with invoke the thread was killed somehow ( but I did managed to pass through this, by setting a Thread.Sleep(OneCentury) , only to get a glorious hang in the next pgProgress.Invoke() ). What I'm actually trying to do is this: Download a list files that need to be updated. Start downloading the files one by one, while updating two progress bars, one reporting total progress and the other one current file progress. I still believe I'm missing something trivial here. Anyway, I can provide you with some snippets, when I get back to the office. Thanks for the help anyway.
Daniel Hi.
[quoted text, click to view] Daniel Moth wrote: > When you say the thread dies do you mean your application exits or it > hangs? If you share some code that replicates this problem we may have > better ideas... Yeap, I'll try to provide some code. It just needs some cleaning. [quoted text, click to view] > For your scenario, the BackgroundWorker may be suitable (usually is when > a background operation needs to report progress to the UI): > http://www.danielmoth.com/Blog/2004/12/backgroundworker-for-cf-10.html > That's very interesting Daniel. I'll have a look. Thanks again for the reply
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