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• WpfToolkit DataGrid does not work in Windows Phone 7

  - by Igor Zevaka

  I am trying to use WpfToolkit DataGrid in Windows Phone 7 project (Silverligt 4) and it's not working. Here is the XAML: <UserControl x:Class="SilverlightControls.Grid" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" xmlns:wtk="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" d:DesignHeight="480" d:DesignWidth="480"> <Grid x:Name="LayoutRoot" Background="#FF1F1F1F" Width="960"> <Grid x:Name="TitleGrid"> <TextBlock Text="{Binding Title}" Style="{StaticResource PhoneTextPageTitle2Style}"/> </Grid> <wtk:DataGrid> </wtk:DataGrid> </Grid> </UserControl> The project compiles fine but crashes at runtime trying to load this control. The best clue I got so far is from Visual Studio Designer. Once I add wtk:DataGrid to the control the visual designer does not load and below is the exception it displays. Could it be that WpfToolkit relies on PresentationFramework.dll and it's not available in SL4? System.Reflection.Adds.UnresolvedAssemblyException Type universe cannot resolve assembly: PresentationFramework, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35. at System.Reflection.Adds.AssemblyProxy.GetResolvedAssembly() at System.Reflection.Adds.AssemblyProxy.get_FullName() at Microsoft.Windows.Design.Metadata.ReflectionMetadataContext.PrepareAttributes(Reflectable`1 reflectableAssembly) at Microsoft.Windows.Design.Metadata.ReflectionMetadataContext.PrepareAttributes(Reflectable`1 reflectableType) at MS.Internal.Metadata.ClrType.GetAttributes[T](ReflectionMetadataContext context, IReflectable`1 member, ITypeMetadata attributeType, Boolean merge, AttributeMergeCache& cache) at MS.Internal.Metadata.ClrMember`1.GetLocalAttributes(ITypeMetadata attributeType) at MS.Internal.Design.Metadata.Xaml.XamlType.GetSpecialProperty(Int32 idx, PropertyIdentifier pid) at MS.Internal.Design.Metadata.Xaml.XamlType.get_ContentProperty() at Microsoft.Windows.Design.Metadata.Xaml.XamlExtensionImplementations.GetContentProperty(ITypeMetadata sourceType) at Microsoft.Windows.Design.Metadata.Xaml.XamlExtensions.GetContentProperty(ITypeMetadata source) at MS.Internal.Design.Metadata.ReflectionTypeNode.get_ContentProperty() at MS.Internal.Design.Markup.XmlElement.CalcChildWhitespaceImportant(XamlElement element) at MS.Internal.Design.Markup.XmlElement.ConvertChildrenToXaml(XamlElement result, PrefixScope scope, IParseContext context, IMarkupSourceProvider provider, Boolean childrenAsString) at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider) at MS.Internal.Design.Markup.XmlElement.ConvertChildrenToXaml(XamlElement result, PrefixScope scope, IParseContext context, IMarkupSourceProvider provider, Boolean childrenAsString) at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.ParseElementFromSkeleton(XamlParseContext context, SkeletonNode node, XamlElement parent, Boolean fullElement) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.UpdateSkeleton(IDamageListener listener) at Microsoft.Windows.Design.DocumentModel.Trees.MarkupDocumentTreeManager.Update() at Microsoft.Windows.Design.DocumentModel.MarkupProducer.Update() at Microsoft.Windows.Design.DocumentModel.MarkupProducer.HandleMessage(DocumentTreeCoordinator sender, MessageKey key, MessageArguments args) at Microsoft.Windows.Design.DocumentModel.MarkupProducer.Microsoft.Windows.Design.DocumentModel.IDocumentTreeConsumer.HandleMessage(DocumentTreeCoordinator sender, MessageKey key, MessageArguments args) at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.SendMessage[T](MessageKey`1 key, T args, Boolean isPrivateMessage) at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.QueuedMessage`1.Microsoft.Windows.Design.DocumentModel.IQueuedMessage.Invoke() at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.ProcessQueuedMessages(Object state) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

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• Qt vs .NET - plz no n00bs who don't know wtf they're talking about [closed]

  - by Pirate for Profit

  Man in all these Qt vs. .NET discussions 90% these people don't know WTF they're talking about. Trying to get a real comparison chart going before we embark on a major fucking project. And yes I'm drunk, and yes I use cocaine. Event Handling In Qt the event handling system you just emit signals when something cool happens and then catch them in slots, for instance emit valueChanged(int percent, bool something); and void MyCatcherObj::valueChanged(int p, bool ok){} blocking them and disconnecting them when needed, doing it across threads... once you get the hang of it, it just seems a lot more natural and intuitive than the way the .NET event handling is set up (you know, object sender, CustomEventArgs e). And I'm not just talking about syntax, because in the end the .NET delegate crap is the bomb. I'm also talking about in more than just reflection (because, yes, .NET obviously has much stronger reflection capabilities). I'm talking about in the way the system feels to a human being. Qt wins hands down i m o. Basically, the footprints make more sense and you can visualize the project easier without the clunky event handling system. I wish I could it explain it better. The only thing is, I do love some of the ease of C# compared to C++ and .NET's assembly architecture. That is a big bonus for modular projects, which are a PITA to do in C++. Database Ease of Doing Crap Also what about datasets and database manipulations. I think .net wins here but I'm not sure. Threading/Conccurency How do you guys think of the threading? In .NET, all I've ever done is make like a list of master worker threads with locks. I like QConcurrentFramework, you don't worry about locks or anything, and with the ease of the signal slot system across threads it's nice to get notified about the progress of things. Memory Usage Also what do you think of the overall memory usage comparison. Is the .NET garbage collector pretty on the ball and quick compared to the instantaneous nature of native memory management? Or does it just let programs leak up a storm and lag the computer then clean it up when it's about to really lag? However, I am a n00b who doesn't know what I'm talking about, please school me on the subject.

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• Visual Studio 2010 Extension Manager crashes

  - by Alexey

  After installing a bunch of extensions to try out I restarted VS 2010 and it started crashing. Unfortunately, it consistently crashes when opening Tools | Extension Manager. Any ideas how to fix and avoid a complete uninstall/reinstall? Event log has this: Application: devenv.exe Framework Version: v4.0.30319 Description: The process was terminated due to an unhandled exception. Exception Info: System.AggregateException Stack: at System.Threading.Tasks.TaskExceptionHolder.Finalize()

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• PHP - What are the best/popular libraries for developing CLI apps/scripts?

  - by John Himmelman

  Many of the component libraries and toolkits I'm familiar with lack CLI-specific libraries (zend, kohana, etc..). Are there any libraries/tools that are designed specifically for developing CLI application (such as an abstraction of php's multi-threading library, pcntl/posix)?

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• How to synchronize a python dict with multiprocessing

  - by Peter Smit

  I am using Python 2.6 and the multiprocessing module for multi-threading. Now I would like to have a synchronized dict (where the only atomic operation I really need is the += operator on a value). Should I wrap the dict with a multiprocessing.sharedctypes.synchronized() call? Or is another way the way to go?

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• Accessing a cache with a thread? c#

  - by maxp

  Normally i have a static class that reads and writes to HttpContext.Current.Cache However since adding threading to my project, the threads all get null reference exceptions when trying to retrieve this object. Is there any other way i can access it, workarounds or another cache i can use?

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• Crm 4.0 Custom Page (isv) how to get the current crm UICulture

  - by user203769

  I have a custom page (isv) used in a crm 4.0 solution (through IFrames) and I want it to support multiple languages. I have localized it using resx files, but the UICulture defaults to english event though I have changed it to danish (according to System.Threading.Thread.CurrentUICulture). How do I get the culture of the current user?

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• NUnit GUI Runner and Apartment State

  - by tyndall

  how do you set the apartment state in the NUnit GUI runner? I'm trying to run a single NUnit test with WatiN and I'm getting the message. MyNamespace.LoginTests.CanLogin: System.Threading.ThreadStateException : The CurrentThread needs to have it's ApartmentState set to ApartmentState.STA to be able to automate Internet Explorer.

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• .NET 4 SpinLock

  - by Jon Harrop

  The following test code (F#) is not returning the result I'd expect: let safeCount() = let n = 1000000 let counter = ref 0 let spinlock = ref <| SpinLock(false) let run i0 i1 () = for i=i0 to i1-1 do let locked = ref false try (!spinlock).Enter locked if !locked then counter := !counter + 1 finally if !locked then (!spinlock).Exit() let thread = System.Threading.Thread(run 0 (n/2)) thread.Start() run (n/2) n () thread.Join() !counter I'd expect the SpinLock to mutually exclude the counter and, therefore, for it to return counts of 1,000,000 but, instead, it returns smaller values as if no mutual exclusion is occurring. Any ideas what's wrong?

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• Simple thread-safe non-blocking file logger class in c#

  - by Jason Renlan

  I have a web application, that will log some information to a file. I am looking for a simple thread-safe non-blocking file logger class in c#. I have little experience with threading. I known there are great logging components out there like log4Net, Enterprise Library Logging Block, ELMAH, but I do not want an external dependence for my application. I was thinking about using this queue implementation http://www.codeproject.com/KB/cpp/lockfreeq.aspx

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• .NET SerialPort DataReceived event thread interference with main thread

  - by Kiran

  I am writing a serial communication program using the SerialPort class in C# to interact with a strip machine connected via a RS232 cable. When i send the command to the machine it responds with some bytes depending on the command. Like when i send a "\D" command, i am expecting to download the machine program data of 180 bytes as a continous string. As per the machine's manual, it suggests as a best practice to send an unreognized characters like comma (,) character to make sure the machine is initialized before sending the first command in the cycle. My serial communication code is as follows: public class SerialHelper { SerialPort commPort = null; string currentReceived = string.Empty; string receivedStr = string.Empty; private bool CommInitialized() { try { commPort = new SerialPort(); commPort.PortName = "COM1"; if (!commPort.IsOpen) commPort.Open(); commPort.BaudRate = 9600; commPort.Parity = System.IO.Ports.Parity.None; commPort.StopBits = StopBits.One; commPort.DataBits = 8; commPort.RtsEnable = true; commPort.DtrEnable = true; commPort.DataReceived += new SerialDataReceivedEventHandler(commPort_DataReceived); return true; } catch (Exception ex) { return false; } } void commPort_DataReceived(object sender, SerialDataReceivedEventArgs e) { SerialPort currentPort = (SerialPort)sender; currentReceived = currentPort.ReadExisting(); receivedStr += currentReceived; } internal int CommIO(string outString, int outLen, ref string inBuffer, int inLen) { receivedStr = string.Empty; inBuffer = string.Empty; if (CommInitialized()) { commPort.Write(outString); } System.Threading.Thread.Sleep(1500); int i = 0; while ((receivedStr.Length < inLen) && i < 10) { System.Threading.Thread.Sleep(500); i += 1; } if (!string.IsNullOrEmpty(receivedStr)) { inBuffer = receivedStr; } commPort.Close(); return inBuffer.Length; } } I am calling this code from a windows form as follows: len = SerialHelperObj.CommIO(",",1,ref inBuffer, 4) len = SerialHelperObj.CommIO(",",1,ref inBuffer, 4) If(inBuffer == "!?*O") { len = SerialHelperObj.CommIO("\D",2,ref inBuffer, 180) } A valid return value from the serial port looks like this: \D00000010000000000010 550 3250 0000256000 and so on ... I am getting some thing like this: \D00000010D,, 000 550 D,, and so on... I feel that my comm calls are getting interferred with the one when i send commands. But i am trying to make sure the result of the comma command then initiating the actual command. but the received thread is inserting the bytes from the previous communication cycle. Can any one please shed some light into this...? I lost quite some hair just trying to get this work. I am not sure where i am doing wrong

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• Parallel.For System.OutOfMemoryException

  - by Martin Neal

  We have a fairly simple program that's used for creating backups. I'm attempting to parallelize it but am getting an OutofMemoryException within an AggregateExcption. Some of the source folders are quite large, and the program doesn't crash for about 40 minutes after it starts. I don't know where to start looking so the below code is a near exact dump of all code the code sans directory structure and Exception logging code. Any advise as to where to start looking? using System; using System.Diagnostics; using System.IO; using System.Threading.Tasks; namespace SelfBackup { class Program { static readonly string[] saSrc = { "\\src\\dir1\\", //... "\\src\\dirN\\", //this folder is over 6 GB }; static readonly string[] saDest = { "\\dest\\dir1\\", //... "\\dest\\dirN\\", }; static void Main(string[] args) { Parallel.For(0, saDest.Length, i => { try { if (Directory.Exists(sDest)) { //Delete directory first so old stuff gets cleaned up Directory.Delete(sDest, true); } //recursive function clsCopyDirectory.copyDirectory(saSrc[i], sDest); } catch (Exception e) { //standard error logging CL.EmailError(); } }); } } /////////////////////////////////////// using System.IO; using System.Threading.Tasks; namespace SelfBackup { static class clsCopyDirectory { static public void copyDirectory(string Src, string Dst) { Directory.CreateDirectory(Dst); /* Copy all the files in the folder If and when .NET 4.0 is installed, change Directory.GetFiles to Directory.Enumerate files for slightly better performance.*/ Parallel.ForEach<string>(Directory.GetFiles(Src), file => { /* An exception thrown here may be arbitrarily deep into this recursive function there's also a good chance that if one copy fails here, so too will other files in the same directory, so we don't want to spam out hundreds of error e-mails but we don't want to abort all together. Instead, the best solution is probably to throw back up to the original caller of copy directory an move on to the next Src/Dst pair by not catching any possible exception here.*/ File.Copy(file, //src Path.Combine(Dst, Path.GetFileName(file)), //dest true);//bool overwrite }); //Call this function again for every directory in the folder. Parallel.ForEach(Directory.GetDirectories(Src), dir => { copyDirectory(dir, Path.Combine(Dst, Path.GetFileName(dir))); }); } }

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• Multiple NSOperationQueues?

  - by Infinity

  Hello! I would like to use NSOperations in my application to resolve threading problems. I have read some tutorials and now I know what I have to do, but I have a problem. There is a must to have the same NSOperationQueue in each class. What if I use a new NSOperationQueue in each class. There will be concurrency problems?

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• How to speed up loading the splash screen.

  - by AngryHacker

  I am optimizing the startup of a WinForms app. One issue I identified is the loading of the splash screen form. It takes about half a second to a second. I know that multi-threading is a no-no on UI pieces, however, seeing how the splash screen is a fairly autonomous piece of the application, is it possible to somehow mitigate its performance hit by throwing it one some other thread (perhaps in the way Chrome does it), so that the important pieces of the application can actually get going.

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• NetApp erroring with: STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT

  - by Sobrique

  Since a sitewide upgrade to Windows 7 on desktop, I've started having a problem with virus checking. Specifically - when doing a rename operation on a (filer hosted) CIFS share. The virus checker seems to be triggering a set of messages on the filer: [filerB: auth.trace.authenticateUser.loginTraceIP:info]: AUTH: Login attempt by user server-wk8-r2$ of domain MYDOMAIN from client machine 10.1.1.20 (server-wk8-r2). [filerB: auth.dc.trace.DCConnection.statusMsg:info]: AUTH: TraceDC- attempting authentication with domain controller \\MYDC. [filerB: auth.trace.authenticateUser.loginRejected:info]: AUTH: Login attempt by user rejected by the domain controller with error 0xc0000199: STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT. [filerB: auth.trace.authenticateUser.loginTraceMsg:info]: AUTH: Delaying the response by 5 seconds due to continuous failed login attempts by user server-wk8-r2$ of domain MYDOMAIN from client machine 10.1.1.20. This seems to specifically trigger on a rename so what we think is going on is the virus checker is seeing a 'new' file, and trying to do an on-access scan. The virus checker - previously running as LocalSystem and thus sending null as it's authentication request is now looking rather like a DOS attack, and causing the filer to temporarily black list. This 5s lock out each 'access attempt' is a minor nuisance most of the time, and really quite significant for some operations - e.g. large file transfers, where every file takes 5s Having done some digging, this seems to be related to NLTM authentication: Symptoms Error message: System error 1808 has occurred. The account used is a computer account. Use your global user account or local user account to access this server. A packet trace of the failure will show the error as: STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT (0xC0000199) Cause Microsoft has changed the functionality of how a Local System account identifies itself during NTLM authentication. This only impacts NTLM authentication. It does not impact Kerberos Authentication. Solution On the host, please set the following group policy entry and reboot the host. Network Security: Allow Local System to use computer identity for NTLM: Disabled Defining this group policy makes Windows Server 2008 R2 and Windows 7 function like Windows Server 2008 SP1. So we've now got a couple of workaround which aren't particularly nice - one is to change this security option. One is to disable virus checking, or otherwise exempt part of the infrastructure. And here's where I come to my request for assistance from ServerFault - what is the best way forwards? I lack Windows experience to be sure of what I'm seeing. I'm not entirely sure why NTLM is part of this picture in the first place - I thought we were using Kerberos authentication. I'm not sure how to start diagnosing or troubleshooting this. (We are going cross domain - workstation machine accounts are in a separate AD and DNS domain to my filer. Normal user authentication works fine however.) And failing that, can anyone suggest other lines of enquiry? I'd like to avoid a site wide security option change, or if I do go that way I'll need to be able to supply detailed reasoning. Likewise - disabling virus checking works as a short term workaround, and applying exclusions may help... but I'd rather not, and don't think that solves the underlying problem. EDIT: Filers in AD ldap have SPNs for: nfs/host.fully.qualified.domain nfs/host HOST/host.fully.qualified.domain HOST/host (Sorry, have to obfuscate those). Could it be that without a 'cifs/host.fully.qualified.domain' it's not going to work? (or some other SPN? ) Edit: As part of the searching I've been doing I've found: http://itwanderer.wordpress.com/2011/04/14/tread-lightly-kerberos-encryption-types/ Which suggests that several encryption types were disabled by default in Win7/2008R2. This might be pertinent, as we've definitely had a similar problem with Keberized NFSv4. There is a hidden option which may help some future Keberos users: options nfs.rpcsec.trace on (This hasn't given me anything yet though, so may just be NFS specific). Edit: Further digging has me tracking it back to cross domain authentication. It looks like my Windows 7 workstation (in one domain) is not getting Kerberos tickets for the other domain, in which my NetApp filer is CIFS joined. I've done this separately against a standalone server (Win2003 and Win2008) and didn't get Kerberos tickets for those either. Which means I think Kerberos might be broken, but I've no idea how to troubleshoot further. Edit: A further update: It looks like this may be down Kerberos tickets not being issued cross domain. This then triggers NTLM fallback, which then runs into this problem (since Windows 7). First port of call will be to investigate the Kerberos side of things, but in neither case do we have anything pointing at the Filer being the root cause. As such - as the storage engineer - it's out of my hands. However, if anyone can point me in the direction of troubleshooting Kerberos spanning two Windows AD domains (Kerberos Realms) then that would be appreciated. Options we're going to be considering for resolution: Amend policy option on all workstations via GPO (as above). Talking to AV vendor about the rename triggering scanning. Talking to AV vendor regarding running AV as service account. investigating Kerberos authentication (why it's not working, whether it should be).

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• How to Schedule Method call in Objective C

  - by user359277

  Hi, I am try to do multi-threading in Objective C. What I want to do now is that, for some instance of objects, I want to have to way to call some function 5 seconds later. How can I do that? In Coco 2D, it's very easy to do it. They have something called scheduler. In Objective C, how to do it please? Thanks

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• synchronize sql cennection in multithreading in c#

  - by Lalit Dhake

  I am using multi threading concept to run some process. this process uses the sql connection object to get the data from database.This object is in another class. how to synchronize the sql connection while using multithreading?

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• How to use ResourceManager in a "website" mode ?

  - by Erick

  I am trying here to do a manual translation for the application I am working with. (There is already a working LocalizationModule but it's working dodgy, so I can't use <asp:Localize /> tags. Normally with ResourceManager you are supposed to be using it as Namespace.Folder.Resourcename (in an application). Currently I am translating an existing asp.net "website" (not web application so no namespace here....). The resources are located into a folder name "Locales/resources" which contains "fr-ca.resx" and "en-us.resx". So I used a code with something like this : public static string T(string search) { System.Resources.ResourceManager resMan = new System.Resources.ResourceManager( "Locales", System.Reflection.Assembly.GetExecutingAssembly(), null ); var text = resMan.GetString(search, System.Threading.Thread.CurrentThread.CurrentCulture); if (text == null) return "null"; else if (text == string.Empty) return "empty"; else return text; } and inside the page I have something like this <%= Locale.T("T_HOME") %> When I refresh I have this : Could not find any resources appropriate for the specified culture or the neutral culture. Make sure "Locales.resources" was correctly embedded or linked into assembly "App_Code.9yopn1f7" at compile time, or that all the satellite assemblies required are loadable and fully signed. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Resources.MissingManifestResourceException: Could not find any resources appropriate for the specified culture or the neutral culture. Make sure "Locales.resources" was correctly embedded or linked into assembly "App_Code.9yopn1f7" at compile time, or that all the satellite assemblies required are loadable and fully signed. Source Error: Line 14: System.Resources.ResourceManager resMan = new System.Resources.ResourceManager( "Locales", System.Reflection.Assembly.GetExecutingAssembly(), null ); Line 15: Line 16: var text = resMan.GetString(search, System.Threading.Thread.CurrentThread.CurrentCulture); Line 17: Line 18: if (text == null) Source File: c:\inetpub\vhosts\galerieocarre.com\subdomains\dev\httpdocs\App_Code\Locale.cs Line: 16 I even tried to load the resource with Locales.fr-ca or only fr-ca nothing quite work here.

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• Portability of pthreads-win32 over various compilers.

  - by Artyom

  Hello, I'm using pthreads-win32 for portable threading support for windows. At least, according to the documentation pthreads-win32 should work with MSVC and even MSVC builds provided. But I don't know if the library is tested with latest MSVC compilers like MSVC-2008 and if it is supported under 64bit windows. Does anybody aware of any issues with this library? Note: Do not even try to recommend using Boost.Thread, I'm not interested in. And I'm familiar with Boost.Thread library

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• Getting iPhone touch coordinates without using javascript events?

  - by Stefan Kendall

  Is there any way to get iPhone coordinates without relying on javascript callback events? touchmove generates way too many events to be used in any kind of tight loop (like a game), and without multi-threading, the only option would seem to be non-event driven input coordinates.

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• Eventlet and locking

  - by TheDude

  Since Eventlet uses green threading and asynchronous I/O, do I still need to set locks before accessing objects? My understanding is that greenlets are all part of one thread and locking isn't necessary. Can anyone confirm or deny this?

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• How do I get .NET to garbage collect aggressively?

  - by mmr

  I have an application that is used in image processing, and I find myself typically allocating arrays in the 4000x4000 ushort size, as well as the occasional float and the like. Currently, the .NET framework tends to crash in this app apparently randomly, almost always with an out of memory error. 32mb is not a huge declaration, but if .NET is fragmenting memory, then it's very possible that such large continuous allocations aren't behaving as expected. Is there a way to tell the garbage collector to be more aggressive, or to defrag memory (if that's the problem)? I realize that there's the GC.Collect and GC.WaitForPendingFinalizers calls, and I've sprinkled them pretty liberally through my code, but I'm still getting the errors. It may be because I'm calling dll routines that use native code a lot, but I'm not sure. I've gone over that C++ code, and make sure that any memory I declare I delete, but still I get these C# crashes, so I'm pretty sure it's not there. I wonder if the C++ calls could be interfering with the GC, making it leave behind memory because it once interacted with a native call-- is that possible? If so, can I turn that functionality off? EDIT: Here is some very specific code that will cause the crash. According to this SO question, I do not need to be disposing of the BitmapSource objects here. Here is the naive version, no GC.Collects in it. It generally crashes on iteration 4 to 10 of the undo procedure. This code replaces the constructor in a blank WPF project, since I'm using WPF. I do the wackiness with the bitmapsource because of the limitations I explained in my answer to @dthorpe below as well as the requirements listed in this SO question. public partial class Window1 : Window { public Window1() { InitializeComponent(); //Attempts to create an OOM crash //to do so, mimic minute croppings of an 'image' (ushort array), and then undoing the crops int theRows = 4000, currRows; int theColumns = 4000, currCols; int theMaxChange = 30; int i; List<ushort[]> theList = new List<ushort[]>();//the list of images in the undo/redo stack byte[] displayBuffer = null;//the buffer used as a bitmap source BitmapSource theSource = null; for (i = 0; i < theMaxChange; i++) { currRows = theRows - i; currCols = theColumns - i; theList.Add(new ushort[(theRows - i) * (theColumns - i)]); displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create(currCols, currRows, 96, 96, PixelFormats.Gray8, null, displayBuffer, (currCols * PixelFormats.Gray8.BitsPerPixel + 7) / 8); System.Console.WriteLine("Got to change " + i.ToString()); System.Threading.Thread.Sleep(100); } //should get here. If not, then theMaxChange is too large. //Now, go back up the undo stack. for (i = theMaxChange - 1; i >= 0; i--) { displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create((theColumns - i), (theRows - i), 96, 96, PixelFormats.Gray8, null, displayBuffer, ((theColumns - i) * PixelFormats.Gray8.BitsPerPixel + 7) / 8); System.Console.WriteLine("Got to undo change " + i.ToString()); System.Threading.Thread.Sleep(100); } } } Now, if I'm explicit in calling the garbage collector, I have to wrap the entire code in an outer loop to cause the OOM crash. For me, this tends to happen around x = 50 or so: public partial class Window1 : Window { public Window1() { InitializeComponent(); //Attempts to create an OOM crash //to do so, mimic minute croppings of an 'image' (ushort array), and then undoing the crops for (int x = 0; x < 1000; x++){ int theRows = 4000, currRows; int theColumns = 4000, currCols; int theMaxChange = 30; int i; List<ushort[]> theList = new List<ushort[]>();//the list of images in the undo/redo stack byte[] displayBuffer = null;//the buffer used as a bitmap source BitmapSource theSource = null; for (i = 0; i < theMaxChange; i++) { currRows = theRows - i; currCols = theColumns - i; theList.Add(new ushort[(theRows - i) * (theColumns - i)]); displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create(currCols, currRows, 96, 96, PixelFormats.Gray8, null, displayBuffer, (currCols * PixelFormats.Gray8.BitsPerPixel + 7) / 8); } //should get here. If not, then theMaxChange is too large. //Now, go back up the undo stack. for (i = theMaxChange - 1; i >= 0; i--) { displayBuffer = new byte[theList[i].Length]; theSource = BitmapSource.Create((theColumns - i), (theRows - i), 96, 96, PixelFormats.Gray8, null, displayBuffer, ((theColumns - i) * PixelFormats.Gray8.BitsPerPixel + 7) / 8); GC.WaitForPendingFinalizers();//force gc to collect, because we're in scenario 2, lots of large random changes GC.Collect(); } System.Console.WriteLine("Got to changelist " + x.ToString()); System.Threading.Thread.Sleep(100); } } } If I'm mishandling memory in either scenario, if there's something I should spot with a profiler, let me know. That's a pretty simple routine there. Unfortunately, it looks like @Kevin's answer is right-- this is a bug in .NET and how .NET handles objects larger than 85k. This situation strikes me as exceedingly strange; could Powerpoint be rewritten in .NET with this kind of limitation, or any of the other Office suite applications? 85k does not seem to me to be a whole lot of space, and I'd also think that any program that uses so-called 'large' allocations frequently would become unstable within a matter of days to weeks when using .NET. EDIT: It looks like Kevin is right, this is a limitation of .NET's GC. For those who don't want to follow the entire thread, .NET has four GC heaps: gen0, gen1, gen2, and LOH (Large Object Heap). Everything that's 85k or smaller goes on one of the first three heaps, depending on creation time (moved from gen0 to gen1 to gen2, etc). Objects larger than 85k get placed on the LOH. The LOH is never compacted, so eventually, allocations of the type I'm doing will eventually cause an OOM error as objects get scattered about that memory space. We've found that moving to .NET 4.0 does help the problem somewhat, delaying the exception, but not preventing it. To be honest, this feels a bit like the 640k barrier-- 85k ought to be enough for any user application (to paraphrase this video of a discussion of the GC in .NET). For the record, Java does not exhibit this behavior with its GC.

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• how to use quad core CPU in application

  - by Mayank

  For using all the cores of a quad core processor what do I need to change in my code is it about adding support of multi threading or is it which is taken care by OS itself. I am having FreeBSD and language I am using is C++. I want to give complete CPU cycles to my application at least 90%.

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• synchronize sql connection in multithreading in .NET

  - by Lalit Dhake

  I am using multi threading concept to run some process. this process uses the sql connection object to get the data from database.This object is in another class. how to synchronize the sql connection while using multithreading?

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• .Net4 ConcurrentDictionary: Tips & Tricks

  - by SDReyes

  Hi guys, I started to use the new ConcurrentDictionary from .Net4 yesterday to implement a simple caching for a threading project. But I'm wondering what I have to take care of/be careful about when using it? What have been your experiences using it?

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