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• Error building Visual Studio 2010 Silverlight 4 projects on Windows 7 with XP Mode

  - by Kevin Dente

  I installed Visual Studio 2010 Beta 2 in an XP Mode VM on Windows 7. Then I created a trivial Silverlight 4 (beta) project and tried to build it. I get the following error: Error 1 The "ValidateXaml" task failed unexpectedly. System.IO.FileLoadException: Could not load file or assembly 'file://\tsclient\d\Users\me\Documents\Visual Studio 2010\Projects\SilverlightApplication2\SilverlightApplication2\obj\Debug\SilverlightApplication2.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515) File name: 'file://\tsclient\d\Users\me\Documents\Visual Studio 2010\Projects\SilverlightApplication2\SilverlightApplication2\obj\Debug\SilverlightApplication2.dll' --- System.NotSupportedException: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information. at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) at System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection, Boolean suppressSecurityChecks) at System.Reflection.RuntimeAssembly.InternalLoadFrom(String assemblyFile, Evidence securityEvidence, Byte[] hashValue, AssemblyHashAlgorithm hashAlgorithm, Boolean forIntrospection, Boolean suppressSecurityChecks, StackCrawlMark& stackMark) at System.Reflection.Assembly.LoadFrom(String assemblyFile) at Microsoft.Silverlight.Build.Tasks.ValidateXaml.XamlValidator.Execute(ITask task) at Microsoft.Silverlight.Build.Tasks.ValidateXaml.XamlValidator.Execute(ITask task) at Microsoft.Silverlight.Build.Tasks.ValidateXaml.Execute() at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute() at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(ITaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask, Boolean& taskResult) I believe this is related to the fact that XP Mode redirects the My Documents folder to the host, turning it into a network share location, and some sort of CAS / security policy is being triggered. Anyone know how to fix it?

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• C# Taking a element off each time (stack)

  - by Sef

  Greetings, Have a question considering a program that stimulates a stack.(not using any build in stack features or any such) stack2= 1 2 3 4 5 //single dimension array of 5 elements By calling up a method "pop" the stack should look like the following: Basically taking a element off each time the stack is being "called" up again. stack2= 1 2 3 4 0 stack2= 1 2 3 0 0 stack2= 1 2 0 0 0 stack2= 1 0 0 0 0 stack2= 0 0 0 0 0 - for (int i = 1; i <= 6; i++) { number= TryPop(s2); //use number ShowStack(s2, "s2"); } Basically I already have code that fills my array with values (trough a push method). The pop method should basically take the last value and place it on 0. Then calls up the next stack and place the following on 0 (like shown above in stack2). The current pop method that keeps track of the top index (0 elements = 0 top, 1 element = 1 top etc..). Already includes a underflow warning if this goes on 0 or below (which is correct). public int Pop() { if(top <= 0) { throw new Exception("Stack underflow..."); } else { for (int j = tabel.Length - 1; j >= 0; j--) { //...Really not sure what to do here. } } return number; }/*Pop*/ Since in the other class I already have a loop (for loop shown above) that simulates 6 times the s2 stack. (first stack: 1 2 3 4 0, second stack 1 2 3 0 0 and so on.) How exactly do I take a element off each time? Either I have the entire display on 0 or the 0 in the wrong places / out of index errors. Thanks in advance!

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• asp.net MVC HandleError

  - by boris callens

  How do I go about the [HandleError] filter in asp.net MVC Preview 5? I set the customErrors in my web.config file <customErrors mode="On" defaultRedirect="Error.aspx"> <error statusCode="403" redirect="NoAccess.htm"/> <error statusCode="404" redirect="FileNotFound.htm"/> </customErrors> and put [HandleError] above my Controller Class like this: [HandleError] public class DSWebsiteController: Controller{ [snip] public ActionResult CrashTest() { throw new Exception("Oh Noes!"); } } Then I let my controllers inherit from this class and call CrashTest() on them. Visual studio halts at the error and after pressing f5 to continue, I get rerouted to Error.aspx?aspxerrorpath=/sxi.mvc/CrashTest (where sxi is the name of the used controller. Off course the path cannot be found and I get "Server Error in '/' Application." 404. This site was ported from preview 3 to 5. Everything runs (wasn't that much work to port) except the error handling. When I create a complete new project the error handling seems to work. Ideas? --Note-- Since this question has over 3K views now, I thought it would be beneficial to put in what I'm currently (asp.net mvc 1.0) using. In the mvc contrib project there is a brilliant attribute called "RescueAttribute" You should probably check it out too ;)

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• Mysterious socket / HttpWebRequest timeouts

  - by Daniel Mošmondor

  I have a great app for capturing shoutcast streams :-) . So far, it worked with a charm on dozens of machines, and never exhibited behaviour I found now, which is ultimately very strange. I use HttpWebRequest to connect to the shoutcast server and when I connect two streams, everything's OK. When I go for third one, response = (HttpWebResponse)request.GetResponse(); throws with Connection Timeout exception. WTF? I must point out that I had to create .config for the application in order to allow my headers to be sent out from the application, otherwise it wouldn't work at all. Here it is: <?xml version="1.0" encoding="utf-8" ?> <configuration> <system.net> <settings> <httpWebRequest useUnsafeHeaderParsing = "true" /> </settings> </system.net> </configuration> Does any of this ring a bell?

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• How to find that Mutex in C# is acquired?

  - by TN

  How can I find from mutex handle in C# that a mutex is acquired? When mutex.WaitOne(timeout) timeouts, it returns false. However, how can I find that from the mutex handle? (Maybe using p/invoke.) UPDATE: public class InterProcessLock : IDisposable { readonly Mutex mutex; public bool IsAcquired { get; private set; } public InterProcessLock(string name, TimeSpan timeout) { bool created; var security = new MutexSecurity(); security.AddAccessRule(new MutexAccessRule(new SecurityIdentifier(WellKnownSidType.WorldSid, null), MutexRights.Synchronize | MutexRights.Modify, AccessControlType.Allow)); mutex = new Mutex(false, name, out created, security); IsAcquired = mutex.WaitOne(timeout); } #region IDisposable Members public void Dispose() { if (IsAcquired) mutex.ReleaseMutex(); } #endregion } Currently, I am using my own property IsAcquired to determine whether I should release a mutex. Not essential but clearer, would be not to use a secondary copy of the information represented by IsAcquired property, but rather to ask directly the mutex whether it is acquired by me. Since calling mutex.ReleaseMutex() throws an exception if it is not acquired by me. (By acquired state I mean that the mutex is in not-signaled state when I am owning the mutex.)

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• Run time error: what's wrong?

  - by javacode

  I am getting run time error import javax.mail.*; import javax.mail.internet.*; import java.util.*; public class SendMail { public static void main(String [] args)throws MessagingException { SendMail sm=new SendMail(); sm.postMail(new String[]{"[email protected]"},"hi","hello","[email protected]"); } public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException { boolean debug = false; //Set the host smtp address Properties props = new Properties(); props.put("mail.smtp.host", "webmail.emailmyname.com"); // create some properties and get the default Session Session session = Session.getDefaultInstance(props, null); session.setDebug(debug); // create a message Message msg = new MimeMessage(session); // set the from and to address InternetAddress addressFrom = new InternetAddress(from); msg.setFrom(addressFrom); InternetAddress[] addressTo = new InternetAddress[recipients.length]; for (int i = 0; i < recipients.length; i++) { addressTo[i] = new InternetAddress(recipients[i]); } msg.setRecipients(Message.RecipientType.TO, addressTo); // Optional : You can also set your custom headers in the Email if you Want msg.addHeader("MyHeaderName", "myHeaderValue"); // Setting the Subject and Content Type msg.setSubject(subject); msg.setContent(message, "text/plain"); Transport.send(msg); } } Error Exception in thread "main" java.lang.NoClassDefFoundError: SendMail Caused by: java.lang.ClassNotFoundException: SendMail at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) Could not find the main class: SendMail. Program will exit.

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• Rest WebService error handling.

  - by Pratik

  Hi there, I am using RestWebservice for few basic operations , like creating/searching. The request xml looks something like this <customer> <name/> ..... </customer> For a successful operation I return the same customer XML with extra fields populated in it(eg. systemId etc which we blank in the request) . with Response.Status=2000 For an unsuccessful operation i return something like this with different error codes . e.g Response.Status = 422(Unprocessable entity) Response.Status= 500(Internal Server Error) and few others.. <errors> <error> An exception occurred while creating the customer</error> <error> blah argument is not valid.</error> </errors> Now i am not sure , whether this is the correct way of sending the errors to the client. Maybe it should be present in the header of the response. I will really appreciate any help. Thanks!

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• Logging exceptions during bean injection

  - by Marc W

  I think this is a pretty basic question, but after Googling around I can't seem to find the answer. What I need is a way to log some custom output with log4j during Spring bean construction. I have a factory class called ResponderFactory (being used as an instance factory in Spring) with a factory method that can throw 2 different types of exception. public CollectorResponder collectorResponder(String inputQueueName) throws ConfigurationException, BrokerConnectionException {} Now, normally I could wrap a call to this method in a try-catch block with 2 catch clauses to handle the logging situations for each of the exceptions. However, if I'm using Spring to inject this CollectorResponder, created with the factory, into another class I don't see how this is possible. <bean id="responderFactory" class="com.package.ResponderFactory"> <constructor-arg index="0" ref="basicDispatcher" /> <constructor-arg index="1" value="http://localhost:9000" /> </bean> <bean id="collectorResponder" class="com.package.CollectorResponder" factory-bean="responderFactory" factory-method="collectorResponder"> <constructor-arg value="collector.in" /> </bean> <bean id="collectorConsumer" class="com.package.CollectorConsumer"> <constructor-arg ref="collectorResponder" /> </bean> Again, I want to catch these exceptions when the collectorResponder bean is instantiated. Right now I'm dealing with this is CollectorConsumer when I instantiate using new CollectorResponder(...). Is there any way I can do this?

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• How to read a database record with a DataReader and add it to a DataTable

  - by Olga

  Hello I have some data in a Oracle database table(around 4 million records) which i want to transform and store in a MSSQL database using ADO.NET. So far i used (for much smaller tables) a DataAdapter to read the data out of the Oracle DataBase and add the DataTable to a DataSet for further processing. When i tried this with my huge table, there was a outofmemory exception thrown. ( I assume this is because i cannot load the whole table into my memory) :) Now i am looking for a good way to perform this extract/transfer/load, without storing the whole table in the memory. I would like to use a DataReader and read the single dataRecords in a DataTable. If there are about 100k rows in it, I would like to process them and clear the DataTable afterwards(to have free memory again). Now i would like to know how to add a single datarecord as a row to a dataTable with ado.net and how to completly clear the dataTable out of memory: My code so far: Dim dt As New DataTable Dim count As Int32 count = 0 ' reads data records from oracle database table' While rdr.Read() 'read n records and add them to a dataTable' While count < 10000 dt.Rows.Add(????) count = count + 1 End While 'transform data in the dataTable, and insert it to the destination' ' flush the dataTable after insertion' count = 0 End While Thank you very much for your response!

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• wcf 4.0 service on IIS7

  - by Jan

  I am currently developing a service with wcf 4.0 (visual studio 2010 RC). When I try my service on the Visual Studio Development Server, it all works perfect. However, when I tree to run my service on IIS7 on a windows 7 machine, the service doesn't work anymore. (I already changed the framework version on my application pool). When I call an operation on the service, like the default operation GetData when I create a service, I get an error. I used the WCF test client to connect to the service. When I call the operation on the service, the Visual Studio Just-In-Time debugger shows the following message: An unhandled win32 exception occured in w3wp.exe The Just-In-Time debugger was launched without necessary security permissions. To debug this proces, the JIT debugger must be run as an administrator. Would you like to debug the proces? As far as I know, I am running Visual Studio as an administrator and this is probably the process that starts the JIT debugger. The only option I have is to debug the W3WP process, which is probably not the right thing to do. What can I do the make the Service to run on IIS7?

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• Maximum page fetch with maximum bandwith

  - by Ehsan

  Hi I want to create an application like a spider I've implement fetching page as the following code in multi-thread application but there is two problem 1) I want to use my maximum bandwidth to send/receive request, how should I config my request to do so (Like Download Accelerator application and the like) cause I heard the normal application will use 66% of the available bandwidth. 2) I don't know what exactly HttpWebRequest.KeepAlive do, but as its name implies I think i can create a connection to a website and without closing the connection sending another request to that web site using existing connection. does it boost performance or Im wrong ?? public PageFetchResult Fetch() { PageFetchResult fetchResult = new PageFetchResult(); try { HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(URLAddress); HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); Uri requestedURI = new Uri(URLAddress); Uri responseURI = resp.ResponseUri; string resultHTML = ""; byte[] reqHTML = ResponseAsBytes(resp); if (!string.IsNullOrEmpty(FetchingEncoding)) resultHTML = Encoding.GetEncoding(FetchingEncoding).GetString(reqHTML); else if (!string.IsNullOrEmpty(resp.CharacterSet)) resultHTML = Encoding.GetEncoding(resp.CharacterSet).GetString(reqHTML); req.Abort(); resp.Close(); fetchResult.IsOK = true; fetchResult.ResultHTML = resultHTML; } catch (Exception ex) { fetchResult.IsOK = false; fetchResult.ErrorMessage = ex.Message; } return fetchResult; }

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• Oracle Data Provider and casting

  - by mrjoltcola

  I use Oracle's specific data provider, not the Microsoft provider that is being discontinued. The thing I've found about ODP.NET is how picky it is with data types. Where JDBC and other ADO providers just convert and make things work, ODP.NET will throw an invalid cast exception unless you get it exactly right. Consider this code: String strSQL = "SELECT DOCUMENT_SEQ.NEXTVAL FROM DUAL"; OracleCommand cmd = new OracleCommand(strSQL, conn); reader = cmd.ExecuteReader(); if (reader != null && reader.Read()) { Int64 id = reader.GetInt64(0); return id; } Due to ODP.NET's pickiness on conversion, this doesn't work. My usual options are: 1) Retrieve into a Decimal and return it with a cast to an Int64 (I don't like this because Decimal is just overkill, and at least once I remember reading it was deprecated...) Decimal id = reader.GetDecimal(0); return (Int64)id; 2) Or cast in the SQL statement to make sure it fits into Int64, like NUMBER(18) String strSQL = "SELECT CAST(DOCUMENT_SEQ.NEXTVAL AS NUMBER(18)) FROM DUAL"; I do (2), because I feel its just not clean pulling a number into a .NET Decimal when my domain types are Int32 or Int64. Other providers I've used are nice (smart) enough to do the conversion on the fly. Any suggestions from the ODP.NET gurus?

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• Any good tools or tips for fuzz testing Windows forms applications?

  - by Ogre Psalm33

  I'm maintaining a ~300K LOC C# legacy thick-client application with a Windows.Forms interface. The app is full of little bugs and quirks. For example, I recently discovered a bug where if a users edits and tabs (not clicks) through cells on a DataViewGrid, and leaves the a certain cell selected, the app gets an "Object reference not set to an instance of an object" exception. I discover (or get a bug report of) something new like this about every week or two. I've had enough, and was thinking of trying some sort of fuzz testing on the application to try to ferret out undiscovered issues. If I roll-my-own fuzz testing, I'd assume I at least need to be able to generate test harnesses that run pieces of my app (main window, FormX, FormY, FormZ, ...) independently and try to inject events into them. I was trying to look for tools suited for this, but so far have come up with nothing for Win Forms. (There seems to be no shortage of fuzz testing tools for web apps, however). Any helpful ideas?

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• Java Swing NullPointerException when drawing

  - by juFo

  I'm using a custom JLayeredPane. I have several Shapes which needed to be drawn on different layers in the JLayeredPane. To test this I create a JPanel and ask its graphics. Then I draw a test rectangle on that JPanel (preparing the graphics) and in my paintComponent method from the JLayeredPane I finally draw everything. But this fails (NullPointerException). public class MyCustomPanel extends JLayeredPane { // test JPanel testpane; Graphics g2; // test // constructor public MyCustomPanel() { testpane = new JPanel(); this.add(testpane, new Integer(14)); g2 = testpane.getGraphics(); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); g2.drawRect(10, 10, 300, 300); } } // run: //Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException // at view.MyCustomPanel.paintComponent(MyCustomPanel.java:65) Why can't I draw on such a JPanel from within my JLayeredPane? I can draw directly on my JLayeredPane from within my paintComponent method but that's on the default Panel from the JLayeredPane. I need to create and draw on several layers which are added in my JLayeredPane. What am I doing wrong? :s

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• ERROR! (Using Excel's named ranges from C#)

  - by mcoolbeth

  In the following, I am trying to persist a set of objects in an excel worksheet. Each time the function is called to store a value, it should allocate the next cell of the A column to store that object. However, an exception is thrown by the Interop library on the first call to get_Range(). (right after the catch block) Does anyone know what I am doing wrong? private void AddName(string name, object value) { Excel.Worksheet jresheet; try { jresheet = (Excel.Worksheet)_app.ActiveWorkbook.Sheets["jreTemplates"]; } catch { jresheet = (Excel.Worksheet)_app.ActiveWorkbook.Sheets.Add(Type.Missing, Type.Missing, Type.Missing, Type.Missing); jresheet.Visible = Microsoft.Office.Interop.Excel.XlSheetVisibility.xlSheetVeryHidden; jresheet.Name = "jreTemplates"; jresheet.Names.Add("next", "A1", true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); } Excel.Range cell = jresheet.get_Range("next", Type.Missing); cell.Value2 = value; string address = ((Excel.Name)cell.Name).Name; _app.ActiveWorkbook.Names.Add(name, address, false, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); cell = cell.get_Offset(1, 0); jresheet.Names.Add("next", ((Excel.Name)cell.Name).Name, true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); }

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• Memory leak of java.lang.ref.WeakReference objects inside JDK classes

  - by mandye

  The following simple code reproduces the growth of java.lang.ref.WeakReference objects in the heap: public static void main(String[] args) throws Exception { while (true) { java.util.logging.Logger.getAnonymousLogger(); Thread.sleep(1); } } Here is the output of jmap command within a few seconds interval: user@t1007:~ jmap -d64 -histo:live 29201|grep WeakReference 8: 22493 1079664 java.lang.ref.WeakReference 31: 1 32144 [Ljava.lang.ref.WeakReference; 106: 17 952 com.sun.jmx.mbeanserver.WeakIdentityHashMap$IdentityWeakReference user@t1007:~ jmap -d64 -histo:live 29201|grep WeakReference 8: 23191 1113168 java.lang.ref.WeakReference 31: 1 32144 [Ljava.lang.ref.WeakReference; 103: 17 952 com.sun.jmx.mbeanserver.WeakIdentityHashMap$IdentityWeakReference user@t1007:~ jmap -d64 -histo:live 29201|grep WeakReference 8: 23804 1142592 java.lang.ref.WeakReference 31: 1 32144 [Ljava.lang.ref.WeakReference; 103: 17 952 com.sun.jmx.mbeanserver.WeakIdentityHashMap$IdentityWeakReference Note that jmap command forces FullGC. JVM settings: export JVM_OPT="\ -d64 \ -Xms200m -Xmx200m \ -XX:MaxNewSize=64m \ -XX:NewSize=64m \ -XX:+UseParNewGC \ -XX:+UseConcMarkSweepGC \ -XX:MaxTenuringThreshold=10 \ -XX:SurvivorRatio=2 \ -XX:CMSInitiatingOccupancyFraction=60 \ -XX:+UseCMSInitiatingOccupancyOnly \ -XX:+CMSParallelRemarkEnabled \ -XX:+DisableExplicitGC \ -XX:+CMSClassUnloadingEnabled \ -XX:+PrintGCTimeStamps \ -XX:+PrintGCDetails \ -XX:+PrintTenuringDistribution \ -XX:+PrintGCApplicationConcurrentTime \ -XX:+PrintGCApplicationStoppedTime \ -XX:+PrintGCApplicationStoppedTime \ -XX:+PrintClassHistogram \ -XX:+ParallelRefProcEnabled \ -XX:SoftRefLRUPolicyMSPerMB=1 \ -verbose:gc \ -Xloggc:$GCLOGFILE" java version "1.6.0_18" Java(TM) SE Runtime Environment (build 1.6.0_18-b07) Java HotSpot(TM) Server VM (build 16.0-b13, mixed mode) Solaris 10/Sun Fire(TM) T1000

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• What Language Feature Can You Just Not Live Without?

  - by akdom

  I always miss python's built-in doc strings when working in other languages. I know this may seem odd, but it allows me to cut down significantly on excess comments while still providing a clean description of my code and any interfaces therein. What Language Feature Can You Just Not Live Without? If someone were building a new language and they asked you what one feature they absolutely must include, what would it be? This is getting kind of long, so I figured I'd do my best to summarize: Paraphrased to be language agnostic. If you know of a language which uses something mentioned, please at it in the parenthesis to the right of the feature. And if you have a better format for this list, by all means try it out (if it doesn't seem to work, I'll just roll back). Regular Expressions ~ torial (Perl) Garbage Collection ~ SaaS Developer (Python, Perl, Ruby, Java, .NET) Anonymous Functions ~ Vinko Vrsalovic (Lisp, Python) Arithmetic Operators ~ Jeremy Ross (Python, Perl, Ruby, Java, C#, Visual Basic, C, C++, Pascal, Smalltalk, etc.) Exception Handling ~ torial (Python, Java, .NET) Pass By Reference ~ Chris (Python) Unified String Format WalloWizard (C#) Generics ~ torial (Python, Java, C#) Integrated Query Equivalent to LINQ ~ Vyrotek (C#) Namespacing ~ Garry Shutler () Short Circuit Logic ~ Adam Bellaire ()

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• Lightweight spinlocks built from GCC atomic operations?

  - by Thomas

  I'd like to minimize synchronization and write lock-free code when possible in a project of mine. When absolutely necessary I'd love to substitute light-weight spinlocks built from atomic operations for pthread and win32 mutex locks. My understanding is that these are system calls underneath and could cause a context switch (which may be unnecessary for very quick critical sections where simply spinning a few times would be preferable). The atomic operations I'm referring to are well documented here: http://gcc.gnu.org/onlinedocs/gcc-4.4.1/gcc/Atomic-Builtins.html Here is an example to illustrate what I'm talking about. Imagine a RB-tree with multiple readers and writers possible. RBTree::exists() is read-only and thread safe, RBTree::insert() would require exclusive access by a single writer (and no readers) to be safe. Some code: class IntSetTest { private: unsigned short lock; RBTree<int>* myset; public: // ... void add_number(int n) { // Aquire once locked==false (atomic) while (__sync_bool_compare_and_swap(&lock, 0, 0xffff) == false); // Perform a thread-unsafe operation on the set myset->insert(n); // Unlock (atomic) __sync_bool_compare_and_swap(&lock, 0xffff, 0); } bool check_number(int n) { // Increment once the lock is below 0xffff u16 savedlock = lock; while (savedlock == 0xffff || __sync_bool_compare_and_swap(&lock, savedlock, savedlock+1) == false) savedlock = lock; // Perform read-only operation bool exists = tree->exists(n); // Decrement savedlock = lock; while (__sync_bool_compare_and_swap(&lock, savedlock, savedlock-1) == false) savedlock = lock; return exists; } }; (lets assume it need not be exception-safe) Is this code indeed thread-safe? Are there any pros/cons to this idea? Any advice? Is the use of spinlocks like this a bad idea if the threads are not truly concurrent? Thanks in advance. ;)

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• Java: Cleaning up what causes a connection reset

  - by Zombies

  There seems to be some confusion as well contradicting statements on various SO answers: http://stackoverflow.com/questions/585599/whats-causing-my-java-net-socketexception-connection-reset . You can see here that the accepted answer states that the connection was closed by other side. But this is not true, closing a connection doesn't cause a connection reset. It is cauesed by "an underlying TCP/IP error." What I want to know is if a SocketException: Connection reset means really besides "unerlying TCP/IP Error." What really causes this? As I doubt it has anything to do with the connection being closed (since closing a connection isn't an exception worthy flag, and reading from a closed connection is, but that isn't an "underlying TCP/IP error." My hypothesis is this Connection reset is caused from a server's failure to acknowledge an ACK packet (either wholly or just improperly as per TCP/IP). And that a SocketTimeoutException is generated only when no data is generated to be read (since this is thrown during a read after a certain duration, and read is waiting for data, but is not concerned with ACK packets). In other words, read() throws SocketTimeoutException if it didn't read any bytes of actual data (DATA LAYER) in its allotted time.

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• NullReferenceException when initializing NServiceBus within web application Application_Start method

  - by SteveBering

  I am running the 2.0 RTM of NServiceBus and am getting a NullReferenceException when my MessageModule binds the CurrentSessionContext to my NHibernate sessionfactory. From within my Application_Start, I call the following method: public static void WithWeb(IUnityContainer container) { log4net.Config.XmlConfigurator.Configure(); var childContainer = container.CreateChildContainer(); childContainer.RegisterInstance<ISessionFactory>(NHibernateSession.SessionFactory); var bus = NServiceBus.Configure.WithWeb() .UnityBuilder(childContainer) .Log4Net() .XmlSerializer() .MsmqTransport() .IsTransactional(true) .PurgeOnStartup(false) .UnicastBus() .ImpersonateSender(false) .LoadMessageHandlers() .CreateBus(); var activeBus = bus.Start(); container.RegisterInstance(typeof(IBus), activeBus); } When the bus is started, my message module starts with the following: public void HandleBeginMessage() { try { CurrentSessionContext.Bind(_sessionFactory.OpenSession()); } catch (Exception e) { _log.Error("Error occurred in HandleBeginMessage of NHibernateMessageModule", e); throw; } } In looking at my log, we are logging the following error when the bind method is called: System.NullReferenceException: Object reference not set to an instance of an object. at NHibernate.Context.WebSessionContext.GetMap() at NHibernate.Context.MapBasedSessionContext.set_Session(ISession value) at NHibernate.Context.CurrentSessionContext.Bind(ISession session) Apparently, there is some issue in getting access to the HttpContext. Should this call to configure NServiceBus occur later in the lifecycle than Application_Start? Or is there another workaround that others have used to get handlers working within an Asp.NET Web application? Thanks, Steve

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• Loading user controls programatically into a placeholder (asp.net(vb))

  - by Phil

  In my .aspx page I have; <%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" AspCompat="True" %> <%@ Register src="Modules/Content.ascx" tagname="Content" tagprefix="uc1" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <div> <asp:PlaceHolder ID="Modulecontainer" runat="server"></asp:PlaceHolder> </div> </form> </body> </html> In my aspx.vb I have; Try Dim loadmodule As Control loadmodule = Me.LoadControl("~/modules/content.ascx") Modulecontainer.Controls.Add(loadmodule) Catch ex As Exception Response.Write(ex.ToString & "<br />") End Try The result is an empty placeholder and no errors. Thanks a lot for any assistance

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• SQL Server SELECT stored procedure according to combobox.selectedvalue

  - by Jay

  In order to fill a datagridview according to the selectedvalue of a combobox I've tried creating a stored procedure. However, as I'm not 100% sure what I'm doing, depending on the WHERE statement at the end of my stored procedure, it either returns everything within the table or nothing at all. This is what's in my class: Public Function GetAankoopDetails(ByRef DisplayMember As String, ByRef ValueMember As String) As DataTable DisplayMember = "AankoopDetailsID" ValueMember = "AankoopDetailsID" If DS.Tables.Count > 0 Then DS.Tables.Remove(DT) End If DT = DAC.ExecuteDataTable(My.Resources.S_AankoopDetails, _Result, _ DAC.Parameter(Const_AankoopID, AankoopID), _ DAC.Parameter("@ReturnValue", 0)) DS.Tables.Add(DT) Return DT End Function Public Function GetAankoopDetails() As DataTable If DS.Tables.Count > 0 Then DS.Tables.Remove(DT) End If DT = DAC.ExecuteDataTable(My.Resources.S_AankoopDetails, _Result, _ DAC.Parameter(Const_AankoopID, AankoopID), _ DAC.Parameter("@ReturnValue", 0)) DS.Tables.Add(DT) Return DT End Function This is the function in the code behind the form I've written in order to fill the datagridview: Private Sub GridAankoopDetails_Fill() Try Me.Cursor = Cursors.WaitCursor dgvAankoopDetails.DataSource = Nothing _clsAankoopDetails.AankoopDetailsID = cboKeuze.SelectedValue dgvAankoopDetails.DataSource = _clsAankoopDetails.GetAankoopDetails Catch ex As Exception MessageBox.Show("An error occurred while trying to fill the data grid: " & ex.Message, "Oops!", MessageBoxButtons.OK) Finally Me.Cursor = Cursors.Default End Try End Sub And finally, this is my stored procedure: (do note that I'm not sure what I'm doing here) USE [Budget] GO /****** Object: StoredProcedure [dbo].[S_AankoopDetails] Script Date: 04/12/2010 03:10:52 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE [dbo].[S_AankoopDetails] ( @AankoopID int, @ReturnValue int output ) AS declare @Value int set @Value =@@rowcount if @Value = 0 begin SELECT dbo.tblAankoopDetails.AankoopDetailsID, dbo.tblAankoopDetails.AankoopID, dbo.tblAankoopDetails.ArtikelID, dbo.tblAankoopDetails.Aantal, dbo.tblAankoopDetails.Prijs, dbo.tblAankoopDetails.Korting, dbo.tblAankoopDetails.SoortKorting, dbo.tblAankoopDetails.UitgavenDeelGroepID FROM dbo.tblAankoopDetails INNER JOIN dbo.tblAankoop ON dbo.tblAankoopDetails.AankoopID = dbo.tblAankoop.AankoopID INNER JOIN dbo.tblArtikel ON dbo.tblAankoopDetails.ArtikelID = dbo.tblArtikel.ArtikelID INNER JOIN dbo.tblUitgavenDeelGroep ON dbo.tblAankoopDetails.UitgavenDeelGroepID = dbo.tblUitgavenDeelGroep.UitgavenDeelGroepID WHERE dbo.tblAankoopDetails.Deleted = 0 and dbo.tblAankoopDetails.AankoopID = @AankoopID ORDER BY AankoopID if @@rowcount >0 begin set @ReturnValue=999 end else begin set @ReturnValue=997 end end if @Value >0 begin --Dit wil zeggen dat ik een gebruiker wil ingeven die reeds bestaat. (998) set @ReturnValue=998 end Does anyone know what I need to do to resolve this?

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• Create an SQL Express 2008 database in C# code, but login fails when trying to connect with a sysadm

  - by Andrés Gonzales

  I have a piece of code that creates an SQL Server Express 2008 in runtime, and then tries to connect to it to execute a database initialization script in Transact-SQL. The code that creates the database is the following: private void CreateDatabase() { using (var connection = new SqlConnection( "Data Source=.\\sqlexpress;Initial Catalog=master;" + "Integrated Security=true;User Instance=True;")) { connection.Open(); using (var command = connection.CreateCommand()) { command.CommandText = "CREATE DATABASE " + m_databaseFilename + " ON PRIMARY (NAME=" + m_databaseFilename + ", FILENAME='" + this.m_basePath + m_databaseFilename + ".mdf')"; command.ExecuteNonQuery(); } } } The database is created successfully. After that, I try to connect to the database to run the initialization script, by using the following code: private void ExecuteQueryFromFile(string filename) { string queryContent = File.ReadAllText(m_filePath + filename); this.m_connectionString = string.Format( @"Server=.\SQLExpress; Integrated Security=true;Initial Catalog={0};", m_databaseFilename); using (var connection = new SqlConnection(m_connectionString)) { connection.Open(); using (var command = connection.CreateCommand()) { command.CommandText = queryContent; command.CommandTimeout = 0; command.ExecuteNonQuery(); } } } However, the connection.Open() statement fails, throwing the following exception: Cannot open database "TestData" requested by the login. The login failed. Login failed for user 'MYDOMAIN\myusername'. I am completely puzzled by this error because the account I am trying to connect with has sysadmin privileges, which should allow me to connect any database (notice that I use a connection to the master database to create the database in the first place).

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• android: tesseract force close

  - by Vishnu Mohan G

  I tried the tesseract tutorial here and get the following error: 06-03 01:18:52.626: E/AndroidRuntime(15103): FATAL EXCEPTION: main 06-03 01:18:52.626: E/AndroidRuntime(15103): java.lang.ExceptionInInitializerError 06-03 01:18:52.626: E/AndroidRuntime(15103): at o.c.r.LetsTryOCrActivity.onCreate(LetsTryOCrActivity.java:28) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1784) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.app.ActivityThread.access$1500(ActivityThread.java:123) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:939) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.os.Handler.dispatchMessage(Handler.java:99) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.os.Looper.loop(Looper.java:130) 06-03 01:18:52.626: E/AndroidRuntime(15103): at android.app.ActivityThread.main(ActivityThread.java:3835) 06-03 01:18:52.626: E/AndroidRuntime(15103): at java.lang.reflect.Method.invokeNative(Native Method) 06-03 01:18:52.626: E/AndroidRuntime(15103): at java.lang.reflect.Method.invoke(Method.java:507) 06-03 01:18:52.626: E/AndroidRuntime(15103): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847) 06-03 01:18:52.626: E/AndroidRuntime(15103): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605) 06-03 01:18:52.626: E/AndroidRuntime(15103): at dalvik.system.NativeStart.main(Native Method) 06-03 01:18:52.626: E/AndroidRuntime(15103): Caused by: java.lang.UnsatisfiedLinkError: Couldn't load lept: findLibrary returned null 06-03 01:18:52.626: E/AndroidRuntime(15103): at java.lang.Runtime.loadLibrary(Runtime.java:429) 06-03 01:18:52.626: E/AndroidRuntime(15103): at java.lang.System.loadLibrary(System.java:554) 06-03 01:18:52.626: E/AndroidRuntime(15103): at com.googlecode.tesseract.android.TessBaseAPI.(TessBaseAPI.java:42) 06-03 01:18:52.626: E/AndroidRuntime(15103): ... 14 more Please help me solve this. thanks in Advance!.

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• Cannot return view model after POST

  - by Interfector

  HI, I am trying to return a model after a POST but I receive the following error: Exception Details: System.InvalidOperationException: Operation is not valid due to the current state of the object. Line 29: public UsersModel getUser(Int32 id) { Line 30: return ( Line 31: from users in db.NUsers Line 32: join userSettings in db.NUsersSettings The code in the controller looks like this: [AcceptVerbs( HttpVerbs.Post )] public ActionResult Edit( NUsers user ) { //Other code that doesn't affect the error :) UsersModel userDetails = this.usersObj.getUser( user.UserID ); return View( userDetails ); } The getUser method looks like this: public UsersModel getUser(Int32 id) { return ( from users in db.NUsers join userSettings in db.NUsersSettings on users.UserID equals userSettings.UserID where users.UserID == id select new UsersModel { UserId = Convert.ToInt32( users.UserID ), Email = Convert.ToString( users.Email ), FirstName = Convert.ToString( users.FirstName ), LastName = Convert.ToString( users.LastName ), Language = Convert.ToString( userSettings.Language ), Phone = Convert.ToString( users.Phone ) } ).First(); } and finally the UsersModel if you think it is relevant: public class UsersModel { public int UserId; public string Email; public string FirstName; public string LastName; public string Language; public string Phone; public List<NLanguages> Languages; public UsersModel() { Models.Languages languagesObj = new Models.Languages(); Languages = languagesObj.getLanguages(); } } Any thoughts on what might be causing the error and what can I do to fix it? Thx

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