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  • JSTL expression evaluation from a string

    - by Venkatesh
    Is it possible to evaluate a String as EL expression in JSP and get value from it? I need an expression like ${model.${fieldPath}} where fieldPath will contain the required object path from a nested object model. I can get the actual field path by using but I am not sure how to evaluate a string and get the value from it Any help regarding this would be highly appreciated.

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  • How do I write sql data into a textbox after a submit type event

    - by Matt
    Finishing up some homework and Im having trouble with figuring out how to take information generated in sql column(a primary key set up to assign a record number to a customer example 1046) at submit and writing it to my redirected recipt page. I call it recipt.aspx. Any takers Professor says to use a datareader...but things go bad after that. public partial class _Default : System.Web.UI.Page { String cnStr = "EDITED FOR THE PURPOSE OF NOT DISPLAYED SQL SERVERta Source=111.11.111.11; uid=xxxxxxx; password=xxxx; database=xxxxxx; "; String insertStr; SqlDataReader reader; SqlConnection myConnection = new SqlConnection(); protected void submitbutton_Click(object sender, EventArgs e) { myConnection.ConnectionString = cnStr; try { //more magic happens as myConnection opens myConnection.Open(); insertStr = "insert into connectAssignment values ('" + TextBox2.Text + "','" + TextBox3.Text + "','" + TextBox4.Text + "','" + TextBox5.Text + "','" + bigtextthing.Text + "','" + DropDownList1.SelectedItem.Value + "')"; //magic happens as Connection string is assigned to connection object and passes in the SQL statment //associate the command to the the myConnection connection object SqlCommand cmd = new SqlCommand(insertStr, myConnection); cmd.ExecuteNonQuery(); Session["passmyvalue1"] = TextBox2.Text; Session["passmyvalue2"] = TextBox3.Text; Session["passmyvalue3"] = TextBox4.Text; Session["passmyvalue4"] = TextBox5.Text; Session["passmyvalue5"] = bigtextthing.Text; Session["I NEED SOME HELP RIGHT HERE"] =Textbox6.Text; Response.Redirect("receipt.aspx"); } catch { bigtextthing.Text = "Error submitting" + "Possible casues: Internet is down,server is down, check your settings!"; } finally { myConnection.Close(); TextBox2.Text = ""; TextBox3.Text = ""; TextBox4.Text = ""; TextBox5.Text = ""; bigtextthing.Text = ""; } //reset validators? } The recipt page public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if(Session["passmyvalue1"] != null) { TextBox1.Text = (string)Session["passmyvalue1"]; TextBox2.Text = (string)Session["passmyvalue2"]; TextBox3.Text = (string)Session["passmyvalue3"]; TextBox4.Text = (string)Session["passmyvalue4"]; TextBox5.Text = (string)Session["passmyvalue5"]; TextBox6.Text = I don't know ; } } } THanks for the help

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  • Why would an error get thrown inside my try-catch?

    - by George Johnston
    Why would my try-catch block still be throwing an error when it's handled? Exception Details: System.NullReferenceException: Object reference not set to an instance of an object. Try Here >> : _MemoryStream.Seek(6 * StartOffset, 0) _MemoryStream.Read(_Buffer, 0, 6) Catch ex As IOException // Handle Error End Try Edit: Cleaned the question up to remove the extraneous information.

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  • Activity gets killed while executing the camera intent

    - by BlackRider
    In my app I call the system camera to take a picture, and then handle the result in onActivityResult. You know, the usual. It used to work, but now my calling activity gets killed while I'm taking the picture. Specifically, onDestroy() is called on my activity right after I press the camera shutter. The photo does get taken & saved (I've checked that the file gets written on the SD card). After I accept the photo, instead of returning to the calling activity and invoking onActivityResult, the previous activity in the activity stack gets called. I see no exceptions in the logcat. My custom exception handler doesn't get called. If it matters, my app also includes a service that listens to GPS updates, but I unregister all the receivers in onPause(). Here's the call stack for MyCallingActivity.onDestroy(): Thread [<1> main] (Suspended (breakpoint at line 303 in NewPlaceDetailsActivity)) NewPlaceDetailsActivity.onDestroy() line: 303 ActivityThread.performDestroyActivity(IBinder, boolean, int, boolean) line: 2663 ActivityThread.handleDestroyActivity(IBinder, boolean, int, boolean) line: 2694 ActivityThread.access$2100(ActivityThread, IBinder, boolean, int, boolean) line: 117 BinderProxy(ActivityThread$H).handleMessage(Message) line: 968 ActivityThread$H(Handler).dispatchMessage(Message) line: 99 Looper.loop() line: 130 ActivityThread.main(String[]) line: 3687 Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method] Method.invoke(Object, Object...) line: 507 ZygoteInit$MethodAndArgsCaller.run() line: 842 ZygoteInit.main(String[]) line: 600 NativeStart.main(String[]) line: not available [native method] This is how I start the camera activity, in case you're wondering: protected void startCamera() { createPhotoDirsIfNeeded(); String fileName = "temp.jpg"; ContentValues values = new ContentValues(); values.put(MediaStore.Images.Media.TITLE, fileName); m_capturedImageUri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values); m_photoFileName = APP_PHOTO_PATH + "/" + DateFormat.format(DATE_FORMAT, Calendar.getInstance().getTime()) + ".jpg"; File picFile = new File(m_photoFileName); if(picFile.exists()) { picFile.delete(); } // start the camera activity Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(picFile)); startActivityForResult(intent, IntentHelper.REQUEST_TAKE_PHOTO); } How can I find out why does my activity get killed, AND removed from the stack instead of being created again?

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  • Random <hr/> that I don't know how to get rid of!

    - by Anonymous the Great
    There is no extra <hr/> on the page, and I cannot figure out why it is there. Do you see anything that is causing it? I am sorry for posting the whole thing, I do not know exactly where it starts. The <hr/> is at the top somewhere, but I'm not sure where. <?php print "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"; ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <font face="Segoe UI"> <body> <script type="text/javascript"> /*function detectBrowser() { var browser = navigator.appCodeName; if (browser!="Mozilla") {document.location.href="noaccess.php"; alert(browser);} } detectBrowser(); */ </script> <title>Second</title> <link rel="stylesheet" type="text/css" href="allCSS.css"/> <center> <!--<img align="right" src="logo.png" id="headerimg"/>--> <input type="image" id="headerimg" src="logo.png" align="right" onclick="toggleh();"/> <ul align="center" class=""> <div class="menu"> <ul class="nav"> <li><strong><a href="index.php">Home</a></strong> <ul> <li><a href="games.php">Games</a></li> <li><a href="browse.php">Browse</a></li> <li><a href="catalogue.php">Catalogue</a></li> <li><a href="forum.php">Forums</a></li> </ul> </li> <li><strong><a href="games">Games</a></strong> <ul> <li><a href="profile.php">Profile</a></li> <li><a href="settings.php">Settings</a></li> </ul> </li> <li><strong><a href="contact">Contact</a></strong> <ul> <li><a href="contact/index.php">Phone</a></li> <li><a href="contact/index.php">Email</a></li> <li><a href="contact/index.php">Mail</a></li> </ul> </li> </div> </center> </body> <center> <?php echo '<div id="msg">'; include 'message.txt'; echo '</div>'; //include 'hits.txt'; ?> <p> <?php function ChangeText($txt) { $txt='<script type="text/javascript">get();</script>'; echo '<script type="text/javascript">change();</script>'; $filename="message.txt"; $fp=fopen($filename,'w'); fwrite($fp,'<h4 class="hmsg">' . $txt . '</h4>'); fclose($fp); } ?> <script type="text/javascript"> <!-- window.onload=enter; function enter() { //alert("Welcome!"); //hideCMD(); } function get(text) { text=document.getElementById("ta").value; return text; } function toggleh() { var element=document.getElementById("headerimg"); if (element.style.display!="none"){element.style.display="none";} else {element.style.display="";} } function change(text) { text=document.getElementById("ta").value; if (text=="toggle") {toggleh(); return;} if (text=="home") {document.location.href="index.html"; return;} if (text.match("goto:*")) {var loc=text.substring(5,text.length); document.location.href=loc; return;} if (text.match("ban:*")) {var loc=text.substring(4,text.length); document.location.href=loc; return;} document.getElementById("msg").innerHTML='<h2 class="hmsg">'+text+'</h2>'; } function hideCMD() { document.getElementById("cmd").style.display="none"; } //--> </script> </head> <body> <div id="msg"> </div> <p id="cmd"> <hr class="cmdbar"></hr> <input class="panela" type="text" value="" id="ta" maxLength="20"/> <input class="panelb" type="image" src="submit.png" alt="Submit" onclick='change();'/> </p> </center> <p class="hide">HELLO!</p> </font> </html>

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  • Objective-C retain counts in dealloc

    - by Michael Waterfall
    I'm seeing something fairly strange here, I've got breakpoints set in various dealloc methods in my app, and on inspection, the retain counts of the object self varies from 1 to 0. When dealloc is called, will the retain count of the object be set to 0 already? I'm using print (int) [self retainCount] in the console to test this. The 0's seem to only appear in the dealloc of my NSOperation's that are being run in an NSOperationQueue. Any idea why this is?

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  • Design pattern for adding / removing elements

    - by de3
    Wikipedia's definition for Iterator pattern design: the Iterator pattern is a design pattern in which iterators are used to access the elements of an aggregate object sequentially without exposing its underlying implementation. Iterator interface in java provides the following methods hasNext() next() remove() Is there a pattern design, or a java interface for inserting / deleting elements, and getting length of the aggregate object, in addition to iterating them? I know remove() is an optional method that can be used once per call to next(), but I am implementing a circular FIFO array and need a method delete() independent of iterator's next().

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  • understanding z buffer formates direct x

    - by numerical25
    A z buffer is just a 3d array that shows what object should be written in front of another object. each element in the array represents a pixel that holds a value from 0.0 to 1.0. My question is if that is all a z buffer does, then why are some buffers 24bit, 32bit, and 16 bit ??

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  • Ambiguous scénario for iPhone memory management

    - by gotye
    Hey guys, i have some difficulties to understand this scénario ... i create an object i set its retained property to something i Forget to release its property i release the object as i didn't release the property in the dealloc method, Will the scénario result in a memory leak or Will the property be released automatically ? And yes, i read the memory management guide ;) cheers, gotye.

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  • Forms Designer Error Display HTML Source

    - by Pranay Rana
    I i am unable to see the design view of a winform app Errors are: One or more errors encountered while loading the designer. The errors are listed below. Some errors can be fixed by rebuilding your project, while others may require code changes. The event Click is read-only and cannot be changed. at System.ComponentModel.Design.EventBindingService.EventPropertyDescriptor.SetValue(Object component, Object value) at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeAttachEventStatement(IDesignerSerializationManager manager, CodeAttachEventStatement statement) at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeStatement(IDesignerSerializationManager manager, CodeStatement statement)

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  • Database Schema for Machine Tags?

    - by Gabriel
    Machine tags are more precise tags: http://www.flickr.com/groups/api/discuss/72157594497877875. They allow a user to basically tag anything as an object in the format object:property=value Any tips on a rdbms schema that implements this? Just wondering if anyone has already dabbled with this. I imagine the schema is quite similar to implementing rdf triples in a rdbms

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  • VB.NET Get Assembly Version information

    - by Berlioz
    How do I get my .NET Winforms app 2.0 to automatically update it's publish revision integer subsequent to issuing the publish command from within VS08. Trying to use the following C# as a guide object[] attrs = System.Reflection.Assembly.GetEntryAssembly().GetCustomAttributes(true); foreach (object o in attrs) if (o.GetType() == typeof(System.Reflection.AssemblyFileVersionAttribute)) label1.Text = ((System.Reflection.AssemblyFileVersionAttribute) o).Version;

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  • What is the difference between using IDisposable vs a destructor in C#?

    - by j0rd4n
    When would I implement IDispose on a class as opposed to a destructor? I read this article, but I'm still missing the point. My assumption is that if I implement IDispose on an object, I can explicitly 'destruct' it as opposed to waiting for the garbage collector to do it. Is this correct? Does that mean I should always explicitly call Dispose on an object? What are some common examples of this?

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  • Can a class Extend or Override himself?

    - by EBAGHAKI
    Suppose we have a class. We create an object from the class and when we do the class Extends himself base on the object initialization value.. For example: $objectType1 = new Types(1); $objectType1->Activate(); // It calls an activation function for type 1 $objectType2 = new Types(2); $objectType2->Activate(); // It calls an activation function for type 2 I don't want to use the standard procedure of class extending: class type1 extends types{}

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  • Do i need to dispose of MySqlCommand?

    - by acidzombie24
    I find it incredibly annoying to write a using statement on every one of my queries (which require its own command or write parameters.clear()) which sometimes require declaring variables outside of the using block. Its so incredibly annoying and looks much dirtier compared to the version without disposing the object. Do i need to dispose of it? what happens if i dont? I do know its good practice to dispose of an object when it has that interface.

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  • c# event fires windows form incorrectly

    - by MikeW
    I'm trying to understand what's happening here. I have a CheckedListBox which contains some ticked and some un-ticked items. I'm trying to find a way of determining the delta in the selection of controls. I've tried some cumbersome like this - but only works part of the time, I'm sure there's a more elegant solution. A maybe related problem is the myCheckBox_ItemCheck event fires on form load - before I have a chance to perform an ItemCheck. Here's what I have so far: void clbProgs_ItemCheck(object sender, ItemCheckEventArgs e) { // i know its awful System.Windows.Forms.CheckedListBox cb = (System.Windows.Forms.CheckedListBox)sender; string sCurrent = e.CurrentValue.ToString(); int sIndex = e.Index; AbstractLink lk = (AbstractLink)cb.Items[sIndex]; List<ILink> _links = clbProgs.DataSource as List<ILink>; foreach (AbstractLink lkCurrent in _links) { if (!lkCurrent.IsActive) { if (!_groupValues.ContainsKey(lkCurrent.Linkid)) { _groupValues.Add(lkCurrent.Linkid, lkCurrent); } } } if (_groupValues.ContainsKey(lk.Linkid)) { AbstractLink lkDirty = (AbstractLink)lk.Clone(); CheckState newValue = (CheckState)e.NewValue; if (newValue == CheckState.Checked) { lkDirty.IsActive = true; } else if (newValue == CheckState.Unchecked) { lkDirty.IsActive = false; } if (_dirtyGroups.ContainsKey(lk.Linkid)) { _dirtyGroups[lk.Linkid] = lkDirty; } else { CheckState oldValue = (CheckState)e.NewValue; if (oldValue == CheckState.Checked) { lkDirty.IsActive = true; } else if (oldValue == CheckState.Unchecked) { lkDirty.IsActive = false; } _dirtyGroups.Add(lk.Linkid, lk); } } else { if (!lk.IsActive) { _dirtyGroups.Add(lk.Linkid, lk); } else { _groupValues.Add(lk.Linkid, lk); } } } Then onclick of a save button - I check whats changed before sending to database: private void btSave_Click(object sender, EventArgs e) { List<AbstractLink> originalList = new List<AbstractLink>(_groupValues.Values); List<AbstractLink> changedList = new List<AbstractLink>(_dirtyGroups.Values); IEnumerable<AbstractLink> dupes = originalList.ToArray<AbstractLink>().Intersect(changedList.ToArray<AbstractLink>()); foreach (ILink t in dupes) { MessageBox.Show("Changed"); } if (dupes.Count() == 0) { MessageBox.Show("No Change"); } } For further info. The definition of type AbstractLink uses: public bool Equals(ILink other) { if (Object.ReferenceEquals(other, null)) return false; if (Object.ReferenceEquals(this, other)) return true; return IsActive.Equals(other.IsActive) && Linkid.Equals(other.Linkid); }

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  • Enterprise Library--Validator.cs How Abstract Class having definition??

    - by Soham
    Consider this piece of code: public abstract class Validator { protected Validator() { } protected abstract void ValidateCore(object instance, string value, IList<ValidationResult> results); public void Validate(object instance, string value, IList<ValidationResult> results) { if (null == instance) throw new ArgumentNullException("instance"); if (null == results) throw new ArgumentNullException("results"); ValidateCore(instance, value, results); } } TAKE a look at Validate() overload, how can an abstract class have definitions like this?

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  • Instance Failure in asp.net

    - by user85511
    I have a web application that is working perfectly in my system. However, when I copied it to another system, I couldn't login to the application. There is an error: Server Error in '/' Application. -------------------------------------------------------------------------------- Instance failure. 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.InvalidOperationException: Instance failure. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [InvalidOperationException: Instance failure.] System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject) +4858423 System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) +90 System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) +257 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +221 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +189 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +4859187 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) +31 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) +433 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) +66 System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) +499 System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +65 System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +117 System.Data.SqlClient.SqlConnection.Open() +122 System.Web.DataAccess.SqlConnectionHolder.Open(HttpContext context, Boolean revertImpersonate) +87 System.Web.DataAccess.SqlConnectionHelper.GetConnection(String connectionString, Boolean revertImpersonation) +221 System.Web.Security.SqlMembershipProvider.GetPasswordWithFormat(String username, Boolean updateLastLoginActivityDate, Int32& status, String& password, Int32& passwordFormat, String& passwordSalt, Int32& failedPasswordAttemptCount, Int32& failedPasswordAnswerAttemptCount, Boolean& isApproved, DateTime& lastLoginDate, DateTime& lastActivityDate) +815 System.Web.Security.SqlMembershipProvider.CheckPassword(String username, String password, Boolean updateLastLoginActivityDate, Boolean failIfNotApproved, String& salt, Int32& passwordFormat) +105 System.Web.Security.SqlMembershipProvider.CheckPassword(String username, String password, Boolean updateLastLoginActivityDate, Boolean failIfNotApproved) +42 System.Web.Security.SqlMembershipProvider.ValidateUser(String username, String password) +78 System.Web.UI.WebControls.Login.AuthenticateUsingMembershipProvider(AuthenticateEventArgs e) +60 System.Web.UI.WebControls.Login.OnAuthenticate(AuthenticateEventArgs e) +119 System.Web.UI.WebControls.Login.AttemptLogin() +115 System.Web.UI.WebControls.Login.OnBubbleEvent(Object source, EventArgs e) +101 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37 System.Web.UI.WebControls.Button.OnCommand(CommandEventArgs e) +118 System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +166 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565 -------------------------------------------------------------------------------- Version Information: Microsoft .NET Framework Version:2.0.50727.3053; ASP.NET Version:2.0.50727.3053 What could be the reason for such an error? How could I solve this?

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  • LoadClip problem

    - by Mango
    Hi, i have a loadClip problem. appears in the movie in the final stage, not do the movie animation. Any Tip? appears in the film as the final stage, not so animation var imageListener:Object = new Object(); var imageLoader:MovieClipLoader = new MovieClipLoader(); imageLoader.addListener(imageListener); imageLoader.loadClip("handsketch_animation.swf", pages_cont); stop();

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  • JSON parsing using JSON.net

    - by vbNewbie
    I am accessing the facebook api and using the json.net library (newtonsoft.json.net) I declare a Jobject to parse the content and look for the specific elements and get their values. Everything works fine for the first few but then I get this unexplained nullexception error " (Object reference not set to an instance of an object) Now I took a look at the declaration but cannot see how to change it. Any help appreciated: Dim jobj as JObject = JObject.Parse(responseData) Dim message as string = string.empty message = jobj("message").tostring The error occurs at the last line above.

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  • What's the life-time of a thread-local value in Python?

    - by Carlos Valiente
    import threading mydata = threading.local() def run(): # When will the garbage collector be able to destroy the object created # here? After the thread exits from ``run()``? After ``join()`` is called? # Or will it survive the thread in which it was created, and live until # ``mydata`` is garbage-collected? mydata.foo = object() t = threading.Thread(target=run) t.start() t.join()

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  • Using Core Data Concurrently and Reliably

    - by John Topley
    I'm building my first iOS app, which in theory should be pretty straightforward but I'm having difficulty making it sufficiently bulletproof for me to feel confident submitting it to the App Store. Briefly, the main screen has a table view, upon selecting a row it segues to another table view that displays information relevant for the selected row in a master-detail fashion. The underlying data is retrieved as JSON data from a web service once a day and then cached in a Core Data store. The data previous to that day is deleted to stop the SQLite database file from growing indefinitely. All data persistence operations are performed using Core Data, with an NSFetchedResultsController underpinning the detail table view. The problem I am seeing is that if you switch quickly between the master and detail screens several times whilst fresh data is being retrieved, parsed and saved, the app freezes or crashes completely. There seems to be some sort of race condition, maybe due to Core Data importing data in the background whilst the main thread is trying to perform a fetch, but I'm speculating. I've had trouble capturing any meaningful crash information, usually it's a SIGSEGV deep in the Core Data stack. The table below shows the actual order of events that happen when the detail table view controller is loaded: Main Thread Background Thread viewDidLoad Get JSON data (using AFNetworking) Create child NSManagedObjectContext (MOC) Parse JSON data Insert managed objects in child MOC Save child MOC Post import completion notification Receive import completion notification Save parent MOC Perform fetch and reload table view Delete old managed objects in child MOC Save child MOC Post deletion completion notification Receive deletion completion notification Save parent MOC Once the AFNetworking completion block is triggered when the JSON data has arrived, a nested NSManagedObjectContext is created and passed to an "importer" object that parses the JSON data and saves the objects to the Core Data store. The importer executes using the new performBlock method introduced in iOS 5: NSManagedObjectContext *child = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType]; [child setParentContext:self.managedObjectContext]; [child performBlock:^{ // Create importer instance, passing it the child MOC... }]; The importer object observes its own MOC's NSManagedObjectContextDidSaveNotification and then posts its own notification which is observed by the detail table view controller. When this notification is posted the table view controller performs a save on its own (parent) MOC. I use the same basic pattern with a "deleter" object for deleting the old data after the new data for the day has been imported. This occurs asynchronously after the new data has been fetched by the fetched results controller and the detail table view has been reloaded. One thing I am not doing is observing any merge notifications or locking any of the managed object contexts or the persistent store coordinator. Is this something I should be doing? I'm a bit unsure how to architect this all correctly so would appreciate any advice.

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