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  • DRY jQuery for RESTful PUT/DELETE links

    - by Aupajo
    I'm putting together PUT/DELETE links, a la Rails, which when clicked create a POST form with an hidden input labelled _method that sends the intended request type. I want to make it DRYer, but my jQuery knowledge isn't up to it. HTML: <a href="/articles/1" class="delete">Destroy Article 1</a> <a href="/articles/1/publish" class="put">Publish Article 1</a> jQuery: $(document).ready(function() { $('.delete').click(function() { if(confirm('Are you sure?')) { var f = document.createElement('form'); $(this).after($(f).attr({ method: 'post', action: $(this).attr('href') }).append('<input type="hidden" name="_method" value="DELETE" />')); $(f).submit(); } return false; }); $('.put').click(function() { var f = document.createElement('form'); $(this).after($(f).attr({ method: 'post', action: $(this).attr('href') }).append('<input type="hidden" name="_method" value="PUT" />')); $(f).submit(); return false; }); });

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  • Objective C Naming Convention for an object that owns itself

    - by Ed Marty
    With the latest releases of XCode that contain static analyzers, some of my objects are throwing getting analyzer issues reported. Specifically, I have an object that owns itself and is responsible for releasing itself, but should also be returned to the caller and possibly retained there manually. If I have a method like + (Foo) newFoo the analyzer sees the word New and reports an issue in the caller saying that newFoo is expected to return an object with retain +1, and it isn't being released anywhere. If I name it + (Foo) getFoo the analyzer reports an issue in that method, saying there's a potential leak because it's not deallocated before returning. My class basically looks like this: + (Foo *) newFoo { Foo *myFoo = [[[Foo new] retain] autorelease]; [myFoo performSelectorInBackground:@selector(bar) withObject:nil]; return myFoo; } - (void) bar { //Do something that might take awhile [self release]; } The object owns itself and when its done, will release itself, but there's nowhere that it's being stored, so the static analyzer sees it as a leak somewhere. Is there some naming or coding convention to help?

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  • Multiple forms + HAML + jQuery + Javascript submit

    - by Jay Godse
    Hi. I have a HAML page that lists some links to delete "things" that looks like this %div %a.form_submit Delete Thing 1 %form{:href=>"#", :id=>'comment_1', :method=>'post', :action=>'/thing/delete'} %input{:type=>'hidden', :name=>'thingid', :value=>'1'} %input{:type=>'submit', style='display:none'} %div %a.form_submit Delete Thing 22 %form{:href=>"#", :id=>'comment_22', :method=>'post', :action=>'/thing/delete'} %input{:type=>'hidden', :name=>'thingid', :value=>'22'} %input{:type=>'submit', style='display:none'} The intention is to have a link "Delete XX" which will delete something specific. A page could have a number of these links, and each link is for a specific "thing". I also have a piece of (unobtrusive) jQuery javascript that adds a click handler to each form as follows: $('a.form_submit').click(function(event) { $('form').submit(); event.preventDefauilt(); }); This works when there is one form on a page. However, if I have more than one form on a page, how do I ensure that clicking "Delete Thing 1" will trigger a submit() event only on the form with id='comment_1'?

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  • Job queueing and execute Mechanism

    - by Calm Storm
    In my webservice all method calls submits jobs to a queue. Basically these operations take long time to execute, so all these operations submit a Job to a queue and return a status saying "Submitted". Then the client keeps polling using another service method to check for the status of the job. Presently, what I do is create my own Queue, Job classes that are Serializable and persist these jobs (i.e, their serialized byte stream format) into the database. So an UpdateLogistics operation just queues up a "UpdateLogisticsJob" to the queue and returns. I have written my own JobExecutor which wakes up every N seconds, scans the database table for any existing jobs, and executes them. Note the jobs have to persisted because these jobs have to survive app-server crashes. This was done a long time ago, and I used bespoke classes for my Queues, Jobs, Executors etc. But now, I would like to know has someone done something similar before? In particular, Are there frameworks available for this ? Something in Spring/Apache etc Any framework that is easy to adapt/debug and plays well along with libraries like Spring will be great.

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  • Error in Android's clearCheck() for RadioGroup?

    - by Manuel R. Ciosici
    I'm having an issue with RadioGroup's clearChecked(). I'm displaying a multiple choice question to the user and after the user selects an answer I check the answer, give him some feedback and then move to the next question. In the process of moving to the next question I clearCheck on the RadioGroup. Can anyone explain to me why the onCheckedChanged method is called 3 times? Once when the change actually occurs (with the user changes), once when I clearCheck(with -1 as the selected id) and once in between (with the user changes again)? As far as I could tell the second trigger is provoked by clearCheck. Code below: private void checkAnswer(RadioGroup group, int checkedId){ // this makes sure it doesn't blow up when the check is cleared // also we don't check the answer when there is no answer if (checkedId == -1) return; if (group.getCheckedRadioButtonId() == -1) return; // check if correct answer if (checkedId == validAnswerId){ score++; this.giveFeedBack(feedBackType.GOOD); } else { this.giveFeedBack(feedBackType.BAD); } // allow for user to see feedback and move to next question h.postDelayed(this, 800); } private void changeToQuestion(int questionNumber){ if (questionNumber >= this.questionSet.size()){ // means we are past the question set // we're going to the score activity this.goToScoreActivity(); return; } //clearing the check gr.clearCheck(); // give change the feedback back to question imgFeedback.setImageResource(R.drawable.question_mark); //OTHER CODE HERE } and the run method looks like this public void run() { questionNumber++; changeToQuestion(questionNumber); }

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  • In Safari, using jQuery a Form Input Text Field does not receive focus after alert is displayed. Why

    - by Rob
    I have an ASPX web form. I use jQuery to simply my Javascript. I use a Javascript validation script to validate each of the form fields' values. If an error occurs, I popup an alert with an error message. Then I transfer focus to the underlying element. Here are examples I have tried. Using jQuery: var Form_FieldDef = function(name) { this.name = name; this.SetFocus = function() { $('#' + this.name)[0].focus(); } this.Validate = function() { var isvalid = true; if ( $.trim($('#' + this.name).val()) == '') { alert("Your entry is empty"); this.SetFocus(); isvalid = false; } return isvalid; } } This works on IE7, IE8, Opera, Chrome, and Firefox. It does not work on Safari 4 on PC. I don't have a Mac. So I changed the SetFocus method to this. this.SetFocus = function() { var fld = document.getElementById(this.name); if (fld != null) fld.focus(); } This works on IE7, IE8, Opera, Chrome, and Firefox. It does not work on Safari 4 on PC. I stepped through the code with VS 2008 debugger, and I'm calling the focus method on the underlying element.

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  • Same random numbers from instantiated class

    - by user1797202
    I'm learning C# and created a class within my program that holds a random number generator: class RandomNumberGenerator { Random RNG = new Random(); // A bunch of methods that use random numbers are in here } Inside this class are a few methods that use the RNG. Data gets sent here from other parts of the program, gets processed, then gets returned. One of the methods does the following: // Method works something like this int Value1 = RNG.Next(x, y); int Value2 = RNG.Next(x, y); int Value3 = RNG.Next(x, y); The x, y values are to be sent here from another class. So, I have to create an instance of the RandomNumberGenerator within that class so I can call its methods and pass the x and y values to it. class DoStuff { RandomNumberGenerator Randomizer = new RandomNumberGenerator // Here I call a bunch of Randomizer methods that give me values I need } The problem in the above method is that I get the same numbers every time for all three values. I'm not sure if it's because they're so close together and Randomizer's seed value hasn't had time to change or if I'm doing something wrong when I create a new instance of the RandomNumberGenerator class. I've gone through a bunch of answers on here already and typically problems like this are due to people creating many new Random objects when they run methods (thus setting the seed for all of them to the same value), but the only new Random object I create is within the RandomNumberGenerator class. I then instantiate that once within the other class so I can pass it data and use its methods. Why is this happening and how would I fix this?

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  • Django Save Incomplete Progress on Form

    - by jimbob
    I have a django webapp with multiple users logging in and fill in a form. Some users may start filling in a form and lack some required data (e.g., a grant #) needed to validate the form (and before we can start working on it). I want them to be able to fill out the form and have an option to save the partial info (so another day they can log back in and complete it) or submit the full info undergoing validation. Currently I'm using ModelForm for all the forms I use, and the Model has constraints to ensure valid data (e.g., the grant # has to be unique). However, I want them to be able to save this intermediary data without undergoing any validation. The solution I've thought of seems rather inelegant and un-django-ey: create a "Save Partial Form" button that saves the POST dictionary converts it to a shelf file and create a "SavedPartialForm" model connecting the user to partial forms saved in the shelf. Does this seem sensible? Is there a better way to save the POST dict directly into the db? Or is an add-on module that does this partial-save of a form (which seems to be a fairly common activity with webforms)? My biggest concern with my method is I want to eventually be able to do this form-autosave automatically (say every 10 minutes) in some ajax/jquery method without actually pressing a button and sending the POST request (e.g., so the user isn't redirected off the page when autosave is triggered). I'm not that familiar with jquery and am wondering if it would be possible to do this.

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  • Detect modification of variable at runtime in C/C++

    - by YuppieNetworking
    Hello, I am developing a library in C++ where users/programmer will extend a class BaseClass that has a method initArray. This method should be implemented by the user/programmer and it should normally initialize all elements of the array m_arr. Here is a snipplet, modified to this example: class BaseClass { public: BaseClass(int n) { m_arr = new double[n]; size = n; }; virtual ~BaseClass(); int size; double* m_arr; virtual int initArray(); }; Sometimes, the user/programmer implements a initArray that does not initialize some elements of m_arr. What I would like is to create a function in my library that checks if initArray did initialize all elements of m_arr. This function should be called by a sanity-check rutine at runtime. My question: is it possible to detect changes on this array? I can only think of initializing the array with some invalid values (like NaN or Inf), call initArray and check that all values have changed. Thanks for your ideas, David

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  • Linked List Inserting strings in alphabetical order

    - by user69514
    I have a linked list where each node contains a string and a count. my insert method needs to inset a new node in alphabetical order based on the string. if there is a node with the same string, then i increment the count. the problem is that my method is not inserting in alphabetical order public Node findIsertionPoint(Node head, Node node){ if( head == null) return null; Node curr = head; while( curr != null){ if( curr.getValue().compareTo(node.getValue()) == 0) return curr; else if( curr.getNext() == null || curr.getNext().getValue().compareTo(node.getValue()) > 0) return curr; else curr = curr.getNext(); } return null; } public void insert(Node node){ Node newNode = node; Node insertPoint = this.findIsertionPoint(this.head, node); if( insertPoint == null) this.head = newNode; else{ if( insertPoint.getValue().compareTo(node.getValue()) == 0) insertPoint.getItem().incrementCount(); else{ newNode.setNext(insertPoint.getNext()); insertPoint.setNext(newNode); } } count++; }

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  • Is it OK to set state within Event Raising methods?

    - by Greg
    I ran across this pattern in the code of a library I'm using. It sets state within the event raising method, but only if the event is not null. protected virtual void OnMyEvent(EventArgs e) { if(MyEvent != null) { State = "Executing"; // Only sets state if MyEvent != null. MyEvent(this,e); } } Which means that the state is not set when overriding the method: protected override void OnMyEvent(EventArgs e) { base.OnMyEvent(e); Debug.Assert( State == "Executing" ); // This fails } but is only set when handling the event: foo.MyEvent += (o, args) => Debug.Assert(State == "Executing"); // This passes Setting state within the if(MyEvent != null) seems like bad form, but I've checked the Event Design Guidelines and it doesn't mention this. Do you think this code is incorrect? If so, why? (Reference to design guidelines would be helpful). Edit for Context: It's a Control, I'm trying to create subclass of it, and the state that it's setting is calling EnsureChildControls() conditionally based upon there being an event handler. I can call EnsureChildControls() myself, but I consider that something of a hack.

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  • Implementations details of drag and drop of file path in cocoa.

    - by foo
    Hi, I'm trying to get a part of my window to react to drag and drop. In this case to copy the file path to the file being dropped on the view. I have looked over some documentation but I still have some problems to see exactly where I should implement my methods for drag and drop. I have seen some examples but almost all of them assumes that I want to drop an image on the view. I'm pretty new to cocoa and Xcode so, I have some problems with seeing the exact relation between interface builder and the generated code. I have created a subclass to NSView, called drop zone like this: #import <Cocoa/Cocoa.h> @interface dropZone : NSView { } @end I then use an NSRect to color it grey like this: #import "dropZone.h" @implementation dropZone - (void)drawRect:(NSRect)rect { NSRect bounds = [self bounds]; [[NSColor grayColor] set]; [NSBezierPath fillRect:bounds]; } @end I then drag this class to my window in interface builder. But I will need to implement the registerForDraggingTypes method, but where? I have also seen a convenience method in the Apple docs for file paths like this: dragFile:fromRect:slideBack:event: that might work.

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  • REST design: what verb and resource name to use for a filtering service

    - by kabaros
    I am developing a cleanup/filtering service that has a method that receives a list of objects serialized in xml, and apply some filtering rules to return a subset of those objects. In a REST-ful service, what verb shall I use for such a method? I thought that GET is a natural choice, but I have to put the serialized XML in the body of the request which works but feels incorrect. The other verbs don't seem to fit semantically. What is a good way to define that Service interface? Naming the resource /Cleanup or /Filter seems weird mainly because in the examples I see online, it is always a name rather than a verb being used for resource name. Am I right to feel that REST services are better suited for CRUD operations and you start bending the rules in situations like this service? If yes, am I then making a wrong architectural choice. I've pushed to develop this service in REST-ful style (as opposed to SOAP) for simplicity, but such awkward cases happen a lot and make me feel like I am missing something. Either choosing REST where it shouldn't be used or may be over-thinking some stuff that doesn't really matter? In that case, what really matters?

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  • C++ creating generic template function specialisations

    - by Fire Lancer
    I know how to specialise a template function, however what I want to do here is specialise a function for all types which have a given method, eg: template<typename T> void foo(){...} template<typename T, if_exists(T::bar)>void foo(){...}//always use this one if the method T::bar exists T::bar in my classes is static and has different return types. I tried doing this by having an empty base class ("class HasBar{};") for my classes to derive from and using boost::enable_if with boost::is_base_of on my "specialised" version. However the problem then is that for classes that do have bar, the compiler cant resolve which one to use :(. template<typename T> typename boost::enable_if<boost::is_base_of(HasBar, T>, void>::type f() {...} I know that I could use boost::disable_if on the "normal" version, however I do not control the normal version (its provided by a third party library and its expected for specialisations to be made, I just don't really want to make explicit specialisations for my 20 or so classes), nor do I have that much control over the code using these functions, just the classes implementing T::bar and the function that uses it. Is there some way to tell the compiler to "always use this version if possible no matter what" without altering the other versions?

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  • Django Admin Running Same Query Thousands of Times for Model

    - by Tom
    Running into an odd . . . loop when trying to view a model in the Django admin. I have three related models (code trimmed for brevity, hopefully I didn't trim something I shouldn't have): class Association(models.Model): somecompany_entity_id = models.CharField(max_length=10, db_index=True) name = models.CharField(max_length=200) def __unicode__(self): return self.name class ResidentialUnit(models.Model): building = models.CharField(max_length=10) app_number = models.CharField(max_length=10) unit_number = models.CharField(max_length=10) unit_description = models.CharField(max_length=100, blank=True) association = models.ForeignKey(Association) created = models.DateTimeField(auto_now_add=True) updated = models.DateTimeField(auto_now=True) def __unicode__(self): return '%s: %s, Unit %s' % (self.association, self.building, self.unit_number) class Resident(models.Model): unit = models.ForeignKey(ResidentialUnit) type = models.CharField(max_length=20, blank=True, default='') lookup_key = models.CharField(max_length=200) jenark_id = models.CharField(max_length=20, blank=True) user = models.ForeignKey(User) is_association_admin = models.BooleanField(default=False, db_index=True) show_in_contact_list = models.BooleanField(default=False, db_index=True) created = models.DateTimeField(auto_now_add=True) updated = models.DateTimeField(auto_now=True) _phones = {} home_phone = None work_phone = None cell_phone = None app_number = None account_cache_key = None def __unicode__(self): return '%s' % self.user.get_full_name() It's the last model that's causing the problem. Trying to look at a Resident in the admin takes 10-20 seconds. If I take 'self.association' out of the __unicode__ method for ResidentialUnit, a resident page renders pretty quickly. Looking at it in the debug toolbar, without the association name in ResidentialUnit (which is a foreign key on Resident), the page runs 14 queries. With the association name put back in, it runs a far more impressive 4,872 queries. The strangest part is the extra queries all seem to be looking up the association name. They all come from the same line, the __unicode__ method for ResidentialUnit. Each one is the exact same thing, e.g., SELECT `residents_association`.`id`, `residents_association`.`jenark_entity_id`, `residents_association`.`name` FROM `residents_association` WHERE `residents_association`.`id` = 1096 ORDER BY `residents_association`.`name` ASC I assume I've managed to create a circular reference, but if it were truly circular, it would just die, not run 4000x and then return. Having trouble finding a good Google or StackOverflow result for this.

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  • android listview order changed when called notifyDataSetChanged

    - by 9nix00
    hi,all. when I use notifyDataSetChanged(), the listview display order will be change . like this 3 2 1 when current activy was created. but when I change the data. it will be 1 2 3 I don't want the order changed and i dont understand why its happening. This is a piece of code from my adapter class public static class ItemAdapter extends BaseAdapter { private String[] mData; private LayoutInflater mInflater; // I called this method to change data public void setEditText(int position, final String item) { mData[position] = item; notifyDataSetChanged(); } } I change data at some dialog like this builder = new AlertDialog.Builder(ct); builder.setTitle(R.string.pickStatus) .setView(edBuffer) .setPositiveButton(R.string.save, new DialogInterface.OnClickListener() { @Override public void onClick( DialogInterface dialog, int id) { // TODO Auto-generated method stub canPop = true; final String tmp = edBuffer.getText().toString(); KbonezLog.e(String.format( "set into key %d", key)); //use mData key to set value setEditText(key, tmp); dialog.dismiss(); }})

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  • Why can a public class not inherit from a less visible one?

    - by Dan Tao
    I apologize if this question has been asked before. I've searched SO somewhat and wasn't able to find it. I'm just curious what the rationale behind this design was/is. Obviously I understand that private/internal members of a base type cannot, nor should they, be exposed through a derived public type. But it seems to my naive thinking that the "hidden" parts could easily remain hidden while some base functionality is still shared and a new interface is exposed publicly. I'm thinking of something along these lines: Assembly X internal class InternalClass { protected virtual void DoSomethingProtected() { // Let's say this method provides some useful functionality. // Its visibility is quite limited (only to derived types in // the same assembly), but at least it's there. } } public class PublicClass : InternalClass { public void DoSomethingPublic() { // Now let's say this method is useful enough that this type // should be public. What's keeping us from leveraging the // base functionality laid out in InternalClass's implementation, // without exposing anything that shouldn't be exposed? } } Assembly Y public class OtherPublicClass : PublicClass { // It seems (again, to my naive mind) that this could work. This class // simply wouldn't be able to "see" any of the methods of InternalClass // from AssemblyX directly. But it could still access the public and // protected members of PublicClass that weren't inherited from // InternalClass. Does this make sense? What am I missing? }

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  • Objective C iPhone performance issue

    - by Asad Khan
    Ok guys I am developing an iPhone app I have a Model class which follows a Singleton design pattern. Now I have an NSArray in it which is initialized to around some 1000 NSStrings in the init method. Now I need to use this data in some view controller. so I import Model.h, I create an array of NSString objects in view controller & set the data to it. But now the problem is that now I have 2000 NSStrings currently allocated, which I believe is not a good thing on iPhone due to memory considerations. releasing model object wont help because I've overrided release method to release nothing according to the pattern & I cannot change the design now because now a lot of code works on the assumption of model being a singleton. & in future maybe the initial NSStrings may grow to 2000 or even more & then I'll have 4000 NSStrings allocated at one time .... I am a little confused on how to go about it any suggestions

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  • how to pass value to controller??

    - by rajesh
    When I try to pass url value to controller action, action is not getting the required value. I'm sending the value like this: function value(url,id) { alert(url); document.getElementById('rating').innerHTML=id; var params = 'artist='+id; alert(params); // var newurl='http://localhost/songs_full/public/eslresult/ratesong/userid/1/id/27'; var myAjax = new Ajax.Request(newurl,{method: 'post',parameters:params,onComplete: loadResponse}); //var myAjax = new Ajax.Request(url,{method:'POST',parameters:params,onComplete: load}); //alert(myAjax); } function load(http) { alert('success'); } and in the controller I have: public function ratesongAction() { $user=$_POST['rating']; echo $user; $post= $this->getRequest()->getPost(); //echo $post; $ratesongid= $this->_getParam('id'); } But still not getting the result. I am using zend framework.

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  • Accessing my own datalayer using RIA & Silverlight

    - by Norsten
    Is it possible for me to connect to my own data provide via WCF RIA services? I've created a small datalayer that connnects to DynamicAX datasource. I would like to use Silverlight 4 & RIA service to access that datalayer. At it's most basic -I've done the following... 1) I've added an empty domainclass to the webproject and in that class I created a simple method to return a string... [EnableClientAccess()] public class ProjectService : DomainService { public string TestViaRIA() { return "Hello!"; } } 2) I then added reference to the web project in my silvelight class and created a bit of code to try and invoke the method... using ProjectApp.Web; namespace ProjectApp.Views { public partial class ProjectControl : UserControl { public ProjectControl() { InitializeComponent(); ProjectContext ctx = new ProjectContext(); var x = ctx.TestViaRIA(); testTextBox.Text = x.ToString(); } } } the returned value is "{System.ServiceModel.DomainServices.Client.InvokeOperation}". I'm obviously doing something wrong here and I would appreciate some guidance on how I can achive this. Thanks in advance

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  • Is it possible to cancel function override in parent class and use function from top level parent

    - by Anatoliy Gusarov
    class TopParent { protected function foo() { $this->bar(); } private function bar() { echo 'Bar'; } } class MidParent extends TopParent { protected function foo() { $this->midMethod(); parent::foo(); } public function midMethod() { echo 'Mid'; } public function generalMethod() { echo 'General'; } } Now the question is if I have a class, that extends MidParent because I need to call class Target extends MidParent { //How to override this method to return TopParent::foo(); ? protected function foo() { } } So I need to do this: $mid = new MidParent(); $mid->foo(); // MidBar $taget = new Target(); $target->generalMethod(); // General $target->foo(); // Bar UPDATE Top parent is ActiveRecord class, mid is my model object. I want to use model in yii ConsoleApplication. I use 'user' module in this model, and console app doesn't support this module. So I need to override method afterFind, where user module is called. So the Target class is the class that overrides some methods from model which uses some modules that console application doesn't support.

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  • Why does my plist file exist even when I've uninstalled an app and wiped the simulator?

    - by just_another_coder
    I am trying to detect the existence of a plist file on application start. When my data class (descendant of NSObject) is initialized, it loads the plist file. Before it loads, it checks to see if the file exists, and if it doesn't, it sets the data = nil instead of trying to process the array of data in the plist file. However, every time it starts it indicates the file exists. Even when I uninstall the app in the organizer and when wiping the simulator directory (iPhone Simulator/3.0/Applications). I have the following static method in a library class named FileIO: +(BOOL) fileExists:(NSString *)fileName { NSString *path = [FileIO getPath:fileName]; // gets the path to the docs directory if ([[NSFileManager defaultManager] fileExistsAtPath:path]) return YES; else return NO; } In my data class: //if( [FileIO fileExists:kFavorites_Filename] ) [FileIO deleteFile:kFavorites_Filename]; if ([FileIO fileExists:kFavorites_Filename]) {NSLog(@"exists"); The "exists" is logged every time unless I un-comment the method to delete the file. How can the file exist if I've deleted the app? I've deleted the simulator directory and uninstalled on the device but both say it still exists. What gives???

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  • std::bad_cast from parent to child?

    - by polyglot
    For simplicity, class Parent {} class Child1 : Parent {} class Child2 : Parent {} Elsewhere, I created instances of Child1 and Child2 and store it in same vector under Parent: // . . . in .h file, for example vector<Parent> vector_of_parent; // . . . in one particular method Child1 c1(); Child2 c2(); vector_of_parent.push_back(c1); vector_of_parent.push_back(c2); // . . . Then in another method which has access to vector_of_parent, I tried void doSomething(Parent& some_child) { // wrapped in a try block somehow... Child1& c = dynamic_cast<Child1&> some_child; // do something if the cast is successful } void otherMethod() { doSomething(vector_of_parent.at(0)); // vector_of_parent.at(0) is a Child1 } Why is there a std:bad_cast when I call otherMethod()?

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  • Setting Cursor property has no effect (C#)

    - by Knarf Navillus
    Hello, I have a class that I've derived from System.Windows.Forms.Panel, and my application has a main form with one of these panels. On the whole, the panel works great! The only thing I'm having trouble with is setting the cursor. Whether I'm setting it to one of the static members of the Cursors class (Default, WaitCursor, etc.) or setting it to a custom cursor that I've loaded from a resource, the end result is the same: it does nothing. I still see the default mouse pointer, no matter what. This line of code is inside a method of my panel-derived class: this.Cursor = Cursors.WaitCursor; I can set a break point there, and see that this line is being hit when I expect it to. I've also created an override for the OnCursorChanged method, and set a breakpoint in there just to see if it's being triggered. I can verify that both breakpoints are being hit when I expect them to. However, the cursor just never changes. There must be something that I'm missing. Does anyone have any ideas? P.S. I also did try setting Current.Cursor as well, however that did not help.

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  • How do I make a lock that allows only ONE thread to read from the resource ?

    - by mare
    I have a file that holds an integer ID value. Currently reading the file is protected with ReaderWriterLockSlim as such: public int GetId() { _fileLock.EnterUpgradeableReadLock(); int id = 0; try { if(!File.Exists(_filePath)) CreateIdentityFile(); FileStream readStream = new FileStream(_filePath, FileMode.Open, FileAccess.Read); StreamReader sr = new StreamReader(readStream); string line = sr.ReadLine(); sr.Close(); readStream.Close(); id = int.Parse(line); return int.Parse(line); } finally { SaveNextId(id); // increment the id _fileLock.ExitUpgradeableReadLock(); } } The problem is that subsequent actions after GetId() might fail. As you can see the GetId() method increments the ID every single time, disregarding what happens after it has issued an ID. The issued ID might be left hanging (as said, exceptions might occur). As the ID is incremented, some IDs might be left unused. So I was thinking of moving the SaveNextId(id) out, remove it (the SaveNextId() actually uses the lock too, except that it's EnterWriteLock). And call it manually from outside after all the required methods have executed. That brings out another problem - multiple threads might enter the GetId() method before the SaveNextId() gets executed and they might all receive the same ID. I don't want any solutions where I have to alter the IDs after the operation, correcting them in any way because that's not nice and might lead to more problems. I need a solution where I can somehow callback into the FileIdentityManager (that's the class that handles these IDs) and let the manager know that it can perform the saving of the next ID and then release the read lock on the file containing the ID. Essentialy I want to replicate the relational databases autoincrement behaviour - if anything goes wrong during row insertion, the ID is not used, it is still available for use but it also never happens that the same ID is issued. Hopefully the question is understandable enough for you to provide some solutions..

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