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  • Undefined behaviour with non-virtual destructors - is it a real-world issue?

    - by Roddy
    Consider the following code: class A { public: A() {} ~A() {} }; class B: public A { B() {} ~B() {} }; A* b = new B; delete b; // undefined behaviour My understanding is that the C++ standard says that deleting b is undefined behaviour - ie, anything could happen. But, in the real world, my experience is that ~A() is always invoked, and the memory is correctly freed. if B introduces any class members with their own destructors, they won't get invoked, but I'm only interested in the simple kind of case above, where inheritance is used maybe to fix a bug in one class method for which source code is unavailable. Obviously this isn't going to be what you want in non-trivial cases, but it is at least consistent. Are you aware of any C++ implementation where the above does NOT happen, for the code shown?

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  • how does serializable work in java?

    - by Karl Trumstedt
    If I have an instance of a class that I store in a session I need to make it serializable. This class has a static variable, will this be serialized in every instance stored? The static variable is a reference to a cache containing a lot of data in the background. Will all of this data be serialized? If so, it seems preferable to make this variable transient and re-fetch the cache instance each time the instance is restored. Maybe not store the cache instance at all in the class. Will the constructor execute when a class is restored from a serialized state? if not is there any other method I can use to re-instate a transient variable?

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  • PropertyGrid + interface

    - by nilphilus
    public interface ITest { void Somethink(); } public class Test1 : ITest { public void Somethink() { /* do stuff */ } public int Test1Property { get; set; } } public class Test2 : ITest { public void Somethink() { /* do stuff */ } public float Test2Property { get; set; } } //Main class public class MainClass { [TypeConverter(ExpandableObjectConverter)] public ITest test { get; set; } } Ok, i have sth like this. Instance of MainClass is selected by PropertyGrid. How to make a DropDownList of objects of classes which implement ITest (here Test1 and Test2)

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  • AngularJS not validating email field in form

    - by idipous
    I have the html below where I have a form that I want to submit to the AngularJS Controller. <div class="newsletter color-1" id="subscribe" data-ng-controller="RegisterController"> <form name="registerForm"> <div class="col-md-6"> <input type="email" placeholder="[email protected]" data-ng-model="userEmail" required class="subscribe"> </div> <div class="col-md-2"> <button data-ng-click="register()" class="btn btn-primary pull-right btn-block">Subsbcribe</button> </div> </form> </div> And the controller is below app.controller('RegisterController', function ($scope,dataFactory) { $scope.users = dataFactory.getUsers(); $scope.register = function () { var userEmail = $scope.userEmail; dataFactory.insertUser(userEmail); $scope.userEmail = null; $scope.ThankYou = "Thank You!"; } }); The problem is that no validation is taking place when I click the button. It is always routed to the controller although I do not supply a correct email. So every time I click the button I get the {{ThankYou}} variable displayed. Maybe I do not understand something.

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  • Using svn remove - preserve file on disk instead of having it deleted?

    - by user246114
    Hi, I am creating an eclipse project, which generates a lot of files I don't want to keep under version control. For example, it creates a project folder like: project/ bin/ horse.class cow.class src/ horse.java cow.java so what I do is add the project folder to svn, like: svn add project this puts everything under control, even the bin and .class files. All of those files will have the little 'a' next to them. How can I simply remove the 'add' status from those files? If I try: svn remove bin/horse.class I have to use the --force option and it deletes the file from disk. Is there a way to simply remove it from source but not delete the file from disk? Thanks

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  • C++ and Dependency Injection in unit testing

    - by lhumongous
    Suppose I have a C++ class like so: class A { public: A() { } void SetNewB( const B& _b ) { m_B = _b; } private: B m_B; } In order to unit test something like this, I would have to break A's dependency on B. Since class A holds onto an actual object and not a pointer, I would have to refactor this code to take a pointer. Additionally, I would need to create a parent interface class for B so I can pass in my own fake of B when I test SetNewB. In this case, doesn't unit testing with dependency injection further complicate the existing code? If I make B a pointer, I'm now introducing heap allocation, and some piece of code is now responsible for cleaning it up (unless I use ref counted pointers). Additionally, if B is a rather trivial class with only a couple of member variables and functions, why introduce a whole new interface for it instead of just testing with an instance of B? I suppose you could make the argument that it would be easier to refactor A by using an interface. But are there some cases where two classes might need to be tightly coupled?

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  • Many-to-one relation exception due to closed session after loading

    - by Nick Thissen
    Hi, I am using NHibernate (version 1.2.1) for the first time so I wrote a simple test application (an ASP.NET project) that uses it. In my database I have two tables: Persons and Categories. Each person gets one category, seems easy enough. | Persons | | Categories | |--------------| |--------------| | Id (PK) | | Id (PK) | | Firstname | | CategoryName | | Lastname | | CreatedTime | | CategoryId | | UpdatedTime | | CreatedTime | | Deleted | | UpdatedTime | | Deleted | The Id, CreatedTime, UpdatedTime and Deleted attributes are a convention I use in all my tables, so I have tried to bring this fact into an additional abstraction layer. I have a project DatabaseFramework which has three important classes: Entity: an abstract class that defines these four properties. All 'entity objects' (in this case Person and Category) must inherit Entity. IEntityManager: a generic interface (type parameter as Entity) that defines methods like Load, Insert, Update, etc. NHibernateEntityManager: an implementation of this interface using NHibernate to do the loading, saving, etc. Now, the Person and Category classes are straightforward, they just define the attributes of the tables of course (keeping in mind that four of them are in the base Entity class). Since the Persons table is related to the Categories table via the CategoryId attribute, the Person class has a Category property that holds the related category. However, in my webpage, I will also need the name of this category (CategoryName), for databinding purposes for example. So I created an additional property CategoryName that returns the CategoryName property of the current Category property, or an empty string if the Category is null: Namespace Database Public Class Person Inherits DatabaseFramework.Entity Public Overridable Property Firstname As String Public Overridable Property Lastname As String Public Overridable Property Category As Category Public Overridable ReadOnly Property CategoryName As String Get Return If(Me.Category Is Nothing, _ String.Empty, _ Me.Category.CategoryName) End Get End Property End Class End Namespace I am mapping the Person class using this mapping file. The many-to-one relation was suggested by Yads in another thread: <id name="Id" column="Id" type="int" unsaved-value="0"> <generator class="identity" /> </id> <property name="CreatedTime" type="DateTime" not-null="true" /> <property name="UpdatedTime" type="DateTime" not-null="true" /> <property name="Deleted" type="Boolean" not-null="true" /> <property name="Firstname" type="String" /> <property name="Lastname" type="String" /> <many-to-one name="Category" column="CategoryId" class="NHibernateWebTest.Database.Category, NHibernateWebTest" /> (I can't get it to show the root node, this forum hides it, I don't know how to escape the html-like tags...) The final important detail is the Load method of the NHibernateEntityManager implementation. (This is in C# as it's in a different project, sorry about that). I simply open a new ISession (ISessionFactory.OpenSession) in the GetSession method and then use that to fill an EntityCollection(Of TEntity) which is just a collection inheriting System.Collections.ObjectModel.Collection(Of T). public virtual EntityCollection< TEntity Load() { using (ISession session = this.GetSession()) { var entities = session .CreateCriteria(typeof (TEntity)) .Add(Expression.Eq("Deleted", false)) .List< TEntity (); return new EntityCollection< TEntity (entities); } } (Again, I can't get it to format the code correctly, it hides the generic type parameters, probably because it reads the angled symbols as a HTML tag..? If you know how to let me do that, let me know!) Now, the idea of this Load method is that I get a fully functional collection of Persons, all their properties set to the correct values (including the Category property, and thus, the CategoryName property should return the correct name). However, it seems that is not the case. When I try to data-bind the result of this Load method to a GridView in ASP.NET, it tells me this: Property accessor 'CategoryName' on object 'NHibernateWebTest.Database.Person' threw the following exception:'Could not initialize proxy - the owning Session was closed.' The exception occurs on the DataBind method call here: public virtual void LoadGrid() { if (this.Grid == null) return; this.Grid.DataSource = this.Manager.Load(); this.Grid.DataBind(); } Well, of course the session is closed, I closed it via the using block. Isn't that the correct approach, should I keep the session open? And for how long? Can I close it after the DataBind method has been run? In each case, I'd really like my Load method to just return a functional collection of items. It seems to me that it is now only getting the Category when it is required (eg, when the GridView wants to read the CategoryName, which wants to read the Category property), but at that time the session is closed. Is that reasoning correct? How do I stop this behavior? Or shouldn't I? And what should I do otherwise? Thanks!

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  • JQuery cycle plugin + PNG overlay + Image alt text as title conflict

    - by Dave
    I am trying to achive the following: Create an image gallery using the JQuery Cycle plugin that shows images with titles (taken from the alt text) Each image has a PNG absolutley posiioned over the top to achieve rounded corners effect Here's my gallery HTML: <div id="slideshow" class="pics"> <div class="photo-container" > <img src="/path/to/image" alt="alt text as title" /> <img class="mask" src="path/to/mask" /> </div> </div><!-- /slideshow --> <div id="title"></div> Here's my Jquery gallery function: $(function() { $('#slideshow').after('<div id="nav" class="nav"><span style="margin: 0 5px 0 30px;">next image</span>').cycle({ fx: 'fade', timeout: 0, cleartypeNoBg: true, pager: '#nav', next: '#slideshow', before: onBefore }); function onBefore() { $('#title').html(this.alt); } $('#nav a').after('<span>&gt;</span>') }); </script> Here is my CSS that handles the mask: .photo-container { position: relative; display: block; overflow:hidden; border: none; } img.mask { position: absolute; top: 0; left: 0; overflow:hidden; border: none; } The above does not output the alt text into the "title" div. When I remove the mask, it works: <div id="slideshow" class="pics"> <img src="/path/to/image" alt="alt text as title" /> </div><!-- /slideshow --> <div id="title"></div> Any ideas why the additonal div / image is casuing the title to not display? Thank you

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  • ruby subclass filter

    - by Nik
    Hey! Maybe I am getting the idea of a subclass wrong, but I have a Person model and it has an attrib called "age" so Person.first.age #=> '20' Now I want to have a model that's basically persons 55 or older so I know I can have a class like this: class Senior < Person end But how can I "pre-filter" the Senior class so that every object belonging to that class has age = 55? Senior.first.age #=> 56 Thanks!

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  • jQuery show/hide for FAQ using the next() function

    - by jon_brockman
    Maybe it's because it's Friday but I'm stuck on a simple problem. I'm building a FAQ page where a user clicks on a question, revealing the answer beneath it. I'm trying to get the next() function to just grab the next instance of an "answer" div but, despite not getting any JS errors, the hidden div isn't showing. Here's the code: .answer { display:none; } $("a.question").click(function(){ $(this).next(".answer").toggle(); }); <a href="#" class="question">Queston 1</a> <div class="answer">Answer 1</div> <a href="#" class="question">Queston 2</a> <div class="answer">Answer 2</div>

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  • calling a function from a set of overloads depending on the dynamic type of an object

    - by Jasper
    I feel like the answer to this question is really simple, but I really am having trouble finding it. So here goes: Suppose you have the following classes: class Base; class Child : public Base; class Displayer { public: Displayer(Base* element); Displayer(Child* element); } Additionally, I have a Base* object which might point to either an instance of the class Base or an instance of the class Child. Now I want to create a Displayer based on the element pointed to by object, however, I want to pick the right version of the constructor. As I currently have it, this would accomplish just that (I am being a bit fuzzy with my C++ here, but I think this the clearest way) object->createDisplayer(); virtual void Base::createDisplayer() { new Displayer(this); } virtual void Child::createDisplayer() { new Displayer(this); } This works, however, there is a problem with this: Base and Child are part of the application system, while Displayer is part of the GUI system. I want to build the GUI system independently of the Application system, so that it is easy to replace the GUI. This means that Base and Child should not know about Displayer. However, I do not know how I can achieve this without letting the Application classes know about the GUI. Am I missing something very obvious or am I trying something that is not possible?

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  • How get divs count in jquery?

    - by Pandiya Chendur
    I used this jquery each function and iterated my json data with it.... $.each(data.Results, function() { divs += '<div class="resultsdiv"><br /> <span style="display: inline-block;width:150px;" class="resultName">' + this.Mat_Name + '</span><span class="resultfields" style="padding-left:10px;"> Measurement&nbsp;:</span>&nbsp;<span class="resultfieldvalues">' + this.Mes_Name + '</span>&nbsp;<a href="/Materials/Delete/' + this.Id + '"> Delete</a>&nbsp;<a href="/Materials/Details/' + this.Id + '">Details</a>&nbsp; <a href="/Materials/Edit/' + this.Id + '">Edit</a></div>'; }); alert(divs.length); doesnt seem to get the count.... Any suggestion...

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  • Setting custom SQL in django admin

    - by eugene y
    I'm trying to set up a proxy model in django admin. It will represent a subset of the original model. The code from models.py: class MyManager(models.Manager): def get_query_set(self): return super(MyManager, self).get_query_set().filter(some_column='value') class MyModel(OrigModel): objects = MyManager() class Meta: proxy = True Now instead of filter() I need to use a complex SELECT statement with JOINS. What's the proper way to inject it wholly to the custom manager?

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  • Showing multiple elements onClick

    - by Nimbuz
    HTML: <ul id="mode"> <li><a href="#tab1">tab1</a> <div class="extra">tada</div> </li> <li><a href="#tab2">tab2</a> <div class="extra">tada</div> </li> </ul> <div id="tab1" class="tab-content" style="display: none">content 1</div> <div id="tab2" class="tab-content" style="display: none">content 2</div> ? jQuery: $(function(){ var mode = $('#mode'); var arrow = $('<span/>', {'class': 'arrow'}); $('li a', mode).bind('click.mytabs', function() { $('li', mode).removeClass('active'); $(this).parent().addClass('active').append(arrow); var a = $(this).attr('href'); $('.tab-content').hide(); $(a).show(); return false; }).filter(':first').triggerHandler('click.mytabs'); // eq(0) works as well }); JSFiddle here: http://jsfiddle.net/wwMJL/ I'd like to also show each li's 'extra' div on click and hide when the tab is inactive, what do I need to change in the code? Thanks!

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  • Comparing objects and inheritance

    - by ereOn
    Hi, In my program I have the following class hierarchy: class Base // Base is an abstract class { }; class A : public Base { }; class B : public Base { }; I would like to do the following: foo(const Base& one, const Base& two) { if (one == two) { // Do something } else { // Do something else } } I have issues regarding the operator==() here. Of course comparing an instance A and an instance of B makes no sense but comparing two instances of Base should be possible. (You can't compare a Dog and a Cat however you can compare two Animals) I would like the following results: A == B = false A == A = true or false, depending on the effective value of the two instances B == B = true or false, depending on the effective value of the two instances My question is: is this a good design/idea ? Is this even possible ? What functions should I write/overload ? My apologies if the question is obviously stupid or easy, I have some serious fever right now and my thinking abilities are somewhat limited :/ Thank you.

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  • Adding a ActionPerformed Array to a String Array

    - by user267490
    Hey, Before you guys ask, yes I've searched online for the answer, but everything I found just leaves a lil confuse and nothing is recent so asking in those forums won't really help. My problems is this: I have an array that holds my name for a menu. String[] fontColor = new String[] {"Red", "Blue", "Green"}; for (int i = 0; i < fontColors.length; i++) { JMenuItem fontC = new JMenuItem(fontColors[i]); fontC.addActionListener(new fontColorAction()); changeFontColor.add(fontC); } Then I have an array that holds my color change in a class called fontColorAction in that class I have another array that does the same thing as my string array except all thats in the statement is textarea.setForeground(colorArr[i]); that will set the setForeground() in order, but now how do I successfully attact the action listner in my class to my menuItems? my class looks like this private class fontColorAction implements ActionListener { Color[] colorArr - new Color[] {"Color.RED","Color.BLUE","Color.GREEN"}; public void actionPerformed(ActionEvent e){ for(i = 0; i < collorArr.length; i++){ textarea.setForeground(colorArr[i]); } } }

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  • Access asp:CheckBox inner input from jQuery

    - by abatishchev
    I have a jQuery array acting on each control having corresponding class: function Foobar() { $('.foo').each(function() { // do something with $(this) } } I can access client-side controls like <input class="foo"> and server-side controls like asp:TextBox CassClass="foo"> But setting CssClass for asp:RadioButton doesn't make a sense. Here is generated code: <span class="foo"> <input type="radio" /> </span> How to set class for inner input or another way gather it using jQuery?

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  • "Overriding" instance variables in subtype: Possible risks?

    - by sebastiangeiger
    Say I had a class SuperClass and two subclasses SubClassA and SubClassB that inherit from SuperClass. abstract class SuperClass{ ... List someList; ... } class SubClassA extends SuperClass{ ... List<String> someList; ... } class SubClassB extends SuperClass{ ... List<Integer> someList; ... } That way it is convenient because I can get someList.size() in Superclass and have Typesafety in the Subclasses. The problem is that it does not "feel" right, can you think of potential hazards this apporach has that I am not aware of?

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  • What's my best approach on this simple hierarchy Java Problem?

    - by Nazgulled
    First, I'm sorry for the question title but I can't think of a better one to describe my problem. Feel free to change it :) Let's say I have this abstract class Box which implements a couple of constructors, methods and whatever on some private variables. Then I have a couple of sub classes like BoxA and BoxB. Both of these implement extra things. Now I have another abstract class Shape and a few sub classes like Square and Circle. For both BoxA and BoxB I need to have a list of Shape objects but I need to make sure that only Square objects go into BoxA's list and only Circle objects go into BoxB's list. For that list (on each box), I need to have a get() and set() method and also a addShape() and removeShape() methods. Another important thing to know is that for each box created, either BoxA or BoxB, each respectively Shape list is exactly the same. Let's say I create a list of Square's named ls and two BoxA objects named boxA1 and boxA2. No matter what, both boxA1 and boxA2 must have the same ls list. This is my idea: public abstract class Box { // private instance variables public Box() { // constructor stuff } // public instance methods } public class BoxA extends Box { // private instance variables private static List<Shape> list; public BoxA() { // constructor stuff } // public instance methods public static List<Square> getList() { List<Square> aux = new ArrayList<Square>(); for(Square s : list.values()) { aux.add(s.clone()); // I know what I'm doing with this clone, don't worry about it } return aux; } public static void setList(List<Square> newList) { list = new ArrayList<Square>(newList); } public static void addShape(Square s) { list.add(s); } public static void removeShape(Square s) { list.remove(list.indexOf(s)); } } As the list needs to be the same for that type of object, I declared as static and all methods that work with that list are also static. Now, for BoxB the class would be almost the same regarding the list stuff. I would only replace Square by Triangle and the problem was solved. So, for each BoxA object created, the list would be only one and the same for each BoxB object created, but a different type of list of course. So, what's my problem you ask? Well, I don't like the code... The getList(), setList(), addShape() and removeShape() methods are basically repeated for BoxA and BoxB, only the type of the objects that the list will hold is different. I can't think of way to do it in the super class Box instead. Doing it statically too, using Shape instead of Square and Triangle, wouldn't work because the list would be only one and I need it to be only one but for each sub class of Box. How could I do this differently and better? P.S: I could not describe my real example because I don't know the correct words in English for the stuff I'm doing, so I just used a box and shapes example, but it's basically the same.

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  • How to implement a private virtual function within derived classes?

    - by Dane
    Hi, I know why I want to use private virtual functions, but how exactly can I implement them? For example: class Base{ [...] private: virtual void func() = 0; [...] } class Derived1: puplic Base{ void func() { //short implementation is ok here } } class Derived2: puplic Base{ void func(); //long implementation elsewhere (in cpp file) } [...] void Derived2::func() { //long implementation } The first version is ok but not always possible. Isn't the second version simply name hiding? How do you define the Base::func() of Derived2, if you cannot do it within the class declaration of Dereived2? Thanks

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  • How do I configure encodings (UTF-8) for code executed by Quartz scheduled Jobs in Spring framework

    - by Martin
    I wonder how to configure Quartz scheduled job threads to reflect proper encoding. Code which otherwise executes fine within Springframework injection loaded webapps (java) will get encoding issues when run in threads scheduled by quartz. Is there anyone who can help me out? All source is compiled using maven2 with source and file encodings configured as UTF-8. In the quartz threads any string will have encoding errors if outside ISO 8859-1 characters: Example config <bean name="jobDetail" class="org.springframework.scheduling.quartz.JobDetailBean"> <property name="jobClass" value="example.ExampleJob" /> </bean> <bean id="jobTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean"> <property name="jobDetail" ref="jobDetail" /> <property name="startDelay" value="1000" /> <property name="repeatCount" value="0" /> <property name="repeatInterval" value="1" /> </bean> <bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean"> <property name="triggers"> <list> <ref bean="jobTrigger"/> </list> </property> </bean> Example implementation public class ExampleJob extends QuartzJobBean { private Log log = LogFactory.getLog(ExampleJob.class); protected void executeInternal(JobExecutionContext ctx) throws JobExecutionException { log.info("ÅÄÖ"); log.info(Charset.defaultCharset()); } } Example output 2010-05-20 17:04:38,285 1342 INFO [QuartzScheduler_Worker-9] ExampleJob - vÖvÑvñ 2010-05-20 17:04:38,286 1343 INFO [QuartzScheduler_Worker-9] ExampleJob - UTF-8 The same lines of code executed within spring injected beans referenced by servlets in the web-container will output proper encoding. What is it that make Quartz threads encoding dependent?

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  • What do you name the "other" kind of view-model in an MVVM project?

    - by DanM
    With MVVM, I think of a view-model as a class that provides all the data and commands that a view needs to bind to. But what happens when I have a database entity object, say a Customer, and I want to build a class that shapes or flattens the Customer class for use in a data grid. For example, maybe this special Customer object would have a property TotalOrders, which is actually calculated using a join with a collection of Order entities. My question is, what do I call this special Customer class? In other situations, I'd be tempted to call it a CustomerViewModel, but I feel like "overloading" the notion of a view-model like this would be confusing in an MVVM project. What would you suggest?

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  • creating new instance fails PHP

    - by as3isolib
    I am relatively new to PHP and having some decent success however I am running into this issue: If I try to create a new instance of the class GenericEntryVO, I get a 500 error with little to no helpful error information. However, if I use a generic object as the result, I get no errors. I'd like to be able to cast this object as a GenericEntryVO as I am using AMFPHP to communicate serialize data with a Flex client. I've read a few different ways to create constructors in PHP but the typical 'public function Foo()' for a class Foo was recommended for PHP 5.4.4 //in my EntryService.php class public function getEntryByID($id) { $link = mysqli_connect("localhost", "root", "root", "BabyTrackingAppDB"); if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); exit(); } $query = "SELECT * FROM Entries WHERE id = '$id' LIMIT 1"; if ($result = mysqli_query($link, $query)) { // $entry = new GenericEntryVO(); this is where the problem lies! while ($row = mysqli_fetch_row($result)) { $entry->id = $row[0]; $entry->entryType = $row[1]; $entry->title = $row[2]; $entry->description = $row[3]; $entry->value = $row[4]; $entry->created = $row[5]; $entry->updated = $row[6]; } } mysqli_free_result($result); mysqli_close($link); return $entry; } //my GenericEntryVO.php class <?php class GenericEntryVO { public function __construct() { } public $id; public $title; public $entryType; public $description; public $value; public $created; public $updated; // public $properties; } ?>

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