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  • How do I alias the scala setter method 'myvar_$(myval)' to something more pleasing when in java?

    - by feydr
    I've been converting some code from java to scala lately trying to tech myself the language. Suppose we have this scala class: class Person() { var name:String = "joebob" } Now I want to access it from java so I can't use dot-notation like I would if I was in scala. So I can get my var's contents by issuing: person = Person.new(); System.out.println(person.name()); and set it via: person = Person.new(); person.name_$eq("sallysue"); System.out.println(person.name()); This holds true cause our Person Class looks like this in javap: Compiled from "Person.scala" public class Person extends java.lang.Object implements scala.ScalaObject{ public Person(); public void name_$eq(java.lang.String); public java.lang.String name(); public int $tag() throws java.rmi.RemoteException; } Yes, I could write my own getters/setters but I hate filling classes up with that and it doesn't make a ton of sense considering I already have them -- I just want to alias the _$eq method better. (This actually gets worse when you are dealing with stuff like antlr because then you have to escape it and it ends up looking like person.name_\$eq("newname"); Note: I'd much rather have to put up with this rather than fill my classes with more setter methods. So what would you do in this situation?

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  • C++ destructor problem with boost::scoped_ptr

    - by bb-generation
    I have a question about the following code: #include <iostream> #include <boost/scoped_ptr.hpp> class Interface { }; class A : public Interface { public: A() { std::cout << "A()" << std::endl; } virtual ~A() { std::cout << "~A()" << std::endl; } }; Interface* get_a() { A* a = new A; return a; } int main() { { std::cout << "1" << std::endl; boost::scoped_ptr<Interface> x(get_a()); std::cout << "2" << std::endl; } std::cout << "3" << std::endl; } It creates the following output: 1 A() 2 3 As you can see, it doesn't call the destructor of A. The only way I see to get the destructor of A being called, is to add a destructor for the Interface class like this: virtual ~Interface() { } But I really want to avoid any Implementation in my Interface class and virtual ~Interface() = 0; doesn't work (produces some linker errors complaining about a non existing implementation of ~Interface(). So my question is: What do I have to change in order to make the destructor being called, but (if possible) leave the Interface as an Interface (only abstract methods).

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  • Conversion between different template instantiation of the same template

    - by Naveen
    I am trying to write an operator which converts between the differnt types of the same implementation. This is the sample code: template <class T = int> class A { public: A() : m_a(0){} template <class U> operator A<U>() { A<U> u; u.m_a = m_a; return u; } private: int m_a; }; int main(void) { A<int> a; A<double> b = a; return 0; } However, it gives the following error for line u.m_a = m_a;. Error 2 error C2248: 'A::m_a' : cannot access private member declared in class 'A' d:\VC++\Vs8Console\Vs8Console\Vs8Console.cpp 30 Vs8Console I understand the error is because A<U> is a totally different type from A<T>. Is there any simple way of solving this (may be using a friend?) other than providing setter and getter methods? I am using Visual studio 2008 if it matters.

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  • jQuery slideDown + CSS Floats

    - by danilo
    I'm using a HTML Table with several rows. Every second row - containing details about the preceding row - is hidden using CSS. When clicking the first row, the second row gets showed using jQuery show(). This is quite nice, but I would prefer the slideDown-Effect. The problem is, inside the details row, there are two floating DIVs, one floating on the left, and one on the right. Now if i slideDown the previously hidden row, the contained DIVs behave strange and "jump around". See this animated gif to understand what I mean: http://ich-wars-nicht.ch/tmp/lunapic_127365879362365_.gif The markup: <tr class="row-vm"> <td>...</td> ... </tr> <tr class="row-details"> <td colspan="8"> <div class="vmdetail-left"> ... </div> <div class="vmdetail-right"> ... </div> </td> </tr> The CSS: .table-vmlist tr.row-details { display: none; } div.vmdetail-left { float: left; width: 50%; } div.vmdetail-right { float: right; width: 50%; } And the jQuery code: if ($(this).next().css('display') == 'none') { // Show details //$(this).next().show(); $(this).next().slideDown(); } else { // Hide details //$(this).next().hide(); $(this).next().slideUp(); } Is there a way to fix this behavior, and to implement a nice slideDown-effect?

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  • ItemUpdating called twice after ItemAdded in event receiver

    - by Jason
    I've created an event receiver to handle the ItemAdded and ItemUpdating events on a document library in SharePoint 2010. I've encountered a problem where when I add a document to the library (e.g. by saving it back from Word) the ItemAdded method is correctly called however this is then followed by two calls to ItemUpdating. I have removed all code from my handlers to ensure that it's not something I'm doing inside that is causing the problem. They literally look like: public override void ItemUpdating(SPItemEventProperties properties) { } public override void ItemAdded(SPItemEventProperties properties) { } Does anyone have a solution to this issue? Here is my elements.xml file for the event receiver: <Elements xmlns="http://schemas.microsoft.com/sharepoint/"> <Receivers ListTemplateId="101"> <Receiver> <Name>DocumentsEventReceiverItemUpdating</Name> <Type>ItemUpdating</Type> <Assembly>$SharePoint.Project.AssemblyFullName$</Assembly> <Class>My.Namespace.DocumentsEventReceiver</Class> <SequenceNumber>10000</SequenceNumber> <Synchronization>Synchronous</Synchronization> </Receiver> <Receiver> <Name>DocumentsEventReceiverItemAdded</Name> <Type>ItemAdded</Type> <Assembly>$SharePoint.Project.AssemblyFullName$</Assembly> <Class>My.Namespace.DocumentsEventReceiver</Class> <SequenceNumber>10000</SequenceNumber> <Synchronization>Synchronous</Synchronization> </Receiver> </Receivers> </Elements>

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  • Measuring how "heavily linked" a node is in a graph

    - by Eduardo León
    I have posted this question at MathOverflow.com as well. I am no mathematician and English is not my first language, so please excuse me if my question is too stupid, it is poorly phrased, or both. I am developing a program that creates timetables. My timetable-creating algorithm, besides creating the timetable, also creates a graph whose nodes represent each class I have already programmed, and whose arcs represent which pairs of classes should not be programmed at the same time, even if they have to be reprogrammed. The more "heavily linked" a node is, the more inflexible its associated class is with respect to being reprogrammed. Sometimes, in the middle of the process, there will be no option but to reprogram a class that has already been programmed. I want my program to be able to choose a class that, if reprogrammed, affects the least possible number of other already-programmed classes. That would mean choosing a node in the graph that is "not very heavily linked", subject to some constraints with respect to which nodes can be chosen. EDIT: The question was... Do you know any algorithm that measures how "heavily linked" a node is?

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  • Preserving timestamps on Clojure .clj files when building shaded jar via Maven Shade Plugin

    - by Dereference
    When using the maven-shade-plugin to package our jar artifact that contained a few Clojure libs and some Java. We were using AOT compilation for our Clojure code. When we loaded the jar, it was having very slow load times. AOT compilation is supposed to help this quite a bit, but that wasn't what we were seeing. We noticed in java jar -verbose output that there was a lot of JVM__DEFINE_CLASS calls happening when Clojure classes were being loaded. This didn't make sense, since more of our Clojure code was AOT compiled to .class files. Turns out the maven-shade-plugin creates all new files, with new timestamps in the final artifact Clojure uses the timestamp information on a .clj file vs. a .class file, to determine if the file needs to be recompiled. The maven-shade-plugin was causing the .clj file and it's associated .class file to have the same timestamp, so Clojure always chose to dynamically recompile the source. The only workaround that we have been able to figure out, at this point, is to write a script that would re-open the shaded jar and bump the .clj file timestamps back to some time in the past, so that they wouldn't be equal to the timestamps of their associated .class files. Does anyone know of a better approach?

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  • Hibernate Search + Spring

    - by Zane
    I'm trying to integrate Hibernate Search with Spring, but I can't seem to index anything. I was able to get Hibernate Search to work without Spring, but I'm having a problem integrating it with Spring. Any help would be much appreciated. Below is my springmvc-servlet.xml: <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean"> <property name="persistenceUnitName" value="enewsclipsPersistenceUnit" /> </bean> And here is my DAO class: @Repository public class SearchDaoImpl implements SearchDao { JpaTemplate jpaTemplate; @Autowired public SearchDaoImpl(EntityManagerFactory entityManagerFactory) { this.jpaTemplate = new JpaTemplate(entityManagerFactory); } @SuppressWarnings("unchecked") public void updateSearchIndex() { /* Implement the callback method */ jpaTemplate.execute(new JpaCallback() { public Object doInJpa(EntityManager em) throws PersistenceException { List<Article> articles = em.createQuery("select a from Article a").getResultList(); FullTextEntityManager ftEm = Search.getFullTextEntityManager(em); ftEm.getTransaction().begin(); for(Article article : articles) { System.out.println("Indexing Item " + article.getTitle()); ftEm.index(article); } ftEm.getTransaction().commit(); return null; } }); } } I think that it may have to do with the transactions but I'm not exactly sure. If you could just point me in the right direction, that would be helpful too! Thank you.

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  • Why doesn't the spring @Autowire work with java generics

    - by testing123
    Inspired by spring data awesomeness I wanted to create a abstract RESTController that I could extend for a lot of my controllers. I created the following class: @Controller public abstract class RESTController<E, PK extends Serializable, R extends PagingAndSortingRepository<E, PK>> { @Autowired private R repository; @RequestMapping(method=RequestMethod.GET, params={"id"}) @ResponseBody public E getEntity(@RequestParam PK id) { return repository.findOne(id); } ... } I was hoping that the generics would allow me to @Autowire in the repository but I get the following error: SEVERE: Allocate exception for servlet appServlet org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [org.springframework.data.repository.PagingAndSortingRepository] is defined: expected single matching bean but found 3: [groupRepository, externalCourseRepository, managedCourseRepository] at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:800) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294) I understand what the error is telling me, there is more than one match for the @Autowire. I am confused because I thought by creating the following controller it would work: @Controller @RequestMapping(value="/managedCourse") public class ManagedCourseController extends RESTController<ManagedCourse, Long, ManagedCourseRepository> { ... } This is easy enough to work around by doing having a method like this in the RESTController: protected abstract R getRepository(); and then doing this in your implementing class: @Autowired private ManagedCourseRepository repository; @Override protected ManagedCourseRepository getRepository() { return repository; } I was just wondering if someone had any thoughts of how I could get this to work.

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  • Call to a member function get_segment() error

    - by hogofwar
    I'm having this problem with this piece of PHP code: class Core { public function start() { require("funk/funks/libraries/uri.php"); $this->uri = new uri(); require("funk/core/loader.php"); $this->load = new loader(); if($this->uri->get_segment(1) != "" and file_exists("funk/pages/".$uri->get_segment(1).".php")){ Only a snippet of the code The best way I can explain it is that it is a class calling upon another class (uri.php) and i am getting the error: Fatal error: Call to a member function get_segment() on a non-object in /home/eeeee/public_html/private/funkyphp/funk/core/core.php on line 11 (the if($this-uri-get_segment(1) part) I'm having this problem a lot and it is really bugging me. the library code is: <?php class uri { private $server_path_info = ''; private $segment = array(); private $segments = 0; public function __construct() { $segment_temp = array(); $this->server_path_info = preg_replace("/\?/", "", $_SERVER["PATH_INFO"]); $segment_temp = explode("/", $this->server_path_info); foreach ($segment_temp as $key => $seg) { if (!preg_match("/([a-zA-Z0-9\.\_\-]+)/", $seg) || empty($seg)) unset($segment_temp[$key]); } foreach ($segment_temp as $k => $value) { $this->segment[] = $value; } unset($segment_temp); $this->segments = count($this->segment); } public function segment_exists($id = 0) { $id = (int)$id; if (isset($this->segment[$id])) return true; else return false; } public function get_segment($id = 0) { $id--; $id = (int)$id; if ($this->segment_exists($id) === true) return $this->segment[$id]; else return false; } } ?>

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  • Mercurial Subrepos, how to control which changeset I want to use for a subrepo?

    - by Lasse V. Karlsen
    I am reading up on subrepos, and have been running some tests locally, seems to work OK so far, but I have one question. How do I specify/control which changeset I want to use for a particular subrepo? For instance, let's say I have the following two projects: class library application o fourth commit o second commit, added a feature | | o third commit o initial commit | | o second commit |/ o initial commit Now, I want the class library as a subrepo of my application, but due to the immaturity of the longest branch (the one ending up as fourth commit), I want to temporarily use the "second commit" tip. How do I go about configuring that, assuming it is even possible? Here's a batch file that sets up the above two repos + adds the library as a subrepo. If you run the batch file, it will output: [C:\Temp] :test ... v4 As you can see from that last line there, it verifies the contents of the file in the class library, which is "v4" from the fourth commit. I'd like it to be "v2", and persist as "v2" until I'm ready to pull down a newer version from the class library repository. Can anyone tell me if it is possible to do what I want, and if so, what I need to do in order to lock my subrepo to the right changeset? Batch-file: @echo off if exist app rd /s /q app if exist lib rd /s /q lib if exist app-clone rd /s /q app-clone rem == app == hg init app cd app echo program>main.txt hg add main.txt hg commit -m "initial commit" echo program+feature1>main.txt hg commit -m "second commit, added a feature" cd .. rem == lib == hg init lib cd lib echo v1>lib.txt hg add lib.txt hg commit -m "initial commit" echo v2>lib.txt hg commit -m "second commit" hg update 0 echo v3>lib.txt hg commit -m "third commit" echo v4>lib.txt hg commit -m "fourth commit" cd .. rem == subrepos == cd app hg clone ..\lib lib echo lib = ..\lib >.hgsub hg add .hgsub hg commit -m "added subrepo" cd .. rem == clone == hg clone app app-clone type app-clone\lib\lib.txt

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  • PHP what is faster to use

    - by user1631500
    What is faster / better to use? To put html into variables and print them later, or to just html print / echo print the content based on condition? EXAMPLE 1:(html into variables) if(!isset($_SESSION['daddy'])) { $var = "<span class='something'>Go here:<a href='#'>Click</a></span> <span class='something'>Go here:<a href='#'>Click</a></span>" } else { $one=$_SESSION["one"]; $two=$_SESSION["two"]; $three=$_SESSION["three"]; $var = You are cool enough to view the content; } echo $var; EXAMPLE 2:(print based on condition) if(!isset($_SESSION['daddy'])) { $var = 1; } else { $one=$_SESSION["one"]; $two=$_SESSION["two"]; $three=$_SESSION["three"]; $var = 0; } if ($var==1) { ?> <span class='something'>Go here:<a href='#'>Click</a></span> <span class='something'>Go here:<a href='#'>Click</a></span <?php } else { ?> You are cool enough to view the content. <?php } ?>

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  • ServiceStack razor default page

    - by Tom
    Say I have 2 pages /NotADefault.cshtml /Views/Default.cshtml Question 1. Now I run it, page A always gets called implicitly as start-up default page no matter what I name it. Page B will only be called when I explicitly call localhost/View/Default. How do I make page B (the one in View folder) my default page? Question 2. I also have NotADefaultService.cs and DefaultService.cs. I give each page a Service class at the back. However, when page A is called NotADefaultService.cs never gets called. Only DefaultService.cs gets called when page B is called... My observation is that only the pages in the View folder will get their back-end service class working. Outside of View folder it doesn't work. Combining Q1 and Q2. How do I: Option 1. get the backend service class working under / root outside "View" folder? OR Option 2. appoint /View/Default.schtml as my default at start-up where the service class can be hit?

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  • SWIG: From Plain C++ to working Wrapper

    - by duckworthd
    Hi everyone. I've been trying to create a SWIG wrapper for this tiny little C++ class for the better part of 3 hours with no success, so I was hoping one of you out there could lend me a small hand. I have the following class: #include <stdio.h> class Example { public: Example(); ~Example(); int test(); }; #include "example.h" Along with the implementation: Example::Example() { printf("Example constructor called\n"); } Example::~Example() { printf("Example destructor called\n"); } int Example::test() { printf("Holy shit, I work!\n"); return 42; } I've read through the introduction page ( www.swig.org/Doc1.3/Java.html ) a few times without gaining a whole lot of insight into the situation. My steps were Create an example.i file Compile original alongside example_wrap.cxx (no linking) link resulting object files together Create a little java test file (see below) javac all .java files there and run Well steps 4 and 5 have created a host of problems for me, starting with the basic ( library 'example' not found due to not being in java's path ) to the weird ( library not found even unless LD_LIBRARY_PATH is set to something, even if it's nothing at all). I've included my little testing code below public class test2 { static { String libpath = System.getProperty("java.library.path"); String currentDir = System.getProperty("user.dir"); System.setProperty("java.library.path", currentDir + ":" + libpath); System.out.println(System.getProperty("java.library.path")); System.loadLibrary("example"); } public static void main(String[] args){ System.out.println("It loads!"); } } Well, if anyone has navigated these murky waters of wrapping, I could not be happier than if you could light the way, particularly if you could provide the example.i and bash commands to go along with it.

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  • Silverlight Image Data Binding

    - by Alexander
    I am new to Silverlight, and have an issue with binding. I have a class ItemsManager, that has inside its scope another class Item. class ItemsManager { ... class Item : INotifyPropertyChanged { ... private BitmapImage bitmapSource; public BitmapImage BitmapSource { get { return bitmapSource; } set { bitmapSource = value; if(PropertyChanged != null )PropertyChanged("BitmapSource") } } } } I do the following in code to test binding: { ItemsManager.Instance.AddItem("123"); //Items manager started downloading item visual //part (in my case bitmap image png) Binding b = new Binding("Source"); b.Source = ItemsManager.Instance.GetItem("123").BitmapSource; b.BindsDirectlyToSource = true; Image img = new Image(); img.SetBinding(Image.SourceProperty, b); img.Width = (double)100.0; img.Height = (double)100.0; LayoutRoot.Children.Add(img); } Once image is loaded, image doesn't appear. Though, if I set directly after image has been loaded its source, it displays well. I also noticed that PropertyChanged("BitmapSource") never fires, because PropertyChanged is null, like Image never binded to it. I am looking forward to hearing from you!

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  • c# Why can't open generic types be passed as parameters?

    - by Rich Oliver
    Why can't open generic types be passed as parameters. I frequently have classes like: public class Example<T> where T: BaseClass { public int a {get; set;} public List<T> mylist {get; set;} } Lets say BaseClass is as follows; public BaseClass { public int num; } I then want a method of say: public int MyArbitarySumMethod(Example example)//This won't compile Example not closed { int sum = 0; foreach(BaseClass i in example.myList)//myList being infered as an IEnumerable sum += i.num; sum = sum * example.a; return sum; } I then have to write an interface just to pass this one class as a parameter as follows: public interface IExample { public int a {get; set;} public IEnumerable<BaseClass> myIEnum {get;} } The generic class then has to be modified to: public class Example<T>: IExample where T: BaseClass { public int a {get; set;} public List<T> mylist {get; set;} public IEnumerable<BaseClass> myIEnum {get {return myList;} } } That's a lot of ceremony for what I would have thought the compiler could infer. Even if something can't be changed I find it psychologically very helpful if I know the reasons / justifications for the absence of Syntax short cuts.

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  • Call event from original thread ??

    - by user311883
    Hi all, Here is my problem, I have a class which have a object who throw an event and in this event I throw a custom event from my class. But unfortunately the original object throw the event from another thread and so my event is also throw on another thread. This cause a exception when my custom event try to access from controls. Here is a code sample to better understand : class MyClass { // Original object private OriginalObject myObject; // My event public delegate void StatsUpdatedDelegate(object sender, StatsArgs args); public event StatsUpdatedDelegate StatsUpdated; public MyClass() { // Original object event myObject.AnEvent += new EventHandler(myObject_AnEvent); } // This event is called on another thread private void myObject_AnEvent(object sender, EventArgs e) { // Throw my custom event here StatsArgs args = new StatsArgs(..........); StatsUpdated(this, args); } } So when on my windows form I call try to update a control from the event StatsUpdated I get a cross thread exception cause it has been called on another thread. What I want to do is throw my custom event on the original class thread, so control can be used within it. Anyone can help me ?

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  • IE8 problems with .animate() of opacity property - descendant remains opaque throughout

    - by Fabian
    Basically I have something like this: <ul> <li> <a> <div class="trigger-layer"></div> <div class="title-layer">Text here</div> <div class="hover-layer"></div> </a> </li> </ul> I use jQuery to animate the <ul> as follow: $ul = xxx (where I assign the selector to var $ul) $ul.animate({opacity: 0}, 1000, function() {$ul.css("display", "none")}); However in IE8, as the <ul> fades off, the <div class="title-layer">Text here</div> remains clear and opaque. Finally the animation ends, the display: none; property is applied onto the <ul> and the text disappears aburptly.

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  • Random number generation in MVC applications

    - by SlimShaggy
    What is the correct way of generating random numbers in an ASP.NET MVC application if I need exactly one number per request? According to MSDN, in order to get randomness of sufficient quality, it is necessary to generate multiple numbers using a single System.Random object, created once. Since a new instance of a controller class is created for each request in MVC, I cannot use a private field initialized in the controller's constructor for the Random object. So in what part of the MVC app should I create and store the Random object? Currently I store it in a static field of the controller class and lazily initialize it in the action method that uses it: public class HomeController : Controller { ... private static Random random; ... public ActionResult Download() { ... if (random == null) random = new Random(); ... } } Since the "random" field can be accessed by multiple instances of the controller class, is it possible for its value to become corrupted if two instances attempt to initialize it simultaneously? And one more question: I know that the lifetime of statics is the lifetime of the application, but in case of an MVC app what is it? Is it from IIS startup till IIS shutdown?

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  • Validating Checkbox and Radio Button in C#

    - by Solution
    Hi, I am using c# for coding! Below is my html for checkbox and radion button <input type="radio" style="float: left;" name="documents" id="Checkbox9" value="yes" runat="server" /> <label style="width: 35px!important;" class="checkbox"> <%=GetResourceString("c_HSGStudent")%> </label> <input type="radio" style="float: left;" name="documents" id="Checkbox10" value="no" runat="server" /> <label style="width: 25px!important;" class="checkbox"> <%=GetResourceString("c_HSGParent")%> </label> <input type="radio" style="float: left;" cheked name="documents" id="Radio1" value="yes" runat="server" /> <label style="width: 35px!important;" class="checkbox"> <%=GetResourceString("c_HSGStudent")%> </label> <input type="radio" style="float: left;" name="documents" id="Radio2" value="no" runat="server" /> <label style="width: 25px!important;" class="checkbox"> <%=GetResourceString("c_HSGParent")%> </label> You can see I have two checkboxes and two radio buttons, My problem is that on my submit button click I want to check whether user have checked at-least one checkbox or radio button. It will be good if we can have .NET solution like (customvalidator). Please suggest! Thanks

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  • C++ polymorphism and slicing

    - by Draco Ater
    The following code, prints out Derived Base Base But I need every Derived object put into User::items, call its own print function, but not the base class one. Can I achieve that without using pointers? If it is not possible, how should I write the function that deletes User::items one by one and frees memory, so that there should not be any memory leaks? #include <iostream> #include <vector> #include <algorithm> using namespace std; class Base{ public: virtual void print(){ cout << "Base" << endl;} }; class Derived: public Base{ public: void print(){ cout << "Derived" << endl;} }; class User{ public: vector<Base> items; void add_item( Base& item ){ item.print(); items.push_back( item ); items.back().print(); } }; void fill_items( User& u ){ Derived d; u.add_item( d ); } int main(){ User u; fill_items( u ); u.items[0].print(); }

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  • Is is possible to do an end-run around generics covariance in C# < 4 in this hypothetical situation?

    - by John Feminella
    Suppose I have a small inheritance hierarchy of Animals: public interface IAnimal { string Speak(); } public class Animal : IAnimal { public Animal() {} public string Speak() { return "[Animal] Growl!"; } } public class Ape : IAnimal { public string Speak() { return "[Ape] Rawrrrrrrr!"; } } public class Bat : IAnimal { public string Speak() { return "[Bat] Screeeeeee!"; } } Next, here's an interface offering a way to turn strings into IAnimals. public interface ITransmogrifier<T> where T : IAnimal { T Transmogrify(string s); } And finally, here's one strategy for doing that: public class Transmogrifier<T> : ITransmogrifier<T> where T : IAnimal, new() { public T Transmogrify(string s) { T t = default(T); if (typeof(T).Name == s) t = new T(); return t; } } Now, the question. Is it possible to replace the sections marked [1], [2], and [3] such that this program will compile and run correctly? If you can't do it without touching parts other than [1], [2], and [3], can you still get an IAnimal out of each instance of a Transmogrifier in a collection containing arbitrary implementations of an IAnimal? Can you even form such a collection to begin with? static void Main(string[] args) { var t = new Transmogrifier<Ape>(); Ape a = t.Transmogrify("Ape"); Console.WriteLine(a.Speak()); // Works! // But can we make an arbitrary collection of such animals? var list = new List<Transmogrifier< [1] >>() { // [2] }; // And how about we call Transmogrify() on each one? foreach (/* [3] */ transmogrifier in list) { IAnimal ia = transmogrifier.Transmogrify("Bat"); } } }

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  • Why are controls (null) in awakeFromNib?

    - by fuzzygoat
    This is a follow on from another question regarding why I could not set UIControls in awakeFromNib. The answer to that is that as you can see below the controls are nil in the awakeFromNib, although they are initialised to the correct objects by the time we get to viewDidLoad. I setup the view the same as I always do, should I be doing something different to access them here, the xib(nib) was designed and saved with the current version of Image Builder. CODE: @interface iPhone_TEST_AwakeFromNibViewController : UIViewController { UILabel *myLabel; UIImageView *myView; } @property(nonatomic, retain)IBOutlet UILabel *myLabel; @property(nonatomic, retain)IBOutlet UIImageView *myView; @end . @synthesize myLabel; @synthesize myView; -(void)awakeFromNib { NSLog(@"awakeFromNib ..."); NSLog(@"myLabel: %@", [myLabel class]); NSLog(@"myView : %@", [myView class]); //[myLabel setText:@"AWAKE"]; [super awakeFromNib]; } -(void)viewDidLoad { NSLog(@"viewDidLoad ..."); NSLog(@"myLabel: %@", [myLabel class]); NSLog(@"myView : %@", [myView class]); //[myLabel setText:@"VIEW"]; [super viewDidLoad]; } OUTPUT: awakeFromNib ... myLabel: (null) myView : (null) viewDidLoad ... myLabel: UILabel myLabel: UIImageView Much appreciated ... gary

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  • Nhibernate, can i improve my MAPPING or Query

    - by dbones
    take this simple example A staff class which references other instances of the staff class public class Staff { public Staff() { Team = new List<Staff>(); } public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual IList<Staff> Team { get; set; } public virtual Staff Manager { get; set; } } The Fluent Mapping public class StaffMap : ClassMap<Staff> { public StaffMap() { Id(x => x.Id); Map(x => x.Name); References(x => x.Manager).Column("ManagerId"); HasMany(x => x.Team).KeyColumn("ManagerId").Inverse(); } } Now I want to run a query, which will load all the Staff and eager load the manager and Team members. This is what I came up with IList<Staff> resutls = session.CreateCriteria<Staff>() .SetFetchMode("Team", FetchMode.Eager) .SetResultTransformer(Transformers.DistinctRootEntity) .List<Staff>(); however the SQL (does what i want) has duplicate columns, 2 team2_.ManagerId and 2 team2_.Id SELECT this_.Id as Id0_1_, this_.Name as Name0_1_, this_.ManagerId as ManagerId0_1_, team2_.ManagerId as ManagerId3_, team2_.Id as Id3_, team2_.Id as Id0_0_, team2_.Name as Name0_0_, team2_.ManagerId as ManagerId0_0_ FROM [SelfRef].[dbo].[Staff] this_ left outer join [SelfRef].[dbo].[Staff] team2_ on this_.Id=team2_.ManagerId The question is, should this be happening? did i do something wrong in the query or map? or is it a feature of the HHib im using (which is Version 2.1.0.4000)? many thanks in advance

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  • Ruby on Rails: How to create associated models on the fly ?

    - by Misha Moroshko
    I have the following models: class Product < ActiveRecord::Base belongs_to :brand belongs_to :model accepts_nested_attributes_for :brand, :model ... end class Brand < ActiveRecord::Base has_many :products has_many :models ... end class Model < ActiveRecord::Base has_many :products belongs_to :brand accepts_nested_attributes_for :brand ... end I have a problem to create a new product. Here is the relevant code in the controller: class ProductsController < ApplicationController ... def create @product = Product.new(params[:product]) if @product.save ... # Here is the error end ... end When user adds a new brand and a new model, params[:product] contains the following: "brand_attributes"=>{"name"=>"my_new_brand"} "model_attributes"=>{"model_no"=>"my_new_model"} and I got the following error: Mysql2::Error: Column 'brand_id' cannot be null: INSERT INTO `models` ... because model has a foreign key brand_id which is not set. I can't set it because the brand (like the model) is created on the fly when the product is created. I don't want to create the brand before the product, because then I the product has errors, I will need to delete the created brand. Then I tried to change params[:product] like this: "brand_attributes"=>{"name"=>"my_new_brand", "model_attributes"=>{"model_no"=>"my_new_model"}} but I end up with this: unknown attribute: model_attributes What would be the proper way to handle this ?

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