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  • Inheritance Problem in Perl OOP

    - by Sam
    Hello, I have a sub class that calls a method from a super class. and the method in the super class use a method that is defined in the super class as asbstract(not really abstract) but implemented in the sub class. for example: package BaseClass; sub new { } sub method1 { return someAbstractMethod(); } sub someAbtsractMethod { die "oops, this is an abstract method that should be implemented in a subclass" ; } 1; package SubClass; sub new { } sub someAbtsractMethod { print "now we implement the asbtract method"; } 1; now when I do: $sub = new SubClass(); $sub-method1(); It calls the abstract message and i get the specified error message. if I took off the abstractmethod from the super class and just leave the implementation in the subclass, It does not recognize the method and I get subroutine abstractmethod not found error.

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  • How do I get the XAML comiler to use textual content property on custom classes?

    - by Duncan
    Given a simple C# class definition like: [System.Windows.Markup.ContentProperty("PropertyOne")] public class SimpleBase { public string PropertyOne { get; set; } public string PropertyTwo { get; set; } } why is it not possible to ommit the sys:string tags around the word Test in the xaml below. <custom:SimpleBase x:Class="TestType" xmlns:custom="clr-namespace:ConsoleApplication1;assembly=" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:sys="clr-namespace:System;assembly=mscorlib"> <sys:String>Test</sys:String> </custom:SimpleBase> Somehow the compiler correctly coverts text to string for the type String, why doesn't it work for my custom type? The context can be found on my blog: http://www.deconflations.com/?tag=xaml

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  • How would I use HTMLAgilityPack to extract the value I want

    - by Nai
    For the given HTML I want the value of id <div class="name" id="john-5745844"> <div class="name" id="james-6940673"> UPDATE This is what I have at the moment HtmlDocument htmlDoc = new HtmlDocument(); htmlDoc.Load(new StringReader(pageResponse)); HtmlNode root = htmlDoc.DocumentNode; List<string> anchorTags = new List<string>(); foreach (HtmlNode div in root.SelectNodes("//div[@class='name' and @id]")) { HtmlAttribute att = div.Attributes["id"]; Console.WriteLine(att.Value); } The error I am getting is at the foreach line stating: Object reference not set to an instance of an object.

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  • WPF: change DataTemples according to Value

    - by Kave
    I have a class called Cell with two properties. One is called Value of type int? And the other is called Candidates of type ObservableCollection during the initialization I am utilizing a DataTemplateSelector to choose between two datatemplates for two different scenarios. If the Value property has a value then template A should be used to present the Cell class. However if the Value property is null Then template B should be used to present the Cell class. While this works perfectly fine during the initialization however during the runtime the templates don't change any more when the value of the Value property actually changes. Is the approach of using DataTemplateSelector the wrong approach to change DataTemplates dynamically? What would you recommend I should do? Many thanks,

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  • ToolStripComboBox.SelectedItem change does not propagate to binding source

    - by Marius
    My binding is set up as this: _selectXAxisUnitViewModelBindingSource = new BindingSource(); _selectXAxisUnitViewModelBindingSource.DataSource = typeof(SelectXAxisUnitViewModel); _selectedUnitComboBoxBindingSource = new BindingSource(); _selectedUnitComboBoxBindingSource.DataSource = _selectXAxisUnitViewModelBindingSource; _selectedUnitComboBoxBindingSource.DataMember = "AvailableUnits"; _selectedUnitComboBox.ComboBox.DataSource = _selectedUnitComboBoxBindingSource; _selectedUnitComboBox.ComboBox.DisplayMember = String.Empty; _selectedUnitComboBox.ComboBox.ValueMember = String.Empty; _selectedUnitComboBox.ComboBox.DataBindings.Add("SelectedItem", _selectXAxisUnitViewModelBindingSource, "SelectedUnit", true, DataSourceUpdateMode.OnPropertyChanged); // this is a bug in the .Net framework: http://connect.microsoft.com/VisualStudio/feedback/details/473777/toolstripcombobox-nested-on-toolstripdropdownbutton-not-getting-bindingcontext _selectedUnitComboBox.ComboBox.BindingContext = this.BindingContext; The property "AvailableUnits" is a collection of strings and the "SelectedUnit" is a string-property. Now the dropdown list is populated as expected, but when I select and item in the list, the change is not propagated to the binding source. Any idea what I am doing wrong?

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  • Using Interfaces in action signature

    - by Dmitry Borovsky
    Hello, I want to use interface in Action signature. So I've tried make own ModelBinder by deriving DefaultModelBinder: public class InterfaceBinder<T> : DefaultModelBinder where T: new() { protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType) { return base.CreateModel(controllerContext, bindingContext, typeof(T)); } } public interface IFoo { string Data { get; set; } } public class Foo: IFoo /*other interfaces*/ { /* a lot of */ public string Data { get; set; } } public class MegaController: Controller { public ActionResult Process( [ModelBinder(typeof(InterfaceBinder))]IFoo foo){/bla-bla-bla/} } But it doesn't work. Does anybody have idea how release this behaviour? And yes, I know that I can make my own implementation of IModelBinder, but I'm looking for easier way.

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  • Define Instance Variable Outside of Method Defenition (ruby)

    - by Ell
    Hi all, I am developing (well, trying to at least) a Game framework for the Ruby Gosu library. I have made a basic event system wherebye each Blocks::Event has a list of handlers and when the event is fired the methods are called. At the moment the way to implement an event is as follows: class TestClass attr_accessor :on_close def initialize @on_close = Blocks::Event.new end def close @on_close.fire(self, Blocks::OnCloseArgs.new) end end But this method of implementing events seems rather long, my question is, how can I make a way so that when one wants an event in a class, they can just do this class TestClass event :on_close def close @on_close.fire(self, Blocks::OnCloseArgs.new) end end Thanks in advance, ell.

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  • design a large scale network for an organization

    - by Essam
    hello.i am so new to networking i want to design a large scale network for an organization with HQ and two branches. i want to use class A address for that.my questions are: if i am using the network address 30.0.0.0 for the whole organization how can it be different from another organization company or whatever which is using the same address in another country? now i have the three locations for this organization,so i need 5 subnets [one for the HQ,two for branch A and branch B , one for connecting A to HQ and one for connecting branch B with HQ since i will use central DHCP server at the HQ,is that(number of subnetting) right? is it advisable to use class A or class B for this organization it term of address that will be wasted (lets say it is a university with two branches in two different states)?! that is all your help is highly appropriated.

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  • C++ 'mutable' keyword

    - by Rob
    A while ago I came across some code that marked a member variable of a class with the 'mutable' keyword. As far as I can see it simply allows you to modify a variable in a 'const' method: class Foo { private: mutable bool done_; public: void doSomething() const { ...; done_ = true; } }; Is this the only use of this keyword or is there more to it than meets the eye? I have since used this technique in a class, marking a boost::mutex as mutable allowing const functions to lock it for thread-safety reasons, but, to be honest, it feels like a bit of a hack.

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  • Grails searchable plugin

    - by Don
    Hi, In my Grails app, I'm using the Searchable plugin for searching/indexing. I want to write a Compass/Lucene query that involves multiple domain classes. Within that query when I want to refer to the id of a class, I can't simply use 'id' because all classes have an 'id' property. Currently, I work around this problem by adding the following property to a class Foo public Long getFooId() { return id } static transients = ['fooId'] Then when I want to refer to the id of Foo within a query I use 'fooId'. Is there a way I can provide an alias for a property in the searchable mapping rather than adding a property to the class?

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  • Invoke an Overloaded Constructor through this keyword (What's the Different between this two Sample code?)

    - by Alireza Dehqani
    using System; namespace ConsoleApplication1 { class Program { static void Main() { // Sample Sample ob = new Sample(); // line1 // Output for line1 /* * Sample(int i) * Sample() / // Sample2 Sample2 ob2 = new Sample2(); // line2 // Output for line2 / * Sample2() */ } } class Sample { // Fields private int a; // Constructors public Sample(int i) // Main Constructor { Console.WriteLine(" Sample(int i)"); a = i; } // Default Constructor public Sample() : this(0) { Console.WriteLine(" Sample()"); } } class Sample2 { // fields private int a; // Constructors public Sample2(int i) { Console.WriteLine("Sample2(int i)"); a = i; } public Sample2() { Console.WriteLine("Sample2()"); a = 0; } } }

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  • belongs_to with a custom class_name not producing proper foreign key in Rails 3

    - by Tony
    I am updating an application to Rails 3 and I am having trouble creating a custom foreign key. I have something like this: class Product < ActiveRecord::Base belongs_to :owner, :class_name => 'User' ... end class User < ActiveRecord::Base has_many :products ... end class ProductsController < ApplicationController before_filter :authenticate_user! def index @products = current_user.products end end The view: <%- @products.each do |p| -%> <%= p.created_at %><br /> <%- end -%> I get this error in my Rails log: Mysql::Error: Unknown column 'products.user_id' in 'where clause': SELECT `products`.* FROM `products` WHERE (`products`.user_id = 1) It should see the belongs_to :owner and look for a foreign key called owner_id. I even tried explicitly setting the foreign key and that does not work. I also checked lighthouse for a possible Rails 3 bug but no luck.

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  • What to name an array of flags?

    - by Chris
    I have a project where lots of the objects hold state by maintaining simple boolean flags. There are lots of these, so I maintain them within a uint32_t and use bit masking. There are now so many flags to keep track of, I've created an abstraction for them (just a class wrapping the uint32_t) with set(), clear(), etc. My question: What's a nice accurate, concise name for this class? What name could I give this class so that you'd have a reasonable idea what it was [for] knowing the name only? Some ideas I had: FlagBank FlagArray etc Any ideas? Thanks in advance! Cheers, -Chris

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  • Using xsl:key to store result of boolean expression

    - by hielsnoppe
    In my transformation there is an expression some elements are repeatedly tested against. To reduce redundancy I'd like to encapsulate this in an xsl:key like this (not working): <xsl:key name="td-is-empty" match="td" use="not(./node()[normalize-space(.) or ./node()])" /> The expected behaviour is the key to yield a boolean value of true in case the expression is evaluated successfully and otherwise false. Then I'd like to use it as follows: <xsl:template match="td[not(key('td-is-empty', .))]" /> Is this possible and in case yes, how?

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  • What is a custom collection?

    - by Win Coder
    A Group of objects. However i am having confusion in the following case. A sample class Class A { public string; } Class A_list { public A[] list; public A_list(A[] _list) { list = new A[_list.length]; for (int i = 0; i < _list.Length; i++) { list[i] = _list[i]; } } } static void Main(String[] args) { A[] names = new A[3] { new A("some"), new A("another"), new A("one"), }; A_list just_an_object = new A_list(names); } Which of the above is a custom collection the array or the object that holds array as a field or are both custom collections.

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  • BLL returning the right Type of an instance

    - by Younes
    I have a class "Artikel" and there i write some Business Logic. I also have a class "tArtikel" which is a type. In my class "Artikel" I work with "tArtikel" and returns are of that type. Now when i instantiate an "Artikel" i want it to be of type "tArtikel", so what i tried in my code is: public tArtikel Artikel() { tArtikel artikel = new tArtikel(); } Which results in: "'Artikel' member names cannot be the same as their enclosing type". How would i set this up correctly?

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  • Setting a value into a object using reflection

    - by marionmaiden
    Hello I have an object that has a lot of attributes, each one with it's getter and setter. Each attribute has a non primitive type, that I don't know at runtime. For example, what I have is this: public class a{ private typeA attr1; private typeB attr2; public typeA getAttr1(){ return attr1; } public typeB getAttr2(){ return attr2; } public void setAttr1(typeA at){ attr1 = at; } public void setAttr2(typeB at){ attr2 = at; } } public class typeA{ public typeA(){ // doesn't matter } } public class typeB{ public typeB(){ // doesn't matter } } So, using reflection, I obtained the setter method for an attribute. Setting a value in the standard way is something like this: a test = new a(); a.setAttr1(new typeA()); But how can I do this using reflection? I already got the setAttr1() method using reflection, but I don't know how to create a new typeA object to be inserted in the setter.

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  • Custom tool error: Command.proto:11:18: "Message2" is not defined.

    - by cornerback84
    I am using the latest version of protobuf-net with VS2008 integration. I have created 2 messages (Message1 and Message2), 1 message in 1 proto file. When I try to reference Message2 in Message1 the code generator tool gives me error "Message2" is not defined and won't generate the code file. The package for both messages is same. It look like that because of the integration of the tool with VS2008 it expects all the messages in same .proto file to compile. Currently I have to paste an empty message with same name in Message1.proto file, like this: message Message1 { optional Message2 message2 = 1; } message Message2 { } And then later on remove the declaration of class Message2 from Message1.cs. Are there any settings that I need to do so to avoid this error, or is providing an empty declaration the only way?

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  • Write to static field - is FindBugs wrong in this case?

    - by htorque
    I have a Java class like this: public class Foo { public static int counter = 0; public void bar(int counter) { Foo.counter = counter; } } FindBugs warns me about writing to the static field counter via the instance method bar. However, if I change the code to: public class Foo { public static int counter = 0; public static void setCounter(int counter) { Foo.counter = counter; } public void bar(int counter) { setCounter(counter); } } Then FindBugs won't complain. Isn't that wrong? I'm still writing to a static field from an instance method, just via a static method - no?

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  • How to convert an existing callback interface to use boost signals & slots

    - by the_mandrill
    I've currently got a class that can notify a number of other objects via callbacks: class Callback { virtual NodulesChanged() =0; virtual TurkiesTwisted() =0; }; class Notifier { std::vector<Callback*> m_Callbacks; void AddCallback(Callback* cb) {m_Callbacks.push(cb); } ... void ChangeNodules() { for (iterator it=m_Callbacks.begin(); it!=m_Callbacks.end(); it++) { (*it)->NodulesChanged(); } } }; I'm considering changing this to use boost's signals and slots as it would be beneficial to reduce the likelihood of dangling pointers when the callee gets deleted, among other things. However, as it stands boost's signals seems more oriented towards dealing with function objects. What would be the best way of adapting my code to still use the callback interface but use signals and slots to deal with the connection and notification aspects?

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  • How to call angular javascript directive methods from the global scope

    - by user1659278
    I have a directive like the one of the examples from AngularJS, shown below. How can I call the toggle method from the global scope? I want to be able to toggle the zippy from some legacy code. myApp.directive('zippy', function(){ return { restrict: 'E', replace: true, transclude: true, scope: { title:'bind' }, template: '<div class="zippy">' + '<div class="title">{{title}}</div>' + '<div class="body" ng-transclude></div>' + '</div>', link: function(scope, element, attrs) { var title = angular.element(element.children()[0]), opened = true; title.bind('click', toggle); function toggle() { opened = !opened; element.removeClass(opened ? 'closed' : 'opened'); element.addClass(opened ? 'opened' : 'closed'); } toggle(); } } });

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  • Multiple key/value pairs in HTTP POST where key is the same name

    - by randombits
    I'm working on an API that accepts data from remote clients, some of which where the key in an HTTP POST almost functions as an array. In english what this means is say I have a resource on my server called "class". A class in this sense, is the type a student sits in and a teacher educates in. When the user submits an HTTP POST to create a new class for their application, a lot of the key value pairs look like: student_name: Bob Smith student_name: Jane Smith student_name: Chris Smith What's the best way to handle this on both the client side (let's say the client is cURL or ActiveResource, whatever..) and what's a decent way of handling this on the server-side if my server is a Ruby on Rails app? Need a way to allow for multiple keys with the same name and without any namespace clashing or loss of data.

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  • Modelling a manyToMany relationship with attributes

    - by Javi
    Hello, I have a ManyToMany relationship between two classes, for instance class Customer and class Item. A customer can buy several items and an item can be bought by different customers. I need to store extra information in this relationship, for example the day when the item was bought. I wonder how is this usually modelled in JPA, cause I'm not sure how to express this in code. Do I have to create a new class to model all the attributes of the relationship and make a manyToMany relationship between the other classes or is a better way to do this? Thanks

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  • How do I set a VB.Net ComboBox default value

    - by Mr Ed
    I can not locate the correct method to make the first item in a combo box visible. The app starts with an empty combo box. The user makes a radio box selection then clicks Go! (how original). The combo box is loaded via an LDAP query. All this is working just fine. The problem is the combo box still appears to the user to be empty. They must click the arrow to see the options. How do I make the first option 'visible' after the users clicks Go!? I thought it would be simple... Thanks, Ed

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  • Game Key Events: Event or Method Overload?

    - by Ell
    If you were going to develop a game in say, Ruby, and you were provided with a game framework, would you rather act on key up/down events by overloading a method on the main window like so: class MyGameWindow < Framework::GameWindow def button_down(id) case id when UpArrow do_something when DownArrow do_something end end end Or have an event class with which you can make a method and assign a handle to it, like so: class MyGameWindow < Framework::GameWindow def initialize key_down.add_handler(method(:do_something)) end def do_something puts "blah blah" end end Please give your views, which do you think would be better in a game developement area, and thanks in advance, ell.

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