Search Results

Search found 4593 results on 184 pages for 'constructor injection'.

Page 126/184 | < Previous Page | 122 123 124 125 126 127 128 129 130 131 132 133  | Next Page >

• Implementing operator< in C++

  - by Vulcan Eager

  I have a class with a few numeric fields such as: class Class1 { int a; int b; int c; public: // constructor and so on... bool operator<(const Class1& other) const; }; I need to use objects of this class as a key in an std::map. I therefore implement operator<. What is the simplest implementation of operator< to use here?

  Read the article

• Are returned locals automatically xvalues

  - by mark

  Following on from a comment I made on this: passing std::vector to constructor and move semantics Is the std::move necessary in the following code, to ensure that the returned value is a xvalue? std::vector<string> buildVector() { std::vector<string> local; // .... build a vector return std::move(local); } It is my understanding that this is required. I have often seen this used when returning a std::unique_ptr from a function, however GManNickG made the following comment: It is my understanding that in a return statement all local variables are automatically xvalues (expiring values) and will be moved, but I'm unsure if that only applies to the returned object itself. So OP should go ahead and put that in there until I'm more confident it shouldn't have to be. :) Can anyone clarify if the std::move is necessary? Is the behaviour compiler dependent?

  Read the article

• WxWidgets custom events

  - by Klaus

  Hello, I'm trying to use a custom event in my WxWidgets C++ application, like described here. In the constructor of my wxApp: Connect(wxID_ANY, wxCommandEventHandler(APP::OnMyEvent)); Then the function that should catch the event: void APP::OnMyEvent(wxCommandEvent& event) { exit(0); //testing } Finally, to test it: wxCommandEvent MyEvent(wxEVT_COMMAND_BUTTON_CLICKED); wxPostEvent(this, MyEvent); I launch the thing...but it seems that the event is not posted or not caught. Does someone understand this behaviour ?

  Read the article

• Confusion about Nullable<T> constraints

  - by n535

  Greetings everybody. I am sorry, if this was already asked before (searched in vain) or is really very simple, but i just can't get it. The MSDN definition of a Nullable type, states, that it is defined in a following manner: [SerializableAttribute] public struct Nullable<T> where T : struct, new() So the question is quite straightforward: How is this definition possible? Or this is just a typo? Every value type already has a default constructor. Indeed, when i try to compile something like this, the compiler reasonably says, that it is illegal to apply both constraints at the same time, because the second one is implicitly included in a first one. Thanks in advance.

  Read the article

• Are we using IoC effectively?

  - by Juliet

  So my company uses Castle Windsor IoC container, but in a way that feels "off": All the data types are registered in code, not the config file. All data types are hard-coded to use one interface implementation. In fact, for nearly all given interfaces, there is and will only ever be one implementation. All registered data types have a default constructor, so Windsor doesn't instantiate an object graph for any registered types. The people who designed the system insist the IoC container makes the system better. We have 1200+ public classes, so its a big system, the kind where you'd expect to find a framework like Windsor. But I'm still skeptical. Is my company using IoC effectively? Is there an advantage to new'ing objects with Windsor than new'ing objects with the new keyword?

  Read the article

• How can I add a field with an array value to my Perl object?

  - by superstar

  What's the difference between these two constructors in perl? 1) sub new { my $class = shift; my $self = {}; $self->{firstName} = undef; $self->{lastName} = undef; $self->{PEERS} = []; bless ($self, $class); return $self; } 2) sub new { my $class = shift; my $self = { _firstName => shift, _lastName => shift, _ssn => shift, }; bless $self, $class; return $self; } I am using the second one so far, but I need to implement the PEERS array in the second one? How do I do it with the second constructor and how can we use get and set methods on those array variables?

  Read the article

• defining a simple implicit Arbitary

  - by FredOverflow

  I have a type Foo with a constructor that takes an Int. How do I define an implicit Arbitrary for Foo to be used with scalacheck? implicit def arbFoo: Arbitrary[Foo] = ??? I came up with the following solution, but it's a bit too "manual" and low-level for my taste: val fooGen = for (i <- Gen.choose(Int.MinValue, Int.MaxValue)) yield new Foo(i) implicit def arbFoo: Arbitrary[Foo] = Arbitrary(fooGen) Ideally, I would want a higher-order function where I just have to plug in an Int => Foo function. I managed to cut it down to: implicit def arbFoo = Arbitrary(Gen.resultOf((i: Int) => new Foo(i))) But I still feel like there has got to be a slightly simpler way.

  Read the article

• Why does my array initialization code cause a StackOverflowException to be thrown?

  - by MCS

  The following line of code in my class constructor is throwing a StackOverflowException: myList = new string[]{}; // myList is a property of type string[] Why is that happening? And what's the proper way to initialize an empty array? UPDATE: The cause was in the set method, in which I was attempting to trim all values. What's wrong with this code: set { for (int i = 0; i < myList.Length; i++) { if (myList[i] != null) myList[i] = myList[i].Trim(); } }

  Read the article

• How can I access and change elements in this private readonly property?

  - by CrimsonX

  I'm trying to figure out how I am able to successfully change a "readonly" array. I have this: namespace ConsoleApplication1 { class Program { static void Main(string[] args) { MyClass myClass = new MyClass(); myClass.Time[5] = 5; // How is this legal? } } public class MyClass { private readonly uint[] time; public IList<uint> Time { get { return time; } } public MyClass() { time = new uint[7]; } } } As I Note above, I would expect that Time[5] would be illegal due to the fact that public IList Time does not have a setter. Additionally, how can I create an array in the constructor which is read-only and unchangeable outside of this class?

  Read the article

• Accessing a Clip Inside Another Clip in a Loaded SWF-File

  - by Anders

  I'm writing a card game in AS3. The artist I'm working with has produced (in Flash CS4) a single swf-file containing all the card graphics and animations. The structure of the fla working file looks something like this: - Scene - CardGraphics (Movie Clip) - CardFront - CardBack - CardValueImage (Movie Clip) ... In the program I create 52 instances of my Card class, each having a MovieClip instance created from the loaded swf. The idea is to set the frame of the CardValueImage MovieClip to correspond to the Card instance's suit and rank member variables. However, I can't figure out how I access CardValueImage and call gotoAndStop (or whatever method I will need to call). This is basically what I want to do: // Card Class [Embed(source = 'CardGraphics.swf')] private static var CardsClip:Class; private var clip:MovieClip = new CardsClip; // Card Constructor this.valueImageFrame = suit * 13 + rank; // Calculate which frame contains the // graphical representation of this card this.clip.CardValueImage.gotoAndStop(valueImageFrame);

  Read the article

• How to retrieve XML attribute for custom control

  - by David

  I've created a combo box control with a edittext and spinner. I'm trying to let the android:prompt attribute be passed onto the spinner, which means I need to catch it in the constructor which passes my the AttributeSet and set it on the spinner. I can't figure out how to get the value of the prompt. I'm trying, int[] ra = { android.R.attr.prompt }; TypedArray ta = context.getTheme().obtainStyledAttributes(ra); int id = ta.getResourceId(0, 0); I get back 0, which means it didn't find the attribute. I also did a ta.count() which returned 0. So I'm not getting anything back. My XML simply defines an android:prompt value. Thanks

  Read the article

• 2 Classes need each other declared C++

  - by Prodigga

  I have a "Game" class which holds all the games settings and manages the game. I have a "Grid" class which is the grid the game is played on. The "Game" class initializes a "Grid" object as one of its members (passing itself ("this") as one of the parameters for "Grid"s constructor).. The "Grid" object therefor needs to deal with a "Game*" pointer. To do this it needs to know what "Game" is; i need to declare it before "Grid". But "Game" uses "Grid"...so it also needs "Grid" declared before it. so confused on how to include headers/etc correctly here..

  Read the article

• Can there be two public section in a class? If yes then why ? And in which circumstances we do so?

  - by Abhi

  Dear all I have a doubt related to class. For example class A { public: A() { ..... ..... } void cleanup() { .... .... .... } public: UINT a; ULONG b; }; In the above example there are two public section, In first section i am defining constructor and the method and in the second section i am declaring data members. Does the above class i.e. A is correct. Can we do so? If yes then why we needed and in which circumstances we should use it? Also we can do the entire thing in one section then why un necessary we r taking two section...? Thanks and regards Abhineet Agarwal

  Read the article

• different explanation

  - by Delirium tremens

  The following code echoes 5, not 10: $global_obj = null; class my_class { var $value; function my_class() { global $global_obj; $global_obj = &$this; } } $a = new my_class; $a->my_value = 5; $global_obj->my_value = 10; echo $a->my_value; "Upon first examination, it would seem that the constructor of my_class stores a reference to itself inside the $global_obj variable. Therefore, one would expect that, when we later change the value of $global_obj-my_value to 10, the corresponding value in $a would change as well. Unfortunately, the new operator does not return a reference, but a copy of the newly created object." Please, give me a different explanation.

  Read the article

• Ruby on Rails: building a model with an attribute not in the database?

  - by randombits

  I have a model that sets one of its attributes based off of a form parameter that a user submits. The model is a child resource to a parent resource Home. A hypothetical example is the following: A class Person has an age attribute. The user submits a birthdate as an HTTP POST parameter and from that, I need to derive the age of the user. So I'd do something like this: @home.people.build(:name => params[:name], :birthdate => params[:birthdate]) Rails would barf on that for obvious reasons, complaining it doesn't know what the attribute birthdate is. What's the proper way of going about this? Is it possible to use the build constructor with the supplied solution so that my foreign key relations are also setup properly? If not, what's a better way to work around this problem?

  Read the article

• Relvance of 'public' contructor in abstract class.

  - by Amby

  Is there any relevance of a 'public' constructor in an abstract class? I can not think of any possible way to use it, in that case shouldn't it be treated as error by compiler (C#, not sure if other languages allow that). Sample Code: internal abstract class Vehicle { public Vehicle() { } } The C# compiler allows this code to compile, while there is no way i can call this contructor from the outside world. It can be called from derived classes only. So shouldn't it allow 'protected' and 'private' modifiers only. Please comment.

  Read the article

• Singletons and other design issues

  - by Ahmed Saleh

  I have worked using different languages like C++/Java and currently AS3. Most applications were computer vision, and small 2D computer games. Most companies that I have worked for, they use Singletons in a language like AS3, to retrieve elements or classes in an easy way. Their problem is basically they needs some variables or to call other functions from other classes. In a language like AS3, there is no private constructor, and they write a hacky code to prevent new instances. In Java and C++ I also faced the situation that I need to use other classe's members or to call their functions in different classes. The question is, is there a better or another design, to let other classes interact with each others without using singletons? I feel that composition is the answer, but I need more detailed solutions or design suggestions.

  Read the article

• How to set default values to the properties of dynamically loaded types at runtime for XML serializa

  - by Erkan Y.

  I need to serialize dynamically loaded types' classes using XMLSerializer. When using XML serializer non initialized values are not being serialized. I dont have control over the assemblies I am working with so can not use XML attributes for specifying default values on properties. So I think I need to set all properties and sub properties to their default values recursively and then serialize. ( Please let me know if there is any better way ) Followed this : Activator.CreateInstance(propType); but above line complains about not having a parameterless constructor for some types. Tried this : subObject = FormatterServices.GetUninitializedObject(propType); but this one gives an error "value was invalid" with no inner exception. Please let me know if you need any further information.

  Read the article

• android java.lang.OutOfMemoryError

  - by xiangdream

  hi, all, when i download large data from website, i got this error information: I/global (20094): Default buffer size used in BufferedInputStream constructor. It would be better to be explicit if an 8k buffer is required. D/dalvikvm(20094): GC freed 6153 objects / 3650840 bytes in 335ms I/dalvikvm-heap(20094): Forcing collection of SoftReferences for 3599051-byte al location D/dalvikvm(20094): GC freed 320 objects / 11400 bytes in 144ms E/dalvikvm-heap(20094): Out of memory on a 3599051-byte allocation. I/dalvikvm(20094): "Thread-9" prio=5 tid=17 RUNNABLE I/dalvikvm(20094): | group="main" sCount=0 dsCount=0 s=0 obj=0x439b9480 I/dalvikvm(20094): | sysTid=25762 nice=0 sched=0/0 handle=4065496 anyone can help me?

  Read the article

• Trouble dragging and dropping gui components onto other .net forms using NHibernate

  - by IsaacB

  Hi, using VS2008, here. I have a GUI component that loads some stuff from a database mapped by nhibernate in its constructor. When I drag and drop this component onto another form from the toolbox, NHibernate complains that it can't find the config file in program files\visual studio 9\common7\ide. Why is it looking here for the cfg file? I'm actually calling database stuff through another project in the same solution, and the cfg file is located at the root of that project. copy/pasting the cfg file over to there does work, but I'm working with svn here and I don't want to have configuration files outside the repository. Something else that would help would be turning off how it tries to load the data in the form design screen. How would I do that?

  Read the article

• How can I access and modify objects inside frames with AS3 in a permanent way?

  - by curro

  I have a MovieClip symbol created with flash in a fla file library. There is a textfield in frame one of this movieclip's timeline . There is another frame in the movieclip timeline. There is a custon class definition for this symbol. It is a flipping card in a memory game. I access the textfield by going to frame 2 (gotoAndStop(2)) and setting the textfield's text property ( this.field.text = "hello" ). However if I go to frame 1 and then return to frame 2, the text becomes the original one in the library's symbol. I have to modify the text propery again in a showFace method I've written. Besides, I cannot pass parameters in the constructor because it is a symbol in the library and that would give errors. I find this behaviour of flash extremely weird. Is there a way I can set properties inside frames permanently? Thank you

  Read the article

• PHP OOP: Avoid Singleton/Static Methods in Domain Model Pattern

  - by sunwukung

  I understand the importance of Dependency Injection and its role in Unit testing, which is why the following issue is giving me pause: One area where I struggle not to use the Singleton is the Identity Map/Unit of Work pattern (Which keeps tabs on Domain Object state). //Not actual code, but it should demonstrate the point class Monitor{//singleton construction omitted for brevity static $members = array();//keeps record of all objects static $dirty = array();//keeps record of all modified objects static $clean = array();//keeps record of all clean objects } class Mapper{//queries database, maps values to object fields public function find($id){ if(isset(Monitor::members[$id]){ return Monitor::members[$id]; } $values = $this->selectStmt($id); //field mapping process omitted for brevity $Object = new Object($values); Monitor::new[$id]=$Object return $Object; } $User = $UserMapper->find(1);//domain object is registered in Id Map $User->changePropertyX();//object is marked "dirty" in UoW // at this point, I can save by passing the Domain Object back to the Mapper $UserMapper->save($User);//object is marked clean in UoW //but a nicer API would be something like this $User->save(); //but if I want to do this - it has to make a call to the mapper/db somehow $User->getBlogPosts(); //or else have to generate specific collection/object graphing methods in the mapper $UserPosts = $UserMapper->getBlogPosts(); $User->setPosts($UserPosts); Any advice on how you might handle this situation? I would be loathe to pass/generate instances of the mapper/database access into the Domain Object itself to satisfy DI - At the same time, avoiding that results in lots of calls within the Domain Object to external static methods. Although I guess if I want "save" to be part of its behaviour then a facility to do so is required in its construction. Perhaps it's a problem with responsibility, the Domain Object shouldn't be burdened with saving. It's just quite a neat feature from the Active Record pattern - it would be nice to implement it in some way.

  Read the article

• C# property in a form class only accessable after formload event

  - by Spooky2010

  using vs2008, c# Howdy, Im instantiating and calling Form B from Form A. FormB has some custom properties, to allow me to pass it things like sqlAdaptors and dataset instances. When i instantiate and show Form B from Form A as a dialog form with a Using statement, it all works fine, but i find the properties i pass are not available in Form B until after the form_load event has fired. I was under the impression the properties when passed to a instantiated class should be available from a constructor, but this is not the case. If it try to access the properties before the form load event i get a null reference exception. Is this correct behavior ? It is very annoying. thanks for any help

  Read the article

• AutoMapper and Linq expression.

  - by Raffaeu

  I am exposing the Dto generated from AutoMapper to my WCF services. I would like to offer something like that from WCF: IList GetPersonByQuery(Expression predicate); Unfortunately I need back an expression tree of Person as my DAL doesn't know the DTO. I am trying this wihtout success: var func = new Func<Person, bool>(x => x.FirstName.Contains("John")); var funcDto = Mapper.Map<Func<Person, bool>, Func<PersonDto, bool>>(func); Console.WriteLine(func.ToString()); Console.WriteLine(funcDto.ToString()); THe error that I get is: ----> System.ArgumentException : Type 'System.Func`2[TestAutoMapper.PersonDto,System.Boolean]' does not have a default constructor Do you have any suggestions?

  Read the article

• Best way to test if a generic type is a string? (c#)

  - by Rex M

  I have a generic class that should allow any type, primitive or otherwise. The only problem with this is using default(T). When you call default on a value type or a string, it initializes it to a reasonable value (such as empty string). When you call default(T) on an object, it returns null. For various reasons we need to ensure that if it is not a primitive type, then we will have a default instance of the type, not null. Here is attempt 1: T createDefault() { if(typeof(T).IsValueType) { return default(T); } else { return Activator.CreateInstance<T>(); } } Problem - string is not a value type, but it does not have a parameterless constructor. So, the current solution is: T createDefault() { if(typeof(T).IsValueType || typeof(T).FullName == "System.String") { return default(T); } else { return Activator.CreateInstance<T>(); } } But this feels like a kludge. Is there a nicer way to handle the string case?

  Read the article

< Previous Page | 122 123 124 125 126 127 128 129 130 131 132 133  | Next Page >