constructor

问题 I have the same problem as Promisify imported class (constructor) with bluebird in ES6 + babel. The accepted answer seems to have a bug but I couldnt comment on that thread (not enough reputation points), so am creating a new question. The bug seems to be in: var o = new lib.C(); // get object o.then(function(data){ // access data }); I get a run-time error: ~/node_modules/bluebird/js/main/promise.js:114 return this._then(didFulfill, didReject, didProgress, ^ TypeError: undefined is not a

问题 Consider the following code classes. public class A { public A() { callCreation(); } protected void callCreation() { System.out.println("A Created!!"); } } public class B extends A { protected void callCreation() { System.out.println("B Created!!"); } } public class C extends B { protected void callCreation() { System.out.println("C Created!!"); } public static void main(String[] args) { A a = new A(); A b = new B(); A c = new C(); } } The output of running the class C is given below. A

问题 I have a class which looks like: public class WidgetDao : AbstractDao<Widget>, IWidgetDao { public WidgetDao(ISession session) : base (session) { } } My code has build errors if I attempt to remove this constructor on code which looks like: public IWidgetDao GetWidgetDao() { return _widgetDao ?? (_widgetDao = new WidgetDao(_session)); } I sort of understand the reason why I get a build error... there's no explicit WidgetDao constructor which takes one parameter. However, WidgetDao inherits

问题 I am experimenting with DOM event handlers, and I put in my Constructor's prototype a function that works on the DOM div element, which is a property created by the constructor in my object. It displays the object correctly, but the only thing that does not work is that it thinks that in my method, .keyCode , is a property of undefined and gives me an error message: TypeError: Cannot read property 'keyCode' of undefined (line 16 in function KeyBlock.move) This is my method, along with my

问题 I'm writing a program in C++11, which analyses chess positions and computes some interesting statistics. The data I'm loading in is formatted into a structure struct board{ board(long int hash1,long int hash2); }; and I'm storing everything in another structure struct data_struct{ vector<board> allboards; void read_data(char* filename); //other member functions }; Previously I was reading in data from a text file, but I'm working on a computer cluster where file I/O is expensive and I have to

问题 I am asking this in response to this answer. I'm using an example of Variable and Var - edit Pls note I am asking where to use Var or Variable : Class NewClass { private String Variable = ""; Public Class (String Var) { NewClass.Var = Variable; } } OR private String Variable = ""; Public Class (String Variable) { NewClass.Variable = Var; // OR WHATEVER OTHER COMBINATIONS IT MAY BE. } } Which ones are the class variables, how does this differ from the parameters and which goes where? edit I

问题 I'm trying to get the name of an object and put it in an array after it's defined, I tried doing this code, but the name ended up being undefined any help? function command(category, help, callback) { this.category = category; this.help = help; this.do = callback; cmndlist[category].push(this.name); }; 回答1: Objects do not have a name or name property (unless you add one yourself). If you're referring to the variable name that references the object, that is not possible to access. 回答2: Let's

问题 Im new with Microsoft Unity Container, so my question may be trivial. I got to register and resolve instances for classes with only one parameterless constructor. Now I wish to learn how to register and resolve a class with a simple constructor. Here is my class. public class MyClass { private string a1; public string A1 { get { return a1; } set { a1 = value; } } private int a2; public int A2 { get { return a2; } set { a2 = value; } } public MyClass() { this.a1 = "aaaaa"; this.a2 = 1; }

问题 I am trying to initialize a base class and a subclass without having to copy the constructor. This is what I got: tstbase.pm: package tstbase; use Exporter qw(import); our @EXPORT = qw(&new); my %config = ( "class" => "tstbase", ); sub new { my $class = shift; my $self; $self->{"name"} = $config{"class"}; bless ($self, $class); return $self; }; 1; tstsubclass.pm: package tstsubclass; use tstbase; my %config = ( "class" => "tstsubclass", ); 1; tst.pl: #!/usr/bin/perl use tstsubclass; my

问题 In my C++ code, I have a const array of objects of a struct type. This structure has some const members. My hardware compiler (GHS Multi2000) throw the warning: warning#368-D: class defines no constructor to initialize the following: Is this warning alright? I read online that this can be ignored. It is simply that the compiler expects const members to be initialized in the constructor initialization list. Can this warning be suppressed? 回答1: The warning is all right, and meaningful. What