inheritance

Add a Property to Entity Class in ViewModel

由 被刻印的时光 ゝ 提交于 2019-12-25 05:30:42
问题 I have a profile with a EntityCollection of ProfileUser. In this Class I have a Profile_ID ald a Profile relation and a User_ID but no USer relation, because User is in another Database. In a Datagrid I want to access via User.Username I tried this, but ofc it doesnt work... public EntityCollection<ProfileUser> ProfileUsers { get { if (profile != null) return profile.ProfileUser; else return null; } set { profile.ProfileUser = value; } } and here my custom Class public class

Python - calling ancestor methods when multiple inheritance is involved

由 匆匆过客 提交于 2019-12-25 05:21:27
问题 Edit: I'm using Python 3 (some people asked). I think this is just a syntax question, but I want to be sure there's nothing I'm missing. Notice the syntax difference in how Foo and Bar are implemented. They achieve the same thing and I want to make sure they're really doing the same thing. The output suggests that there are just two ways to do the same thing. Is that the case? Code: class X: def some_method(self): print("X.some_method called") class Y: def some_method(self): print("Y.some

Cleanest way to fix this castings behavior

由 落花浮王杯 提交于 2019-12-25 05:18:18
问题 Imagine I have a list with 50 different type of a certain subclasses of Node which I expect to be the same type or get a ClassException if not. I have a method which receives this list and a node holding and expeting a certain type I would like to do something like this: public <E extends Node> receive(List<Node> list, Node<E extends Node> node){ for (Node element : list ){ node.addElement((E) element); //Type erasure, if you put wrong node no CastException in Runtime } } but avoid doing this

Preventing multiple objects from being printed

由 我只是一个虾纸丫 提交于 2019-12-25 05:06:54
问题 For my final CS180 project we have been given the task of creating a program that randomly generates some perishable and nonperishable items that would be found in a grocery cart and then printing a receipt for a customer. The problem I am running into is finding a way to check the frequency of an item being created and preventing the item from printing multiple times on a receipt. For example, if someone buys 5 peaches the I want the output to be Peach $.99 X 5, total $4.95, instead of

php self() with current object's constructor

由 ￡可爱￡侵袭症＋ 提交于 2019-12-25 05:04:55
问题 What's the proper way to get new self() to use the current instance's constructor? In other words, when I do: class Foo{ function create(){ return new self(); } } Class Bar extends Foo{ } $b = new Bar(); echo get_class($b->create()); I want to see: Bar instead of: Foo 回答1: public static function create() { $class = get_called_class(); return new $class(); } This should work. class Foo{ public static function create() { $class = get_called_class(); return new $class(); } } class Bar extends

Inheritance in Java simple clarification

由 ﹥＞﹥吖頭↗ 提交于 2019-12-25 04:59:10
问题 So, I have this: public class A { public int a = 0; public void m(){ System.out.println("A"+a); } } And this: public class B extends A { public int a = 5 ; public void m (){ System.out.println("B"+a); } public static void main(String[] args) { A oa = new A(); B ob = new B(); A oab = ob; oa.m(); ob.m(); oab.m(); System.out.println("AA"+oa.a); System.out.println("BB"+ob.a); System.out.println("AB"+oab.a); } } Output: A0 B5 B5 AA0 BB5 AB0 I don't understand why oab.m(); output is B5 instead of

JavaScript Inheritance and Hoisting

由 ☆樱花仙子☆ 提交于 2019-12-25 04:48:12
问题 In my current web project, I'm working with multiple JavaScript files, each containing type definitions that inherit from other types. So in any given file, I could have something like ... function Type(){ ParentType.call(this); } Type.prototype = Object.create( ParentType.prototype ); Type.prototype.constructor = Type; ... with the ParentType declared similarly in another file: function ParentType(){ this.data = ""; } Since working with many JavaScript files becomes bothersome in the <head>

Understanding Object Inheritance

由 可紊 提交于 2019-12-25 04:39:27
问题 In a previous question (linked here), there were some unresolved issues about object inheritance which remain unclear. (my use of terminologies may be incorrect - please edit accordingly - thank you) Put simply, why does the superclass not inherit the properties of a subclass that has been expressly assigned to it. A code example: UIView *view = nil; UILabel *label = [[UILabel alloc] init]; label.text = @"some text..."; view = label; // view has not inherited any UILabel properties view.text

C# - Why can I not cast a List<MyObject> to a class that inherits from List<MyObject>?

由 有些话、适合烂在心里 提交于 2019-12-25 04:33:30
问题 I've got an object, which I'll call MyObject. It's a class that controls a particular data row. I've then got a collection class, called MyObjectCollection: public class MyObjectCollection : List<MyObject> {} Why can I not do the following: List<MyObject> list = this.DoSomethingHere(); MyObjectCollection collection = (MyObjectCollection)list; Thanks in advance. Edit: The error is InvalidCastException 回答1: My guess is that DoSomethingHere doesn't return an instance of MyObjectCollection . Let

C# adding control from another class

由 风格不统一 提交于 2019-12-25 04:14:41
问题 I want to add form controls dynamically to my form from another class which inherits the form class. Everything works fine but it does not add the controls at run time. Here is my sample code: namespace Namespace1 { public partial class Form1 : Form { ..... } ....... }// end of Namespace1 namespace Namespace2 { public class1:Form1 { public Button button = new Button(); public void method1() { button1.Name="button1"; //flowlayoutcontrol1 is a public control on Form1 flowlayoutcontrol1.Controls
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