overriding

问题 I'm wondering if it is possible to override the default value of a field when it is returned. Say I had a model: class ModelA(models.Model) name = models.CharField(max_length=30) Is there any way that calling modela_instance.name can return a modified value, for example name + " foo", but have the code that appends foo run by default within the model itself, so all I would need to do is call name to get the appended value? I should elaborate and say that what I'm actually hoping to do is have

问题 I want to change the width and height of jquery slider UI. I am using ui-lightness theme. I tried to override the default jquery.css by adding the following code in my style sheet. .ui-slider .ui-slider-horizontal { height: .6em; } .ui-slider .ui-slider-handle { position: absolute; z-index: 2; width: 1em; height: 1em; cursor: default; } But the above css has no effect. jquery.css overrides the above style and I see no change in the slider. How to override the default jquery.css styles? 回答1:

问题 Assume you have a class that defines virtual methods with the access specifier public. Can you change the access specifier on your overriden methods? I am assuming no. Looking for an explanation. 回答1: Yes you can, but it "doesn't grok". Take a look at Overriding public virtual functions with private functions in C++ 回答2: The answer is: sort of. You can only change the access of members the derived class has access to. The type of inheritance has no effect - this only controls the default

问题 In a C++ program, we have 3 streams: stdin , stdout , and stderr . Can I override these in a console application and use them in a application that uses forms? For example, if in some base class, I have cout<< "..." , can I "redirect" to something visual (like a Windows Form)? 回答1: What I would recommend doing is having a class which wraps around an iostream like this : #include <iostream> #define LOG Log() class Log { public: Log(){} ~Log() { // Add an newline. std::cout << std::endl; }

问题 I'm trying to achieve something like this public abstract class BaseEvent { public abstract void Dispatch(IEventHandler handler); } public class MyEvent : BaseEvent { public override void Dispatch(IMyEventHandler handler) { handler.OnMyEvent(this); } } public interface IEventHandler { } public interface IMyEventHandler : IEventHandler { void OnMyEvent(MyEvent e); } The problem is that the compiler complains saying that MyEvent doesn't implement BaseEvent since Dispatch is taking an

问题 I generally override the ToString() method to output the property names and the values associated to them. I got a bit tired of writing these by hand so I'm looking for a dynamic solution. Main: TestingClass tc = new TestingClass() { Prop1 = "blah1", Prop2 = "blah2" }; Console.WriteLine(tc.ToString()); Console.ReadLine(); TestingClass: public class TestingClass { public string Prop1 { get; set; }//properties public string Prop2 { get; set; } public void Method1(string a) { }//method public

问题 Are class methods and methods in the eigenclass (or metaclass) of that class just two ways to define one thing? Otherwise, what are the differences? class X # class method def self.a "a" end # eigenclass method class << self def b "b" end end end Do X.a and X.b behave differently in any way? I recognize that I can overwrite or alias class methods by opening the eigenclass: irb(main):031:0> class X; def self.a; "a"; end; end => nil irb(main):032:0> class X; class << self; alias_method :b, :a;

问题 I'm wondering if there is any good reason why this behaviour is possible in the current PHP 5.4 implementation: trait T { public function test(PDO $pdo) {} } class C { use T; public function test(DOMDocument $dom) {} } I thought that the fact that a class uses a trait, guaranteed that this class had a specific interface available. But here, if we inadvertently override the trait method for another purpose, we don't even receive a Strict Standards notice, as with classic inheritance. Is this

问题 How can I make it so that any class that inherits from my base class is forced to override a specific method? I don't want to use a protocol, because that wouldn't make this behavior automated. @interface MyBaseClass : NSObject { } - (void)performAnAction; @end @implementation MyBaseClass - (void)performAnAction { @throw([NSException exceptionWith...]); } @end 回答1: How exactly do you mean, force them to override it? If you simply implement the parent method like so: - (void)performAction {

问题 Working with a PHP library class, and I'd like to wrap all of its public functions in a subclass... Something along the lines of: class BaseClass { function do_something() { some; stuff; } function do_something_else() { other; stuff; } /* * 20-or-so other functions here! */ } class SubClass extends BaseClass { function magicalOverrideEveryone() { stuff-to-do-before; // i.e. Display header call_original_function(); // i.e. Display otherwise-undecorated content stuff-to-do-after; // i.e.