AS3检查类是否扩展了另一个类

Question

在AS3中，我试图检查一个对象是否是一个实例，或者扩展了一个特定的类。如果对象是ClassName的实例，则使用诸如if (object is ClassName)之类的东西可以很好地工作，但如果它是延伸的类的实例ClassName，则不能正常工作。

伪代码示例：

class Foo {} 
class Bar extends Foo {} 

var object = new Bar(); 

if (object is Foo){ /* not executed */ } 
if (object is Foo){ /* is executed */ } 

我想是这样的：

class Foo {} 
class Bar extends Foo {} 

var object = new Bar(); 

if (object is Foo){ /* is executed */ } 

任何想法吗？

Answer 1

package { 
import flash.display.Sprite; 



public class Main extends Sprite { 
    public function Main() { 
    var bar:Bar=new Bar(); 
    trace("bar is Bar",bar is Bar);//true 
    trace("bar is Foo:",bar is Foo);//true 
    trace("bar is IKingKong:",bar is IKingKong);//true 
    trace(describeType(bar)); 
    //<type name="Main.as$0::Bar" base="Main.as$0::Foo" isDynamic="false" isFinal="false" isStatic="false"> 
    //<extendsClass type="Main.as$0::Foo"/> 
    //<extendsClass type="Object"/> 
    //<implementsInterface type="Main.as$0::IKingKong"/> 
    //</type> 
    } 
} 
} 
interface IKingKong{} 
class Foo implements IKingKong{} 
class Bar extends Foo{} 

Answer 2

使用一个接口或abtract类，你应该能够做到这一点

var object:Foo = new Bar(); 
if (object is Foo){ /* is executed */ } 

//or 
var object:IFoo = new Bar(); 
if (object is IFoo){ /* is executed */ } 

Answer 3

package 
{ 
import flash.display.Sprite; 
import flash.utils.getQualifiedSuperclassName; 

public class Test extends Sprite 
    { 
    public function Test() 
     { 
     trace(getQualifiedSuperclassName(this)); //returns "flash.display::Sprite" 
     } 
    } 
} 

Answer 4

你可以这样做：

class Foo {} 
class Bar extends Foo {} 

var object = new Bar(); 

if (object as Foo != null) { /* is executed */ }