我想实现这个方法

 函数isInstance（一：类，B：类）：布尔;
 

这是AS3与类的工作。 注意，影片剪辑扩展Sprite。的

 跟踪（影片剪辑是雪碧）; // 假
跟踪（Sprite是影片剪辑）; // 假
跟踪（Sprite是雪碧）; // 假
跟踪（雪碧是Object）; // 真正
 

我一直在努力的下一个code，但它不工作：

  / **
*如果收益类的实例A可强制转换为类B的瞬间
* /
私有函数isInstance（一：类，B：类）：布尔{
    VAR超：CLASS = A;
    做 {
        如果（超== b）{
            返回true;
        }
        超= getSuperclass之（一）;
    }而（超！= NULL）;

    返回false;
}

私有函数getSuperclass之（claz：类）：类{
    VAR qualifiedSuperclassName：字符串= getQualifiedSuperclassName（claz）;
    VAR的returnValue：类= getDefinitionByName（qualifiedSuperclassName）为类;
    返回的returnValue;
}
 

解决方案

在此网站上找到解决方案。

这是这么简单：

 私有函数isSubclassOfSkyboy（一：类，B：类）：布尔
{
    如果（INT（一）| INT（B）！）返回false;
    回报（A == b || a.prototype的instanceof B）;
}
 

这里有一个使用的instanceof 从AS3 pcated这是德$ P $。据我了解，他无法取代的是是在这种情况下，但纠正我，如果我错了。评论之前的任何方式阅读文章。

I want to implement this method

function isInstance(a:Class, b:Class):Boolean;

This is how AS3 work with Classes. Note that MovieClip extends Sprite.

trace(MovieClip is Sprite); // false
trace(Sprite is MovieClip); // false
trace(Sprite is Sprite); // false
trace(Sprite is Object); // true

I been trying the next code but it is not working:

/**
* return if instance of class 'a' can be cast to instant of class 'b'
*/
private function isInstance(a:Class, b:Class):Boolean{
    var superclass:Class = a;
    do {
        if (superclass == b) {
            return true;
        }
        superclass = getSuperClass(a);
    } while (superclass != null);

    return false;
}

private function getSuperClass(claz:Class):Class{
    var qualifiedSuperclassName:String = getQualifiedSuperclassName(claz);
    var returnValue:Class = getDefinitionByName(qualifiedSuperclassName) as Class;
    return returnValue;
}

Found solution in this site.

It is simple as that:

private function isSubclassOfSkyboy(a:Class, b:Class): Boolean
{
    if (int(!a) | int(!b)) return false;
    return (a == b || a.prototype instanceof b);
}

There is a use here of instanceof that been deprecated from as3. As I understood he cannot be replaced with is in this case, but correct me if I am wrong. Any way read the article before commenting.