这是一个问题，最好的在code解释。

This is a problem that's best explained in code.

我看不出 active_button.upState ，这是我所知道的是一个文本字段（见trace语句），神不知鬼不觉变成一个DisplayObject，当我尝试访问文字颜色属性。

I don't see how active_button.upState, which I know is a TextField (see trace statements), mysteriously turns into a DisplayObject when I try to access the textColor property.

我已经包含下面的错误信息，以供参考。

I've included the error messages below for reference.

另外，为什么是它，当我有，我知道为SimpleButton对象（同样，见踪迹），我需要将其转换为SimpleButton的，以便将其存储在一个变种？这没有任何意义，我。

Also, why is it that when I have an object that I know is a SimpleButton (again, see traces) I need to cast it to SimpleButton in order to store it in a var? That doesn't make any sense to me.

所有帮助是非常AP preciated。谢谢你。

All help is much appreciated. Thanks.

public class Menu extends MovieClip
{
    private var active_button:SimpleButton;

    public function Menu() 
    {
        // menu_list is a collection of SimpleButtons, I make the first one the 'active_button' and give each a MOUSE_DOWN event listener.
        trace( menu_list.getChildAt( 0 )); // writes [object SimpleButton]
        active_button = SimpleButton( menu_list.getChildAt( 0 )); // Cast is required here. Otherwise throws Error 1118. Strange. Why is that?

        for( var i:Number = 0; i < menu_list.numChildren; i++ )
        {
            menu_list.getChildAt( i ).addEventListener( MouseEvent.MOUSE_DOWN, menuClick );
        }
    }

    private function menuClick( e:Event ) : void
    {
        trace( e.target ); // writes [object SimpleButton]
        active_button = SimpleButton( e.target ); // Cast is required here. Otherwise throws Error 1118. Still Strange.
        trace( active_button ); // writes [object SimpleButton]. Normal.
        trace( active_button.upState ); // writes [object TextField]. Normal.
        active_button.upState.textColor = 0xAAAAAA; // Throws Error 1119. WTF?! textColor is a perfectly valid property of active_button.upState. Why is it suddenly type DisplayObject?
    }
}

错误：

1118：静态类型flash.display使用的值的隐式强制：要的DisplayObject一个可能无关的类型flash.display一：SimpleButton的

1118: Implicit coercion of a value with static type flash.display:DisplayObject to a possibly unrelated type flash.display:SimpleButton.

1119：可能未定义的属性文字颜色的通过静态类型flash.display使用参考访问：的DisplayObject

1119: Access of possibly undefined property textColor through a reference with static type flash.display:DisplayObject

编辑：我凝聚我的问题一点点，张贴http://stackoverflow.com/questions/2165095/as3-why-does-datatype-automatically-change-from-textfield-to-displayobject-on-it

I've condensed my question a little bit and posted as http://stackoverflow.com/questions/2165095/as3-why-does-datatype-automatically-change-from-textfield-to-displayobject-on-it

推荐答案

凡是被从图像显示拉被归类为可能的最低dinominator（例如displayObject的），因为虽然SimpleButton的是一个DisplayObject，不是所有的DisplayObject将SimpleButtons 。 这可能是你的第二个问题的原因也一样，只是在执行中略有不同。有没有在SimpleButton的一个直接引用，指出纽约州北部是一个TextField？

Anything that is pulled from the displaylist is classed as the lowest possible dinominator (eg. displayObject), as although SimpleButton is a displayObject, not all displayObjects will be SimpleButtons. This is probably the reason for your second problem too, just slightly different in execution. is there a direct reference in SimpleButton that states upState is a TextField?

尝试关闭编译严格模式，看看是否有帮助。 看类型检查的LiveDocs 了解详情

try switching off Strict Mode of compilation and see if it helps. see Type Checking Livedocs for more information