Why would I get ReferenceError #1065: "Variable title is not defined."

Question

Well of course it's not defined. It's a dynamic class, and strict mode compilation is turned off so that I don't have to declare the property to compile it.

I've created a library item named "Page" with a single TextField instance named "title".

Page's class is defined in an ActionScript file, and it's assigned to the library item in export for ActionScript.

Page's ActionScript file defines the class as a "dynamic" class, so I should not be getting this runtime error. I turned off strict mode compiling, since it seems to be designed to check the presense of property definitions at compile time for dynamic classes like MovieClip.

public dynamic class Page extends MovieClip

{

public function Page()

{

super();

var text:String = title.text; //title can be moused over in the debugger here and shows the correct value, but the flash player throws a runtime error when it tries to access it, but it shouldn't because this is a dynamic class.

}

So why am I getting a runtime error for the field "title". It makes no sense, because if I step to that line in the FlashDevelop debugger and hold the mouse over "title", it shows that it is in fact the instance of the TextField that I'm trying to access. Yet the player throws an error when I actually try to access it.

Is it a problem or limitation with the access style (i.e. would it work fine if I accessed it as "this.title" or "this["title"]"?

James22s22 · Answer

Nevermind. This was apparently a browser caching issue. The Page base class is defined in the main interface swf, and is externally referenced through its swc in an external "lesson" file that declare a subclass of Page. It was this custom subclass of Page which was throwing the error (basically the same as the simplified example I wrote for my post, where it simply tried to access "title" as a dynamic property of the Page). What happened is the browser was caching an old version of the lesson file with the old definition of the class that was not declared as dynamic. I had received the error before, then updated the class, then I was surprised to see the error persist. It suddenly dawned on me that the browser was probably caching the old version, so I cleared the cache and it seems to work fine now.

Actually, it is a problem after all. I forgot I had updated it to use "this.title" syntax on the page I tested after clearing the cache, but the other pages that try to access title directly as "title" still throw the error. So it seems to be some sort of quirk in how flash accesses properties of a dynamic class. If you try to access them direclty, it must do so in a way that requires the property to be defined, but if you access it via "this.title" or this["title"], the it seems to resolve the property value without throwing the error.

This sucks. I was really trying to not have to write "this." for every property. The entire display list is dynamically generated from some custom XML that allows me to call constructors and set complex type-safe properties, and during construction it was copying each item into a Dictionary by name. This Dictionary was then assigned to the page class as "items", so I was accessing each display object as "item.name". Then I got the brilliant idea of just making Page and its subclasses "dynamic" so that I could just add the DIctionary values on the Page instance itself. I thought I would be able to access the dyamic properties just by their name such as "title", but lo and behold, Flash strikes again, and I have to use dot notation anyway. What do you all think? Any solutions?

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