Technology Tips Blog

Something that all AS3 programmers run into in their career is having to take a text value from an external file and use it to reference an object on the Flash stage. This is easy if the object is not deeply nested.

var s:String = "mcMyClip";

MovieClip(this)[s].play();

What happens if the string being passed is a path to a deeply nested object? For example: “mcMyClip.mcClipChild.mcClipGrandchild” Unfortunately the Flash compiler does not parse the string used in direct references (square braces) so using the following code will cause the compiler to try and reference an object instance name of “mcMyClip.mcClipChild.mcClipGrandchild”

var s:String = "mcMyClip.mcClipChild.mcClipGrandchild";

MovieClip(this)[s].play();

To resolve this issue we need to create a simple, reusable, function to parse the path and return an object reference. This can be done as follows:

private function getReference(st:String):*
{
	var t:Array = st.split(".");     //** Create an array for the path
	var tg:* = MovieClip(this);   //** Establish the path start point

	for each( var str:String in t)  //** Loop through the path elements
	{
		tg = tg[str];              //** Assign new object reference to return value
	}
	return tg;                         //** Return new object reference to caller
}

This code works well for referencing any type of object no matter how deeply it is nested.