Archive | July 2011

Flex Error #1009: Cannot access a property or method of a null object reference (update)

A couple of years ago I wrote a post discussing the Flex error #1009 (cannot access a property or method of a null object reference). If you’ve done any serious amount of Flex coding I’m sure you’ve run into this error a number of times.

While there are a few possible causes, the post discussed how a lack of understanding of the Flex component creation lifecycle could be a possible culprit. While everything in the post is still technically accurate (for Flex 3) I find that I often just use bindings if I need to set a property of a child component.

So… here’s the fourth way to solve the problem (at least for simpler use cases).

<?xml version="1.0" encoding="utf-8"?>
<mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml">

	<mx:Script>
		<![CDATA[

			[Bindable]
			public var buttonLabel:String;
								
		]]>
	</mx:Script>

	<mx:Button id="button" label="{ buttonLabel }"/>

</mx:Canvas>

I realize this is pretty obvious to most Flex programmers, I just wanted to clarify for people who are new to Flex and are finding the old post.

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