Programming Flex 3

Enabling Data Binding for Custom Classes

Data binding is enabled for some types of objects by default, but to make it work for custom classes, enable data binding with the [Bindable] metadata tag which tells the Flex compiler to configure whatever it precedes. Use [Bindable] with:

• A class

• A property

• An implicit getter method

• An implicit setter method

Note

For data binding to work when using implicit getters and setters, you need a getter and a setter for every property that you want to use data binding.

When you use the [Bindable] metadata tag before a class declaration, it marks all the public properties and all the getter and setter pairs as data-binding-enabled:

[Bindable]
public class Example {

When you use [Bindable] before a property declaration, it sets just that property as data-binding-enabled:

[Bindable]
private var _exampleProperty:String;

When you use [Bindable] before a getter and/or setter method, that method becomes data-binding-enabled. If a getter and setter have the same name, you must place the [Bindable] metadata tag before only one of them. If you have only a getter method, the method works only as the source for data binding. If you have only a setter method, the method works only as the destination for data binding:

[Bindable]
public function get exampleGetter():String {
    return "example";
}

Always enable both the contents of a custom class and an instance of the class (if instantiated using ActionScript) to use the instance for data binding. Consider the simple class in ...