DataBinding under the hood (part 2): Features

There are many different ways how to use DataBinding.
Beyond the obvious ones there are a few more which could be a nice feature for some weird hacks…

Flex gives us 4 different techniques to use DataBinding:

• Curly Brackets in MXML
• Binding tag
• BindingUtils
• ChangeWatcher

Lets have an overview of the possibilities of each technique:

Curly Brackets in MXML

The most obvious one: Binding a source value to a destination value:

This works also for readOnly properties and static constants. You can omit the Bindable metadata tag because the Binding is only triggered at application startup. Static variables are not supported (the Adobe docs are not correct at this). Also Binding to style properties are not supported.

To add 2 way Binding simply use the curly brackets syntax in both objects crosswise:

[code lang="actionscript3"]


[/code]

Here some code examples for Actionscript and E4X expressions:

[code lang="actionscript3"]
// Method calls and calculations


// Perform string concatenation


// Perform a conditional operation using a ternary operator


// E4X expressions

[/code]

A nice feature which is probably not typically used in your daily work, is the possibility to bind to functions. You can use a function as source for your Binding:
(Read more…)

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Category: Actionscript,Flash,Flex