About Binding - Adobe FLEX 2-MIGRATING APPLICATIONS TO FLEX 2 Manual

CHAPTER 5
5
Binding
This topic describes the steps required to convert properties in your applications to be usable
as the source for a data binding expression in Adobe Flex.
For more information binding, see Chapter 5, "Using Metadata Tags in Custom
Components," in Creating and Extending Flex 2 Components.
Contents

About binding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Binding from a property . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Binding with Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
About binding
In Flex 1.5, it was possible to use any public property defined as a variable or Array as the
source for a data binding expression. When a public property is the source of a data binding
expression, Flex automatically copies its value to a destination property when the value of the
source property changes.
Any property can be the destination of a data binding expression. That means you do not
have to write an special code to support the destination property of a data binding expression.
Using any property as the source for data binding is supported in Flex 2, but you must
explicitly identify the property or the property's class as bindable using the
[Bindable]
metadata tag. The property may be defined as a variable or defined by using both a setter and
a getter method. If you attempt to use a property as the source of a data binding expression,
and that property does not support binding, Flex throws a warning and does not update the
destination value of the when the source value changes.
Using Arrays and DataProviders as the source for data binding expressions in Flex 2 is not
supported and you should convert your DataProviders to use the new Collections API. For
more information, see "Binding with Arrays" on page 110.
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