mx.binding.utils

# BindingUtils - AS3 Flex

Package | mx.binding.utils
Class | public class BindingUtils
Inheritance | BindingUtils Object

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

The BindingUtils class defines utility methods for performing data binding from ActionScript. You can use the methods defined in this class to configure data bindings.

More examples

Defining data bindings in ActionScript

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About data binding

Public Properties
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| Property | Defined By
--- | --- | ---
|  | constructor : Object A reference to the class object or constructor function for a given object instance. | Object

Public Methods
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| Method | Defined By
--- | --- | ---
|  | bindProperty(site:Object, prop:String, host:Object, chain:Object, commitOnly:Boolean = false, useWeakReference:Boolean = false):ChangeWatcher [static] Binds a public property, prop on the site Object, to a bindable property or property chain. | BindingUtils
|  | bindSetter(setter:Function, host:Object, chain:Object, commitOnly:Boolean = false, useWeakReference:Boolean = false):ChangeWatcher [static] Binds a setter function, setter, to a bindable property or property chain. | BindingUtils
|  | hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined. | Object
|  | isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter. | Object
|  | propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable. | Object
|  | setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations. | Object
|  | toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions. | Object
|  | toString():String Returns the string representation of the specified object. | Object
|  | valueOf():Object Returns the primitive value of the specified object. | Object

Method Detail

### bindProperty

()
method

`public static function bindProperty(site:Object, prop:String, host:Object, chain:Object, commitOnly:Boolean = false, useWeakReference:Boolean = false):ChangeWatcher`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Binds a public property, `prop` on the `site` Object, to a bindable property or property chain. If a ChangeWatcher instance is successfully created, `prop` is initialized to the current value of `chain`.

Parameters

| `site:Object` — The Object defining the property to be bound to `chain`.
| `prop:String` — The name of the public property defined in the `site` Object to be bound. The property will receive the current value of `chain`, when the value of `chain` changes.
| `host:Object` — The object that hosts the property or property chain to be watched. The `host` maintains a list of `sites` to update when `prop` changes.
| `chain:Object` — A value specifying the property or chain to be watched. Legal values are:

- String containing the name of a public bindable property of the host object.
- An Object in the form: `{ name: property name, getter: function(host) { return host[property name] } }`. This Object must contain the name of, and a getter function for, a public bindable property of the host object.
- A non-empty Array containing a combination of the first two options that represents a chain of bindable properties accessible from the host. For example, to bind the property `host.a.b.c`, call the method as: `bindProperty(site, prop, host, ["a","b","c"])`.

Note: The property or properties named in the `chain` argument must be public, because the `describeType()` method suppresses all information about non-public properties, including the bindability metadata that ChangeWatcher scans to find the change events that are exposed for a given property. However, the getter function supplied when using the `{ name, getter }` argument form described above can be used to associate an arbitrary computed value with the named (public) property.

| `commitOnly:Boolean` (default = `false`)`` — Set to `true` if the handler should be called only on committing change events; set to `false` if the handler should be called on both committing and non-committing change events. Note: the presence of non-committing change events for a property is indicated by the `[NonCommittingChangeEvent(<event-name>)]` metadata tag. Typically these tags are used to indicate fine-grained value changes, such as modifications in a text field prior to confirmation.
| `useWeakReference:Boolean` (default = `false`)`` — Determines whether the reference to `site` is strong or weak. A strong reference (the default) prevents `site` from being garbage-collected. A weak reference does not. Added for Flex 4.

Returns

| `ChangeWatcher` — A ChangeWatcher instance, if at least one property name has been specified to the `chain` argument; null otherwise.

### bindSetter

()
method

`public static function bindSetter(setter:Function, host:Object, chain:Object, commitOnly:Boolean = false, useWeakReference:Boolean = false):ChangeWatcher`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Binds a setter function, `setter`, to a bindable property or property chain. If a ChangeWatcher instance is successfully created, the setter function is invoked. The setter must have the following function signature:

          function mySetterFunction(object:Object):void {
              //Do whatever you want with the value of the bound property.
          }

where `object` contains the current value of `chain`.

Parameters

| `setter:Function` — Setter method to invoke with an argument of the current value of `chain` when that value changes.
| `host:Object` — The host of the property. See the `bindProperty()` method for more information. The `host` maintains a list of `setters` to update when `prop` changes.
| `chain:Object` — The name of the property, or property chain. See the `bindProperty()` method for more information.
| `commitOnly:Boolean` (default = `false`)`` — Set to `true` if the handler should be called only on committing change events. See the `bindProperty()` method for more information.
| `useWeakReference:Boolean` (default = `false`)`` — Determines whether the reference to `setter` is strong or weak. A strong reference (the default) prevents `setter` from being garbage-collected. A weak reference does not. Added for Flex 4.

Returns

| `ChangeWatcher` — A ChangeWatcher instance, if at least one property name has been specified to the `chain` argument; null otherwise.

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Mon Apr 10 2017, 12:28 PM -07:00