The following example shows how you can detect changes to an Object object by listening for the propertyChange event on the ObjectProxy instance.
Full code after the jump.
<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/09/27/detecting-changes-to-an-object-using-the-flex-objectproxy-class/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white"
creationComplete="init();">
<mx:Script>
<![CDATA[
import mx.events.PropertyChangeEvent;
import mx.utils.ObjectProxy;
private var object:Object = {};
private var objectProxy:ObjectProxy;
private function init():void {
objectProxy = new ObjectProxy(object);
objectProxy.addEventListener(PropertyChangeEvent.PROPERTY_CHANGE, updateChange);
objectProxy.name = "My Object";
objectProxy.id = 31;
/* Note: Any assignments made directly to the "object"
Object do not dispatch the propertyChange event. */
object.isDebug = false;
object.id = 33;
/* Note: Even though the earlier assignment to the "id"
property didn't dispatch the propertyChange event,
the "oldValue" property is still displayed as 33. */
objectProxy.id = 45;
}
private function updateChange(evt:PropertyChangeEvent):void {
arrColl.addItem(evt);
}
]]>
</mx:Script>
<mx:ArrayCollection id="arrColl" />
<mx:DataGrid dataProvider="{arrColl}"
sortableColumns="false"
draggableColumns="false"
width="100%"
height="100%">
<mx:columns>
<mx:DataGridColumn dataField="type" />
<mx:DataGridColumn dataField="property" />
<mx:DataGridColumn dataField="newValue" />
<mx:DataGridColumn dataField="oldValue" />
<mx:DataGridColumn dataField="source" />
</mx:columns>
</mx:DataGrid>
</mx:Application>
View source is enabled in the following example.
{ 10 comments… read them below or add one }
Sweet! Will this work for custom classes (like below) as well?
package Classes{ [Bindable] public class Users{ public var UserBadgeID:String = ""; public var UserEmail:String = ""; public function Users(){ } } }Man, this rocks…didn’t know about that objectProxy….very tight!!!
I copied and pasted the above code in a new flex application and i get the following error:
1137: Incorrect number of arguments. Expected no more than 0.
Even i search in help about the constructor of ObjectProxy class and this it should working, it doesn’t leave to put any arguments in new ObjectProxy object creation.
I ‘m using Flex 2.0.1
Antonis,
Sorry, I think I only tested using the Flex 3 Beta.
Peter
I also download and install flex builder 3 (Flex 3 M3 (Beta 2)) and same error occured.
1137: Incorrect number of arguments. Expected no more than 0.
Antonis,
I just double checked with Beta 2 and didn’t see any errors at compile-time or run-time.
Are you sure you’re publishing with the beta 2 SDK and not an earlier version? Also, which version of Flash Player are you using? (if you aren’t sure, I recently added an “About you” page to this site at http://blog.flexexamples.com/about-you/).
Peter
I finnally found the cause of the error.
I had created a new project with name ObjectProxy and the applacation name was ObjectProxy too.
So there was a name conflict when the ObjectProxy object was created.
Thanks for your time.
Actually I think you don’t have to use ObjectProxy for that.
Try this:
public class Test { [Bindable] public var test:Boolean; }—
var t:Test = new Test(); t.addEventListener("propertyChange", Handler.onPropertyChange); t.test = true;You will get and event also… even if your object doesn’t extend event dispatcher. I’ve tested this code Flex Builder 3 Beta 2.
The above works on Flex Builder 2 also. You don’t need to use ObjectProxy. In JavaScript 1.5 the equivalent is Object.watch().
Hello,
I have coupled this method with an editable datagrid to submit each change, and no problem, it rock’s !
But now I have another datagrid with a combobox cellRenderer column (like in this example : http://philflash.inway.fr/flex/dgRendererSimple/srcview/index.html) but the cellRenderer doesn’t fire the PropertyChangeEvent… maybe the affectation is made programmatically ?? I have tried to simulate the event (in the onChange method of the cellRenderer) but no way… any idea to solve that ?
Thanks in advance for any suggestion