Connecting flex and weborb? - asp.net

Question

im a newbie in flex. Im have a question :)
I have
[Bindable]
private var model:AlgorithmModel = new AlgorithmModel();
private var serviceProxy:Algorithm = new Algorithm( model );
In MXML
private function Show():void
{
// now model.Solve_SendResult = null
while(i<model.Solve_SendResult.length) //
{
Draw(); //draw cube
}
}
private function Solve_Click():void
{
//request is a array
Request[0] = 2;
Request[1] = 2;
Request[2] = 3;
serviceProxy.Solve_Send(request);
Show();
}
<s:Button x="386" y="477" label="Solve" click="Solve_Click();"/>
And when i call serviceProxy.Solve_Send(request); with request is array and i want use model.Solve_SendResult in my code flex to draw many cubes use papervison3d but in the first time i received model.Solve_SendResult = null . But when I click again then everything OK.
Anyone help me? Thanks?

Answer 1

The model.Solve_SendResult object contains a result of the executed serviceProxy.Solve_Send(request) method. The Solve_Send will be executed asynchronously and as a result, at the moment when you fire the show method the Solve_SendResult object may be still null.
As a solution, you can use the following:
Create a custom event
package foo
{
import flash.events.Event;
public class DrawEvent extends Event
{
public static const DATA_CHANGED:String = "dataChanged";
public function DrawEvent(type:String, bubbles:Boolean=false, cancelable:Boolean=false)
{
super(type, bubbles, cancelable);
}
}
}
In your Algorithm class define the following:
[Event(name=DrawEvent.DATA_CHANGED, type="foo.DrawEvent")]
public class Algorithm extends EventDispatcher{
//your code
In the Solve_SendHandler method of the Algorithm class add the following
public virtual function Solve_SendHandler(event:ResultEvent):void
{
dispatchEvent(new DrawEvent(DrawEvent.DATA_CHANGED));
//your code
}
In your MXML class create onLoad method and add an event listener to an instance of the Algorithm class as it shown below:
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="onLoad()">
public function onLoad():void
{
serviceProxy.addEventListener(DrawEvent.DATA_CHANGED, onDataChanged);
}
private function onDataChanged(event:DrawEvent):void{
while(i<model.Solve_SendResult.length) //
{
Draw(); //draw cube
}
}
make the following changes in the Solve_Click() method:
private function Solve_Click():void
{
//request is a array
Request[0] = 2;
Request[1] = 2;
Request[2] = 3;
serviceProxy.Solve_Send(request);
}
That is it! So, basically the code above do the following: you added a listener to your service (algorithm class), and the listener is listening for the DrawEvent.DATA_CHANGED event. The DrawEvent.DATA_CHANGED will be dispatched when your client receive a result of the Solve_Send invocation. Thus, the onDataChanged will draw your cube or do whatever you want :)
The approach above is basic and you have to know how events work in flex and how you can deal with it. Additional information is available here:
http://livedocs.adobe.com/flex/3/html/help.html?content=createevents_3.html
http://livedocs.adobe.com/flex/3/html/help.html?content=events_07.html
Regards,
Cyril