How Do I Programmatically Dispatch an Itemclick Event in Flex 3?

Question

Hi,
I need some help with programmatically dispatching an itemclick event in Flex 3.
For example, I've got a popupmenubutton as follows:
<mx:PopUpMenuButton
    id="myPopUpMenuButton"
    label="Neighborhoods"
    dataProvider="{myNeighborhoodList}"
    itemClick="myPopUpMenuButtonClickHandler(event)"
/>
Let's say that the myNeighborhoodList contains 3 choices: Old Port, Newport, Southport.
In another piece of code, I want to programmatically dispatch the myPopUpMenuButton itemclick event as if "Newport" were chosen. How do I do that?
FYI, I posted this question on Stack Overflow, but I didn't get a reply.
Thank you!
-Laxmidi

Answer 1

Ok , here is how I solve the problem architecturally.  One class should be responsible for the viewstack index.  This class can respond to events dispatched anywhere.  So it goes a little something like this.
The view stack
<Viewstack selctedIndex="{stackIndex}">
  <Script>
      [Bindable] public var stackIndex:int;
   </Script>
  <ViewOne />
  <ViewTwo/>
  <ViewThree />
</Viewstack/>
StackPresentation.as
public var stackCount:int;
[Bindable] public var stackIndex:int;
public function startUp():int
    stackIndex = someRandomNumberGenerator( 0 , stackCount );
     return stackIndex;
public function changeStackHandler( newStackIndex:int ):void
    stackIndex = newStackIndex;
There are a few things I must explain here.
1.  The stackIndex of the StackPresentation class in "injected" into the Viewstack class.  This can be accomplished using a number of frameworks.  Personally I use Mate , but there is a whole cornucopia of DI frameworks ( Prana , RobotLegs , Swiz ...).
2.  When you want to change the stack index from any part of the application , you dispatch an event like the one I posted earlier.  Your framework will wire this event to the StackPresentation.  The event will have some parameters ( i.e var newStackIndex:int ) which it uses to go to the next stack index , it could very well be different from what I posted as this is an example.
The advantages of this are numerous.  But they all stem from "separation of concern".   The view class is responsible for being a view , and the presentation is responsible for coordinating the state of the view class.  The other advantage is that if some other part of the application wants to change the viewstack index , it MUST go through the presentation layer , preventing a "ball of mud" type of approach.  This greatly cuts down on the number of bugs and the time it takes to resolve them.  In scenarios where there is a problem , you only have to look at a few things , the logic in the presentation class ( which lends itself to unit-testing) and the cases where the event triggering the change is dispatched.  Hope this helps.
Sincerely ,
  Ubu