I really enjoy the flex states framework. You define a few states for your control, and then can set child controls to only appear in certain states. Check out this code:

<s:states>
    <s:State name="signin"/>
    <s:State name="register"/>
</s:states>

<mx:FormItem label="Last name:" includeIn="register" id="lastNameItem" alpha="0.0">
    <s:TextInput id="lastName" width="220"/>
</mx:FormItem>

Now the last name form will only appear in the register screen. This would be really useful I think in .NET where you use the page for views like update / insert. I was considering extending the Page element to have a states property using extension methods, and adding the include in to controls. This way I could auto-hide controls based on the current view at render time.

What is even cooler in Flex, is that you can use different handlers / properties based on the current state.

<s:Button label="Sign in" label.register="Register" id="loginButton" 
        enabled="true" click.signin="signin()" click.register="register()"/>

I'm sure there's a way I could implement something similar to this as well.

Do you think this is a good idea? Or does it just add a level of abstraction to framework that already has a poor separation of concerns?