FastInject by id works if objects declared in the context have an id.
Context configuration
<fx:Declarations>
<foo:FooBar1 />
<foo:FooBar2 id="fooBar2" />
</fx:Declarations>
FastInject in your component
<fx:Declarations>
<parsley:FastInject injectionComplete="handlerInjectComplete(event)">
<parsley:Inject property="foobar1" type="{FooBar1}" />
<parsley:Inject property="foobar2" objectId="fooBar2"/>
</parsley:FastInject>
</fx:Declarations>
<fx:Script>
<![CDATA[
[Bindable]
public var foobar1:FooBar1;
[Bindable]
public var foobar2:FooBar2;
protected function handlerInjectComplete(event:Event):void
{
if(foobar1) trace("foobar1 available");
if(foobar2) trace("foobar2 available");
}
]]>
</fx:Script>
This works for me.