I've seen "undefined" all by itself in the console window before, but I could figure out what it meant. This time, I'm getting it in the opening line of the constructor for CollectionEvent (super(type, bubbles, cancelable);). I think it was triggered by a write to an XMLListCollection. There doesn't seem to be anything undefined about it--the this pointer looks good and all that parameters do, too. It has rather a large stack trace but no helpful information about what's undefined. How do I get to the next debugging step?
undefined
at mx.events::CollectionEvent()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\events\CollectionEvent.as:116]
at mx.collections::ListCollectionView/handlePropertyChangeEvents()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1245]
at mx.collections::ListCollectionView/listChangeHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1120]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::XMLListAdapter/itemUpdateHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:523]
at mx.collections::XMLListAdapter/itemUpdated()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:321]
at mx.collections::XMLListAdapter/xmlNotification()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:620]
at Function/()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\utils\XMLNotifier.as:81]
at AddressNode/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressNode.as:192]
at AddressTree/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressTree.as:37]
at UMTAControl/ValidateDisplayLines_()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:90]
at UMTAControl/OnChangeXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:82]
at UMTAControl/OnChXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:79]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::ListCollectionView/dispatchEvent()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:879]
at mx.collections::ListCollectionView/handlePropertyChangeEvents()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1248]
at mx.collections::ListCollectionView/listChangeHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1120]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::XMLListAdapter/itemUpdateHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:523]
at mx.collections::XMLListAdapter/itemUpdated()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:321]
at mx.collections::XMLListAdapter/xmlNotification()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:620]
at Function/()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\utils\XMLNotifier.as:81]
at AddressNode/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressNode.as:192]
at AddressTree/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressTree.as:37]
at UMTAControl/ValidateDisplayLines_()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:90]
at UMTAControl/OnChangeXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:82]
at UMTAControl/OnChXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:79]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::ListCollectionView/dispatchEvent()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:879]
at mx.collections::ListCollectionView/handlePropertyChangeEvents()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1248]
at mx.collections::ListCollectionView/listChangeHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1120]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::XMLListAdapter/itemUpdateHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:523]
at mx.collections::XMLListAdapter/itemUpdated()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:321]
at mx.collections::XMLListAdapter/xmlNotification()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:620]
at Function/()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\utils\XMLNotifier.as:81]
at AddressNode/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressNode.as:192]
at AddressTree/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressTree.as:37]
at UMTAControl/ValidateDisplayLines_()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:90]
at UMTAControl/OnChangeXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:82]
at UMTAControl/OnChXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:79]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::ListCollectionView/dispatchEvent()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:879]
at mx.collections::ListCollectionView/handlePropertyChangeEvents()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1248]
at mx.collections::ListCollectionView/listChangeHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\ListCollectionView.as:1120]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at mx.collections::XMLListAdapter/itemUpdateHandler()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:523]
at mx.collections::XMLListAdapter/itemUpdated()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:321]
at mx.collections::XMLListAdapter/xmlNotification()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\collections\XMLListAdapter.as:620]
at Function/()[C:\autobuild\3.5.0\frameworks\projects\framework\src\mx\utils\XMLNotifier.as:81]
at AddressNode/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressNode.as:192]
at AddressTree/DisplayLinesInLabels()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\AddressTree.as:37]
at UMTAControl/ValidateDisplayLines_()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:90]
at UMTAControl/OnChangeXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:82]
at UMTAControl/OnChXML()[C:\Users\PL\Documents\projects\AMHS-FlexProject\src\ubimex\modules\MTARoutingControl\UMTAControl.as:79]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
That's right, those other instances of "undefined" were all due to infinite recursion causing stack overflow (and not the kind that gives well-thought feedback).
I imagined these callbacks were similar to the MFC model, where messages were queued and only processed when the app developer's code was finished executing (and I think duplicate messages might have been merged sometimes). Clearly that's not what's going on here--a change is being made and the callback is executed immediately. I guess I won't be able to reliably detect changes to this XMLListCollection :(
Thanks guys.