Listener callback casts custom event data back to event.eventData?

I have a simple subclass of event.EventData to pass data to listeners:

classdef (ConstructOnLoad) tuningEventData < event.EventData
  properties
      path
      value
  end

    methods
        function obj = tuningEventData(path, value)
            obj.path = path;
            obj.value = value;
        end
    end
end

I trigger an event, passing a tuningEventData object:

notify(obj, 'tuningChange', tuningEventData(path, val));

Now I have one listener receiving this and triggering yet another event in its callback method, which I'd like to pass on the same tuningEventData object:

function handleTuningChange(obj, src, data)
    notify(obj, 'tuningChange', data);          
end

But listeners to this new event do not receive the tuningEventData object. They receive an EventData object instead which obviously doesn't have the path and value properties.

The only way to pass on a tuningEventData object seems to be creating a new object in the first listener's callback:

function handleTuningChange(obj, src, data)
    notify(obj, 'tuningChange', tuningEventData(data.path, data.value));          
end

Why can't I just send the data object straight on? Is my tuningEventData class missing something?

Answer 1

[Taylan Kanber]

Change obj.path and obj.value to data.path and data.value