I would like to ovverride the method.  I want it to have the dispatcher run a checkaccess() if it is on the main thread and if not do a dispatcher invoke(). 

When I update my collection on a different thread  and raise the changed event it of course doesnt like it.I am trying to keep my business logic seperate from the UI and would prefer not to pass a dispatcher object.

If anyone has any ideas on how to better handle doing so please let me know.

Thanks.