The report Parameter as of now can only be Boolean, Date, Int, Float or String. It would be great to be able to have a Guid parameter. This is particularly useful when passing a Guid to a child report parameter that in turns needs to be a Guid again to be run in the query. As of today we must convert the Master Guid to String to be able to assign it to a parameter then the child report reconverts it into a Guid to be passed to the query