Hello,

First thing that comes up in my mind as why this is not working, is because in the converter you are creating a new object of your underlying business class.

RIACATClaimNumberResponseEntity entity = new RIACATClaimNumberResponseEntity

This will always fail, because this object will never be in the items source of the Combo. You need to return an object from that items source (or as an alternative use SelectedIndex property and return a valid index).