At the moment RadDropDownList can be bound for a Web Service, but there are no Client Events which allow developers to handle and control actions happening during the data binding process. For example: - Event fired, before the request is made (OnClientItemRequesting). - Event fired, after the response is received (OnClientItemRequested). - Event fired if the request call has failed (OnClientItemRequestFailed).
not really sure why this wasn't created when the control was released since your goal was to replace radcombobox in certain scenarios. This control should have been release with most of the same client-side functionalities of radcombobox except for the ability to type in text.