Thank you for contacting Telerik support.
Please, find the attached project which demonstrates how to bind RadDateTimePicker. For more information about RadDateTimePicker simple binding please take a look at this help
In regards to the issue with RadTimePicker in design time, we are already aware of it and it is logged in our internal issue tracking system. We will provide fix for it in our next release, which is due in June.
Do not hesitate to contact us if you have other questions.
the Telerik team