I'm having a lot of trouble getting the vanilla RangeValidator and RequireFieldValidator to work with the RadDatePicker from the classic suite of controls.
Here in the documentation, you can find example of how to use RequiredFieldValidator to check if a DateTime has been selected. Documentation for classic controls
Thanks for the link, but alas it did not solve my problem.
The in-built min-max validators don't give error messages, and don't allow the use of a validation summary. And for some reason they trigger the RequiredValidator when they are transgressed.
I need to seriously think about using a TextBox so the input can be validated on the client-side.