I need to validate date strings input with keyboard

I’m working on a project where a user inputs date via a touchscreen keyboard into a database. We have to work with the clients database as is, and there is a strict datatype requirement for the date. The date has to exist on the calender ie. 2-29-04 works but 2-29-05 does not (leap year).

Now, I know how to make a calendar/event schedule with the date object, and do have the option of just ploping a calendar in front of them to navigate through and select a valid date, and this seems like the best idea right now. However, I would like to know if anyone has just validated user input dates via keyboard into a field, so I could just keep the keyboard up there for them, instead of switching the interface around so much.

Thanks for any help.