title: How to check if string is a valid DateTime Format string in Delphi
body: <p>I want user to be able to manually enter format of the datetime fields in the program. I have Tedit component. For example if user enters 'HH:nn', then this is a valid datetime format string and all datetime components should change format property to this, but if he enters 'asd', it is not. Is there a quick way to check this, without writing my own function?</p>