Valid Characters in Edit boxes

Any chance there is a way to add valid characters for edit boxes in MyGUI? For example, in some boxes I want the user to be able to use alphabets only, sometimes alphanumeric but without special characters etc. etc.

eventEditTextChange
store cursor position
validate text
restore cursor position

Thanks, I did something similar (albeit this is much simpler) but I wondered if there the functionality was built-in. Not a big deal at all. Thanks for the solution!