How to change user input from 0123 to 01:23

Hello everyone.

I have some entrys in a xaml file with numeric keyboards and I want to make some kind of validation check and change for the input.

So if someone types in 0122, afterwards it should display as 01:22. Or if its different then 00:00-23:59 it should display nothing.

Do you guys have some simple tutorials or other hints for implementing such function?
Where in the code does regex come into play ?

Thanks in advance, any help is appreciated.