c# - what is the simplest and correct way to calculate age? -

possible duplicate:
how calculate someone's age in c#?

hi, simple question. need calculate age , allow people 21. use timespan? given inputting date need check if >=21.

suggestions?

the easiest way isn't calculate age - it's see whether birthday after limit:

datetime twentyoneyearsago = datetime.today.addyears(-21);  if (birthdate > twentyoneyearsago) {     // sorry, you're young } 

note on february 29th on leap year, addyears return february 28th on relevant earlier year. that's want in case, if user has entered actual date.