for code ofinvalid date,month and year

See more:

C#

hello sir,,
i make a simple progrram so i have diffcultes
i use mask txt box for showing dateof birth for the user
but in this user input any month ,date and year so they take
but i want only 31 days and 12 month and particular year come
if user insert invalid date, month or year so show message this is invaild date, month and year
please anyone give the code of this problem
Thank you........