how to convert date formate dd/mm/yyyy to yyyy-mm-dd using masktextbox in vb.net

[asagarali]

i am write this code.. but error is occurs.

result = Date.ParseExact (txtPurchaseDat e.Text.ToString , "yyyyMMddHHmmss ", System.Globaliz ation.CultureIn fo.InvariantCul ture))



error is:-String was not recognized as a valid DateTime.
plz freds help me for solving this error

[Nightraven]

result= dateandtime.tos tring ("dd/mm/yy")