Upload File and Overwrite if exists with Confirmation in ASP.Net

Hi All,

i want if a file exists then it ask for "do u want 2 overwrite ?" with yes or no confirmation ,,, if yes then overwrite otherwise not.

i want to do this with the help of ConfirmationExtender with a textbox becase the user can enter some info like who is the user and overwrite on what reason.

Thanks in advance.....