how to calculate copy process remaining time?

hi,

I have made an application in that i am copying content of a folder to another folder in that i want to show my own progress dialog windows like that of windows,in that i have to show remaining time of copy process,,so how
will i calculate the remaining time of popy process.

thank you

You either:

1) Guess, and form a progress bar off of the total size

2) Break the file into "Chunks", measure each chunk time, and calculate on the fly.

3) Use a library component which already does this