how to recover deleted file using vb.net

Something like this used to be trivial in the old file allocation table (FAT) system; I've done it. With the NT file system (NTFS) format, however, unplanned file recovery is essentially impossible if the file has actually been deleted. To my knowledge, there is no managed code for even retrieving a file out of the trash, although I suspect you could cobble something together with the COM API.

If you need to target a non-Windows environment, then all bets are off. Apple, Linux and other OSes have their own methods for file management; even if you could write something that worked on Windows, it will not work on anything other than Windows.

Your best bet would be to regularly schedule a backup of files that must be preserved, and implement a file recovery system that way. It would be a massive undertaking to write, though, and will never come up to the quality of a commercial product.

I would say that you are barking up the wrong tree.