File upload

there is no change in the rule even it is in asp.net , as far as i concern it doesn't allow to store two files with the same name, and GAC is the only place where you can store two files with the same name but different version numbers.

A file system is a file system. A GUID is a string, another easier way is to use a loop to search for the filename with a number appended until the file does not exist. Of course, if you want to show the original filename in your UI, you need some metadata that tells you the filename to show, as opposed to the filename you had to use.

It depends on how you're uploading it.

If it's via windows sockets or the query string, you have to write code that will open the file in such a was as to overwrite the file if it already exists.

If you're doing it via FTP, (I think) you have to delete the file on the remote machine (again, via a FTP command) before uploading it. It's been a long time since I did any FTP stuff, so you may be able to specify that existing files are overwritten when they're uploaded.