Don't lock files of application while running

Question

I am creating a software application that is able to update itself. After the start, the application checks if there are updates avaiable, download those files (assemblies),

Answer 1

I guess you are downloading assemblies directly in place of the old assemblies. Lets say you have an assembly myprogram.dll . First download the new updated dll with a different name ( _myprogram.dll for example) . Fire an event after the download is competed that will replace the myprogram.dll with _myprogram.dll. This event should declare all running processes to stop at first then replace the assemblies. replacement should take at a moment. You cannot avoid the service cut on this moment.

EDİT:

There should be a process that will always running and checking for updates. Send the name of the files to this process first. The process will now it will download for example 5 files. The process should download the files in a predefined name format(Concatenating it with underscore for example). After the process finishes downloading 5th file the process should kill all other processes ( or preferably only the processes related to the downloaded assemblies), then replace the assemblies with the newer ones. Than start the processes again.