There are 2 classes, depending on whether you are doing a single file operation, or whether you need repeated cached file access over a length of time:
File – Static methods for one off access
FileInfo – Create an instance of a FileInfo class to access files over a length of time.
Both have the same functionality, so its just a decision on whether you want the overhead of creating a class to carry out File IO. This will be down to the number of times the file will be accessed and whether the information being accessed needs to be cached to increase performance (if so use FileInfo).
Auxilliary class to manipulate complete directory strings:
Use for things like, GetFileName, GetDIrectoryName etc
Classes To Work With (Look in for all available methods)