Programming C# 4.0, 6th Edition

Chapter 11. Files and Streams

Almost all programmers have to deal with storing, retrieving, and processing information in files at some time or another. The .NET Framework provides a number of classes and methods we can use to find, create, read, and write files and directories In this chapter we’ll look at some of the most common.

Files, though, are just one example of a broader group of entities that can be opened, read from, and/or written to in a sequential fashion, and then closed. .NET defines a common contract, called a stream, that is offered by all types that can be used in this way. We’ll see how and why we might access a file through a stream, and then we’ll look at some other types of streams, including a special storage medium called isolated storage which lets us save and load information even when we are in a lower-trust environment (such as the Silverlight sandbox). Finally, we’ll look at some of the other stream implementations in .NET by way of comparison. (Streams crop up in all sorts of places, so this chapter won’t be the last we see of them—they’re important in networking, for example.)

Inspecting Directories and Files

We, the authors of this book, have often heard our colleagues ask for a program to help them find duplicate files on their system. Let’s write something to do exactly that. We’ll pass the names of the directories we want to search on the command line, along with an optional switch to determine whether we want to recurse into subdirectories or not. ...