C# 4.0 in a Nutshell, 4th Edition

Chapter 14. Streams and I/O

This chapter describes the fundamental types for input and output in .NET, with emphasis on the following topics:

• The .NET stream architecture and how it provides a consistent programming interface for reading and writing across a variety of I/O types

• Manipulating files and directories on disk

• Isolated storage and its role in segregating data by program and user

This chapter concentrates on the types in the System.IO namespace, the home of lower-level I/O functionality. The .NET Framework also provides higher-level I/O functionality in the form of SQL connections and commands, LINQ to SQL and LINQ to XML, Windows Communication Foundation, Web Services, and Remoting.

Stream Architecture

The .NET stream architecture centers on three concepts: backing stores, decorators, and adapters, as shown in Figure 14-1.

Figure 14-1. Stream architecture

A backing store is the endpoint that makes input and output useful, such as a file or network connection. Precisely, it is either or both of the following:

• A source from which bytes can be sequentially read

• A destination to which bytes can be sequentially written

A backing store is of no use, though, unless exposed to the programmer. A Stream is the standard .NET class for this purpose; it exposes a standard set of methods for reading, writing, and positioning. Unlike an array, where all the backing data exists in memory at once, ...