Chapter 13 - File IO and Isolated Storage pps

Chapter 13. File I/O and

Isolated Storage

Hoang Anh Viet

[email protected]

Hanoi University of Technology

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Microsoft

Objectives

“The System.IO namespace allows you to interact with a machine’s file

and directory structure. Over the course of this chapter, you will

learn how to programmatically create (and destroy) a directory

system as well as move data into and out of various streams (file

based, string based, memory based, etc.). The latter part of this

chapter examines the role of isolated storage, which allows you to

persist per-user data into a safe sandbox, regardless of the security

settings of a target machine. To understand certain aspects of the

System.IO.IsolatedStorage API, you will also receive an overview of

Code Access Security (CAS).…”

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Microsoft

Roadmap

1. Exploring the System.IO namespace

2. Working with File System

3. The Abstract System Class

4. Working with StreamWriters and StreamReaders

5. Working with StringWriters and StringReaders

6. Working with BinaryWriters and BinaryReaders

7. Programmatically “Watching” Files

8. Performing Asynchronous File I/O

9. An Overview of Isolated Storage

10. Introducing Object Serialization

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Microsoft

13.1 Exploring the System.IO namespace

 System.IO namespace is the region of the base class

libraries devoted to file-based (and memory-based) input

and output (I/O) services

 System.IO defines a set of classes, interfaces,

enumerations, structures, and delegates, most of which

are contained in mscorlib.dll

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Nonabstract I/O Class

Type

Description

BinaryReader, BinaryWriter These types allow you to store and retrieve primitive data types

(integers, Booleans, strings, and whatnot) as a binary value.

BufferedStream This type provides temporary storage for a stream of bytes that may

be committed to storage at a later time

Directory, DirectoryInfo These types are used to manipulate a machine’s directory structure.

The Directory type exposes functionality using static members. The

DirectoryInfo type exposes similar functionality from a valid object

reference.

DriveInfo This type provides detailed information regarding the drives used by a

given machine.

File, FileInfo These types are used to manipulate a machine’s set of files. The File

type exposes functionality using static members. The FileInfo type

exposes similar functionality from a valid object reference.

FileStream This type allows for random file access (e.g., seeking capabilities)with

data represented as a stream of bytes.

Figure 13.1 Key Members of the System.IO Namespace

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Nonabstract I/O Class

Type

Description

FileSystemWatcher This type allows you to monitor the modification of external files in a

specified directory.

MemoryStream This type provides random access to streamed data stored in memory

rather than a physical file.

Path This type performs operations on System.String types that contain file

or directory path information in a platform-neutral manner.

StreamWriter, StreamReader These types are used to store (and retrieve) textual information to (or

from) a file. These types do not support random file access.

StringWriter, StringReader Like the StreamReader/StreamWriter types, these classes also work

with textual information. However, the underlying storage is a string

buffer rather than a physical file.

Figure 13.1 Key Members of the System.IO Namespace (Cont.)