Event Driven Programming

Streams

Streams

source that provides bytes, files, I/O etc.

Input Streams

File where data can be read

Output Streams

where data can be written ex. printer

System.IO

namespace that contains classes, Allows read n’ write of files

File Stream

Class that is used to create byte-oriented stream

FileStream (string filename, FileMode mode)

Code Of File Stream

mode

parameter that specifies how files are opened

FileMode.Create

new output file, will be overwritten if the file already exists

FileMode.CreateNew

creates new output file, not existing

FileMode.Open

Opens an Existing file

FileMode.OpenOrCreate

Opens existing file, If not creates one

FileMode.Truncate

open existing file, Truncates the content

ReadByte

read a single byte from a file, returns an integer as a value

Read

reads specified number of bytes from a file into an array

WriteByte

writes specified byte into the file

Flush

instantly writes data into the file

void Close

closes the file, releases system resources allocated

Seek

used to relocate file pointer in the file

Seek()

allows setting the file position indicator to a preferred location

Seek() Syntax

Long Seek (long n, SeekOrigin Location)

bool CanRead

returns true, if stream can be read

bool CanSeek

returns true, if stream supports position request

bool CanTimeout

returns true, if stream can timeout

bool CanWrite

returns true, if stream can be written

long length

contains size of the stream

int ReadTimeout

indicates time before timeout occurs for read

int WriteTimeout

indicates time before timeout occurs for write

Stream Writer

write character to a stream

StreamWriter (Stream stream)

creates character-based output stream

StreamWriter (string fileName)

open file directly (sw)

Close()

closes the file , mandatory to StreamReader

write()

file stream class, writes into specified file

WriteLine()

line by line, write into file

StreamReader

class that read character from aa byte stream

StreamReader (Stream stream)

name of open stream ex. I/O

StreamReader (string fileName)

specifies the name of the file to open

Read () sr

from the file stream, Reads content

ReadLine() sr

from file stream, reads content line by line

ReadToEnd()

current location to end of stream, reads all characters

Peek()

returns value of stream without moving file pointer

Seek()

sets the file pointer at desired position

Assemblies

files that contain compiled code

.dll

reusable components

.exe

standalone applications

Metadata

includes information about data types

Manifest

holds information of the assembly

Private assembly

simplest, used only within software package, 2 not a problem, not require registry entries

Shared assembly

libraries that other application can use

Name collision

same name of class with other shared assemblies, might overwrite assembly, give a unique or strong name to avoid collision

GAC (Global assembly cache)

enables app to share assembly, required to add assembly to special directory, centralized location

Creating shared assembly

1. create project containing class file

2. strong name (strong.snk) located at solutions explorer

3. specify the key filename AssemblyInfo.cs

4. Compile project to create, extension will be .dll