Page 1 .NET et C #

Transcription

Page 1 .NET et C #

The .NET Framework
Richness
.NET et C #
s
API
1
COM
Win32
Win16
1980
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s
ent
pon
m
o
C
Windows
3.0
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1990
s
vice
S er
MFC
2000
2
.NET & CLR Common Language Runtime
Présentation .NET & .NET Framework
Microsoft propose 4 langages
C#, C++,VB.NET,ASP.NET
dont C# est le premier recommandé par
Microsoft
Autres langages supportés
Perl, Cobol, Eiffel, J#, Oberon,Component Pascal,
Python, Smalltalk
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Mécanisme de fonctionnement de MS.NET
CLI Standards
chien
.vb
chat
.cs
VS.NET
C#
ECMA-334
Les applications c#, VB, c++ peuvent communiquer via le CLR
En réalité le même programme peut etre écrit dans un lagage et décompilé dans un autre
On retrouve les memes classes/packages dans les differentes environnements, CS, VB, C++
souris
c++
JScript
VB
VC/MC++
System.Web
UI
SessionState
HtmlControls
Caching
Security
WebControls
Configuration
Debugger
System.Web.Services
Protocols
Discovery
Description
Designers
System.Data (ADO.NET)
ADO
chien
MSIL
SDK Tools
souris
MSIL
ILDbDump
CLR : moteur exécution
SN
en langage commun
ILDAsm
déploiement
MetaInfo
PEVerify
Windows
Linux (?)
JIT
JIT
Boot Loader
Threads
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Printing
Imaging
Text
System.Xml
XSLT
Adapters
CorDBG
ILAsm
chat
MSIL
System.Drawing
Drawing2D
SQL
Design
ComponentModel
Serialization
XPath
System
Collections
IO
Security
Configuration
Net
ServiceProcess
Diagnostics
Reflection
Text
Remoting
Globalization
Resources
Threading
Serialization
ECMA-335
CLR : Common Language Runtime
JIT : Just in Time (2eme compilateur)
System.WinForms
Design
Runtime
InteropServices
Common Language Runtime
GC
App Domain Loader
JIT
MSIL
Common Type System
Class Loader
Platform Abstraction Layer
Sync
Timers
Networking
Filesystem
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Qu’est-ce c’est C# ?
Le framework .NET Les classes du framework
Tous les langages de l’environnement .NET ont acceès au mêmes classes, notamment, les classes fondementales
System.Web
Services
Description
Discovery
Protocols
UI
HtmlControls
Caching
Configuration
Security
SessionState
Button
MessageBox
ListControl
WebControls
SQL
SQLTypes
Collections
Configuration
Diagnostics
Globalization
IO
Net
Reflection
Resources
System.Drawing
Drawing2D
Imaging
System.Data
OLEDB
Design
Langage proposé par Microsoft, standardisé par ECMA, ressemble la syntaxe de
Java
System.Windows.Forms
Form
Printing
Text
Combinaison entre la force de C++ et la simplicité de Visual Basic
Cross Plate-forme
Cross Langage
System.Xml
XSLT
XPath
Langage orienté objet
Une partie évolue vers langage orienté et langage de programmation de component
Dérivé de C++
MFC est remplacée par librairie .NET Framework
Serialization
System
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Security
ServiceProcess
Text
Threading
Runtime
InteropServices
Remoting
Serialization
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C# : comment ça marche ?
‘.exe’
‘.dll’
.cs
Code source
CLS
‘Règle de
tranformation
en .NET’
Just in Time
Compiler
JIT
Microsoft
Intermediate
Language
(MSIL)
C# vs C++
Avantages C#
Code
natif
(selon OS)
Plus ouvert, plus de productivité
productivité, programmes
plus fiables et moins difficile a mettre au point
Interopé
Interopérabilité
rabilité dans le futur avec Framework
.Net (Windows, »Linux,Unix »)
De plus en plus utilisé
utilisé dans les applications
financiè
financières (front & middle) au dé
détriment du
C++
Inconvé
Inconvénients C#
Apprendre nouveau concept de base (.Net)
Apprendre nouveau langage (temps d’
d’estimation
CLR Common Runtime Language
environ 4 semaines)
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Avantages C#
Inconvénients de C#
Peu de pointeur
Conversion automatique (boxing)
list.Add(1);
list.Add(13.12);
Versioning
C# demande le développer de clarifier la création de la version librairie
créée.
Technologie Windows 100%, porter Framework sur Linux “à voir” (projet
Mono)
Utilise le keyword ‘new’ et ‘override
Utiliser la librairie de framework .NET
.NET et C# sont des "standards ouverts" ne signifie pas nécessairement des
"environnements ouverts".
Threading, Collection, XML, ADO+, ASP+, GDI+ & WinForms libraries
C# élimine header .h
C# non pointeur (très limité).
C# est un langage objet orienté pur avec tous les objets et types dérivés de
la classe Object.
Codé géré (pas besoin de ‘’free’’ et ‘’delete’’ – garbage collector)
Possibilité d’intégrer du code source natif C ou C++
La première fois est lente (à cause de compilateur 2-time)
Relativement nouveau (bibliotheques spécialisées, …)
Plus détails :
http://msdn.microsoft.com/library/default.asp?url=/library/enus/cscon/html/vclrfcompa
risonbetweenccsharp.asp
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Opérateurs
Instructions
Blocs
Libellés
Selections
{ ... }
Unaires :
Arithmétiques :
Décalage :
Relationnels :
Logiques :
Conditionnels :
Assignation :
+
!
~
++x
--x
*
/
% +
<<
>>
<
>
<=
>=
==
!=
& ^ |
&& || ?:
=
*=
/=
%=
+=
-=
<<=
>>=
&=
^=
|=
.NET Framework, C# et .NET Remoting
(T)x
C#
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;
x: instruction;
if(x == 1)
{
if(y == 2)
{
F();
}
else
{
G();
}
}
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switch(i)
{
case 0:
case 1:
Choix();
break;
default:
ChoixAutre();
break;
}
C#
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Instructions
for(int i = 0; i < n; i++) { ... }
foreach(object o in collection) {
break;
goto libelle;
continue;
return value;
... }
Sauts
Gestion des exceptions
try
{ ... }
catch(ArgumentException e)
{ ... }
catch(Exception e)
{ ... }
finally
{ ... }
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throw new Exception();
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Types
Itérations
while(x != 0) { ... }
do { ... } while(x == 0);
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Valeurs
Types prédéfinis
Enumérations
Structures
Allocation dans la pile (stack)
Ne peut être null
Références
Tableaux
Délégués
Classes
Interfaces
Allocation dans le tas (heap)
Peut être null
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Types prédéfinis
Type
Description
Exemple
object
Type de base de tous les autres types
object o = null;
string
Séquence de caractères Unicode
string s = "Hello";
sbyte
Entier signé de 8 bits
sbyte val = 12;
short
short val = 12;
int
int val = 12;
long
long val1 = 12;
long val2 = 34L;
byte
Entier non signé de 8 bits
byte val = 12;
ushort
ushort val = 12;
uint
uint val1 = 12;
uint val2 = 34U;
ulong
ulong
ulong
ulong
ulong
float
Flottant simple précision (32 bits, 1.7E +/- 308 15 chiffres significatifs)
float val = 1.23F;
double
Flottant double précision (64 bits, 3.4E +/- 38, 7 chiffres significatifs)
double val1 = 1.23;
double val2 = 4.56D;
bool
Booléen
bool val1 = true;
bool val2 = false;
char
Caractère Unicode
char val = 'h';
decimal
Décimal (28 chiffres significatifs)
decimal val = 1.23M;
val1
val2
val3
val4
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=
=
=
=
Enumerations
enum Color : long
{
Red,
Green,
Blue
}
Color color;
switch(color)
{
case Color.Red:
...
break;
case Color.Blue:
...
break;
12;
34U;
56L;
78UL;
case Color.Green:
...
break;
default:
break;
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}
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Structures
struct Point
{
public int x,y;
public Point(int x, int y) { this.x = x; this.y = y; }
}
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Tableaux
struct Point
{
public int x,y;
}
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Une dimension
int[] myArray = new int[] {1, 3, 5, 7, 9};
string[] weekDays = {"Sun","Sat","Mon","Tue","Wed","Thu","Fri"};
Plusieurs dimensions
int[,,] myArray = new int [4,2,3];
int[,] myArray = new int[,] {{1,2}, {3,4}, {5,6}, {7,8}};
Jagged (tableau de tableaux)
int[][,] myJaggedArray = new int [3][,]
{
new int[,] { {1,3}, {5,7} },
new int[,] { {0,2}, {4,6}, {8,10} },
new int[,] { {11,22}, {99,88}, {0,9} }
};
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Orientation Objet
Class basics
class myClass
{
programmation procédurale : P.P. (Pascal, C, etc.)
private string myVar;
public myClass()
{
}
programmation orientée objet : P.O.O. (C++, Java, C#)
protected void myMethod(int parameter)
{
//do stuff here
}
Principaux concepts de la programmation objet
Encapsulation, abstraction, interfaces, …
Héritage (simple, multiple)
Polymorphisme
}
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Inheritance
Classes
C# only supports single inheritance
Specify inheritance like so:
Nom
Attribut d’accessibilité
public
protected
private
internal
protected internal
Attribut abstract (abstrait)
Attribut sealed (sellé)
Classe de base (héritage simple de classe)
Interfaces implémentées (héritage multiple d’interfaces)
Membres
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class myClass : myBaseClass
non limité
limité à la classe et aux classes dérivées
limité à la classe
limité à l’assemblage
limité à l’assemblage et aux classes dérivées
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Method example
Membres
class myClass
{
private string myVar;
public myClass()
{
}
public void myMethod(int parameter)
{
//do stuff here
}
public static void PrintStuff()
{
}
Constantes
Champs
Méthodes
Constructeurs
Destructeurs
Types
Propriétés
Indexeurs
Opérateurs
Événements
}
class myCallerClass
{
public myCallerClass()
{
myClass.PrintStuff();
myClass myInstance= new myClass();
myInstance.myMethod(5);
}
}
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Constantes
public class Color
{
public static readonly Color Black = new Color(0, 0, 0);
public static readonly Color White = new Color(255, 255, 255);
private byte red, green, blue;
public Color(byte r, byte g, byte b) {
red = r;
green = g;
blue = b;
}
}
class B
{
public const int X = C.Z + 1;
public const int Y = 10;
}
class C
{
public const int Z = B.Y + 1;
}
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Champs
class A
{
public const double X = 1.0;
public const double Y = 2.0;
public const double Z = 3.0;
}
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Attributs d’accessibilité
public
protected
private
internal
non limité
Attributs
new
static
readonly
volatile
champ cachant (classe dérivé)
champ de classe
champ en lecture seule (initialisé par le constructeur)
champ volatile
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Méthodes
Nom
public
non limité
protected
private
internal
Attributs new, static, virtual (virtuel), abstract, sealed, override
(surcharge), extern
Méthodes abstraites
public abstract class Shape
{
public abstract void Paint(Graphics g, Rectangle
r);
}
public class Ellipse: Shape
{
public override void Paint(Graphics g, Rectangle
r) {
g.DrawEllipse(r);
}
}
Type de retour
Paramètres
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public class Box: Shape
{
public override void Paint(Graphics g, Rectangle
r) {
g.DrawRect(r);
}
}
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Properties
Méthodes virtuelles
Properties are NOT fields
Fields are variables declared in the class
Properties are “wrappers” for fields
Get/Set:
class A
{
public virtual void F() {
Console.WriteLine("A.F"); }
}
class B: A
{
public override void F() {
Console.WriteLine("B.F"); }
}
private string mystring;
public string MyString {
get { return mystring; }
set {mystring = value; }
}
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class Test
{
static void Main() {
B b = new B();
A a = b;
a.F();
a.F();
}
}
> B.F
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Constructeurs (instance)
Constructeur (classe)
Initialiser l’instance d’une classe
En cas d’absence de constructeur, un constructeur sans paramètre est implicitement créé
Initialiser une classe
Ne peut être appelé explicitement
Appelé automatiquement
Pas d’attribut d’accessibilité, pas de paramètre
class Point
{
public double x, y;
public Point()
{
this.x = 0;
this.y = 0;
}
public Point(double x, double y)
{
this.x = x;
this.y = y;
}
}
class A
{
public static int X;
static A() {
X = B.Y + 1;
}
}
class B
{
public static int Y = A.X + 1;
static B() {}
Console.WriteLine("X = {0}, Y = {1}", A.X, B.Y);
}
}
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Destructeur
Déclaration d’un type à l’intérieur d’une classe
public class List
{
// Private data structure
private class Node
{
public object Data;
public Node Next;
public Node(object data, Node next)
{
this.Data = data;
this.Next = next;
}
}
private Node first = null;
private Node last = null;
// Public interface
public void AddToFront(object o) {...}
public void AddToBack(object o) {...}
public object RemoveFromFront() {...}
public object RemoveFromBack() {...}
public int Count { get {...} }
}
class A
{
public static int X;
static A() {
X = B.Y + 1;
}
}
class B
{
public static int Y = A.X + 1;
static B() {}
Console.WriteLine("X = {0}, Y = {1}", A.X, B.Y);
}
}
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Types
Appelé automatiquement lors du processus de garbage collection
Ne peut être appelé explicitement
Pas d’attribut d’accessibilité, pas de paramètre
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Propriétés
Propriétés
abstract class A
{
int y;
public virtual int X {
get { return 0; }
}
public virtual int Y {
get { return y; }
set { y = value; }
}
public abstract int Z { get; set; }
}
Accéder aux caractéristiques d’un objet ou d’une classe
longueur d’une chaîne de caractères
taille d’un tableau
titre d’une fenêtre
dimensions d’une image
…
Deux comportements
Lecture (get)
Écriture (set)
Mêmes attributs que les méthodes
class B: A
{
int z;
public override int X {
get { return base.X + 1; }
}
public override int Y {
set { base.Y = value < 0? 0: value; }
}
public override int Z {
get { return z; }
set { z = value; }
}
}
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Indexeurs
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Opérateurs
Indexer une classe à la manière d’un tableau
public struct Digit
{
byte value;
public Digit(byte value) {
if (value < 0 || value > 9) throw new ArgumentException();
this.value = value;
}
public Digit(int value): this((byte) value) {}
public class Stack
{
private Node GetNode(int index) {
Node temp = first;
while (index > 0 && temp != null) {
temp = temp.Next;
index--;
}
if (index < 0 || temp == null)
throw new Exception("Index out of range.");
return temp;
}
public object this[int index] {
get {
return GetNode(index).Value;
}
set {
GetNode(index).Value = value;
}
}
}
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C#
public static implicit operator byte(Digit d) {
return d.value;
}
public static explicit operator Digit(byte b) {
return new Digit(b);
}
}
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Opérateurs
Opérateurs
public struct Digit
{
byte value;
this.value = value;
}
public struct Digit
{
byte value;
this.value = value;
}
public static Digit operator+(Digit a, Digit b) {
return new Digit(a.value + b.value);
}
public static bool operator==(Digit a, Digit b) {
return a.value == b.value;
}
public static Digit operator-(Digit a, Digit b) {
return new Digit(a.value - b.value);
}
public static bool operator!=(Digit a, Digit b) {
return a.value != b.value;
}
}
public override bool Equals(object value) {
if (value == null) return false;
if (GetType() == value.GetType()) return this == (Digit)value;
return false;
}
}
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Délégués
Événements
Pointeurs de méthodes (vulgarisation)
Encapsule à la fois un objet et une méthode
Peut « pointer » vers plusieurs méthodes
Mécanisme de notification
Basé sur les délégués
Consommateur d’événements
delegate void D(int x);
class C
{
public static void M1(int i) {...}
public static void M2(int i) {...}
}
class Test
{
D cd1 = new D(C.M1);
// M1
D cd2 = new D(C.M2);
// M2
D cd3 = cd1 + cd2;
// M1 + M2
D cd4 = cd3 + cd1;
// M1 + M2 + M1
D cd5 = cd4 + cd3;
// M1 + M2 + M1 + M1 + M2
}
}
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C#
Traitant
d’événements
Générateur d’événements
Événement
registration
callback
Consommateur d’événements
Traitant
d’événements
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Événements
Espaces de noms
public delegate void EventHandler(object sender, EventArgs e);
Conteneur de classes ou d’espaces de nom
public class Button: Control
{
public event EventHandler Click;
protected void OnClick(EventArgs e) {
if (Click != null) Click(this, e);
}
}
Organiser des classes hiérarchiquement
Structurer les assemblages
public class Form
{
Button Button1 = new Button();
public Form() {
Button1.Click += new EventHandler(Button1_Click);
}
~Form() {
Button1.Click -= new EventHandler(Button1_Click);
}
class A {}
namespace X
{
class B
{
class C {}
}
namespace Y
{
class D {}
}
}
// A
// X
// X.B
// X.B.C
// X.Y
// X.Y.D
Using tells the compiler what prefixes to try on stuff it
can’t figure out:
using System.Collections;
ArrayList myList=new ArrayList()
void Button1_Click(object sender, EventArgs e) {
Console.WriteLine("Button1 was clicked!");
}
}
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Nom
public
protected
private
internal
Interfaces de base (héritage multiple d’interfaces)
Membres
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parameter arrays
ref and out parameters
overflow checking
foreach statement
lock statement
switch on string
Méthodes
Propriétés
Indexeurs
Événements
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non limité
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Productivity features
Interfaces
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ref and out parameters
foreach statement
Use “ref” for in/out parameter passing
Use “out” to return multiple values
Must repeat ref/out at call site
Iteration of arrays
Equivalent to &
public static void Main(string[] args)
args) {
foreach (string s in args)
args) Console.WriteLine(s);
Console.WriteLine(s);
} Iteration of IEnumerable collections
static void Swap(ref
Swap(ref int a, ref int b) {...}
static void Divide(int dividend, int divisor,
out int result, out int remainder) {...}
ArrayList accounts = Bank.GetAccounts(...);
Bank.GetAccounts(...);
foreach (Account a in accounts) {
if (a.Balance < 0) Console.WriteLine(a.CustName);
Console.WriteLine(a.CustName);
}
int x = 1, y = 2;
Swap(ref
Swap(ref x, ref y);
}
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Overflow checking
Switch on string
Integer arithmetic operations
Color ColorFromFruit(string s) {
switch(s.ToLower())
switch(s.ToLower()) {
case "apple":
return Color.Red;
case "banana":
return Color.Yellow;
case "carrot":
return Color.Orange;
default:
throw new InvalidArgumentException();
InvalidArgumentException();
}
}
C, C++, Java silently overflow
checked vs. unchecked contexts
Default is unchecked, except for constants
Change with “/checked” compiler switch
int i = checked(x
checked(x * y);
checked {
int i = x * y;
}
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Polymorphism in C#
Error handling
System.Exception
Gets code information like:
public class Fruit {
public virtual string Shape() {return "Not sure";}
public string Colour() {return "You tell me";}
}
Stack trace
Line and file info
Detailed error message
Use in try…catch block
public class Orange : Fruit {
public new string Colour() {return "Orange";}
public override string Shape() {return "Round";}
}
Fruit
string
string
Orange
string
string
someFruit = new Orange();
a = someFruit.Shape();
//
b = someFruit.Colour();
//
anOrange = (Orange)someFruit;
c = anOrange.Shape();
//
d = anOrange.Colour();
//
…
ArrayList myList;
try {
myList.Clear();
} catch (System.NullReferenceException e) {
Console.WriteLine(“variable not initialized”);
}
"Round"
"You tell me"
To throw an error say:
throw <exception object>
Or:
throw new <exception class>
"Round"
"Orange"
Exceptions are very costly, don’
don’t throw them unless there is
an error
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Generics
Generics
public class List<
List<ItemType>
ItemType>
{
private ItemType[]
object[]
elements;
elements;
ItemType[]
private int count;
Why generics?
Compile-time type checking
Performance (no boxing, no downcasts)
Reduced code bloat (typed collections)
public void Add(ItemType
Add(object
element)
element)
{ {
Add(ItemType
if (count == elements.Length) Resize(count * 2);
elements[count++] = element;
}
C# generics vs. C++ templates
C# generics are checked at declaration
C# generics are instantiated at run-time
C# generics vs. proposed Java generics
public ItemType
object this[int
this[int
index]
index]
{ {
get { return elements[index]; }
set { elements[index] = value; }
}
List<int>
List<int>
intList
intList
= new=List();
new List<int>
();
List<int>();
}
public int Count {
getintList.Add(1);
{ return count; }
intList.Add(2);
}
intList.Add("Three");
intList.Add("Three");
int i = intList[0];
(int)intList[0];
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54
//
//
//
C# generics work over entire type system
C# generics preserve types at run-time
Argument
No
boxingis boxed
Argument
No
boxingis boxed
CompileShould
be
time
an error
Compile-
// No
Cast
cast
required
required
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Page 14
14
Generics In VB
Generics In C++
Public Class List(Of T)
Private elements() As T
Private elementcount As Integer
Public Sub Add(ByVal element As T)
If elementcount = elements.Length Then
Resize(elementcount * 2)
elements(elementcount) = element
count += 1
End Sub
Public Default Property Item(ByVal index As Integer) As T
Get
Return elements(index)
End Get
Set (ByVal Value As T)
Dim intList
elements(index)
As New List(Of
= Value
Integer)
End Set
intList.Add(1)
// No boxing
intList.Add(2)
// No boxing
End
Property
intList.Add("Three")
// Compile-time error
Dim i As Integer = intList(0)
// No cast required
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generic<typename T>
public ref class List {
array<T>^ elements;
int count;
public:
void Add(T element) {
if (count == elements->Length) Resize(count * 2);
elements[count++] = element;
}
property T default [int index] {
T get() { return elements[index]; }
void set(T value) { elements[index] = value; }
}
property int Count {
intList
= gcnew
List<int>();
intList<int>^
get() { return
count;
}
intList->Add(1);
// No boxing
}
intList->Add(2);
// No boxing
};
intList->Add("Three");
// Compile-time error
Daniel HERLEMONT
int i = intList[0];
Throwing an Exception
// No cast required
58
Exception Hierarchy (excerpt)
By an invalid operation (implicit exception)
Exception
SystemException
ArithmeticException
DivideByZeroException
OverflowException
...
NullReferenceException
IndexOutOfRangeException
InvalidCastException
...
ApplicationException
... user-defined exceptions
...
IOException
FileNotFoundException
DirectoryNotFoundException
...
WebException
...
Division by 0
Index overflow
Acess via a null reference
...
By a throw statement (explicit exception)
throw new FunnyException(10);
class FunnyException : ApplicationException {
public int errorCode;
public FunnyException(int x) { errorCode = x; }
}
(By calling a method that throws an exception but does not catch it)
s = new FileStream(...);
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Page 15
15
Traditional Collections
System.Collection namespace introduced in 1.0 version of .NET
Framework
Useful container types
FileStream s = null;
try {
s = new FileStream(curName, FileMode.Open);
...
} catch (FileNotFoundException e) {
Console.WriteLine("file {0} not found", e.FileName);
} catch (IOException) {
Console.WriteLine("some IO exception occurred");
} catch {
Console.WriteLine("some unknown error occurred");
} finally {
if (s != null) s.Close();
}
Lists
Dictionaries
Hashtables
CollectionBase
catch clauses are checked in sequential order.
finally clause is always executed (if present).
Exception parameter name can be omitted in a catch clause.
Exception type must be derived from System.Exception.
If exception parameter is missing, System.Exception is assumed.
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Sample Class Definition
Sample ArrayList Use
ArrayList bookList = new ArrayList();
class Book
{
private int bookNumber = 0;
public int BookNumber
{
get { return this.bookNumber ; }
set { this. bookNumber = value; }
}
for( int i = 0; i < 20; i++)
{
bookList.Add( new Book(i) );
}
IEnumerator listEnum = bookList.GetEnumerator();
while( listEnum.MoveNext() )
{
Console.WriteLine(“{0}”,
((Book)(listEnum.Current)).BookNumber);
}
public Book( int _bookNumber )
{
this.bookNumber = _bookNumber;
}
}
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Page 16
16
Drawbacks
VB.NET Generics Sample 1
Dim testCol As New List(Of int32)()
No type checking enforcement at compile time
For i as int32 = 0 To 19
testCol.Add(i)
Next
Doesn’t prevent adding unwanted types
Can lead to difficult to troubleshoot issues
Runtime errors!
All items are stored as objects
For each someInt As int32 in testCol
Console.WriteLine(“{0}”, someInt)
Next
Must be cast going in and coming out
Performance overhead of boxing and unboxing specific types
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65
Daniel HERLEMONT
C# Generics Sample 1
VB.NET Generics Sample 2
Dim bookList As New List(Of Book)()
ArrayList<int> testCol = new ArrayList<int>();
for (int i = 0; i < 20; i++)
{
testCol.Add(i);
}
For i as int32 = 0 To 19
bookList.Add(New Book(i))
Next
foreach (int someInt in testCol)
{
Console.WriteLine(“{0}”, someInt);
}
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66
For each book As Book in bookList
Console.WriteLine(“{0}”, book.BookNumber)
Next
67
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Page 17
17
C# Generics Sample 2
C++ Templates?
ArrayList<Book> bookList = new ArrayList<Book>();
for (int i = 0; i < 20; i++)
{
bookList.Add( new Book(i) );
}
Generics are NOT equal to Templates
Compile-Time vs. Run-Time
foreach (Book book in bookList)
{
Console.WriteLine(“{0}”, book.BookNumber);
}
Code Bloat?
Pros and Cons for each
Templates = Compile-Time
Generics = Run-Time
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Streaming Framework
System.IO contains types for input and output
Base class Stream defines an abstract protocol for byte-oriented input and output
Specialization for different media
Streams support synchronous and asynchronous protocol
Readers and Writers for formatting
Class Stream
public abstract class Stream : MarshalByRefObject, IDisposable {
public abstract bool CanRead { get; }
public abstract bool CanSeek { get; }
public abstract bool CanWrite { get; }
Stream
FileStream
NetworkStream
MemoryStream
BufferedStream
CryptoStream
DeflateStream
GZipStream
• Elementary properties of
stream
public
public
public
public
abstract int Read(out byte[] buff, int offset, int count);
abstract void Write(byte[] buff, int offset, int count);
virtual int ReadByte();
virtual void WriteByte(byte value);
• Synchronous reading and
writing
public
public
public
public
virtual IAsyncResult BeginRead(…);
virtual IAsyncResult BeginWrite(…);
virtual int EndRead(…);
virtual int EndWrite(…);
• Asynchronous reading and
writing
public abstract long Length { get; }
public abstract long Position { get; set; }
public abstract long Seek(long offset, SeekOrigin origin);
• Length
and actual position
• Positioning
public abstract void Flush();
public virtual void Close();
...
• Flush and close
}
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18
Stream Classes
Readers and Writers
(Stream)
long Length
long Position
bool CanRead
bool CanWrite
bool CanSeek
int Read(byte[] buf, int pos, int len)
int ReadByte()
Write(byte[] buf, int pos, int len)
WriteByte(byte x)
long Seek(long pos, SeekOrigin org)
SetLength(long len)
Flush()
Close()
Sequential
byte streams on
various media
TextReader
StreamReader
NetworkStream
BufferedStream
CryptoStream
string Name
Lock(int pos, int len)
MemoryStream(
byte[]
)
bool DataAvailable
DeflateStream
GZipStream
StringReader
TextWriter
BinaryReader
MemoryStream
is buffered!
Readers and Writers overtake formatting tasks
namespace System.IO
FileStream
Unlock(int pos, int len)
BinaryReader and BinaryWriter for binary data
TextReader and TextWriter for character data
Stream
BinaryWriter
StreamWriter
StringWriter
…
no Seek
FileStream
int Capacity
MemoryStream
NetworkStream
Decorators
byte[] GetBuffer()
WriteTo(Stream s)
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Reader Classes
Writer Classes
(TextReader)
BinaryReader
(TextWriter)
BinaryWriter
int Read()
int ReadBlock(char[] buf, int pos, int len)
int Peek()
string ReadLine()
string ReadToEnd()
Close()
BinaryReader(Stream s)
BinaryReader(Stream s, Encoding e)
byte ReadByte()
bool ReadBoolean()
char ReadChar()
short ReadInt16()
int ReadInt32()
...
Close()
string NewLine
Write(bool b)
Write(char c)
Write(int i)
...
Write(string format, params object[] arg)
WriteLine()
WriteLine(bool b)
WriteLine(char c)
WriteLine(int i)
...
WriteLine(string format, params object[] arg)
Flush()
Close()
Stream BaseStream
BinaryWriter(Stream s)
BinaryWriter(Stream s, Encoding e)
Write(bool b)
Write(char c)
Write(int i)
...
long Seek(int pos, SeekOrigin org)
Flush()
Close()
StreamReader
StringReader
Stream BaseStream
StreamReader(Stream s)
StringReader(string s)
TextReader
BinaryReader
reads characters
reads primitive types in binary form
Unfortunately, it is not possible to set multiple readers to a stream at the same time.
There is no formatted input of numbers, words, etc.
Daniel HERLEMONT
StreamWriter
StringWriter
Stream BaseStream
StreamWriter(Stream s)
StringWriter()
string ToString()
Output of data of primitive types
in binary form
Formatted text output
(only sequentially; no Seek)
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19
Files and Directories
Class File
Namespaces System.IO.File and System.IO.Directory
for working with files and directories
public sealed class File {
public static FileStream Open(string path, FileMode mode);
public static FileStream Open(string path, FileMode m, FileAccess a);
public static FileStream Open(string p, FileMode m, FileAccess a, FileShare s);
public static FileStream OpenRead(string path);
public static FileStream OpenWrite(string path);
public static StreamReader OpenText(string path);
// returns Reader for reading text
public static StreamWriter AppendText(string path);
// returns Writer for appending text
public static FileStream Create(string path);
// create a new file
public static FileStream Create(string path, int bufferSize);
public static StreamWriter CreateText(string path);
public static void Move(string src, string dest);
public static void Copy(string src, string dest);
// copies file src to dest
public static void Copy(string src, string dest, bool overwrite);
public static void Delete(string path);
public static bool Exists(string path);
public static FileAttributes GetAttributes(string path);
public static DateTime GetCreationTime(string path);
public static DateTime GetLastAccessTime(string path);
public static DateTime GetLastWriteTime(string path);
public static void SetAttributes(string path, FileAttributes fileAttributes);
public static void SetCreationTime(string path, DateTime creationTime);
public static void SetLastAccessTime(string path, DateTime lastAccessTime);
public static void SetLastWriteTime(string path, DateTime lastWriteTime);
}
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Directory:
static methods for manipulating directories
File:
static methods for manipulating files
DirectoryInfo:
represents a directory
FileInfo:
represents a file
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Parameter arrays
Fonctionnalités avancées
Can write “printf” style methods
Type-safe, unlike C++
Section critique, exclusion mutuelle
class Account {
int balance;
public Account(int initial) {
balance = initial;
}
int Withdraw(int amount) {
if (balance < 0) throw new Exception("Negative Balance");
lock (this) {
if (balance >= amount) {
balance = balance - amount;
return amount;
}
else {
return 0;
}
}
}
}
Daniel HERLEMONT
C#
static void printf(string fmt,
fmt, params object[] args)
args) {
foreach (object x in args)
args) {
...
}
}
printf("%s %i", s, i);
object[] args = new object[2];
args[0] = s;
args[1] = i;
printf("%s %i", args);
args);
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Page 20
20
Contrôle de débordement lors d’opérations arithmétiques sur les entiers
Boxing / Unboxing
Mécanisme de conversion entre un type valeur et un type référence
class OverFlowTest {
static short x = 32767, y = 32767;
public static int myMethodCheck() {
int z = 0;
try {
z = checked((short)(x + y));
}
catch (System.OverflowException e) {
System.Console.WriteLine(e.ToString());
}
return z;
}
public static int myMethodUncheck() {
int z = unchecked((short)(x + y));
return z;
}
}
C#
Daniel HERLEMONT
boxing :
type valeur type référence
unboxing :
type référence type valeur
int i = 123;
object o = i;
int j = (int)o;
81
81
Fonctionnalités avancées – Code Unsafe
82
82
Fonctionnalités avancées - Unsafe
Code unsafe
C#
Daniel HERLEMONT
Manipulation de bas niveau (pointeurs)
Autorise les conversions de types
Autorise les opérations arithmétiques sur les pointeurs
Semblable à du code C inline – permet de proter du code écrit en C
Allocation sur la pile (stackalloc)
Code unsafe
Fixer l’adresse mémoire d’une variable à l’exécution (fixed)
class Test {
static int x;
int y;
unsafe static void F(int*
F(int* p) {
*p = 1;
}
class Test {
unsafe void Method() {
char* buf = stackalloc char[256];
for(char*
for(char* p = buf;
buf; p < buf + 256; p++) *p = 0;
...
}
}
Test t = new Test();
int[] a = new int[10];
unsafe {
fixed (int* p = &x) F(p);
F(p);
fixed (int* p = &t.y
) F(p);
&t.y)
F(p);
fixed (int* p = &a[0]) F(p);
F(p);
fixed (int* p = a) F(p);
F(p);
}
}
}
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C#
83
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C#
84
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Comparaison C# et VB.NET
C# Example (Syntax)
C#
/* C Style comment */
// C++ Style comment
Object oriented and strong typing
Described as a “...simple, modern, object-oriented, and type-safe programming
language derived from C and C++”.
Bears many syntactic similarities to C++ and Java.
C# is a better programming language because it forces variables to be defined.
C# code runs faster
for large applications where maintenance and performance are required
///Enhanced comment for Documentation Feature
Void SampleProc()
{
int intCounter1=0;
MessageBox.show(“Counter1=” + intCounter1.ToString());
} //end of SampleProc
VB.Net
is the latest release of Microsoft’s Visual Basic language.
VB is an event driven programming language.
Derived heavily from BASIC.
VB enables Rapid Application Development (RAD) of graphical user interface
(GUI) applications.
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VB.Net Example (Syntax)
86
C# Example (Object Oriented)
class App
{
static void Main(string [ ] args)
{
int intCounter=0;
‘Style of comments for VB.Net
Sub SampleProc()
Dim intCounter1 as Integer, intCounter2 as Integer
MessageBox.show(“Counter1=” & intCounter1)
End Sub ‘end of SampleProc
foreach (string arg in args)
{
System.Console.WriteLine(“Counter:” + intCounter.ToString() + “=“ + arg);
} //end of foreach
} //end of Main()
} //end of App{}
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VB.Net Example (Object Oriented)
Language Converters
Class App
Shared Sub Main(ByVal args as String( ) )
Dim arg as String
Dim intCounter as Integer
C# to VB.NET
For Each arg in args
System.Console.Writeline(“Counter: ” & intCounter & “=“ & arg)
http://www.aspalliance.com/aldotnet/examples/translate.aspx
http://www.kamalpatel.net/ConvertCSharp2VB.aspx
Next ‘For Each loop
VB.Net to C#
End Sub ‘end of Main()
End Class ‘end of App{}
http://www.e-iceblue.com
http://www.vbconversions.com
C# & VB.NET Conversion Pocket Reference by Jose Mojica
C# in a Nutshell By Peter Drayton, Ben Albahari, Ted Neward
http://en.wikipedia.org/wiki/Visual_Basic_programming_language
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90
Quelques références
http://msdn.microsoft.com
http://msdn.microsoft.com
http://windows.oreilly.com/news/hejlsberg_0800.html
http://www.csharphelp.com
http://www.csharphelp.com//
http://www.csharphttp://www.csharp-station.com/
station.com/
http://www.csharpindex.com
http://www.csharpindex.com//
http://www.hitmill.com/programming/dotNET/csharp.html
http://www.hitmill.com/programming/dotNET/csharp.html
http://www.chttp://www.c-sharpcorner.com/
sharpcorner.com/
http://msdn.microsoft.com/library/default.asp?URL
=/library/dotnet/csspec/vclrfcsharpspec_Start.htm
dotnet/csspec/vclrfcsharpspec_Start.htm
http://msdn.microsoft.com/library/default.asp?URL=/library/
http://en.wikipedia.org/wiki/C_Sharp_(programming_language)
http://fr.wikipedia.org/wiki/C_sharp
Tutoriel en francais
http://tahe.ftp-developpez.com/fichiers-archive/csharp2008.pdf
http://tahe.developpez.com/dotnet/csharp/
Comparaisons entre langages
http://en.wikipedia.org/wiki/Comparison_of_Java_and_C_Sharp
http://www.25hoursaday.com/CsharpVsJava.html
http://en.wikipedia.org/wiki/Comparison_of_C_Sharp_and_Visual_Basic_.NET
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Page 1 .NET et C #

Transcription

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