2015. GL3. ProgrammationII. Chap1. Introduction à .NET Framework Et à C#

8/17/2019 2015. GL3. ProgrammationII. Chap1. Introduction à .NET Framework Et à C#

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Chapitre 1. Introduction à C# et à Visual Studio 2012

Chapitre 1

Introduction au .NET Framework,à Visual Studio 2012,

et au langage C#

Mohamed RomdhaniMCSD Web Applicatio ns .NET 4.5

2M . Rom dh a n i , J a n v i e r 2 0 1 4

Contenu

Le .NET Framework

Présentation de Visual Studio

Introduction au langage C#


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Le .NET Framework


Qu’est ce que .NET ?

Un Modèle de programmation uni fié

Une plate-forme de déplo iement et d’exécution

Framework .NET : Gratuit & intégré à Windows

Définition : [dot-net]

.NET est une plateforme

complète pour développer,

déployer et exécuter des

Applications Web, Windows, Mobiles et serveur


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Architecture

OS

.NET Framework

Application


Components of the Framework

V i s

u a l S t u d i o

Common Language Runtime Assembly load and execution

Base Class LibraryCore types and services

Frameworks

ASP.NET WinForms WPF WCF etc.

Languages

VB C#Ruby /

Pythonetc.


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Historique du .NET Frameworket de Visual Studio

Version Version Number Release Date Visual Studio

1.0 1 .0.3705.0 13.02.2002 Visual Studio .NET 2002

1.1 1.1.4322.573 24.04.2003 Visual Studio .NET 2003

2.0 2.0.50727.42 07.11.2005 Visual Studio 2005

3.0 3.0.4506.30 06.11.2006

3.5 3.5.21022.8 19.11.2007 Visual Studio 2008

4.0 4.0.30319.1 12.04.2010 Visual Studio 2010

4.5 4.5.40805 12.09.2012 Visual Studio 2012


Historique d’évolution de la CLR

.NET 1.0 .NET 1.1 .NET 2.0

3.0

3.5

.NET 4

2002 2003 2008 CTP!2005-08

CLR 1.0CLR

1.1 CLR 2.0CLR 4

SP1

.NET 4

2008 CTP!

CLR 4.5

4.5


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Caractéristiques de la plateforme.Net

Les langages génèrentdésormais un langagecommun, basé sur des typescommuns : le MSIL(Microsoft IntermediateLanguage)

Ces modules en MSIL sontcompi lés en code machine àla volée (« just in time »)

Astuce : i l es t possible delire le MSIL avec i ldasm

Astuce : i l es t possible dedécompil er avec reflector


Common Language Runtime ( C LR )

Common Type System

JIT (just-in-time) Compiler

Code access security

Garbage Collection

Class Loader

COM Interoperability


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JIT Compilation and Runtime

SourceCode

.cs

Compiler

.exe

MSIL

MSIL

containing

.NET

Assembly

JIT’ter

Enter TitleHere

csc.exe

(Compile time)

Run time

CLR

Memory


MSIL

.NET Languages JIT’ting MSIL

Not an executable

Needs CLR

After JIT compilation (Just-In-Time Compilation)

CPU independent Advantages

Platform independent / any client (that has a suitable framework)

Optimization (even smart compilation)


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What does MS I L look like?

ILDASM.exe


What is the Common Type System?

A set of common types

any language that runs in CLR should implement

no syntax specified

Languages often define aliases

For example

CTS definesSystem.Int324 byte integer

C# defines int as analias of System.Int32

Value Types areallocated on the Stack

Reference Types areallocated on the Heap


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What is an assembly ?

MyAssembly .dll OR .exe

Building blocks of .NET Framework applications

Collection of types and resources that form a logical unit of functionality

MyClassA

MyClassB

MyResource

V 1 . 1 . 2 5 4 . 1

Assembly version< m a j o r > . < m i n o r > . < b u i l d > . < r e v is io n >

Assembly signedwith a digitalcertificate


Organisation du Framework .NET

System

System.IO

Entrées/Sorties

System.Security

System.Collections

Listes, tableaux, etc….

System.Resources

Traduction automatique

System.Text

StringBuilder

System.Text.RegularExpressions

System.Configuration

Accès aux fichiers de config XML.

System.Xml

System.Xml.Schema

Pour les XSD

System.Xml.Serialization

Transformation d’un objet en XML etinversement.

System.Xml.XPath

Parcours optimisé d’un flux XML.

System.Xml.Xsl

Transformation XSLT : formatage

d’un flux XML.

System.Data

ADO.NET

System.Data.OracleClient

Se trouve dans une assemblydistincte.

System.Data.Sql


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What Tools Does the .NET FrameworkProvide?

Makecert.exeCaspol.exe

Gacutil.exeNgen.exe

Ildasm.exe Sn.exe


Présentation de Visual Studio


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Visual Studio 2012:

Intuitive IDE that enables developers to quickly buildapplications in their chosen programming language

Visual Studio 2012 features:

Rapid application developmentServer and data access

Debugging featuresError handlingHelp and documentation

Visual Studio 2012 IDE Overview


Integrated Development Environment (IDE) Project templates

Wizards

Debugging

IntelliSense



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The Structure of Visual Studio Projects andSolutions

Visual Studio Solution

Visual Studio solutions are wrappers for .NET projects

Visual Studio solutions can contain multiple .NET projects

Visual Studio solutions can contain different types of .NET projects

ASP.NET project

.aspx

.aspx.cs .config

.csproj

WPF project

.xaml

.xaml.cs .config

.csproj

Console project

.cs

.config

.csproj



Visual Basic Windows Forms Application(selected)

Default project name

(provided by Visual Studio)Description of selected project

(provided by Visual Studio)


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Visual Studio 2012 IDE Overview (cont.)

Menu in the menu bar Solution Explorer window

Form (WindowsForms a pplication)

Properties

window


Menu Bar and Toolbar

The set of m enus displayed depends on what you are currently doin g in the IDE

You can access common commands from the toolbar icons


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Visual Studio 2012 Useful Shorcuts

Build & Debug Shortcuts

Set/Unset Breakpoint (F9)

Build (F6 or Ctrl +Shift +B)

Start Debugging (F5)

Start Without Debugging (Ctrl +F5)

Stop Debugging (Shift +F5)

Continue (F5)

Step Over (F10)

Step Into (F11)

Step Out (Shift +F11)

Comment / Uncomment (Ctrl +K, C / Ctrl +K, U)

Go to Definition (F12)

Find all References (Shift + F12)

Auto For mat (Ctr l +K, D or Ctr l +E, D)

Surround With (Ctrl +S) Surrounds a block of code with a code snippet.


Introduction au langage C#


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Purpose of C#

C# has been standardized and is described by the ECMA-334 C# Language Specification

C# uses a very similar syntax to C, C++, and Java

C# is the language of choice for many developers who build.NET Framework applications

C#


C# au fil de l’histoire …

[http://jlambert.developpez.com/tutoriels/dotnet/nouveautes-csharp-5/]


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The Structure of a Console Application

usi ng Syst em;

namespace MyFi r s t Appl i ca t i on

{c l ass Pr ogr am

{

s t at i c v oi d Mai n( s t r i ng[ ] ar gs )

{

}

}

}

Bring System namespace into scope

Program class declaration

Main method declaration

Namespace declaration


Key language features

Unified object system

Everything type is an object, even primitives

Single inheritance

Interfaces

Specify methods & interfaces, but no implementation

Structs

A restricted, lightweight (efficient) type

Delegates

Expressive typesafe function pointer

Useful for strategy and observer design patterns


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Hello World example

public class HelloWorld {

public static void Main()

{

// Use the system console object

System.Console.WriteLine(”Hello, World!”);

}

}

Creates a new object type (class) called HelloWorld.

It contains a single method, called Main.

Main contains one line, which writes “Hello, World!” on the display.

The method that performs this action is called WriteLine.

The WriteLine method belongs to the System.Console object.

The keyword “static” means that the method Main can be called even if there is nocurrent instance of the class. It’s a class method, not an instance method.

The line beginning with // is a comment, and does not execute.


Syntax

Case-sensitive

Whitespace has no meaning

Sequences of space, tab, linefeed, carriage return

Semico lons are used to t erminate statements (;)

Curly braces {} enclose code blocks

Comments:

/* comment */

// comment

///

Automatic XML commenting facility


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Classes and Objects

A class combines together

Data

Class variables

Behavior

Methods

A key feature of object-oriented languages

Procedural languages, such as C, did not require clustering of data and behavior

Class/instance distinction

Class defines variables & methods

Need to create instanced of the class, called objects, to use variables & methods

Exception: static methods and variables

Analogy: a jelly bean mold (class) can be used to create a large number of jellybeans (objects, instances of the class)


Inheritance

Operationally

If class B inherits from base class A, it gains all of the variables andmethods of A

Class B can optionally add more variables and methods

Class B can optionally change the methods of A

Uses

Reuse of class by specializing it for a specific context

Extending a general class for more specific uses

Interfaces

Allow reuse of method definitions ofinterface

Subclass must implement methoddefinitions


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Inheritance Example

class A

{

public void display_one()

{

System.Console.WriteLine("I come from A" );

}

}

class B : A

{

public void display_two()

{

System.Console.WriteLine("I come from B, child of A");

}

}

class App

{

static void Main()

{

A a = new A(); // Create instance of A

B b = new B(); // Create instance of B

a.display_one(); // I come from A

b.display_one(); // I come from A

b.display_two(); // I come from B, child of A

}

}


Visibility

A class is a container for data and behavior

Often want to cont rol over which code:

Can read & write data

Can call methods

Access modif ier s: Public

No restrictions. Members visible to any method of any class

Private

Members in class A marked private only accessible to methods of class A

Default visibility of class variables (but is good to state this explicitly)

Protected

Members in class A marked protected accessible to methods of class A and subclasses of A.


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Constructors

Use “ new” to create a new object instance

This causes the “constructor” to be called

A const ructor is a method called when an ob ject is created

C# provides a default constructor for every class

Creates object but takes no other action

Typically classes have explicitly provided constructor

Constructor

Has same name as the class

Can take arguments

Usually public, though not always

Singleton design pattern makes constructor private to ensure only one object instanceis created


Predefined Types

C# predefined types

Reference object, string

Signed sbyte, short, int, long

Unsigned byte, ushort, uint, ulong

Character char (2 byte, Unicode)

Floating-point f loat, double, decimal

Logical bool

Predefined types are simply aliases for system-provided types

For example, int == System.Int32

Unusual types in C#

Bool: Holds a boolean value: “true” or “false”

Decimal : A fixed precision number up to 28 digits plus decimal point

Useful for money calculations : 300.5m (Suffix “m” or “M” indicates decimal)


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Delegates

An object if ied functi on

inherits from System.Delegate

sealed implicitly

looks much like C/C++ style function pointer

eg. delegate int Func(ref int x)

defines a new type: Func: takes int, returns int

declared like a function with an extra keyword

stores a list of methods to call

Example

delegate int Func(ref int x);

int Increment(ref int x) { return x++; }int Decrement(ref int x) { return x--; }Func F1 = new Func(Increment);F1 += Decrement;x = 10;Console.WriteLine(F1(ref x));Console.WriteLine(x);


Events

Special class of delegates given the event keyword

class Room {

public event EventHandler Enter;

public void RegisterGuest(object source, EventArgs e) { … }

public static void Main(string[] args) {

Enter += new EventHandler(RegisterGuest);

if (Enter != null) {Enter(this, new EventArgs());

}

}

}

Enter is an object of type delegate

– when event is “raised” each delegate called

– C# allows any delegate to be attached to an event

– .NET requires only EventHandlers

Adds restrictions to the delegate

– can only raise an event in its defining class

– outside, can only do += and -= : return void


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C# 3.0 Features

Implici tly Typed Local Variables

Extension Methods

Lambda Expressions

Object Initiali zers

Collection Initi alizers


Implicitly Typed Local Variables

Examples:

var i = 5;var s = "Hello";

var d = 1.0;

var numbers = new int[] {1, 2, 3};

var orders = new Dictionary();

Are equivalen t to:

int i = 5;string s = "Hello";

double d = 1.0;

int[] numbers = new int[] {1, 2, 3};

Dictionary orders = new Dictionary();

Errors:

var x; // Error, no initializer to infer type from

var y = {1, 2, 3}; // Error, collection initializer not permitted

var z = null; // Error, null type not permitted


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Extension Methods

Declaration:

public static partial class Extensions { public static int ToInt32(this string s) {

return Int32.Parse(s);}

}

Usage:

string s = "1234";int i = s.ToInt32(); // Same as Extensi ons.ToInt32(s)

Instance methods take precedence over extension methods

Extension methods imported in inner namespace declarations take precedenceover extension methods impor ted in outer namespace declarations


Extension Methods (2)

Declaration:

public static partial class Extensions { public static T[] Slice(this T[] source, int index, int count) {

if (index < 0 || count < 0 || source.Length – index < count)throw new ArgumentException();

T[] result = new T[count]; Array.Copy(source, index, result, 0, count);return result;

}}

Usage:

int[] digits = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

int[] a = digits.Slice(4, 3); // Same as Extensio ns.Slice(dig its, 4, 3)


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Lambda Expressions

Generalized function syntax

x . x + 1

in C# 3.0, have x => x + 1

From anonymous delegate syntax:

del egat e( i nt x) { r et ur n x + 1; }

Can have impl icitl y typed variables

Can have more than one variable

Can have expression or statement body

NB: no statement bodies in preview compiler


Lambda Expressions (2)

Can be converted to delegate type

if parameters and body match

del egat e R Func( A ar g) ;Func f 1 = x => x + 1;Func f 2 = x => x + 1;Func f 3 = x => x + 1;

Participate in type inference

If expression body, get expression trees


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Lambda Expressions (3)

Type inference public static IEnumerable Select(

this IEnumerable source,

Func selector)

{

foreach (T element in source)

yield return selector(element);

}

If call Sel ect ( cust omers, c => c. Name) ;

T, S mapped to appropriate types


Object Initializers

Class representing a point :

public class Point {

private int x, y;

public int X { get { return x; } set { x = value; } }

public int Y { get { return y; } set { y = value; } }

}

New instance can be created using obj ect init ializer:

var a = new Point { X = 0, Y = 1 };

Which is equivalent to:

var a = new Poi nt( );

a.X = 0;

a. Y = 1;


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Object Initializers (2)

Class representing a rectangle: public class Rectangle {

private Point p1, p2;

public Point P1 { get { return p1; } set { p1 = value; } }

public Point P2 { get { return p2; } set { p2 = value; } }

}

New instance can be created using obj ect init ializer:var r = new Rectangle {

P1 = new Point { X = 0, Y = 1 },

P2 = new Point { X = 2, Y = 3 }

};

Which is equivalent to:var r = new Rectangle();

var __p1 = new Point();

__p1.X = 0;

__p1.Y = 1;

r.P1 = __p1;

var __p2 = new Point();

__p2.X = 2;

__p2.Y = 3;

r.P2 = __p2;


Collection Initializers

Example:

List digits = new List { 0, 1, 2};

Is equivalent to:

List digits = new List();

digits.Add(0);

digits.Add(1);digits.Add(2);

List has to implement System.Collections.Generic.ICollectioninterface with the Add(T) method


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Auto-implemented Properties

Backed up by a private field normally inaccessible to programmer (onlyvia the property):

class LightweightCustomer {

public double TotalPurchases { get; set; }

public string Name { get; private set; } // read-only

public int CustomerID { get; private set; } // read-only

}


Anonymous Types

Following expression:new { p1 = e1 , p2 = e2 , … pn = en }

Can be used to define an anonymous t ype :class __Anonymous1 {

private T1 f1 ;

private T2 f2 ;

…

private Tn fn ;

public T1 p1 { get { return f1 ; } set { f1 = value ; } }


…


}

And create its instance usi ng object in it ial izer

Different anonymous object init ili zers that define properties with samenames in the same order generate the same anonymous type:var p1 = new { Name = "Lawnmower", Price = 495.00 };

var p2 = new { Name = "Shovel", Price = 26.95 };

p1 = p2;


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Partial Methods

Can appear only in parti al classes or struct s, and must be void,private and without out parameters:

partial class A {

string _name;

partial void OnNameChanged();

public string Name {

set {

_name = value;

OnNameChanged();

}

}

}

partial class A {

partial void OnNameChanged() {

// Do something

}}


LINQ to Objects

Set o f generic extension m ethods (Select, Where, OrderBy, … + o thers)imp lemented for IEnumerable interface, example:

i nt[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

var numberGr oups = from n in number s group n by n %5 into g

select new {Remai nder = g.Key, Numbers = g.Group};

f oreach ( var g i n numberGr oups) {

Consol e.Wri t eLi ne(

"Number s wi t h a remai nder of {0} when di vi ded by 5: " , g. Remai nder ) ;

) ;

f oreach (i nt n i n g. Numbers ) {

Consol e.Wri t eLi ne( n);

}

}

LINQ to SQL – Classes for SQL data access usingquery expressions

LINQ to XML - Classes fo r XML data access usingquery expressions

LINQ to DataSets - Classes for querying Datasets usingquery expressions (on typed DataSets works s imilarlyas LINQ to SQL)

Numbers with a remainder of 0 when divided by 5:

5

0


4

9


1

6


3

8


7

2


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C# 4.0 Features

Dynamic Typed ob jects

Named and optional Parameters


Dynamic Typed Objects

Calculator calc = GetCalculator();

int sum = calc.Add(10, 20);

object calc = GetCalculator();

Type calcType = calc.GetType();

object res = calcType.InvokeMember("Add",

BindingFlags.InvokeMethod, null,new object[] { 10, 20 });

int sum = Convert.ToInt32(res);ScriptObject calc = GetCalculator();

object res = calc.Invoke("Add", 10, 20);

int sum = Convert.ToInt32(res);

dynamic calc = GetCalculator();

int sum = calc.Add(10, 20);

Statically typed

to be dynamic

Dynamic method

invocation

Dynamic

conversion


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Named and Optional Parameters

Consider this example:

public void M(int x, int y = 5, int z = 7) { }

In this method, the parameters y and z are assigned default values.Calls to thi s method might look like this:

– M(1, 2, 3); // ordinary call of M

M(1, 2); // omitting z – equivalent to M(1, 2, 7)

M(1); // omitting both y and z – equivalent to M(1, 5, 7)

M(1, z: 3); // passing z by name

M(x: 1, z: 3); // passing both x and z by name

M(z: 3, x: 1); // reversing the order of arguments


Covariance & Contravariance

If the type of the return value is subclass

then the delegate is still acceptable

called covariance

If the type of t he args are subclasses

then the delegate is likewise acceptable

called contravariance


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Generic co- and contravariance

If T appears only as an output, it ’s safe to passX fo r X

We call this covariance

C# uses the syntax X

If T appears only as an input, it’s safe to passX for X

We call this contravariance

C# uses the syntax X


Variance en .NET 4.0

System.Collections.Generic.IEnumerable

System.Collections.Generic.IEnumerator

System.Linq.IQueryable

System.Collections.Generic.IComparer

System.Collections.Generic.IEqualityComparerSystem.IComparable

System.Func

System.Action

System.Predicate

System.Comparison

System.EventHandler

Interfaces

Delegates

Documents

2015. GL3. ProgrammationII. Chap1. Introduction à .NET Framework Et à C#