Introducing the .NET Framework with C#

New Official Title!

Student Ambassador

Main Entry: am·bas·sa·dor Pronunciation: am-'ba-s&-d&r, &m-, im-, -"dor, -'bas-d&rFunction: noun

1 : an official envoy; especially : a diplomatic agent of the highest rank accredited to a foreign government or sovereign as the resident representative of his own government or sovereign or appointed for a special and often temporary diplomatic assignment

2 a : an authorized representative or messenger b : an unofficial representative <traveling abroad as ambassadors of goodwill>

Why is Microsoft Doing This?• Make Microsoft tools and technology

accessible• Provide awareness and training opportunities• To LEARN from student developers

Win the hearts and minds of developers

Student Ambassador ProgramRequired Activities

• Deliver Tech Talks– 6 Minimum with 30 student attendees per talk– collect & submit evals

• Start a .NET User Group– Focused on a specific area of .NET or Microsoft

• Support Campus Launch Events• Support Local Field Activities• Drive Awareness of MSDNAA

Student Ambassador ProgramOptional Activities

• Host a Student Programming Contest• Student User Group Projects

– Limited number of opportunities– Need project proposals ASAP

Defining the .NET Framework

• The .NET Framework is– A software development environment– A runtime engine for Managed Code– A platform designed for Internet-Distributed

software• The .NET Framework is an exciting new

computing platform

What is the .NET Framework• A new computing platform designed to

simplify application development• A consistent object-oriented programming

environment• A code-execution environment that:

– Minimizes software deployment and versioning conflicts

– Eliminates the performance problems of scripted or interpreted environments

Primary Components of .NET• .NET Framework Class Libraries

– Object-oriented collection of reusable types– Sits on-top of the Common Language Runtime

• Common Language Runtime (CLR)– Manages code execution at runtime– Memory management, thread management, etc.– Code designed for the CLR is referred to as

“Managed Code”

Operating SystemOperating System

Common Language Runtime (CLR)

Inside the .NET Framework

Base Framework

Data and XML

Web Services User Interface

VB C++ C#

ASP.NET

J# Python …

Secure, integrated class libraries•Unifies programming models across languages

•Enables cross-language integration

•Factored for extensibility

•Designed for tools

Common Language RuntimeExecutes code, maintains security, handles component “plumbing” and dependencies

ASP.NETHigh-productivity environment for building and running Web services

One Runtime For Many Languages

• CLR is an open standard• Any language can make use of CLR services• Any language can use classes written in any

other language• Any language can inherit classes written in any

other language

.NET Framework Class Libraries• Sit on top of the CLR• Reusable types that tightly integrate with the

CLR• Object oriented – inheritance, polymorphism,

etc.• Provide functionality for ASP.NET, XML Web

Services, ADO.NET, Windows Forms, basic system functionality (IO, XML, etc.)

The Common Language Runtime• Code that targets the CLR is referred to as

managed code• All managed code has the features of the

CLR– Object Oriented– Cross-language integration– Cross language exception handling– Multiple version support (no more DLL Hell)

The Common Language Runtime• The CLR manages object layout and references to

objects• Objects whose lifetimes are managed by the CLR are

referred to as Managed Data• Automatic memory management reduces memory

leaks• In managed code you can use:

– Managed Data– Unmanaged data– Both

The Common Language Runtime• All CLR-compliant compilers use a common type

system– Allows for cross-language inheritance– Passing object instances across language barriers– Invoking methods across language barriers

• Managed components expose metadata• Metadata includes

– Resources component was compiled against– Information about types and dependencies (no more

RegServ32

Web Server

Client Client

Web Server

Second-Tier(database or other server)

Second-Tier Second-Tier

Internet Distributed Software

Managed Code and the CLR

• The Common Language Runtime (CLR) is a runtime engine– Manages .NET Code (such as C# applications)– Provides features such as memory management, thread

management, object type safety, security, etc.– Is a part of the .NET Framework

• Managed code– Code that targets the CLR– Any .NET Language, including C#, Visual Basic, C++, Java,

Cobol, etc.

Windows (or other operating oystem)

Common Language Runtime(JIT compilation, memory management, etc.)

Legacy Software

(unmanaged code)

Managed ExecutableReusable

Managed Components

The CLR and Managed Code

IL and Metadata

• All Managed executables consist of– Intermediate Language (IL) instructions– Metadata

• IL – CPU independent machine language– Just-in-time compiled at runtime

• Metadata– Structured information – describes programming constructs including

• Classes definitions, field and method definitions, parameter lists, return types, etc.

using System.Windows.Forms;using System.Drawing;

class MyForm:Form{ public static void Main(){ Application.Run( new MyForm()); } protected override void OnPaint( PaintEventArgs e){ e.Graphics.DrawString( "Hello World!", new Font("Arial",35), Brushes.Blue, 10, 100);

SomeSource.csSomeSource.cs

C# Compiler

SomeSources.exe

IL

Metadata

A Managed Application

From Source Code to Managed .exe

Just-in-Time Compiling

• All managed code runs in native machine language

• However, all managed code is made up of IL and metadata

• The CLR JIT-compiles the IL and metadata– At execution time– Executed directly by CPU

• Allows for the best of both worlds– Code management features– Performance of full-speed execution

Running Process’ Memory

SomeSources.exe

IL

Metadata

JIT Compiler

10010100 10110000 10000000 1011101011011011 11010111 11000010 01110110

Native Machine Language

The CPU executes the JIT-compiled machine code directly

At execution time the IL and Metadata are JIT compiled

Executing a Managed Application

Automatic Memory Management

• The CLR manages memory for managed code– All allocations of objects and buffers made from a Managed

Heap– Unused objects and buffers are cleaned up automatically

through Garbage Collection• Some of the worst bugs in software development are

not possible with managed code– Leaked memory or objects– References to freed or non-existent objects– Reading of uninitialized variables

• Pointerless environment

A

B

E

DC

The Managed Heap

= Object or buffer in memory

class MyClass{ void Method(){ Variable v1; Variable v2;

do{ . . .

Objects A and D will be cleaned up because neither is directly or indirectly referenced

by code

Garbage Collection

Cross Language Support

• The .NET Framework supports many languages• Any compiler can be modified to emit managed executables

– IL and metadata• Languages that target the .NET Framework

– C#, Visual Basic, C++, Java, PERL, COBOL, SmallTalk– Dozens more existing and on the way

• Regardless of source language, all managed code can– Use the same tools– Use the same reusable components– Take advantage of features of the CLR

• Developers use their language of choice

Visual Studio.NET

• A Integrated Development Environment– To develop managed and unmanaged applications– Supports C#, C++, Visual Basic, JavaScript– Many useful tools and wizards

• Not part of the .NET Framework– Not necessary to build or run managed code– The .NET Framework SDK includes command line

compilers

The Framework Class Library• A huge collection of reusable types

– Classes, interfaces, enumerations and structures• For use by any managed code

– Including code written in any managed programming language

• Types for– Common tasks such as collections, file IO, memory and

thread management– GUI and window manipulation– Web form and web service applications

• Totally object oriented toolbox for developers– Ships as part of the .NET Framework

Using the FCL

• Types are arranged in a hierarchy of Namespaces• A type’s full name includes its namespaces

– Form class is actually System.Windows.Forms.Form– Use using to indicate namespaces in source code

• Assembly references are necessary for many types• The SDK documentation is critical for using SDK

types– Includes descriptions– Often includes useful code samples– Indicates namespaces and assemblies for types

Web Server

Client Client

Web Server

Second-Tier(database or other server)

Second-Tier Second-Tier

Distributing Managed Code

Managed Execution Processpublic void Fill(){ DotNetJunkies.StudyGroupPortal.Data.EventDB eDB = new DotNetJunkies.StudyGroupPortal.Data.EventDB(); //Create a data reader IDataReader reader = eDB.GetEventByGuid(_guid); //Advance to the first record in the reader reader.Read(); //Populate this instance of the Event class this.CreateEvent(ref reader); //Close the reader reader.Close();}

MSIL

Language Specific Compiler

AssemblyAssembly

Compilation And Execution

Source Source CodeCode

Language Language CompilerCompiler

CompilationCompilationCodeCode (IL)(IL)

MetadataMetadata

Microsoft Intermediate Language• Managed code is compiled to MSIL• CPU-independent set of instructions

– Loading, storing, initializing and calling methods– Arithmetic and logical operations, etc.– Control flow, exception handling, direct memory

access

Assemblies• Contains MSIL code to be executed• Security boundary – permissions are granted

at the assembly level• Type boundary – all types include the

assembly name they are a part of• Self-describing manifest – metadata that

describes the types in the assembly• Smallest versionable unit in the CLR• Deployment unit

Just-In-Time Compiling• Assemblies are compiled to native code by a

Just-In-Time (JIT) compiler• Compiled assemblies include metadata• No Type Libraries or Interface Definition

Language (IDL)

AssemblyAssembly

Compilation And Execution

Source Source CodeCode

Language Language CompilerCompiler

CompilationCompilation

Before installation or Before installation or the first time each the first time each method is calledmethod is calledExecutionExecution

JIT JIT CompilerCompiler

NativeNativeCodeCode

CodeCode (IL)(IL)

MetadataMetadata

Just-In-Time Compiling• All assemblies must be compiled to native

code before executing• JIT compilers are built into the CLR for every

supported CPU architecture• JIT compilers convert MSIL to native on

demand• Resulting native code is stored for reuse• JIT compiling occurs for each method after

the application is restarted

Summary• .NET Framework is a code execution platform• .NET Framework consists of two primary parts: .NET

Class Libraries, Common Language Runtime• All CLR-compliant compilers support the common

type system• Managed code is object oriented• Managed code is compiled to and assembly (MSIL)

by language specific compiler• Assemblies are compiled to native code by JIT

compiler

Contact Information• Alejandro Simon• Talks Web Page: http://asc0.dynup.net/dotnet• E-Mail: asc0_cate@hotmail.com

Questions?