C# - cs.kau.se · – iteration – selection • Manipulating computers • Level of abstraction differs – assembler, c, c++, java, c#, lisp, prolog, sql • Expressiveness varies

2009-04-02

Datavetenskap, Karlstads universitet 1

Karlstads universitet

Datavetenskap

DVGB07 – VT09

C#.Net

VT 2009


Datavetenskap

DVGB07 – VT09

Course Contents

• C#

– 6 hp approx.

• BizTalk

– 1,5 hp approx.

• No exam, but laborations


Datavetenskap

DVGB07 – VT09

Course contents

• Architecture

• Visual Studio

• Syntax

• Classes

• Forms

• Class Libraries

• Inheritance

• Other C# essentials

• XML + intro BizTalk

• BizTalk

• Seminars

2009-04-02



Datavetenskap

DVGB07 – VT09

Contact

• Thijs Holleboom

• 21F411

• [email protected]

• 054-700 1148

• Per Hurtig

• 21F422


• 054-700 2335

• Inger Bran

• 21E414


• 054-700 1970


Datavetenskap

DVGB07 – VT09

Programming

• All programming is the same– sequence

– iteration

– selection

• Manipulating computers

• Level of abstraction differs– assembler, c, c++, java, c#, lisp, prolog, sql

• Expressiveness varies– Some languages can do more

• If you know programming you can use any language (almost)


Datavetenskap

DVGB07 – VT09

Programming

SequenceIterationSelection

Memory op’sCalculations

Computer

Programming Language

Nifty StuffPre-done stuff

Abstraction

2009-04-02



Datavetenskap

DVGB07 – VT09

C++

Programming

Hardware (computer and peripherals)Machine code

Assembler Assembler

C Byte Code

Virtual Machine

Java

CIL

CLR

C#

Difficult

Full control

Easy

Less control


Datavetenskap

DVGB07 – VT09

Structure of .net technology


Datavetenskap

DVGB07 – VT09

Another visualisation of .net

2009-04-02



Datavetenskap

DVGB07 – VT09

Important concepts

• FCL

– Common class library

• CTS

– Common type system

• CLR

– The environment

everything builds upon.

The ”motor” i a .net

application.


Datavetenskap

DVGB07 – VT09

From code to program


Datavetenskap

DVGB07 – VT09

Common Language Runtime (CLR)

• Is essentially an implementation of the CLI

– Common Language Infrastructure

– Other implementations exist, e.g. the Mono

runtime

• Responsible for almost everything

• Uses only OS for threads and bulk memory

management

2009-04-02



Datavetenskap

DVGB07 – VT09

CLR

• JIT

– just in time-compiler

– Compiles code late

• Garbage Collector

– automatic memory handling

– You don't have to deallocate memory, it is

handled by the garbage collector

– In C/C++ you have to take care of your own

garbage, in C# you don't


Datavetenskap

DVGB07 – VT09

CLR

• Common Type System (CTS)

– All languages in the .net family are basically the same,

except for the syntax

– You can include code written in one language into a

program written in another

• Exception handler

– When something goes wrong, the exception handler

comes into play.


Datavetenskap

DVGB07 – VT09

• All .NET languages

compile to CIL, which

basically is advanced

assembler.

• The JIT compiles parts

of the CIL to native

object code, when that

part of the CIL is

needed.

Stubcode

CIL

Before JIT

Objectcode

After JIT

Common Intermediate Language (CIL)

2009-04-02



Datavetenskap

DVGB07 – VT09

CIL

• Is a strongly typed, verbose, assembler language

• stack-based

• generic

• low-level

• easy to compile

• has more features than are used by any existing supported language

– tail recursion (used in functional languages like LISP)


Datavetenskap

DVGB07 – VT09

CIL Example

.assembly HelloWorld{}

.method public hidebysig static void Main() cil man aged {

.entrypoint ldstr "Hello World!" call void [mscorlib]System.Console::WriteLine(strin g) ret

}


Datavetenskap

DVGB07 – VT09

Garbage Collection

• Allocation is fast, simple list of used memory

instead of linked list

• Works well with cache memory

• Your code is smaller, simpler, and more reliable

– But in a sense uglier

2009-04-02



Datavetenskap

DVGB07 – VT09

Garbage collection

• You never have memory leaks

– But your program is almost always too big

• Old stuff lying around

– Watch out when switching to a language without GC

or your program will leak

• alloc/free in C

• new/delete in C++


Datavetenskap

DVGB07 – VT09

Garbage Collection

• ”You may be thinking that it doesn't matter how garbage collection can help you if it means your program might lock up for several seconds anytime it gets asked to do something. And you'd be right - that did suck, back in the '70's and '80's on Lisp machines and such. ”

• Thus, garbage collection is nowadays a very fast process


Datavetenskap

DVGB07 – VT09

Common Type System (CTS)

• All .Net languages understand each other's data

types

• All use the same primitives

• Classes from different languages can inherit from

each other

• Value types

– scalars, such as integers

– records (eg. structs) and objects(!)

2009-04-02



Datavetenskap

DVGB07 – VT09

CTS

• Same base classes (highest level)

• All .Net languages’ highest objects can be cast to

any other.

• Interfaces are supported

– like in Java

– “Can do” instead of “Is-a” represented by inheritance


Datavetenskap

DVGB07 – VT09

CTS

• All objects inherit via single

inheritance from a top-most

object

• Multiple inheritance is not

supported

– Good(?)

– multiple inheritance is complex

– multiple inheritance is seldom

needed

– interfaces are better

Object

…

…

…

… …


Datavetenskap

DVGB07 – VT09

”Leaving” .NET

• So far, the lesson has covered theoretical aspects

of the .NET architecture

• Only a few things of what we covered have

practical implications

– Garbage collector

– The possibility to interact between .NET languages

• The rest of this lecture will be more practical!

2009-04-02



Datavetenskap

DVGB07 – VT09

Namespaces

• We start with namespaces!

• Divided into layers hierarchically

– divided by period, like System.IO

• Code in different files can belong to the same

namespace

• Use is optional

– Except for components

• Helps avoid name clashes


Datavetenskap

DVGB07 – VT09

Namespaces

• ”using” removes need to type full namespace

name

– using System;

– makes it possible to for instance access

– Console.WriteLine();

– without spelling out

– System.Console.WriteLine();


Datavetenskap

DVGB07 – VT09

Namespaces

namespace x.y{

class Slask{}

}// is shorthand for writingnamespace x{

namespace y{

class Slask{}

}}

If one wants to use class Slask

from another namespace the

namespace must be addressed

Either:

using x.y;…Slask s=new Slask();

or:

x.y.Slask s=new x.y.Slask();

2009-04-02



Datavetenskap

DVGB07 – VT09

Boxing

• Enables conversion from value type to reference

type

• Unboxing does the reverse, converting from

reference box to value type

• Boxing implies making a copy of the value

int i = 123;object box = i;if(box is int)

// box contains an int

int y = (int) box;// y contains int value// contained in box


Datavetenskap

DVGB07 – VT09

Keywords

abstract as base bool breakbyte case catch char checkedclass const continue decimal defaultdelegate do double else enumevent explicit extern false finallyfixed float for foreach gotoif implicit in int interfaceinternal is lock long namespacenew null object operator outoverride params private protected publicreadonly ref return sbyte sealedshort sizeof stackalloc static stringstruct switch this throw truetry typeof uint ulong uncheckedunsafe ushort using virtual voidvolatile while


Datavetenskap

DVGB07 – VT09

Visual Studio

• Graphical environment (IDE) for developing

.net-applications

• Microsoft

• Syntax highlighting

• Code completion

• GUI designer

– drag n drop, very easy to use, supernice

• Easy handling of events

2009-04-02



Datavetenskap

DVGB07 – VT09

Visual Studio – competitors

• .net is standardized

• C# is also standardized

• Other compilers and environments exist

– e.g. Mono for Linux


Datavetenskap

DVGB07 – VT09

Visual Studio (cont’d)


Datavetenskap

DVGB07 – VT09

VS – starting a new project

2009-04-02



Datavetenskap

DVGB07 – VT09

VS – starting…(cont’d)


Datavetenskap

DVGB07 – VT09

VS – editing


Datavetenskap

DVGB07 – VT09

VS – handling events

2009-04-02



Datavetenskap

DVGB07 – VT09

VS – connecting stuff


Datavetenskap

DVGB07 – VT09

VS - finito

Documents

C# - cs.kau.se · – iteration – selection • Manipulating computers • Level of abstraction differs – assembler, c, c++, java, c#, lisp, prolog, sql • Expressiveness varies