A brief introduction to Csharp

• Provide enough information to allow you to follow the code samples • Highlight key differences with Java • Tell you where you can get the compilers • Tell you where to go for more det

A Brief Introduction to C#

David Buksbaum

• Provide enough information to allow you to

follow the code samples

• Highlight key differences with Java

• Tell you where you can get the compilers

• Tell you where to go for more details on C#

• Tell you where to go for more detailed

comparisons with Java

• Not to debate which is better, more important,

faster, slower, or looks better in emacs

Quick Glossary

• BCL – Base Class Library

• CLR – Common Language Runtime

• GUI – Graphic User Interface

• MSIL – Microsoft Intermediate Language

• MS – Microsoft

• SCM – Service Control Manager

• SOA – Service Oriented Architecture

• NET is:

• Microsoft’s Platform for Windows Development

• CLR – the Virtual Machine that runs MSIL aka MS

Byte Code

• BCL aka NET Framework

• A set of compilers that can generate MSIL C#,

Visual Basic, C++, Java (the MS flavor)

• There are 50+ languages that generate MSIL

• http://www.dotnetpowered.com/languages.aspx

• Most interoperate with each other

A Sample C# Application

Application Types

• Console Application

• Has standard streams (out, in, err)

• GUI can be added manually

• Windows Application

• GUI based

• No standard streams (out, in, err)

• Main thread is shared by the GUI message pump & your

code

• Service

• No standard streams (out, in, err)

• Main thread is commandeered by the SCM

• No GUI

Compiler Options from MS

• SDK contains the command line compiler

(C:\WINDOWS\Microsoft.NET\Framework\

{version}\csc.exe)

• {version} looks like v2.0.50727

• Express Edition – Free IDE to work with Visual

C#

• Reduced runctionality version of Visual Studio

• Visual Studio – The full development system

• Optimizations, Data Access, Multi-Language, etc

• $$$

Options Beyond MS

• Mono

• Open source development SDK for NET

• Windows, Linux, Mac OS X, Solaris, Unix

Quick Comparison to Java

• What’s the same

What’s Different & Relevant

What’s Different & Relevant – cont.

• using newtypename = namespace.type;

• Directory structure != namespace hierarchy (as in

C++)

What’s Different & Relevant – cont.

• Properties

• get, set and get/set

• public string MyProperty { get { return(_text); } set { _text =

• CompareHandler ch = new CompareHandler(myMethod);

• bool retval = ch(obj1, obj2);

What’s Different & Relevant – cont.

• Enumerations

• public enum Protocol { UDP, TCP };

• public enum Direction { Up = 0, Down = 1, Left = 2,

What’s Different & Relevant – cont.

• Value Types

• Primitives are the same plus

• Unsigned values

• ubyte, ushort, uint, ulong

• Careful : byte in java is sbyte in C#

• Class objects to wrap primitives

• Int32 x = new Int32(4);

• int x = Int32.Parse(“4”);

What’s Different & Relevant – cont.

• Conversion between value type and reference type

• packet p = new packet();

• object o = (object)p; // boxed

• packet p2 = (packet)o; // unboxed

What’s Different & Relevant – cont.

• Cross Platform Support

• NET from Microsoft is not cross platform

• It is for Windows only

• Mono can run cross platform, but is unproven in

large production environments

• MS is currently resisting moving cross platform

• The future is not set

What’s not Relevant, but Useful

• App Domains

• One or more per process

• Represents a VM hosted logical process

• Communications between App Domains requires

marshalling (IPC)

• Assemblies

• Similar to Java JAR files

• Physically they are EXE and/or DLL files

What’s not Relevant, but Useful

• Attributes

• Meta tags that provide run time information for a

type, NOT the instance

• Example: [Serializable] public class foo { int x; };

• [Serializable] is converted into the class

SerializableAttribute

• Attributes can be retrieved at run time

• Many framework sub-systems use attributes

• Serialization, XML, Interop, Conditional, Obsolete, etc…

What’s not Relevant, but Useful

• Polymorphism

• Methods default to being non-virtual

• To be virtual it must be defined as virtual

• eg: public virtual int Add(int x, int y);

• To override a virtual method, you use the override

keyword

• eg public override int Add(int x, int y);

• Methods not marked virtual are equivalent to Java

final methods

• Methods can be marked with new to break the

What’s not Relevant, but Useful

• Interop

• Access to native code through attributes

• [DllImport(“user32.dll”)] static int

GetSystemMetrics(int);

• The DllImport attribute informs the compiler and

runtime that the tagged method is inside a native

DLL.

• Options such as the actual name in the DLL,

marshalling strategies, calling convention, and more can be set using the attribute

What’s not Relevant, but Useful

• NET 2.0 – out now

• Its all about data

• Tuples & Query constructs

• Network information classes providing statistics, interface

information, and ping

Future of NET Networking

• Windows Communications Foundation

• Formally code named Indigo

• Designed to make SOA an integral part of Windows

• Tight coupling with NET designs

• For more information

• http://msdn.microsoft.com/windowsvista/default.aspx?

pull=/library/en-us/dnlong/html/wcfarch.asp

References

• MS Visual Studio C# Express Edition

• http://msdn.microsoft.com/vstudio/express/visualcsharp/

• MS Visual Studio

• http://msdn.microsoft.com/vstudio/

• Programming C#, Fourth Edition by Jesse

Liberty

(http://search.barnesandnoble.com/booksearch/ isbnInquiry.asp?z=y&isbn=0596006993&itm=2)

• CLR Via C#: Applied Microsoft Net Framework

2.0 Programming by Jeffrey Richter

(http://search.barnesandnoble.com/booksearch/ isbnInquiry.asp?z=y&isbn=0735621632&itm=3 )