1. Introduction to .NET Framework
Po Feng, Tsai

2. How a program is composed and executed
Written by you but executed by a machine (computer)
For programmers
C,C++,Fortran,Basic
For machines
Architecture dependent instruction set (in binary forms)
Translation is required

3. How a program is composed and executed
Source Codes
Compiler
Assembler
Object Codes
Linker
Loader
Assembly Codes
Hardware Architecture

4. Problems for a programmer
Platform dependent
Windows ? Linux ?
Architecture dependent
X86 ? ARM? PPC?
Interfacing with each others
An isolated virtual framework layer

5. The .NET Framework
To provide a convenient and united development and execution environment
C#, VB.NET, C++.NET & Jscript.NET
CLR (Common Language Runtime)
FCL (framework class library)
Languages integration
CTS (Common Type System)
CLS (Common Language Specification)
CLR

6. The .NET Framework Framework class library
Lower level: (Base class library)
Core data type (integer, string, float, object)
Fundamental constructs (collection, I/O …)
Access to resources (Networking, file system…)
Interface to core execution (Threading, debugging …)
Upper level:
SQL
ADO.NET
XML
Web services

7. The .NET Framework

8. Compilation
Source codes are compiled into MSIL (MS Intermediate Language) for the first step
Metadata is used to keep the content information, such as parameters, methods, of the file

9. Execution CLR is the execution engine of .NET framework application
Virtual machine
It manages the following services
Code management
Memory management
Conversion IL into native code
Exception handling
Debugging

10. Compilation & Execution

11. JIT (Just In Time)
Very popular technique used in various virtual machines
Machine codes are generated
Fast
Compiles as needed

12. Introduction to C#
Po Feng, Tsai

13. Getting started Visual C# 2005 Express
System Requirements:
Processor Minimum: 600 megahertz (MHz) Pentium processor Recommended: 1 gigahertz (GHz) Pentium processor
RAM Minimum: 192 megabytes (MB) Recommended: 256 MB
Hard Disk: Up to 1.3 GB of available space may be required

14. About C# C# is announced in July 2000
C# includes the support for structured, component-based, object-oriented programming
Very easy to use
Modern programming

15. Example 1: HelloWorld
In the console window:
Hello World

16. The Class
A type defines a thing including its properties and behaviors
A class is used to define a new type
Blueprints

17. The Method Behaviors are defined by methods
A method is a function owned by your class
Defines what you can do or how it behaves
Usually you can tell what it is for from its name
WriteLine()

18. The Method Declare a method The program entry function Keyword: void
Main()
The program ends when Main() exits

19. The comments You can add your own comments by // /* ……… */
/// (used by Visual Studio)

20. Namespace
Tremendous number of types of the .NET Framework Class Library
Each class in C# must have a unique name
Name collision
Example (two engineers)
Jim: Science.software.engineer
Charlotte: transportation.train.engineer
System.Console.WriteLine();
Keyword: using
using System;
using System.Console; (does not compile !)

21. Console object This is a console program
No GUIs
Monitor is managed by an Console object
It has many behaviors (methods)
WriteLine()
Write()
Console.WriteLine()

22. The Dot operator ( . )
You can use the dot operator to access a method (or data) of a class or object
You can use the dot operator to specify the sub-namespace
Please keep in mind:
C# is case-sensitive

23. The static keyword
It is used to indicate that you can invoke Main() without first creating an object of type HelloWorld
This issue will be covered in later sections

24. Developing the HelloWorld
Console mode (start  cmd)
Need .NET Framework SDK
csc HelloWorld
Use Visual Studio .NET (Integrated Development Environment)

25. Using VS .NET
File  New  Project
Select “Console Application”

26. Using VS .NET

27. Compile & Run Compile Run Build  Build Solution Ctrl+shift+B
Debug  Start Without Debugging
F5 (debug) or Ctrl-F5

28. HelloWorld.exe Contains op-codes written in MSIL Read-only segment
Inserted with standard win32 executable header
Jumps to the JIT compiler
JIT compiler
Generating native instructions (like a normal exe file)