1. .NET Framework & C#

2. MS Intermediate Language
.NET Framework
Problem background
Solution
Common Language Runtime (CLR)
MS Intermediate Language
MSIL Structure
MSIL and Java bytecode
Introduction to C# language
C# Structure
C# Features

3. Problems Background Good code is hard to write
All system features in any language
COM problems
Platform Interoperability
Automatic memory management
Object-Oriented features in and between all PLs
Safety & Security
Better Access to OS functions
Interoperate with COM (both as client & server)

4. Requests for existing feature
Solution (Common Language Runtime) Managed Code in Common Language Runtime
Managed Code
Common Language Runtime
Requests for existing feature
New CLR-Only Feature
Win 32 OS

5. Solution (Microsoft Intermediate Language) Different Languages are Compiled into MSIL
Just-In-Time
compiler
Development tools
Source code :
Any languages
MS Intermediate
Language
Platform specific
code

6. .Net platform features Automatic memory management Explicit Versioning
OO features in any languages
Accessing system functionality throw a hierarchical namespace
Code security
Interoperability with COM

7. Costs:
OS got harder to write
More memory and CPU time

8. CLR structure

9. Compare with traditional ways
C# VB C++ J-script other
Compiler
C++
Intermediate Language
Compiler
JIT econoJIT PreJIT
Executable
Executables
Existing OS
.NET CLR
Machine hardware

10. A simple example

11. TimeComponent.vb Imports Microsoft.VisualBasic
' Declare the namespace that clients will use to access
' the classes in this component
Namespace TimeComponentNS
Public Class TimeComponent
Public Function GetTime(ByVal ShowSeconds As Boolean) As String
If (ShowSeconds = True) Then
Return Now.ToLongTimeString
Else
Return Now.ToShortTimeString
End If
End Function
End Class
End Namespace

12. // Import the namespaces that this program uses, thereby allowing
// us to use the short names of the functions inside them.
using System ;
using TimeComponentNS ;
class MainApp {
// The static method "Main" is an application's entry point
public static void Main()
// Declare and create a new component of the class
// provided by the VB server we wrote
TimeComponent tc = new TimeComponent ( ) ;
// Call the server's GetTime method. Write its
// resulting string to a console window.
Console.Write (tc.GetTime (true)) ; }
Timeclient.cs
using System ;
using TimeComponentNS ;
class MainApp {
public static void Main()
// Declare and create a new component of the class
// provided by the VB server we wrote
TimeComponent tc = new TimeComponent ( ) ;
// Call the server's GetTime method. Write its
// resulting string to a console window.
Console.Write (tc.GetTime (true)) ; }

13. Assembly
A logical collection of one or more exe and dll file containing an application’s code and resources
It contains
1-Codes in MSIL
2-Manifest
A metadata description of the code and resources

14. Metadata What classes and method it contains
What external objects it requires
What version of code it represents

15. Manifest example (TimeComponent.dll)
.assembly extern mscorlib {
.publickeytoken = (B7 7A 5C E0 89 ) // .z\V.4..
.ver 1:0:2411:0 }
.assembly extern Microsoft.VisualBasic
.publickeytoken = (B0 3F 5F 7F 11 D5 0A 3A ) // .?_....:
.ver 7:0:0:0
.assembly TimeComponent
.hash algorithm 0x
.ver 0:0:0:0
.module TimeComponent.dll
// MVID: {144ACC38-E825-45C4-83A6-C2A9E5A901DD}
.imagebase 0x
.subsystem 0x
.file alignment 512
.corflags 0x
// Image base: 0x032a0000

16. Private or Public Private In client directory Public (shared)
In Global Assembly Cache (GAC)
\\winnt\assembly

17. Namespaces A logical division within which a name need to be unique
The best way to handle a large list of system objects and functions
System namespace (implemented in several separated DLLs
We can import a namespace
Your code can have its own namespace

18. Versioning
DLL Hell
Replacing a DLL used by an existing client, with a newer version (or vice versa)
.NET provides a standard way to specify
version
Each client assembly uses its own specified versions of related assemblies

19. Object oriented programming
Whether to smarten up non-object oriented languages or dump down OO languages
.NET provides all languages with inheritance and constructors features
Virtual Object Model

20. All .NET classes inherit from the base class System.Object
Equals
GetHashCode
GetType
ToString

21. Cross-language inheritance
Because of the standardized IL architecture
you can inherit form a class in another
language
For example:
System.Object

22. .NET memory management
.NET CLR provides all languages with automatic memory management.
Garbage collector automatically removes
unreferenced objects
You can force a garbage collection manually

23. Interoperability with COM objects
.NET Supports interoperation with COM object as client or server via a runtime callable wrapper or a COM Callable Wrapper

24. Using COM objects from .NET objects

25. Using .NET objects from COM objects

26. Transaction in .NET
Transaction ensure the integrity of databases during complex operations
Native .NET objects can also participate in transactions with a simple attribute

27. Structured exception handling
.NET provides structured exception handling as a fundamental feature available in and between all languages
The exception handler can tell exactly where the exception originated by using a stack trace

28. Code access security Most software comes from web
A user doesn’t know whether a Web code is safe or not
.NET allows an administrator to specify privileges that each managed code has.
You can specify these privileges in three level
by modifying XML-based files
Enterprise
Machine
User
\\winnt\microsoft.net\framework\[c.v.]\config\