Download - NET Framework & C#
.NET Framework&C#
.NET FrameworkProblem backgroundSolutionCommon Language Runtime (CLR)
MS Intermediate LanguageMSIL StructureMSIL and Java bytecode
Introduction to C# languageC# StructureC# Features
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)
Solution (Common Language Runtime) Managed Code in Common Language Runtime
Requests for existing feature New CLR-Only Feature
Common Language Runtime
Managed Code
Win 32 OS
Solution (Microsoft Intermediate Language)Different Languages are Compiled into MSIL
Source code :Any languages
MS IntermediateLanguage
Platform specificcode
Development tools
Just-In-Time
compiler
.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
Costs:
OS got harder to write More memory and CPU time
CLR structure
Compare with traditional waysC# VB C++ J-script other
Compiler
Intermediate Language
JIT econoJIT PreJIT
Executables
.NET CLR
Compiler
C++
Executable
Existing OS
Machine hardware
A simple example
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 StringIf (ShowSeconds = True) Then
Return Now.ToLongTimeString Else Return Now.ToShortTimeString End If End Function End ClassEnd Namespace
TimeComponent.vb
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)) ; }}
Timeclient.cs
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
Metadata
What classes and method it contains What external objects it requires What version of code it represents
Manifest example (TimeComponent.dll).assembly extern mscorlib{ .publickeytoken = (B7 7A 5C 56 19 34 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 0x00008004 .ver 0:0:0:0}.module TimeComponent.dll// MVID: {144ACC38-E825-45C4-83A6-C2A9E5A901DD}.imagebase 0x00400000.subsystem 0x00000002.file alignment 512.corflags 0x00000001// Image base: 0x032a0000
Private or Public
Private
In client directory Public (shared)
In Global Assembly Cache (GAC)
\\winnt\assembly
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
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
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
All .NET classes inherit from the base class System.Object Equals GetHashCode GetType ToString
Cross-language inheritance
Because of the standardized IL architecture
you can inherit form a class in another
language
For example:
System.Object
.NET memory management
.NET CLR provides all languages with automatic memory management.
Garbage collector automatically removesunreferenced objects
You can force a garbage collection manually
Interoperability with COM objects
.NET Supports interoperation with COM object as client or server via a runtime callable wrapper or a COM Callable Wrapper
Using COM objects from .NET objects
Using .NET objects from COM objects
Transaction in .NET
Transaction ensure the integrity of databases during complex operations
Native .NET objects can also participate in transactions with a simple attribute
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
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\