BCA IPU VB.NET UNIT-I

FEDT VB.NET
F R O N T E N D D E S I G N T O O L
U S I N G
V B . N E T
P R E S E N T A T I O N B Y :
A N K I T V E R M A
( I T D E P A R T M E N T )
A N K I T V E R M A A S S T . P R O F E S S O R
U N I T - 1

Which Book To Follow ?
 Book Bank
 Visual Basic 2010, Step By Step, Michael Halvorson
 Complete Syllabus
 C. Komalavalli, Sanjib K Sahu (Ane Books)
28-11-2014 ANKIT VERMA 2

Languages
 Procedural Language (C)
 Write Procedures
 Object Oriented Language (C++)
 Abstraction
 Polymorphism
 Encapsulation
 Inheritance
 Object Based Language (VB)
 Any three features of OOPS
 Pure Object Oriented Language (Java, .NET)
 OOPS + Classes
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System Hierarchy
 Levels In System Hierarchy

What Is FEDT?
 Front End Design Tool
 Front End
 HTML
 CSS
 Java Script
 .NET
 C# .NET
 ASP .NET
 J# .NET
 VB .NET
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 Back End
 Database
 Oracle
 SQL
 MS Access
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.NET Introduction

Introduction To .NET
 It is Platform Neutral Framework.
 It is layer between OS and Programming Language.
 It support many programming languages like
VB.NET, C#.NET, ASP.NET etc.
 .NET provides a common set of class libraries, which
can be accessed from any .NET base programming
language.

What Is .NET?
 Is .NET a Programming Language? NO
 Is .NET an Operating System? NO
“.NET is a framework”

Why .NET?
 Why Not Use VB?
 VB is very easy
 Not flexible to develop serious applications
 Programmers hate it because it is very easy
 Why Not Java?
 It does not have multi language support
 Slight tough as compared to .NET

Benefits Of .NET Framework
 Consistent Programming Model
 Consistent OOP model across various languages
 Connecting to database
 Retrieving data from database
 Reading text from file
 Writing text in a file
 Cross-platform Support
 Support CLR to run .NET application
 Interoperability between multiple Window OS

Benefits Of .NET Framework
 Language Interoperability
 Piece of code written in one language can be used in other
language.
 Facilitate reuse of code.
 Improves efficiency.
 Automatic Management Of Resources
 Use resources like file, memory, database connection etc.
 Automatically free resources when not in use.
 Ease Of Deployment
 Installation of new components not affect existing
applications.

Versions Of .NET Framework
 .NET Framework 1.0
 Released by Microsoft in February 13, 2002.
 Visual Studio .NET 2002
 Released in April 03, 2003.
 Visual Studio .NET 2003
 Built in support for ASP .NET, ODBC & Oracle Database
 Released in January 22, 2006.
 Visual Studio .NET 2005 & Microsoft SQL Server 2005
 New themes, skins, web controls, data controls in ASP .NET

 Released in November 21, 2006.
 Four new technologies
 Windows Presentation Foundation (WPF)
 Windows Communication Foundation (WCF)
 Windows Workflow Foundation(WF)
 Windows CardSpace (WCS)
 Released in November 19, 2007.
 Features like Language Integrated Query (LINQ), ASP .NET
AJAX, extension methods
 Visual Studio 2008

 Visual Studio 2010

Supported Applications
 Console Application
 Command line application
 Windows Forms
 GUI interface to user
 Web Forms
 Web pages
 Web Services
 Software components that perform task in distributed manner
 Reporting Application
 Windows user interface & report

Client - Server

Two Tier & Three Tier Client-Server Model
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 Two Tier Architecture
 Database (Data Tier)
 Client Application (Client Tier)
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Two Tier & Three Tier Client-Server Model
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 Three Tier Architecture
 Database Layer
 Business Layer
 Client Layer
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.NET Architecture

Components Of .NET Architecture
 Three Components:
 Common Language Runtime (CLR)
 Similar to JVM of Java
 Virtual machine component of framework
 .NET program is monitored by CLR
 Common Type System (CTS)
 Manage datatypes supported by various .NET programming
languages
 Provide language interoperability
 Framework Class Libraries (FCL)
 Similar to class libraries of Java
 Consists of various base classes used to support different services of
framework
28-11-2014 21
CLR CTS FCL
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1. CLR

Common Language Runtime (CLR)
 It is an agent used to execution & verification of code
 Manage services like
 Thread Management
 Memory Management
 Type Safety
 Exception Handling
 Load MSIL (Microsoft Intermediate Language) code
 MSIL code is similar to byte code of java
 MSIL code consists of instructions for loading, storing,
initializing & calling methods on objects
 MSIL code also known as common Intermediate Language

Common Language Runtime (CLR)
 JIT (Just In Time) compiler of CLR compiles code
into native Machine code for executing application
 CLR can execute code written in any language.
 CLR provide code access security & garbage collection
 CLR allows code created in one language can be
communicated in other language
 CRL support common type system, meta data &
common execution environment.
 Managed Code: targets the runtime
 Unmanaged Code: not target the runtime

CLR Architecture
Exception Manager
Security Checker
Type Checker
Class Loader
Debug Engine
Thread Support
Code Manager
Garbage Collector
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 Components Of CLR
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CLR Components
 Compiler & Class Loader
 Compiler compile source code into intermediate code.
 This code consists of MSIL & Meta Data
 These are contained in Portable Executable (PE) file
 Class Loader loads this data in runtime
 Code Manager
 Manage the code during execution
 Allocate memory to objects
 Exception Manager
 Handle exception in both managed & unmanaged code

CLR Components
 Security Checker
 Restricts access to system resources like
 Hard Disk
 MSIL Code
 Thread Support
 Support multithreading
 Debug Engine
 Find & remove the bugs from programs
 Type Checker
 Datatype checking of variable

CLR Components
 Garbage Collector
 Automatic garbage collection of object when object is no longer
in use
 Periodically check heap memory where objects get memory

2. CTS

Common Type System (CTS)
 Type refers to datatypes supported by programming
languages
 Provide common type system for all languages
 CTS support object oriented concepts
 So all types are objects
 Share common data type
 Language Integration
 Code of one language can be inherited by code in other language
 Better Performance
 Type Safety

 Two main types supported by framework
 Value Type
 Primitive or Built In Datatype
 Passed In Methods By Value Method
 Memory Allocated From Stack
 Reference Type
 Store Memory Address Of Variable Using Pointer
 Passed In Methods By Reference Method
 Stored In Heap

 Common Language Specification (CLS)
 CLS is subset of CTS
 As per standard, code written in a CLS must be compliant with
code written in another language.
 Describe guidelines for defining .NET language
 It compile code into Intermediate Language, so this code
executed by CLR.

3. FCL

Framework Class Libraries (FCL)
 Collection Of Reusable, Manageable Classes &
Interfaces
 Provide Support For System Services
 Act As Interface Between Application & Operating
System
 Hierarchical Structure
 Namespace
 Organization of class libraries according to their functionality
called namespace
 All classes of library are object oriented & can be
included in code of any .NET supported language

Class Libraries
 Integration Of 3rd Party Components
 Perform Different Tasks
 Database Connectivity
 String Handling
 I/O Functionality
 File Handling
 Library Split Into Two Parts:
 Basic Class Library (BCL)
 Framework Class Library (FCL)
 FCL is superset of BCL

Class Libraries
Windows Form:
Consists of classes related to design, components, passing messages to user etc.
Web Form (ASP .NET):
Consists of classes related to caching, security, authentication, configuration..
XML:
Consists of classes related to XSLT, XPath, XQuery, Serialization.
Database (ADO .NET):
Consists of classes related to connection, command, retrieving data into reader &
adapter, SQL types, executing procedures

Execution Process

Execution Process
Source Code
(VB .NET,
C#.NET)
Language
Compilers
IL
(EXE /
DLL)
28-11-2014 38
 Compiling .NET Application
 Compiler compiles code into intermediate language as per CLR
specification.
 Metadata is also gathered during compilation.
 All data contained in Assembly File, which can be .EXE or
.DLL
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Execution Process
 Executing The Application
Class
Libraries
Class
Loader
JIT
Compiler
Managed
Code
Output
CLR
(Execution)
(Run Time
Manager)
IL or MSIL
Code

Memory Management

Memory Management
 Resource Allocation
 Automatic memory management is one of the services that
CLR provides during execution.
 The Garbage Collector manages the allocation release of memory
for an application.
 The Microsoft .NET CLR requires that all resources be
allocated from the managed heap.
 Objects are automatically freed when they are no longer needed
by the application.

Memory Management
 Newly created objects are part of a Generation 0,
 The objects that survive a garbage collection are tagged as
Generation 1 and
 The Generation 1 objects that survive another collection are
Generation 2 objects.

Garbage Collection Process
 Every application has a set of roots. Roots identify storage
locations, which refer to objects on the managed heap or to
objects that are set to null.
 The list of active roots is maintained by JIT compiler
and CLR and is made accessible to the garbage
collector’s algorithm.
 When the garbage collector starts running, it makes the
assumption that all objects in the heap are garbage.

 Figure shows a heap with several
allocated objects where the
application’s roots refer directly
to the object A, C, D and F.
 All of these objects become part
of the graph. When adding object
D, the collector notices that this
object refers to object H and
object H is also added to the
graph.
 The collector continues to walk
through all reachable objects
recursively.


 Once this part of the graph is complete, the garbage collector
checks the next root and walks the object again.
 As the garbage collector walks from the object to object, iFit
attempts to add an object to the graph that it previously
added, then the garbage collector can stop walking down the
path.
 Once all the roots have been checked, the garbage collector’s
graph contains the set of all objects that are somehow
reachable from the application’s roots.

 The garbage collector now walks
through the heap linearly, looking
for contiguous block of garbage
objects.
 The garbage collector shifts the non
garbage object down in memory,
removing all the gaps in the heap.
 So, the garbage collection must
modify the application’s root, so that
the pointers point to the object’s
new location.
 In addition, if any object contains a
pointer to another object, the
garbage collector is responsible for
correcting these pointers as well.

 After all the collection has been identified, all the non
garbage has been compacted and all the non garbage pointers
have been fixed up, the next object is positioned just after the
last non garbage object.
 At this point, the new operator is tried again and the resource
requested by an application is successfully created.

Assemblies

Assemblies
 Assembly is a standard for components developed with .NET
 They are building blocks of .NET framework application.
 It is smallest unit of deployment.
 It consists of one or more files (dll, exe, html etc.)
 It is self describing unit & all programs constructed in .NET
are constructed in assemblies only.
 It consists of MSIL, metadata & resources (such as bitmap
that the application require for execution)
 Namespace are also stored in assemblies only. They are
playing important role in deployment & versioning.
 Assemblies can be .DLL or .EXE but they differ in their
content.

Assemblies
 Assembly Manifest
 Assembly consists of assembly
metadata called Assembly Manifest.
 Assembly has one entry point
 CRL does not actually work
with managed modules, it
works with assemblies.
 Assembly is logical grouping of
one or more managed module.
 Assembly is the smallest unit
of reuse, security & versioning.

Assemblies
 When you are using JIT compiler to compile your
code from managed code to active code, the JIT
compiler will look for IL code, that is stored in
portable executable file along with associated
manifest.
 Every time you build a web form or windows form in
.NET, you are building an assembly.
 Every one of these above applications will contain at
least one assembly.

Structure Of Assembly

Assembly Manifest
 The assembly manifest is where
the details of assembly are
stored.
 The assembly is stored within
the DLL or EXE itself.
 Assemblies can either be single
or multi files assemblies and
therefore assemblies manifest
can either be stored as
assembly or as a separate file.

Diagram

Type Metadata
 This metadata contains information on the types that
are exposed by the assembly such as security
permission information, class and interface
information and other assembly information.
 When an application is started in .NET, the
application will look for an assembly in the
installation folder.
 Assemblies that are stored in a local installation folder are
referred to as Private Assemblies.
 If application cannot find assembly in installation folder the
assembly will talk to Global Assembly Cache (GAC) for
an assembly.

Types Of Assemblies
 Static Assemblies
 Dynamic Assemblies
 Private Assemblies
 Public Assemblies or Shared Assemblies

Exception Handling

Exception Handling
 “An exception is error condition or any abnormal
condition or unexpected behavior in program and
disturbs the normal flow of instruction”
 .NET uses Structured Exception Handling.
 Exception Example:
 Arithmetic Exception
 OverFlow Exception
 NullReference Exception

Exception Handling Steps
 When exception is raised, exception object is thrown
to runtime system.
 Object contain
 Cause of exception
 Type of exception
 State of program when exception occurred
 It will handled by runtime & thus leads to abrupt
termination of program.

Need Of Exception Handling
 Handle Runtime Error like
 Unavailability of data
 Trying to access non-existent data
 Trying to update read-only data
 Conversion between data type might fail

Exception Handling Blocks
 Try…………….. Catch…………….. Finally
 Try
 Try Block contain anticipating code which may raise exception.
 Try keyword tell compiler that we want to handle area of
events.
 Catch
 Catch Block is handler to catch the exception.
 Catch block tells application what to do if an error occurs.
 Finally
 Finally Block is optional.
 Finally keyword will occur regardless if the Try-Catch worked
successfully or not.

Program Syntax
 Syntax:
 Try
 <statement>
 Catch Ex as Exception
 <statement>
 End Try

Program
 Program  Output

Code Access Security

Code Access Security (CAS)
 .NET framework has a built in security system called
as CAS.
 CAS enables administrator to control actions
performed by code.
 It is security mechanism through which we can place
the security constraints & controls on source code at
runtime.
 In .NET, security is achieved by CAS Model.
 In CAS Model, CLR checks permission of the code to
access a restricted resource, before granting access.

Security Policy
 Identifying the code that is granted permission to
run.
 Identifying the tasks that a code is allowed to
perform.
 Identifying the tasks that the users are permitted to
perform.
 Identifying the resources that the code can access.

CAS Supported Security Model
 CAS supports the security model by
 Evidence
 Evidence is type of information used to determine the type of rights
that code is granted.
 This information is useful for CLR.
 Security Policies
 When Assembly is loaded, CLR check security policy by running
Evidences.
 Security Policy can be defined in four levels:
 Enterprise
 User
 Machine
 Application

CAS Supported Security Model
 Permission
 Permissions are rights for accessing the particular operations
permitted by Security Policy.
 Present in class System.Security.Permissions namespace.
 Permission Sets
 Named collections of Permissions are known as Permission Sets.

CAS Functions
 Define Permission & Permission Sets that represents
the right to access various system resources.
 Enable code to request the permission set requires in
order to run, permission that would be useful to have
& specifies which permission the code must have.
 Grant permission to each assembly that is loaded,
based on permission requested by code & on the
operations permitted by security policy.
 Enable code to demand that its callers have specific
permissions or process digital signature, thus allow
specific callers to call the particular code.

CAS Benefits
 Restricts what your code can do.
 Restrict which code can call your code.
 Identify code.

THANKYOU
P R E S E N T A T I O N B Y :
A N K I T V E R M A
( I T D E P A R T M E N T )
DOUBTS
A N K I T V E R M A A S S T . P R O F E S S O R

BCA IPU VB.NET UNIT-I

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