Transcript Overview of Microsoft.Net and Vb.Net

Overview of Microsoft.Net
and Vb.Net
ITSE 2349
Spring 2002
Material from Microsoft.Net an Overview for ACC faculty by Stuart
Laughton and Introduction to VB using .Net by Wyatt and Oberg
What is .NET?

What is .NET? (according to some people)
– Microsoft’s version of Java
 What is .NET? (according to Microsoft)
– Microsoft’s platform for XML Web services
– Web Service = software component for the Web
– People use web sites; Programs use Web
Services

What is .NET? (for ACC students)
– Software skills that are in demand
Languages and CLR

Compile to intermediate language (MSILMicrosoft Intermediate Language)

MSIL is JIT (just in time) compiled to native
code and run by the Common Language
Runtime(CLR)

MSIL is designed to support different
languages
.Net Languages

Microsoft ships several languages:
– C#
– VB.NET
– C++
– J#

a new Java like language
looks like VB
managed extensions
Java syntax
3rd party
– COBOL, FORTRAN, LISP
.NET Languages
C#
Source
VB
Source File
Other .NET
Language
Compile
MSIL
Machine independent
JIT Compile
Native Code
Machine Specific
.NET Framework
C#
VB.NET
C++
Other
Common Language Specification
.Net Framework Class Library
Common Language Runtime
Visual
Studio.Net
.NET Framework Overview

Common Language Runtime
– Provides services to executing programs
– Traditionally different environments have different
runtimes. (standard c library, VB runtime)
– The CLR manages execution of code and provides
useful services
– Services are exposed through the programming
languages
– Syntax varies from language to language, but
underlying engine is the same
– Not all languages expose all the features of the CLR
– C# does the best job, but VB.NET does pretty well
.NET Framework Overview

.Net Framework Class Library
– Huge, more than 2500 classes
– All this functionality is built into the .NET
languages
– 4 Main Parts
•
•
•
•
Base class library (networking, I/O, diagnostics, etc.)
Data and XML classes
Windows UI
Web services and Web UI
.NET Framework Overview

Common Language Specification
– Important goal of .NET is to support multiple
languages.
– CLS is an agreement among language designers
and class library designers about what common
subset of features can be relied upon
– Example – do not rely on case for uniqueness for
names – because some languages are not case
sensitive
.NET Framework Overview

Languages in .Net
– Language is basically a lifestyle choice
– Same built in data types are used in all the
languages
– Classes written in one language can be
used in another language
– A class written in one language can inherit
from a class written in another language
MSIL (Microsoft Intermediate Language)

All VB.Net code is compiled to MSIL
– Machine independent
– MSIL is JIT compiled to native code then executed

Metadata
– Detailed info about each code module
•
•
•
•
Version information
All the types
Details of each type
Details about properties and methods of each type
– MSIL and metadata are packaged together
– Metadata enables ‘intellisense’ and enables types
to be converted transparently
Visual Studio.NET

Visual Studio is now one IDE for all the
languages
 When you start, you pick a profile (example,
Visual Basic Developer Profile)
 This arranges the windows and sets up the
environment so it looks like VB
 Most of the VB debugging tools are there
(but, not the immediate window)
Some of the Changes to VB

All VB source files now have extension.vb
 No variant type
 Parentheses always required on all
subroutine calls
 Values returned from functions by using
return keyword
Function CalculatePay(ByVal payRate as Single, hrsWorked as Single) as
Single
Dim grossPay as Single
grossPay = hrsWorked * payRate
Return grossPay
End Function
Some of the Changes to VB
Passing byVal is now the default
 Lower bound of arrays is always 0
 Exception handling

Try
code that might cause error
Catch e as Exception
code to handle error
End Try
Some Changes to OOP in
VB.NET

Objects and classes are more central to .Net
programming
 .Net makes vb into a real OO language
 .Net adds Inheritance to VB
 Shared Members
– A value or procedure associated with all instances
of a class

Set is not needed for instantiation
– myAcct = New BankAccount()
Some Changes to OOP in
VB.NET

Syntax for Properties is different
Private m_Name as String
Public Property Name() as String
Get
Return m_name
End Get
Set(ByVal Value a String)
m_name = Value
End Set
End Property
Some Changes to OOP in
VB.NET

Constructors
– Class_Initialize no longer exists
– A class constructor called New
Public Sub New()
m_acctNo = 0
m_name = “”
m_balance = 0
End Sub
Database Access ADO.NET

Why ADO.NET?
– Web applications have a more loosely
coupled structure
– Many web apps use XML to encode data
that is passed over a network.
– After the data has been extracted and
encoded, the connection can be closed
– ADO.NET facilitates these kind of
disconnected scenarios
Database Access ADO.NET

DataSet object
– Holds in memory a representation of data that was
retrieved
– In XML
– Can hold information from multiple tables
– Also holds information about relationships and
constraints (an in memory database)

Connection object used for connection
oriented applications
 DataAdapter object used for disconnected
applications
ADO.NET Architecture
Application
Disconnected Access
Connected
Access
.NET Data Provider
(connection)
Database
DataSet
XML Data
Disconnected Access
Class Application
MSIL
Internal Format
Table 1
Internal Format
Class DataSet
MSIL
DOM
Data Set
XML
Table 1
Table 2
Table 1
Internal Format
Table 3
Object Model of DataSet
DataSet
Relationships
Collection
Tables
Collection
Relation
Table
Constraints
Collection
Constraint
Primary
Key
Columns
Collection
Rows
Collection
Data
Column
Data Row
Main Challenges for VB
Developers
Learning how to use the classes in the
.Net Framework Class Library
effectively
 Learning to use inheritance effectively
 Visual Studio Changes?
 Learning the ADO.Net architecture
