VB .NET Revisit

1. VB .NET Revisit VB .NET Revisit

2. Software Development Life Cycle • Problem Definition • Requirement Analysis • Systems Design • Implementation • Testing & Debugging • Deployment • Maintenance VB .NET Revisit

3. VB .NET • .NET CLR-compliant language • Event-driven • Object Oriented • Visual Studio .NET • A Rapid Application Development (RAD) environment • An Integrated Development Environment (IDE) • Editor, Command Line Compiler VB .NET Revisit

4. Building HelloWorld with Visual Studio .NET VB .NET Revisit

5. Hello World - Console Imports System ‘ import System namespace Public Module Hello ‘ a Standard Module Public Sub Main() Console.WriteLine("Hello World!") End Sub End Module • A Console application • To compile (by command line compiler): • vbc HelloWorld.vb • To execute: • HelloWorld.exe VB .NET Revisit

6. Hello World - GUI Imports System ' import System namespace Imports System.Drawing Imports System.Windows.Forms Public Class HelloWindows Inherits Form ' inherits System.Windows.Forms.Form Private lblHelloWindows As Label Public Shared Sub Main() Application.Run(New HelloWindows()) End Sub Public Sub New() ' constructor lblHelloWindows = New Label() With lblHelloWindows .Location = New Point(37,31) .Size= New Size(392,64) .Font = New Font("Arial",36) .Text = "Hello, Windows!" .TabIndex = 0 .TextAlign = ContentAlignment.TopCenter End With Me.Text = "Visual Basic .NET" AutoScaleBaseSize = New Size(5, 13) FormBorderStyle = FormBorderStyle.FixedSingle ClientSize = New Size(466,127) Controls.Add(lblHelloWindows) End Sub End Class VB .NET Revisit

7. Hello World - GUI • A Windows Application • To compile: • vbc HelloWorld2.vb /reference:System.dll,System.Drawing.dll,System.Windows.Forms.dll /target:winexe • To execute: • HelloWorld2.exe VB .NET Revisit

8. Class Public Class Student ‘ a base class … End Class Public Class FtStudent Inherits Student … End Class Dim s1 As New Student() Dim s2 As New FtStudent() s1 = s2 VB .NET Revisit

9. Access Modifiers • Control the accessibility of types and types members (including fields, methods, etc.) • Control the accessibility of types and types members (including fields, methods, etc.) • Private: accessible only from within the context in which it is declared • Protected: from within the program in which it is defined and the derived classes • Public: publicly accessible Public Class SomeClass Public Sub DoSomething() End Sub Private Sub InternalHelperSub() End Sub End Class VB .NET Revisit

10. Fundamental Types • Boolean • Byte • Short • Integer • Long • Decimal • Single • Double • Char • String • Date • Object VB .NET Revisit

11. Variables, Literals • Dim bFlag As Boolean = False • Dim datToday As Date = #01/01/2005# • Dim iValue As Integer • Dim lValue As Long • Dim shValue As Short = 128 • Dim sngValue As Single • Dim dblValue As Double • Dim MyString As String VB .NET Revisit

12. Type Conversion • Implicit Type Conversion: • Char -> String • Byte -> Short -> Integer -> Long -> Decimal -> Single -> Double • Explicit Type Conversion (Casting): • CByte() • CShort() • CInt() • CLng() • CDec() • CSng() • CDbl() • CBool() • CChar() • CStr() • CDate() VB .NET Revisit

13. Assignment Statements Dim a, b As SomeClass a = New SomeClass() a.MyPublicMember = “value in a” b = a b = New SomeClass() VB .NET Revisit

14. Operators • +, -, *, / • \ (integer division) • Mod (modulo), 9 Mod 2 • ^ (exponentiation), X^2 • =, <>, <, <=, >, >=, AND, OR, NOT, XOR • TypeOf …Is, TypeOf(x) Is String • Is, s1 Is s2 • Like, s1 Like "a*“ VB .NET Revisit

15. Basic I/O Module Module1 Sub Main() Dim n As Integer Dim s As String Console.Out.WriteLine("HelloWorld! What's your name?") s = Console.In.ReadLine() ‘ read in a string Console.Out.WriteLine("How old are you?") n = Console.In.ReadLine() ‘ read in a number Console.Out.WriteLine("Hi " + s + ", you're " + CStr(n) + " already.") ‘ or Console.Out.WriteLine("Hi {0}, you're {1} already.", s, n) Console.In.ReadLine() ‘ wait to press Enter End Sub End Module VB .NET Revisit

16. Branching Statements (1) • Call SomeMethod() or • SomeMethod() • Exit Do, Exit For, Exit Function, Exit Sub, Exit Try If A = B Then statements End If If A = B Then statements Else statements End If If A = B Then statements ElseIf expression Then statements Else statements End If VB .NET Revisit

17. Branching Statements (2) Select Case strColor Case “red” … Case “green”, “blue” … Case Else … End Select VB .NET Revisit

18. Loop Do While I < 10 … Loop Do … Loop Until I >= 10 For i = 0 to 4 Step 2 Console.WriteLine(i) Next For Each i in iArrary ‘ iArrary is an array … Next For Each obj In col ‘ col is a collection Console.WriteLine(obj.ToString()) Next VB .NET Revisit

19. Array Dim a(4) As Integer For i = 0 to 4 Console.WriteLine(a(i)) Next Dim a() As Integer a = New Integer(2) {} a(0) = 1 a(1) = 2 Dim a() As String = {“First”, “Second”, “Third”} Dim a(5,10) As Integer VB .NET Revisit

20. Enumeration Module Module1 Enum CardSuit clubs = 0 diamonds = 1 hearts = 2 spades = 3 End Enum Sub Main() Dim cs As CardSuit = CardSuit.hearts System.Console.Out.WriteLine("The value cs is {0}", cs) End Sub End Module VB .NET Revisit

21. Structure Module Module1 Structure PixelCoord Public x As Single Public y As Single End Structure Sub Main() Dim p As PixelCoord p.x = 200 p.y = 100 System.Console.Out.WriteLine("The value p.x is {0}", p.x) System.Console.Out.WriteLine("The value p.y is {0}", p.y) End Sub End Module VB .NET Revisit

22. Collection Dim col As New Collection() col.Add(“First item”) col.Add(“Second item”) col.Add(“Third item”) Dim obj As Object For Each obj In col Console.WriteLine(CType(obj, String)) Next Dim i As Integer For i = 1 to col.Count Console.WriteLine(CType(col(i), String)) Next VB .NET Revisit

23. Sub & Function Sub CheckInput() … End Sub Function Square(ByVal i as Integer) As Integer … Return x End Function VB .NET Revisit