program 23: interface

program to demonstrate concept of interface.

-----------------------------------------code---------------------------------------------------------

Imports System.Console

Module Module1

    Sub Main()

        Dim obj1 As New one

        Dim obj2 As New two

        obj1.disp()

        obj1.multiply()

        obj2.disp()

        obj2.multiply()

        ReadKey()

    End Sub

End Module

Public Interface test

    Sub disp()

    Function multiply() As Double

End Interface

Public Class one

    Implements test

    Public i As Double = 12

    Public j As Double = 12.17

    Public Sub disp() Implements test.disp

        WriteLine("sum=" & i + j)

    End Sub

    Public Function multiply() As Double Implements test.multiply

        WriteLine("muliplication=" & i * j)

    End Function

End Class

Public Class two

    Implements test

    Public a As Double = 20

    Public b As Double = 32.17

    Public Sub disp() Implements test.disp

        WriteLine("Welcome to interface")

    End Sub

    Public Function multiply() As Double Implements test.multiply

        WriteLine("multiplication=" & a * b)

    End Function

End Class
-----------------------------------------output----------------------------------------------------

codestrew

program 22: abstract class

 program to demonstrate concept of abstract and not inheritable class.

-----------------------------------------code---------------------------------------------------------

Imports System.Console

Module Module1

    Public MustInherit Class abstractclass

        Public MustOverride Function add() As Integer

        Public MustOverride Function mul() As Integer

    End Class

    Public Class abstractone

        Inherits abstractclass

        Dim i As Integer = 20

        Dim j As Integer = 30

        Public Overrides Function add() As Integer

            Return i + j

        End Function

        Public Overrides Function mul() As Integer

            Return i * j

        End Function

    End Class

    Sub Main()

        Dim a As New abstractone

        WriteLine("sum is:" & a.add())

        WriteLine("multiplication is:" & a.mul())

        ReadKey()

    End Sub

End Module
-----------------------------------------output----------------------------------------------------

codestrew

program 21: base class construction

program to demonstrate concept of base class construction.

-----------------------------------------code---------------------------------------------------------

Imports System.Console

Module Module1

    Sub Main()

        Dim w As New window(10, 5)

        w.drawwindow()

        Dim lb As New listbox(20, 30, "hello..!!")

        lb.drawwindow()

        Console.ReadKey()

    End Sub

End Module

Public Class window

    Private top As Integer

    Private left As Integer

    Public Sub New(ByVal top As Integer, ByVal left As Integer)

        Me.top = top

        Me.left = left

    End Sub

    Public Sub drawwindow()

        WriteLine("Drawing window at {0},{1}", top, left)

    End Sub

End Class

Public Class listbox

    Inherits window

    Public Sub New(ByVal top As Integer, ByVal left As Integer, ByVal tcontent As String)

        MyBase.New(top, left)

        mlstboxcontent = tcontent

    End Sub

    Public Shadows Sub drawwindow()

        Console.WriteLine("..........")

        MyBase.drawwindow()

        Console.WriteLine("Writing string to the listbox:{0}", mlstboxcontent)

    End Sub

    Private mlstboxcontent As String

End Class
-----------------------------------------output----------------------------------------------------

codestrew

program 20: inheritance

program to demonstrate concept of inheritance.

-----------------------------------------code---------------------------------------------------------

Module Module1

    Class A

        Public Sub Show()

            Console.WriteLine("Calling from A")

        End Sub

    End Class

    Class B

        Inherits A

        Public Shadows Sub Show()

            Console.WriteLine("Calling from B")

        End Sub

    End Class

    Class C

        Inherits B

        Public Shadows Sub Show()

            Console.WriteLine("Calling from C")

        End Sub

    End Class

    Public Sub Main()

        Dim x As New A

        x.Show()

        x.Show()

        x.Show()

        Dim y As New B

        y.Show()

        Dim p1 As New C

        p1.Show()

        Console.ReadKey()

    End Sub

End Module
-----------------------------------------output----------------------------------------------------

codestrew

program 19: get & set method

program to change height and width of image using get () and set () property.

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Public Class Class1

    Public hei, wid As Integer

    Public Property height() As Integer

        Get

            Return hei

        End Get

        Set(ByVal value As Integer)

            hei = value

        End Set

    End Property

    Public Property width() As Integer

        Get

            Return wid

        End Get

        Set(ByVal value As Integer)

            wid = value

        End Set

    End Property

End Class

Public Class Form1

    Dim b, c As Integer

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim a As New Class1

        a.height = Val(TextBox1.Text)

        a.width = Val(TextBox2.Text)

        b = a.height

        c = a.width

        PictureBox1.Height = b

        PictureBox1.Width = c

    End Sub

End Class
Sonata Ocean Analog Watch - For Men(Black)
-----------------------------------------output----------------------------------------------------

codestrew

program 18: lowercase to uppercase

program to demonstrate concept of simple class to convert lowercase text to uppercase.

-----------------------------------------code---------------------------------------------------------

Public Class Form1

    Public Class convertpostcode

        Public Function doconvert(ByVal postcode As String) As String

            Dim convertpostcode As String

            convertpostcode = StrConv(postcode, VbStrConv.Uppercase)

            doconvert = convertpostcode

        End Function

    End Class

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim newcode As String

        Dim obj As New convertpostcode

        newcode = obj.doconvert(TextBox1.Text)

        TextBox2.Text = newcode

    End Sub

End Class

End Module
-----------------------------------------output----------------------------------------------------

codestrew

program 17: exception handling (console)

program to demonstrate the concept of exception handling

-----------------------------------------code---------------------------------------------------------

Imports System

Module module1

    Sub main()

        Dim x As Integer = 0

        Dim div As Integer

        Try

            div = 100 / x

            Console.WriteLine("Exception not occured")

        Catch ex As DivideByZeroException

            Console.WriteLine("Exception occured")

       

        Finally

            Console.WriteLine("Finally blocked")

        End Try

        Console.WriteLine("Result is {0}", div)

        Console.ReadKey()

    End Sub

End Module
-----------------------------------------output----------------------------------------------------

  

codestrew

program 16: Enumeration

program to demonstrate Enumeration concept using enum keyword.

-----------------------------------------code---------------------------------------------------------

Imports System

Public Class Form1

    Enum day

        sunday = 1

        monday = 2

        tuesday = 3

        wednesday = 4

        thursday = 5

        friday = 6

        saturday = 7

    End Enum

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Select Case TextBox1.Text

            Case 1

                MsgBox("sunday is " & day.sunday & " day")

            Case 2

                MsgBox("monday is " & day.monday & " day")

            Case 3

                MsgBox("tuesday is " & day.tuesday & " day")

            Case 4

                MsgBox("wednesday is " & day.wednesday & " day")

            Case 5

                MsgBox("thursday is " & day.thursday & " day")

            Case 6

                MsgBox("friday is " & day.friday & " day")

            Case 7

                MsgBox("saturday is " & day.saturday & " day")

            Case Else

                MsgBox("invalid number", , "message")

                TextBox1.Text = ""

        End Select

        TextBox1.Text = ""

    End Sub

End Class
-----------------------------------------output----------------------------------------------------

codestrew

codestrew