' Visual Basic 2008 9.0 .NET Examples - Collections - Introduction - Object Oriented Programming : 
Class Person
    Private m_Name As String
    Public Property Name() As String
        Get
            Name = m_Name
        End Get
        Set(ByVal value As String)
            m_Name = value
        End Set
    End Property
End Class
Module Client1
    Dim persons As Person()
    Dim personsCount As Integer
    Sub Main()
        Dim person1 As Person = New Person
        person1.Name = "John"
        '
        Dim person2 As Person = New Person
        person2.Name = "Jane"
        '
        Console.WriteLine(personsCount)
        '
        AddPerson(person1)
        AddPerson(person2)
        '
        Console.WriteLine(personsCount)
        '
        Console.WriteLine(persons(1).Name)
        '
        Console.ReadLine()
    End Sub
    Sub AddPerson(ByVal item As Person)
        ReDim Preserve persons(personsCount)
        persons(personsCount) = item
        personsCount += 1
    End Sub
End Module
Class Persons
    Private m_Items As Person()
    Default Public ReadOnly Property Item(ByVal index As Integer) As Person
        Get                                                                ' (1)
            Item = m_Items(index)
        End Get
    End Property
    Private m_Count As Integer
    Public ReadOnly Property Count() As Integer
        Get
            Count = m_Count
        End Get
    End Property
    Public Sub Add(ByVal item As Person)
        ReDim Preserve m_Items(Count)
        m_Items(Count) = item
        m_Count += 1
    End Sub
End Class
Module Client2
    Sub Main()
        Dim person1 As Person = New Person
        person1.Name = "John"
        '
        Dim person2 As Person = New Person
        person2.Name = "Jane"
        '
        Dim persons1 As Persons = New Persons
        '
        Console.WriteLine(persons1.Count)
        '
        persons1.Add(person1)
        persons1.Add(person2)
        '
        Console.WriteLine(persons1.Count)
        '
        Console.WriteLine(persons1(1).Name)                                ' (2)
        Console.WriteLine(persons1.Item(1).Name)                           ' (3)
        '
        Console.ReadLine()
    End Sub
End Module
Module Client3
    Sub Main()
        Dim person1 As Person = New Person
        person1.Name = "John"
        '
        Dim persons1 As Persons = New Persons
        persons1.Add(person1)
    End Sub
End Module
Class Rectangle
    Private m_Height As Integer
    Public Property Height() As Integer
        Get
            Height = m_Height
        End Get
        Set(ByVal value As Integer)
            m_Height = value
        End Set
    End Property
    Private m_Width As Integer
    Public Property Width() As Integer
        Get
            Width = m_Width
        End Get
        Set(ByVal value As Integer)
            m_Width = value
        End Set
    End Property
    Public Function GetArea() As Integer
        GetArea = Height * Width
    End Function
End Class
Class Rectangles
    Private m_Items As Rectangle()
    Default Public ReadOnly Property Item(ByVal index As Integer) As Rectangle
        Get
            Item = m_Items(index)
        End Get
    End Property
    Private m_Count As Integer
    Public ReadOnly Property Count() As Integer
        Get
            Count = m_Count
        End Get
    End Property
    Public Sub Add(ByVal rectangle As Rectangle)
        ReDim Preserve m_Items(Count)
        m_Items(Count) = rectangle
        m_Count += 1
    End Sub
    Public Sub RemoveAt(ByVal index As Integer)
        For itemIndex As Integer = index To Count - 2
            m_Items(itemIndex) = m_Items(itemIndex + 1)
        Next
        ReDim Preserve m_Items(Count - 2)
        m_Count -= 1
    End Sub
    Public Function GetTotalArea() As Integer
        For Each item As Rectangle In m_Items
            GetTotalArea += item.GetArea()
        Next
    End Function
End Class
Module Exercise1Solution
    Sub Main()
        Dim rectangle1 As Rectangle = New Rectangle
        rectangle1.Height = 1
        rectangle1.Width = 2
        Console.WriteLine(rectangle1.GetArea())
        '
        Dim rectangle2 As Rectangle = New Rectangle
        rectangle2.Height = 3
        rectangle2.Width = 4
        Console.WriteLine(rectangle2.GetArea())
        '
        Dim rectangles1 As Rectangles = New Rectangles
        rectangles1.Add(rectangle1)
        rectangles1.Add(rectangle2)
        '
        For index As Integer = 0 To rectangles1.Count - 1
            Console.Write(rectangles1(index).GetArea() & " ")
        Next
        Console.WriteLine()
        Console.WriteLine(rectangles1.GetTotalArea())
        '
        rectangles1.RemoveAt(1)
        '
        For index As Integer = 0 To rectangles1.Count - 1
            Console.Write(rectangles1(index).GetArea() & " ")
        Next
        Console.WriteLine()
        Console.WriteLine(rectangles1.GetTotalArea())
        '
        Console.ReadLine()
    End Sub
End Module

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