'Visual Basic 2010 Redefinition - Overridable en Overrides Object Oriented Programming
Class Class1
    Public Overridable Function Method1() As String
        Method1 = "Class1.Method1()"
    End Function
End Class
Class Class2 : Inherits Class1
    Public Overrides Function Method1() As String
        Method1 = "Class2.Method1()"
    End Function
End Class
Module Example1
    Sub Main()
        Dim object1 As Class1 = New Class1
        Console.WriteLine(object1.Method1())                               ' (1)
        '
        Dim object2 As Class2 = New Class2
        Console.WriteLine(object2.Method1())                               ' (2)
        '
        Console.ReadLine()
    End Sub
End Module
Class Class3
    Public Overridable Function Method1() As String
        Method1 = "Class3.Method1()"
    End Function
    Public Overridable Function Method1(ByVal argument As String) As String
        Method1 = "Class3.Method1(" & argument & ")"
    End Function
End Class
Class Class4 : Inherits Class3
    Public Overrides Function Method1() As String ' (1)
        Method1 = "Class4.Method1()"
    End Function
    Public NotOverridable Overrides Function Method1(ByVal argument As String) _
                                                                       As String
        Method1 = "Class4.Method1(" & argument & ")"
    End Function
    Public Overloads Function Method1(ByVal argument1 As String, _
                                      ByVal argument2 As String) As String
        Method1 = "Class4.Method1(" & argument1 & "," & argument2 & ")"
    End Function
End Class
Class Class5 : Inherits Class4
    Public Overrides Function Method1() As String
        Method1 = "Class5.Method1()"
    End Function
End Class
Module Example2
    Sub Main()
        Dim object1 As Class3 = New Class3
        Console.WriteLine(object1.Method1())
        Console.WriteLine(object1.Method1("test"))
        '
        Dim object2 As Class4 = New Class4
        Console.WriteLine(object2.Method1())
        Console.WriteLine(object2.Method1("test"))
        Console.WriteLine(object2.Method1("test1", "test2"))
        '
        Dim object3 As Class5 = New Class5
        Console.WriteLine(object3.Method1())
        Console.WriteLine(object3.Method1("test"))
        Console.WriteLine(object3.Method1("test1", "test2"))
        '
        Console.ReadLine()
    End Sub
End Module
Class Counter
    Protected m_Value As Integer
    Public ReadOnly Property Value() As Integer
        Get
            Value = m_Value
        End Get
    End Property
    Public Overridable Sub Raise()
        m_Value += 1
    End Sub
    Public Overridable Sub Lower()
        m_Value -= 1
    End Sub
End Class
Module Example3
    Sub Main()
        Dim counter As Counter = New Counter
        Console.WriteLine(counter.Value)
        counter.Raise()
        Console.WriteLine(counter.Value)
        counter.Raise()
        Console.WriteLine(counter.Value)
        counter.Lower()
        Console.WriteLine(counter.Value)
        '
        Console.ReadLine()
    End Sub
End Module
Class SpecialCounter : Inherits Counter
    Private m_StepValue As Integer = 1
    Public Property StepValue() As Integer
        Get
            StepValue = m_StepValue
        End Get
        Set(ByVal value As Integer)
            m_StepValue = value
        End Set
    End Property
    Public Overrides Sub Raise()
        m_Value += StepValue
    End Sub
    Public Overrides Sub Lower()
        m_Value -= StepValue
    End Sub
End Class
Module Example4
    Sub Main()
        Dim specialCounter As SpecialCounter = New SpecialCounter
        Console.WriteLine(specialCounter.Value)
        specialCounter.StepValue = 5
        specialCounter.Raise()
        Console.WriteLine(specialCounter.Value)
        specialCounter.Raise()
        Console.WriteLine(specialCounter.Value)
        specialCounter.Lower()
        Console.WriteLine(specialCounter.Value)
        '
        Console.ReadLine()
    End Sub
End Module
Class Person
    Public Sub New(ByVal name As String)
        Me.Name = name
    End Sub
    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
Class Student : Inherits Person
    Public Sub New(ByVal name As String, ByVal classGroup As String)
        MyBase.New(name)
        Me.ClassGroup = classGroup
    End Sub
    Private m_ClassGroup As String
    Public Property ClassGroup() As String
        Get
            ClassGroup = m_ClassGroup
        End Get
        Set(ByVal value As String)
            m_ClassGroup = value
        End Set
    End Property
    Public Overrides Function ToString() As String                         ' (2)
        ToString = Name & " (" & ClassGroup & ")"
    End Function
End Class
Module Example5
    Public Sub Main()
        Dim person1 As Person = New Person("John")
        Console.WriteLine(person1.ToString())                              ' (1)
        '
        Dim student1 As Student = New Student("Jane", "Visual Basic")
        Console.WriteLine(student1.ToString())                             ' (2)
        '
        Console.ReadLine()
    End Sub
End Module
Partial Class Counter
    Public Overrides Function ToString() As String
        ToString = Value.ToString()
    End Function
End Class
Partial Class SpecialCounter
    Public Overrides Function ToString() As String
        ToString = MyBase.ToString() & " - Step : " & StepValue.ToString() ' (1)
    End Function
End Class
Module Example6
    Sub Main()
        Dim counter1 As Counter = New Counter
        Console.WriteLine(counter1.ToString())
        '
        Dim specialCounter1 As SpecialCounter = New SpecialCounter
        Console.WriteLine(specialCounter1.ToString())
        '
        Console.ReadLine()
    End Sub
End Module
Class Employee
    Private m_MonthlySalary As Decimal
    Public Property MonthlySalary() As Decimal
        Get
            MonthlySalary = m_MonthlySalary
        End Get
        Set(ByVal value As Decimal)
            m_MonthlySalary = value
        End Set
    End Property
    Public Overridable Function GetYearlySalary() As Decimal
        GetYearlySalary = MonthlySalary * 12
    End Function
End Class
Class Manager : Inherits Employee
    Private m_Bonus As Decimal
    Public Property Bonus() As Decimal
        Get
            Bonus = m_Bonus
        End Get
        Set(ByVal value As Decimal)
            m_Bonus = value
        End Set
    End Property
    Public Overrides Function GetYearlySalary() As Decimal
        GetYearlySalary = MyBase.GetYearlySalary() + Bonus
    End Function
End Class
Module Exercise1Solution
    Public Sub Main()
        Dim employee1 As Employee = New Employee
        employee1.MonthlySalary = 1000
        Console.WriteLine(employee1.GetYearlySalary())
        '
        Dim manager1 As Manager = New Manager
        manager1.MonthlySalary = 2000
        manager1.Bonus = 10000
        Console.WriteLine(manager1.GetYearlySalary())
        '
        Console.ReadLine()
    End Sub
End Module
Module Exercise2Task
    Sub Main()
        Dim addition1 As Addition = New Addition(3, 4)
        Console.WriteLine(addition1.GetSum())
        Console.WriteLine(addition1.ToString())
        '
        addition1.Operand1 = 5
        addition1.Operand2 = 6
        Console.WriteLine(addition1.GetSum())
        Console.WriteLine(addition1.ToString())
        '
        Console.ReadLine()
    End Sub
End Module
Class Addition
    Public Sub New(ByVal operand1 As Integer, ByVal operand2 As Integer)
        Me.Operand1 = operand1
        Me.Operand2 = operand2
    End Sub
    Private m_Operand1 As Integer
    Public Property Operand1() As Integer
        Get
            Operand1 = m_Operand1
        End Get
        Set(ByVal value As Integer)
            m_Operand1 = value
        End Set
    End Property
    Private m_Operand2 As Integer
    Public Property Operand2() As Integer
        Get
            Operand2 = m_Operand2
        End Get
        Set(ByVal value As Integer)
            m_Operand2 = value
        End Set
    End Property
    Public Function GetSum() As Integer
        GetSum = Operand1 + Operand2
    End Function
    Public Overrides Function ToString() As String
        ToString = Operand1 & " + " & Operand2 & " = " & GetSum()
    End Function
End Class
Module Exercise3Task
    Sub Main()
        Dim airport1 As Airport = New Airport("ZAV", "Brussels")
        Dim airport2 As Airport = New Airport("NYK", "New York Kennedy")
        '
        Dim flight1 As Flight = New Flight(airport1, airport2)
        Dim flight2 As Flight = New Flight(airport2, airport1)
        '
        Dim holiday1 As Holiday = New Holiday
        holiday1.Add(flight1)
        holiday1.Add(flight2)
        '
        For index As Integer = 0 To holiday1.Count - 1
            Console.WriteLine(holiday1.Item(index).ToString())
        Next
        '
        Console.ReadLine()
    End Sub
End Module
Class Holiday
    Private m_Items As Flight()
    Private m_Count As Integer
    Public ReadOnly Property Count() As Integer
        Get
            Count = m_Count
        End Get
    End Property
    Public Sub Add(ByVal flight As Flight)
        ReDim Preserve m_Items(Count)
        m_Items(Count) = flight
        m_Count += 1
    End Sub
    Default Public ReadOnly Property Item(ByVal index As Integer) As Flight
        Get
            Item = m_Items(index)
        End Get
    End Property
End Class
Class Flight
    Public Sub New(ByVal departure As Airport, ByVal arrival As Airport)
        Me.Departure = departure
        Me.Arrival = arrival
    End Sub
    Private m_Departure As Airport
    Public Property Departure() As Airport
        Get
            Departure = m_Departure
        End Get
        Set(ByVal value As Airport)
            m_Departure = value
        End Set
    End Property
    Private m_Arrival As Airport
    Public Property Arrival() As Airport
        Get
            Arrival = m_Arrival
        End Get
        Set(ByVal value As Airport)
            m_Arrival = value
        End Set
    End Property
    Public Overrides Function ToString() As String
        ToString = Departure.ToString() & " -> " & Arrival.ToString()
    End Function
End Class
Class Airport
    Public Sub New(ByVal code As String, ByVal Name As String)
        Me.Code = code
        Me.Name = Name
    End Sub
    Private m_Code As String
    Public Property Code() As String
        Get
            Code = m_Code
        End Get
        Set(ByVal value As String)
            m_Code = value
        End Set
    End Property
    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
    Public Overrides Function ToString() As String
        ToString = Code & " : " & Name
    End Function
End Class
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