pet.vb

编程之道VB.NETt程序设计入门-589M.zip

Public Class Pet

    Private mstrName As String
    Private mdtBirthDate As Date

    Public Sub New(ByVal birthDate As Date)
        mdtBirthDate = birthDate
    End Sub

    Public Property Name() As String
        Get
            Return mstrName
        End Get
        Set(ByVal Value As String)
            mstrName = Value
        End Set
    End Property

    Public ReadOnly Property Age() As Integer
        Get
            Return DateDiff(DateInterval.Year, mdtBirthDate, Now())
        End Get
    End Property

    Public Overridable Sub Move()
        Console.WriteLine(Name & " is moving!")
    End Sub

End Class

Public Class Dog
    Inherits Pet

    Public Sub New(ByVal birthDate As Date)
        MyBase.New(birthDate)
    End Sub

    Public Overrides Sub Move()
        Console.WriteLine("Dog " & Name & " is moving!")
    End Sub

    Public Overridable Sub FetchSaucer()
        Console.WriteLine("Dog " & Name & " is fetching saucer!")
    End Sub
End Class

Public Class Cat
    Inherits Pet

    Public Sub New(ByVal birthDate As Date)
        MyBase.New(birthDate)
    End Sub

    Public Overrides Sub Move()
        Console.WriteLine("Cat " & Name & " is moving!")
    End Sub

    Public Overridable Sub CatchMouse()
        Console.WriteLine("Cat " & Name & " is catching mouse!")
    End Sub
End Class

Public Class PersianCat
    Inherits Cat

    Public Sub New(ByVal birthDate As Date)
        MyBase.New(birthDate)
    End Sub

    Public Overrides Sub Move()
        Console.WriteLine("Persian cat " & Name & " is moving!")
    End Sub
End Class