Prototype in VB.NET

   1:  ' Prototype Design Pattern.

   2:  ' See description in //www.vb-net.com/ProgramTheory/Prototype.htm

   3:  Class MainApp

   4:      ' Entry point into console application.

   5:      Public Shared Sub Main()

   6:          ' Create two instances and clone each

   7:          Dim p1 As New ConcretePrototype1("I")

   8:          Dim c1 As ConcretePrototype1 = DirectCast(p1.Clone(), ConcretePrototype1)

   9:          Console.WriteLine("Cloned: {0}", c1.Id)

  10:          Dim p2 As New ConcretePrototype2("II")

  11:          Dim c2 As ConcretePrototype2 = DirectCast(p2.Clone(), ConcretePrototype2)

  12:          Console.WriteLine("Cloned: {0}", c2.Id)

  13:          ' Wait for user

  14:          Console.ReadKey()

  15:      End Sub

  16:  End Class

  17:   

  18:  ' The 'Prototype' abstract class

  19:  MustInherit Class Prototype

  20:      Private _id As String

  21:      ' Constructor

  22:      Public Sub New(id As String)

  23:          Me._id = id

  24:      End Sub

  25:      ' Gets id

  26:      Public ReadOnly Property Id() As String

  27:          Get

  28:              Return _id

  29:          End Get

  30:      End Property

  31:      Public MustOverride Function Clone() As Prototype

  32:  End Class

  33:   

  34:  ' A 'ConcretePrototype' class 

  35:  Class ConcretePrototype1

  36:      Inherits Prototype

  37:      ' Constructor

  38:      Public Sub New(id As String)

  39:          MyBase.New(id)

  40:      End Sub

  41:      ' Returns a shallow copy

  42:      Public Overrides Function Clone() As Prototype

  43:          Return DirectCast(Me.MemberwiseClone(), Prototype)

  44:      End Function

  45:  End Class

  46:   

  47:  ' A 'ConcretePrototype' class 

  48:  Class ConcretePrototype2

  49:      Inherits Prototype

  50:      ' Constructor

  51:      Public Sub New(id As String)

  52:          MyBase.New(id)

  53:      End Sub

  54:      ' Returns a shallow copy

  55:      Public Overrides Function Clone() As Prototype

  56:          Return DirectCast(Me.MemberwiseClone(), Prototype)

  57:      End Function

  58:  End Class