Singleton Example : Singleton « Design Patterns « VB.Net Tutorial

1. VB.Net Tutorial
2. Design Patterns
3. Singleton

Public Class Singleton
  Private Shared SP As Singleton
  Private InnerList as New Collections.ArrayList()

  Private Sub New()
  End Sub 
  
  Public Shared Function Create() As Singleton
    If SP is Nothing Then SP = New Singleton() 
    Return SP
  End Function

  Public ReadOnly Property List As Collections.ArrayList
    Get
      Return InnerList
    End Get
  End Property
End Class

Module SingletonExample
  Sub Main
    Dim CountValue as Integer
    Dim SP As Singleton = Singleton.Create()
    Dim SP2 As Singleton = Singleton.Create()

    SP.List.Add("First")
    SP.List.Add("Second")
    SP.List.Add("Third")

    For CountValue = 0 To SP2.List.Count - 1
      Console.WriteLine(SP2.List.Item(CountValue).ToString())
    Next
  End Sub
End Module

First
Second
Third