Facade in VB.NET

   1:      ' Facade Design Pattern.

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

   3:      Class MainApp

   4:          ' Entry point into console application.

   5:          Public Shared Sub Main()

   6:              Dim facade As New Facade()

   7:              facade.MethodA()

   8:              facade.MethodB()

   9:              ' Wait for user

  10:              Console.ReadKey()

  11:          End Sub

  12:      End Class

  13:   

  14:      ' The 'Subsystem ClassA' class

  15:      Class SubSystemOne

  16:          Public Sub MethodOne()

  17:              Console.WriteLine(" SubSystemOne Method")

  18:          End Sub

  19:      End Class

  20:   

  21:      ' The 'Subsystem ClassB' class

  22:      Class SubSystemTwo

  23:          Public Sub MethodTwo()

  24:              Console.WriteLine(" SubSystemTwo Method")

  25:          End Sub

  26:      End Class

  27:   

  28:      ' The 'Subsystem ClassC' class

  29:      Class SubSystemThree

  30:          Public Sub MethodThree()

  31:              Console.WriteLine(" SubSystemThree Method")

  32:          End Sub

  33:      End Class

  34:   

  35:      ' The 'Subsystem ClassD' class

  36:      Class SubSystemFour

  37:          Public Sub MethodFour()

  38:              Console.WriteLine(" SubSystemFour Method")

  39:          End Sub

  40:      End Class

  41:   

  42:      ' The 'Facade' class

  43:      Class Facade

  44:          Private _one As SubSystemOne

  45:          Private _two As SubSystemTwo

  46:          Private _three As SubSystemThree

  47:          Private _four As SubSystemFour

  48:          Public Sub New()

  49:              _one = New SubSystemOne()

  50:              _two = New SubSystemTwo()

  51:              _three = New SubSystemThree()

  52:              _four = New SubSystemFour()

  53:          End Sub

  54:          Public Sub MethodA()

  55:              Console.WriteLine(vbLf & "MethodA() ---- ")

  56:              _one.MethodOne()

  57:              _two.MethodTwo()

  58:              _four.MethodFour()

  59:          End Sub

  60:          Public Sub MethodB()

  61:              Console.WriteLine(vbLf & "MethodB() ---- ")

  62:              _two.MethodTwo()

  63:              _three.MethodThree()

  64:          End Sub

  65:      End Class