Polymorphism/Serialization SoapFormatter (VB.NET)

Imports System.IO
Imports System.Collections
Imports System.Runtime.Serialization

' Note: When building this code, you must reference the
' System.Runtime.Serialization.Formatters.Soap.dll assembly.
Imports System.Runtime.Serialization.Formatters.Soap
Imports System.Xml.Serialization

Module Module1

    Sub Main()
        'Create some objects
        Dim dObj As New Hashtable()

        dObj(0) = New Line(100, 100)
        dObj(1) = New Circle(50, 10, 10)
        dObj(2) = New Square(10, 10, 20, 20)
        dObj(3) = New DrawingObject()

        Serialize(dObj)

        ' deserialize to a generic list
        Dim deserializedList As New Hashtable(Deserialize())

        ' display the results
        For Each DrawingObject As DrawingObject In deserializedList.Values

            Select Case DrawingObject.GetType().Name
                Case "Line"
                    Console.WriteLine(String.Format("I'm a {0}", DrawingObject.Draw()))
                    Dim line As Line = DirectCast(DrawingObject, Line)
                Case "Circle"
                    Console.WriteLine(String.Format("I'm a {0}", DrawingObject.Draw()))
                    Dim circle As Circle = DirectCast(DrawingObject, Circle)
                Case "Square"
                    Dim square As Square = DirectCast(DrawingObject, Square)
                    Console.WriteLine(String.Format("I'm a {0}", DrawingObject.Draw()))
                Case Else
                    Console.WriteLine(String.Format("I'm just a {0}", DrawingObject.Draw()))
            End Select
        Next
        Console.ReadLine()
    End Sub

    Sub Serialize(data As Hashtable)

        ' Use a file stream here.
        Using fs As New FileStream("Test.soap", FileMode.Create)

            ' Construct a SoapFormatter and use it
            ' to serialize the data to the stream.
            Dim formatter As New SoapFormatter
            Try
                ' Serialize EmployeeList to the file stream
                formatter.Serialize(fs, data)
            Catch e As SerializationException
                Console.WriteLine("Failed to serialize. Reason: " & e.Message)
            End Try

        End Using
    End Sub

    Function Deserialize() As Hashtable
        ' Create an instance of T
        Dim ReturnListOfT1 As New Hashtable()
        ' Open the file containing the data that you want to deserialize.
        Using fs As New FileStream("Test.soap", FileMode.Open)
            ' Construct a SoapFormatter and use it
            ' to serialize the data from the stream.
            Dim formatter As New SoapFormatter
            Try
                fs.Position = 0
                ' Deserialize the hashtable from the file
                ReturnListOfT1 = formatter.Deserialize(fs)

            Catch e As SerializationException
                Console.WriteLine("Failed to deserialize. Reason: " & e.Message)
            End Try
        End Using
        '  return the Deserialized data.
        Return ReturnListOfT1

    End Function

End Module

' The object we are going to Serializing/De-serializing
<XmlInclude(GetType(Line))>
<XmlInclude(GetType(Circle))>
<XmlInclude(GetType(Square))>
<Serializable()>
Public Class DrawingObject

    Public Sub New()
    End Sub

    Public Overridable Function Draw() As String
        Return "generic drawing object."
    End Function
End Class

<Serializable()>
Public Class Square
    Inherits DrawingObject

    Public Overrides Function Draw() As String
        Return "Square."
    End Function

    Public Sub New()
    End Sub

    Public Sub New(x1 As Integer, y1 As Integer, x2 As Integer, y2 As Integer)
        Me.X1 = x1
        Me.Y1 = y1
        Me.X2 = x2
        Me.Y2 = y2
    End Sub

    Public Property X1 As Integer
    Public Property Y1 As Integer

    Public Property X2 As Integer
    Public Property Y2 As Integer
End Class

<Serializable()>
Public Class Line
    Inherits DrawingObject

    Public Overrides Function Draw() As String
        Return "Line."
    End Function

    Public Sub New()
    End Sub

    Public Sub New(x As Integer, y As Integer)

        Me.X = x
        Me.Y = y
    End Sub

    Public Property X As Integer
    Public Property Y As Integer
End Class

<Serializable()>
Public Class Circle
    Inherits DrawingObject

    Public Overrides Function Draw() As String
        Return "Circle."
    End Function

    Public Sub New()
    End Sub

    Public Sub New(radius As Integer, x As Integer, y As Integer)
        Me.Radius = radius
        Me.X = x
        Me.Y = y
    End Sub

    Public Property Radius As Integer
    Public Property X As Integer
    Public Property Y As Integer

End Class