Question

I have a VB.NET singleton class which implements Serializable:

Imports System.IO
Imports System.Runtime.Serialization

<Serializable()> Public Class CoordinateHistory
    Private Shared _thisInstance As CoordinateHistory

    Private gpsHistory As Dictionary(Of DateTime, GpsTimeCoordinate)
    Private gpsTimes As List(Of DateTime)

    Public Event NewStatusInformation(statusInfo As String)

    Protected Sub New()
        gpsHistory = New Dictionary(Of DateTime, GpsTimeCoordinate)
        gpsTimes = New List(Of DateTime)
    End Sub

    Public Shared Function getInstance() As CoordinateHistory
        If _thisInstance Is Nothing Then
            _thisInstance = New CoordinateHistory
        End If

        Return _thisInstance
    End Function

    Public Function getHistoryCount() As Integer
        Return gpsHistory.Count
    End Function

    ' bunch of other class functions below...
End Class

My problem is that I can’t actually call .Serialize() on the instance of this class, like all of the examples online show. What am I doing wrong? Thanks!

Answer 1

I believe the issue is your Protected Sub. If you change it to Public, you may be able to Serialize correctly.

Update

I didn’t have any issues serializing the default instance using a BinaryFormatter:

Dim abData As Byte()

Using oStream As New MemoryStream
    Call (New BinaryFormatter).Serialize(oStream, CoordinateHistory.getInstance())

    abData = oStream.ToArray()
End Using

or an XMLFormatter:

Dim sData As String

Using oStream As New MemoryStream
    Dim oSerializer As New XmlSerializer(CoordinateHistory.getInstance().GetType)

    oSerializer.Serialize(oStream, CoordinateHistory.getInstance())

    sData = Encoding.Default.GetString(oStream.ToArray())
End Using

Perhaps it is the serialization framework you are using?