Object Serialization (binary)

Object Serialization is an interesting subject as so many developers have never had to deal with it. In very basic terms, serialization is simply converting an object to a different format.  We know that an object is an instance of a class and nearly always it is stored in memory (invisible to most developers). We get into serialization/deserialization when we need to persist an object to some sort of long-ish term storage (database, file, or ??) or transport it (via HTTP or TCP socket or ??). The most typical (in my experience) forms of serialization are to a binary or an XML representation.  Over the past several years, I have written a number of processes that transmit data via TCP sockets (an object “factory/distributor”) with many “clients/subscribers” as well as sending data from a client to a web service (for example). In all but the simplest of implementations, sending a serialized object is the best option.

The .Net Framework provides a great deal of functionality to facilitate object serialization and deserialization.  The System.Runtime.Serialization namespace is your friend (and required for the following code samples).

Let’s start with binary serialization:

The easisest example is to serialize (“convert”) an object to a byte array.  This can by done as follows:

        Dim oByte As Byte()
        Dim oMS As New MemoryStream
        Dim oBinaryFormatter As New BinaryFormatter

        oBinaryFormatter.Serialize(oMS, value)
        oByte = oMS.GetBuffer

The question is then, what do I do with a byte array?  Well, converting it to a string allows you to persist that string to storage – use System.Object.Convert such as:

Convert.ToBase64String(oByte)

This returns the string that you are looking for and can be persisted.

You now have a binary serialized object that you want to use again. You must deserialize the string into an object (reverse the process). This code performs those steps:

        Dim _byteArray As Byte()
        Dim _binaryFormatter As New BinaryFormatter

        _byteArray = Convert.FromBase64String(_stringValue)

        Dim _memorySteam As New MemoryStream(_byteArray)
        DeserializeString = oBinaryFormatter.Deserialize(_memorySteam)

Ok, easy. However; when I try this on one of my classes, it fails with something like: “Type ‘WindowsApplication1.Form1’ in Assembly ‘WindowsApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null’ is not marked as serializable.”

This is easily solved.  All classes that are to be serialized must be marked with the serializeable attribute like so:

     <Serializable()> Public Class MyClass

That is the basics of binary object serialization and deserialization. The terms sounds very “fancy” but in reality, it is just a conversion to a form that can be saved or transported –  Easy!