Serialization in .NET

Introduction

Serialization is a process of taking an object and converting into a form so that it can be transported across the network or can be persisted in the storage location. This storage location can be physical file, database or ASP.NET Cache. The form contains the state of the object so that by this format, we can construct the same object a later point in time, which is called Deserialization.

There are three formats of serialization

Binary Serialization             :        Light and compact used in Remoting

SOAP Serialization            :        interoperable use SOAP and  used in web Services

XML Serialization               :        Custom Serialization

XML Serialization

For XML serialization, you need to use the attributes and specify them for each and every public member that you need. But since it is limited that it can serialize only public members, Serization done by it is called custom serialization. It is also known as Shallow Serialization

SOAP and Binary Serialization

XML serializes only public members of the class. You use SOAP or Binary serialization when you need to transport data across the network. SOAP sends it using HTTP Protocol which makes it most interoperable while Binary serialization is known for its light and compact nature. Web Services uses the SOAP Serialization and Remoting uses the Binary Serialization. Infact Serialization is always neccessary when you need the object to transfer across a network. Advantage of using the SOAP or Binary serialization is that you can serialize the entire object and all those object that are being refrenced by it. This is why it is also called Deep Serialization.  If you want any class to serialize through any of these methods then you should use [Serializable] attribute on that class and then you can use the SoapFormater class or BinaryFormatter class to do the serialization. These classes have Serialize and DeSerialize method.  If you will not use SerializableAttribute for the class, then it will raise the exception.

Though this is the easiest way but at time you need the way so that you can decide what fields to serialize and how the serialization actually occurs. You can implement the ISerializable interface in the class. You need two things for that

1. Constructor that is overridden and can handle the Deserialization process
2. GetObject method that tracks about which data is serialized.

A small example below illustrate this all.

 public class Employee :ISerializable

{

private int emp_no;

private string name;

protected TestData(SerializationInfo info,StreamingContext context)
    {
      this.emp_no = info.GetInt32("emp_no");
      this.name = info.GetString("name");
    }

 void ISerializable.GetObjectData(SerializationInfo info,   

         StreamingContext context)
      {
      info.AddValue("emp_no", this.emp_no);
      info.AddValue("name", this.name);
    }

}

}

I hope this introductory serialization information can help you to understands about Serialization with its need  and its effective usage.