Object Serailization in CSharp

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Welcome!

[Object Serialization in C#]


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Role of Object Graphs

When a given object is serialized to a stream, any associated

object references required by the root object areautomatically serialized as well.

The chain of related objects serialized to a stream is

collectively referred to as an Object Graph

Provides a simple way to document how a set of objects refer

to each other.

To establish the relations among objects in a graph, each

object is assigned a unique value, followed by a graph of allrelated items.

Numbers have no real meaning to the outside world.


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Simple Example

Creating a set of classes that model some

automobiles.

Top most Class Car, which has a

Radio.Another class namedJamesBondCar

extends the basic Cartype.

A simple Object graph that models these

relationships is shown below.


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Object Graph

3

2

1

Car

Radio

James Bond Car

Representation

[Car 3, ref 2], [Radio 2], [JamesBondCar 1, ref 3, ref 2]


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Configuring Objects for Serialization

Use of [Serializable] attribute

If some members should not participate in

Serialization you can mark such fields with the

[NonSerialized] attribute.Member variables that do

not need to be remmembered.

The Radio class which has been marked

serializable except for a single member variable.


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Configuring Objects for Serialization

//this class can participate in the .NET serialization

[Serializable]Public class Radio

{

//this member will not participate

[NonSerialized]

private int objectIDNumber = 9;

//other serialized state data

public Radio(){}

public void On(bool state){}

}


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Choosing a serialization Formatter

Next task is to choose which format should be

used when persisting your object graph.

System.Runtime.Serialization.Formatters

namespace contains 2 additional namespaces

(*.Binary and *.Soap)

The BinaryFormatter type serializes your object

graph to a stream using a compact binary format.

The SoapFormatter represents your graph as

SOAP(Simple Object Access Protocol) message

that is expressed using XML data representation.


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To serialize your objects using a binary format, all

you to do is specify the following directive:-

//Persist object graph using a binary format!

using System.Runtime.Serialization.Formatters.Binary;

For SoapFormatters you must set a reference to

System.Runtime.Serialization.Formatters.Soap.dll

and use the following

//Persist object graph using a SOAP format!

using System.Runtime.Serialization.Formatters.Soap;


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Implementation of IFormatter and

IRemotingFormatter by the formatters.

IFormatter defines the key Serialize() and

Deserialze() methods.

IRemotingFormatter interface overloads the above

methods for remoting centric persistence.Derived

from IFormatter interface.


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Serialization using Binary formatter

BinaryFormatter Members

.Members Meaning in Life

Deserialize() Deserializes a stream of bytes

to an object graph.Returns ageneric System.object type and

so need to impose an explicit

cast

Serialize() Serializes an object or graph of

related objects to a

stream.Requires Stream-

derived type as its first

parameter.


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Serialization using SOAP/XML Formatter.

SOAP formatter is similar to the Binary formatter

For Xml formatter , reference to System.Xml.dll

needed and the following directive is used

Using System.Xml.Serialization;

Similar to SOAP and Binary formatter , except

for the Constructor which requires type

information of the item as well as the name of the

XML namespace of the *.xml file.


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Difference between the 3 Types

Binary Serialization - Light and compact used in

Remoting

SOAP Serialization interoperable use SOAP

and used in web Services

XML Serialization - Custom Serialization, also

called Shallow serailization

Web Services uses the SOAP Serialization and

Remoting uses the BinarySerialization.They arecalled deep Serailization.


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Sample Example

Using Binary Formatter

Using System.Runtime.Serialization.Formatters.Binary;

Using System.IO;Public static void Main()

{

//Make a car and change some state data

JamesBondCar myAuto = new JamesBondCar(Fred, 50, false, true);myAuto.TurnOnRadio(true);

myAuto.GoUnderWater();

//Create a file stream to hold the objects state.

FileStream myStream = File.Create(CarData.dat);//Move the object graph into the file stream using a binary format

BinaryFormatter myBinaryFormat = new BinaryFormatter();

myBinaryFormat.Serialize(myStream, myAuto);

myStream.Close();}


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Sample Example

Using SOAP Formatter

Using System.Runtime.Serialization.Formatters.Soap;


{

//Save the same previous car using a Soap format.

FileStream myStream = File.Create(CarSoapData.xml);SoapFormatter mySoapFormat = new SoapFormatter();

mySoapFormat.Serialize(myStream, myAuto);

myStream.Close();

//Read in the Car from the Xml filemyStream = File.OpenRead(CarSoapData.xml);

JamesBondCar carFrom Soap =

(JamesBondCar )mySoapFormat.Deserialize(mystream);

myStream.Close();}


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Sample Example

Using XML Formatter

Using System.Xml.Serialization;


{

//Save the same previous car using a Soap format.

FileStream myStream = File.Create(CarXmlData.xml);XmlSerializer myXmlFormat = new XmlSerializer

(typeof(JamesBondCar), Cars);

myXmlFormat.Serialize(myStream, myAuto);

myStream.Close();//Read in the Car from the Xml file

myStream = File.OpenRead(CarXmlData.xml);

JamesBondCar carFrom Soap =

(JamesBondCar ) myXmlFormat .Deserialize(mystream);myStream.Close();

}


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Customizing the Serialization Process

System.Runtime.Serialization Namespace Core types

Formatter An abstract base class that provides basefunctionality for runtime serialization formatters.

ObjectIDGenerator Generates Ids for Objects in an objectgraph.

ObjectManager Keep tracks of Objects as they are beingdeserialized.

SerializationBinder An abstract base class that providesfunctionality to serialize a type to a stream.

Serailization Info Used by objects that have customserialization behavior.SerializationInfo holds together all thedata needed to serailize or deserialize an object.This class isa property bagthat allows you to establish name/value pairs

to represent the state of an object


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Customizing the Serialization Process

In addition two Key Interfaces used for

Serialization are IFormatter and Iserializable.

Necessary Information required during

Serialization

Qualified name of Object(e.g.MyNamespace.MyClasses.Foo)

Assembly name containing the object(e.g myAsm.dll)

Objects stateful information, contained within aSerializationInfo type.


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The Serialization Process

My Object Formatter

FormatterMy Object

SerailizationInfo

Deserailize()

SerailizationInfo

SerailizationInfo

Stream

Stream

Some storage

device


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First step is to implement the ISerializable interface.

//When u wish to tweak the serialization process//implement the ISerializable

public interface Iserializable

{

public virtual void GetObjectData(SerializationInfo info,

StreamingContext context);

}

GetObjectData() Populates the SerializationInfo paramwith the a series of name/value pairs.


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Must provide a special constructor with the

following signature.[Serializable]

Class SomeClass : Iserializable

{

private SomeClass(SerializationInfo si,StreamingContext ctx)

{

}}

Params are SerializationInfo andStreamingContext


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StreamingContext contains info. About the source

or destination of the bits.The most informationmember of this type is the State Property which

contains the value from the

StreamingContextStates enumeration.


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Streaming Context States

StreamingContextStates Enumeration members are

All

Clone

CrossAppDomain

CrossMachine CrossProcess

File

Other Persistence

Remoting


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Simple example of Custom Serialization

Public class CustomCarType :ISerializable

{

Public string petName;

Public int maxSpeed;

Public CustomCarType(string s, int i)

{

petName = s; maxSpeed = i;

}


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//Return state info to the formatter

Public void GetObjectData(SerializationInfo si,

StreamingContext ctx)

{

si.AddValue(CapPetName, petName.ToUpper());

si.AddValue(maxSpeed, maxSpeed);

}


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//Rehydrate a new object based on the incoming

//Serializationinfo type

Private CustomCarType(SerializationInfo si,

StreamingContext ctx)

{

petName = si.GetString(CarPetName);

maxSpeed = si.GetInt32(maxSpeed);}

}


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Public static int Main(string[] args)

{CustomCarType myAuto = new CustomCarType(Sid, 50);

Stream myStream = File.Create(CarData.dat)

BinaryFormatter myFormatter = new BinaryFormatter();

myFormatter.Serialize(myStream, myAuto);

myStream.close();

mySteam = File.Open(CarData.dat);

//special constructor calledCustomCarType carFromDisk =(CustomCarType)myFormatter.Deserialize(myStream);

return 0;

}


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References

Andrew Torelsens C# and the .NET Platform

http://www.codeproject.com/Purgatory/Serialization_in_NET.asp

http://www.ondotnet.com
http://www.codeproject.com/Purgatory/Serialization_in_NET.asphttp://www.codeproject.com/Purgatory/Serialization_in_NET.asphttp://www.ondotnet.com/http://www.ondotnet.com/http://www.codeproject.com/Purgatory/Serialization_in_NET.asphttp://www.codeproject.com/Purgatory/Serialization_in_NET.asp


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Thank You.

Vipin

Date post:	02-Apr-2018
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Object Serailization in CSharp

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