Storage and Transfer of Data Using
Serialization in .NET

Data management in an application is a very crucial for an application to work efficiently. While the application is executing, the data stored in memory is managed by the .Net framework. However, for the data to be stored into a file or sent to another process or transmitted over the network, it has to be converted to the appropriate form for efficient storage, retrieval, representation and optimization. The conversion can be to a binary or XML or custom format. The conversion is mainly for purposes like faster retrieval, space optimization, better readability (by applications other than .Net), etc.


Serialization is essentially aimed for such a need to convert an object to a format based on the requirement. It is the process of persisting the state of an object to a file or memory stream. It involves two processes, Serializing and Deserializing. Serializing is the process of conversion of the actual data into its converted form (binary or XML or customized) that can be stored or transferred. Deserializing is the reverse process of Serializing in which previously serialized form is converted into the actual data.

The .Net framework facilitates the feature of Serialization by providing a variety of classes that implement it in separate classes for different types of serialization like Binary, XML and Customized forms. The System.Runtime.Serialization namespace contains all these classes. The different types of Serialization are discussed below:

Binary serialization

This type of Serialization is chosen if the receiver of the serialized data is also a .Net application. For example, an application may have to save its data into a file which it can open later. While saving the file, the serialized object gets converted to binary form and on reopening the file, the data can be deserialized to an Object with exactly the same data as before. The BinaryFormatter class is used for this type of serialization. It is usually used for efficiency and speed.

Serialization is essentially aimed for such a need to convert an object to a format based on the requirement. It is the process of persisting the state of an object to a file or memory stream. It involves two processes, Serializing and Deserializing. Serializing is the process of conversion of the actual data into its converted form (binary or XML or customized) that can be stored or transferred. Deserializing is the reverse process of Serializing in which previously serialized form is converted into the actual data.

The .Net framework facilitates the feature of Serialization by providing a variety of classes that implement it in separate classes for different types of serialization like Binary, XML and Customized forms. The System.Runtime.Serialization namespace contains all these classes. The different types of Serialization are discussed below:

Binary serialization

This type of Serialization is chosen if the receiver of the serialized data is also a .Net application. For example, an application may have to save its data into a file which it can open later. While saving the file, the serialized object gets converted to binary form and on reopening the file, the data can be deserialized to an Object with exactly the same data as before. The BinaryFormatter class is used for this type of serialization. It is usually used for efficiency and speed.

SOAP serialization

Serialization of this type is mostly used when data has to be transmitted across a network or read by applications other than .Net. It is mainly used by SOAP Web services. The SOAPFormatter class is used to serialize the data in SOAP form. The procedure for serializing the data in SOAP form is the same as the binary form. The output created through this formatter is different from that of BinaryFormatter and is in XML form. The serialized object is bigger in size than that created using BinaryFormatter and also more readable.

To convert the serialized output to be read by applications in different platforms, the format of SOAP serialized document can be controlled by using the XML Serialization attributes. By this way, options of converting public member of an object instance to an XML element, attribute, enumeration number, etc. can be achieved. This type of Serialization is used when portability is of concern.

XML serialization

XML is universally accepted as an open and standardized text-based document format for storing application-readable information. Since any application executing in some operating system can also process an XML file, this type of serialized XML output provides better interoperability. The text format of the output makes it more user-friendly by helping in giving better readability and easier troubleshooting in maintaining existing applications and develops new applications. Due to the self-describing nature of the serialized XML output, future applications based on the existing ones, can process serialized objects easier and faster. The class, XMLSerializer is used for XML serialization.

By default, the serialized output contains XML elements which exactly map on to the class member of the object instance that was serialized. To control the structure of this serialized output, the serialization attributes can be used to change the names of elements, serialize members as attributes rather than elements and exclude members from serialization.

The framework offers a tool, XSD.exe which can be used to generate XML files based on the required schema. The template of the class newly created (conforming to the required schema) can be used for serialization necessary for making the applications to interoperate with XML based Web services.

Custom serialization

The process by which the serialization and deserialization of an object type is controlled to suit a specific requirement is called Custom serialization. Some of the contexts in which this is required are as below:

Version compatibility: Sometimes, during a change in version of software, there can be significant changes that can occur to the structure of the class that was used for serialization/deserialization. For example, a member variable used in the earlier version is not used in the later version. So, while deserializing such objects, some value has to be provided.

The framework allows implementing the interface, ISerializable to completely control the serialization process. This involves implementing the method, GetObjectData (called during Serialization) and a special constructor used when deserializing. GetObjectData is called during Serialization by the runtime and hence, the required variables to be serialized are added as name/value pairs of the SerializationInfo object passed as parameter to it. Similarly, the constructor passed with SerializationInfo object is used for transferring the values of its variables to the object instance during deserialization.

Handling serialization events: There are many situations in which the object values have to be modified at specific stage of Serialization and Deserialization. For this, the framework allows to handle different binary serialization events (that occur during Serialization and Deserialization) by using BinaryFormatter class which are Serializing, Serialized, Deserializing and Deserialized. The names of the events are self-explanatory. It allows controlling the object by changing its attributes at the required stage of serialization/deserialization.

Context-based serialization: The data that needs to be serialized depends on the context of the process executing deserialization. For example, it is meaningless to serialize current process data as most of them are invalid after the process terminates. Hence, to make decisions based on context related information (user-defined state) and the destination type (whether file, database, another process, etc.), ISerializable interface is implemented to control the serialization accordingly.

Tips:

• By default, the framework provides permission for only code on local computer to access/modify object instance data. For this, the code performing serialization requires the SecurityPermission attribute with the SerializationFormatter flag to be specified (permission not given to internet/intranet code).

• It is better practice to use the Serializable attribute to the class for enabling it to serialize the object with all its members and use NonSerialized attribute for omitting the members(like temporary, calculated values) of the object that need not be serialized.

• For deserializing an object created in older version of the product in the newer application, either customized deserialization method can be used or the newly created attributes can be marked with the tag, OptionalField to avoid exceptions.

Serialization of this type is mostly used when data has to be transmitted across a network or read by applications other than .Net. It is mainly used by SOAP Web services. The SOAPFormatter class is used to serialize the data in SOAP form. The procedure for serializing the data in SOAP form is the same as the binary form. The output created through this formatter is different from that of BinaryFormatter and is in XML form. The serialized object is bigger in size than that created using BinaryFormatter and also more readable.

To convert the serialized output to be read by applications in different platforms, the format of SOAP serialized document can be controlled by using the XML Serialization attributes. By this way, options of converting public member of an object instance to an XML element, attribute, enumeration number, etc. can be achieved. This type of Serialization is used when portability is of concern.

XML serialization


XML is universally accepted as an open and standardized text-based document format for storing application-readable information. Since any application executing in some operating system can also process an XML file, this type of serialized XML output provides better interoperability. The text format of the output makes it more user-friendly by helping in giving better readability and easier troubleshooting in maintaining existing applications and develops new applications. Due to the self-describing nature of the serialized XML output, future applications based on the existing ones, can process serialized objects easier and faster. The class, XMLSerializer is used for XML serialization.

By default, the serialized output contains XML elements which exactly map on to the class member of the object instance that was serialized. To control the structure of this serialized output, the serialization attributes can be used to change the names of elements, serialize members as attributes rather than elements and exclude members from serialization.

The framework offers a tool, XSD.exe which can be used to generate XML files based on the required schema. The template of the class newly created (conforming to the required schema) can be used for serialization necessary for making the applications to interoperate with XML based Web services.

Custom serialization

The process by which the serialization and deserialization of an object type is controlled to suit a specific requirement is called Custom serialization. Some of the contexts in which this is required are as below:

Version compatibility: Sometimes, during a change in version of software, there can be significant changes that can occur to the structure of the class that was used for serialization/deserialization. For example, a member variable used in the earlier version is not used in the later version. So, while deserializing such objects, some value has to be provided.

The framework allows implementing the interface, ISerializable to completely control the serialization process. This involves implementing the method, GetObjectData (called during Serialization) and a special constructor used when deserializing. GetObjectData is called during Serialization by the runtime and hence, the required variables to be serialized are added as name/value pairs of the SerializationInfo object passed as parameter to it. Similarly, the constructor passed with SerializationInfo object is used for transferring the values of its variables to the object instance during deserialization.

Handling serialization events: There are many situations in which the object values have to be modified at specific stage of Serialization and Deserialization. For this, the framework allows to handle different binary serialization events (that occur during Serialization and Deserialization) by using BinaryFormatter class which are Serializing, Serialized, Deserializing and Deserialized. The names of the events are self-explanatory. It allows controlling the object by changing its attributes at the required stage of serialization/deserialization.

Context-based serialization: The data that needs to be serialized depends on the context of the process executing deserialization. For example, it is meaningless to serialize current process data as most of them are invalid after the process terminates. Hence, to make decisions based on context related information (user-defined state) and the destination type (whether file, database, another process, etc.), ISerializable interface is implemented to control the serialization accordingly.

Tips:

• By default, the framework provides permission for only code on local computer to access/modify object instance data. For this, the code performing serialization requires the SecurityPermission attribute with the SerializationFormatter flag to be specified (permission not given to internet/intranet code).

• It is better practice to use the Serializable attribute to the class for enabling it to serialize the object with all its members and use NonSerialized attribute for omitting the members(like temporary, calculated values) of the object that need not be serialized.

• For deserializing an object created in older version of the product in the newer application, either customized deserialization method can be used or the newly created attributes can be marked with the tag, OptionalField to avoid exceptions.

_______________________________________________________________________

Add to My Yahoo!


FREE Subscription

Subscribe to our mailing list and receive new articles
through email. Keep yourself updated with latest
developments in the industry.

Name:
Email:

Note : We never rent, trade, or sell my email lists to
anyone. We assure that your privacy is respected
and protected.

Visit .NET Programming Tutorial Homepage

______________________________________________________

Recommended Resource

|Developing .Net applications for multiple locales | List of Conversion Keywords in C# |Storage and transfer of data using Serialization in .NET |C# (C Sharp) Unified Type System: Reference Types |Using Reflection at Runtime in .NET Framework |What are Generics in C# |Working with Generic Collections in .NET Framework |Working with Graphics in .Net |Working with Isolated Storage in .NET|


| Privacy Policy for www.dotnet-guide.com | Disclosure | Contact |

Copyright - © 2004 - 2017 - All Rights Reserved.