JSON – Serialization and Deserialization

What is JSON?
JSON is another format of expressing data, just like XML. But, JSON is very simpler than XML, and tiny than XML. So, it is becoming popular in the web world to choose the JSON notation over XML since JSON notation are usually shorter, and less data to be transmitted if at all they were to be.
Okay, I understood a little about JSON. Give me an example!
 I know an example will get your understanding much better. Below is a simple example of how an object can be expressed in JSON notation. Let’s take a classical example of a Person object, and expressing myself as an object.
{
   “firstName”: “Rakki”,
   “lastName”:”Muthukumar”,
   “department”:”Microsoft PSS”,
   “address”: {
      “addressline1”: “Microsoft India GTSC”,
      “addressline2”: “PSS – DSI”,
      “city”: “Bangalore”,
      “state”: “Karnataka”,
      “country”: “India”,
      “pin”: 560028
   }
   “technologies”: [“IIS”, “ASP.NET”,“JavaScript”,“AJAX”]
}
In the above example, address is another object inside my Person, and technologies is an array or strings.
 
Express this as a simple .NET class, please!
Here is a simple example.
public class Address
{
    public string addressline1, addressline2, city, state, country;
    public int pin;
}
 public class Person
{
    public string firstName, lastName, department;
    public Address address = new Address();
    public string[] technologies;
}
I get it. Now what? JSON Serialization / Deserialization?
Here. I’ll touch upon how to use System.Web.Script.Serialization.JavaScriptSerializer to convert an existing object into a JSON string.
JavaScriptSerializer js = new JavaScriptSerializer();
Person p1 = new Person();
p1.firstName = "Rakki";
p1.lastName = "Muthukumar";
p1.department = "Microsoft PSS";
p1.address.addressline1 = "Microsoft India GTSC";
p1.address.addressline2 = "PSS - DSI";
p1.address.city = "Bangalore";
p1.address.state = "Karnataka";
p1.address.country = "India";
p1.address.pin = 560028;
p1.technologies = new string[] { "IIS", "ASP.NET", "JavaScript", "AJAX" };
 string str = js.Serialize(p1);

Above code just creates a Person object, and assign some values. Look at the last line where we are actually doing a serialization – means dumping the contents of the object to a JSON notation. Below is the string produced by the above code:

{“firstName”:”Rakki”,”lastName”:”Muthukumar”,”department”:”Microsoft PSS”,”address”:{“addressline1″:”Microsoft India GTSC”,”addressline2″:”PSS – DSI”,”city”:”Bangalore”,”state”:”Karnataka”,”country”:”India”,”pin”:560028},”technologies”:[“IIS”,”ASP.NET”,”JavaScript”,”AJAX”]}

It is the same as how we defined the object before – but in a single line. Now, you have successfully converted your object into a JSON string.

Now how do I deserialize it?
Before going into how to deserialize it, let’s just understand when you might want to deserialize the object. Classical example is a JSON object returned from a web service, or from your client side javascript code, and you will be able to deserialize it in the server side to use the received object.
Person p2 = js.Deserialize(str);
Response.Write(p2.lastName);

p2.lastName would contain “Muthukumar” if your deserialization works fine. I suggest you to use the Deserialize<T> method since it will reduce the type casting you might be doing if you use DeserializeObject() method which returns a System.Object.

Hope this helps!

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