JSON Serializer

We need to install a NuGet package called: Newtonsoft.Json.

Let's create a variable phone with some properties:

var phone = new Phone
    Manufacturer = "Apple",
    Model = "iPhone X",
    Price = 1200.00

Then, press Ctrl and . on the Phone class to generate it.

internal class Phone
    public string Manufacturer { get; set; }
    public string Model { get; set; }
    public double Price { get; set; }

Now, we can try to serialize this object into a JSON string:

var phoneAsJsonString = JsonConvert.SerializeObject(phone);


JSON stands for JavaScript Object Notation.

Press same keys on JsonConvert to add the using statement.

Let's print it to the console and see what we get:


And the result is:

{"Manufacturer":"Apple","Model":"iPhone X","Price":1200.0}

Cool! This is the object serialized into JSON.

We have the option to indent the code to be displayed more nicely:

var phoneAsJsonString = JsonConvert.SerializeObject(phone, Formatting.Indented);

Now, this prints:

  "Manufacturer": "Apple",
  "Model": "iPhone X",
  "Price": 1200.0

Which is indeed more readable for us πŸ‘

As you can see the format is lightweight and easy to interchange between different systems.

Also, if you are familiar with JavaScript, this is the same notation for JS objects.


This JSON string can be stored in a file, a database or sent and received by a Web Application (REST) through HTTP Requests. So, many use cases.

Now, we can do the opposite: because we serialized our object into a JSON string, we can deserialize it into an object again.

var phoneDeserialized = JsonConvert.DeserializeObject<Phone>(phoneAsJsonString);

Two simple things to consider here:

  1. notice that we need to specify the type of the object (in our case <Phone>)
  2. it prints the qualified name (the name of the class). We need to override the ToString method if we want to print its properties instead of its class name.

So, let's override the ToString method to print something more... meaningful, I guess πŸ˜€

public override string ToString()
    return $"{Manufacturer} {Model} ${Price}";

This prints:

Apple iPhone X $1200

Also, there is another serializer which is used internally by .NET called JavaScriptSerializer.

Even Microsoft recommends developers to use the Newtonsoft.Json NuGet package. It's way faster, easier to use etc.


When you read in is called serialize. Wehn you write out is called deserialize.

You can find the source code on GitHub

Data Persistency

We are going to see how to use this JSON serializer to persist data locally in a file.

It's very simple ☺️

First, let's write the JSON string to a file called Phone.json:

File.WriteAllText("Phone.json", phoneAsJsonString);

By default, this file is created in the bin/Debug folder. To find it, you need to right click on the project and open it in File Explorer. There, you can see the folder.

Now, let's read the file and use the string from the file to deserialize the Phone object:

var phoneStringFromFile = File.ReadAllText("Phone.json");

var phoneDeserialized = JsonConvert.DeserializeObject<Phone>(phoneStringFromFile);


But what about XML?

Well, XML is indeed used for similar things being a data formatting language. But, in XML you have a lot of opening and closing tags (as in HTML) which really bloat the string out (verbose format).

With mobile devices, we need to be concerned about the size of the string because this is sent back and forth which can really increase the amount of data traffic.

You can find the source code on GitHub