Json Serialization And Deserialization In C# Complete Guide

JSON Serialization and Deserialization in C#

Key Components:

1. System.Text.Json Namespace: Introduced in .NET Core 3.0, this namespace provides a fast, low-allocating, and standards-compliant JSON serializer and deserializer for use with the System.Object type in C#. The JsonSerializer class in this namespace handles the conversion between JSON and C# objects.

2. Newtonsoft.Json (Json.NET): Before System.Text.Json, the Newtonsoft.Json package was widely used. It offers a robust and flexible set of features to handle JSON data in C#. Newtonsoft.Json is compatible with various .NET versions.

Serialization:

Serialization is the process of converting a C# object into a JSON string. The System.Text.Json namespace provides a straightforward API for this.

Using System.Text.Json:

using System;
using System.Text.Json;

class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

class Program
{
    static void Main()
    {
        Person person = new Person { Name = "John Doe", Age = 30 };
        string jsonString = JsonSerializer.Serialize(person);
        Console.WriteLine(jsonString);  // Output: {"Name":"John Doe","Age":30}
    }
}

Using Newtonsoft.Json:

using System;
using Newtonsoft.Json;

class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
}

class Program
{
    static void Main()
    {
        Person person = new Person { Name = "John Doe", Age = 30 };
        string jsonString = JsonConvert.SerializeObject(person);
        Console.WriteLine(jsonString);  // Output: {"Name":"John Doe","Age":30}
    }
}

Deserialization:

Deserialization is the inverse process, converting a JSON string into a C# object.

Using System.Text.Json:

string jsonString = "{\"Name\":\"John Doe\",\"Age\":30}";
Person person = JsonSerializer.Deserialize<Person>(jsonString);
Console.WriteLine($"Name: {person.Name}, Age: {person.Age}");  // Output: Name: John Doe, Age: 30

Using Newtonsoft.Json:

string jsonString = "{\"Name\":\"John Doe\",\"Age\":30}";
Person person = JsonConvert.DeserializeObject<Person>(jsonString);
Console.WriteLine($"Name: {person.Name}, Age: {person.Age}");  // Output: Name: John Doe, Age: 30

Customization:

Both libraries offer extensive customization options, including handling custom data types, modifying date formats, ignoring null values, and more.

Customizing Output with System.Text.Json:

var options = new JsonSerializerOptions
{
    WriteIndented = true,  // Pretty prints JSON
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase  // Converts property names to camelCase
};

string jsonString = JsonSerializer.Serialize(person, options);
Console.WriteLine(jsonString);

Customizing Output with Newtonsoft.Json:

var settings = new JsonSerializerSettings
{
    Formatting = Formatting.Indented,  // Pretty prints JSON
    NullValueHandling = NullValueHandling.Ignore  // Ignores null properties
};

string jsonString = JsonConvert.SerializeObject(person, settings);
Console.WriteLine(jsonString);

Handling Complex Types:

Both libraries can handle complex types such as collections, nested objects, and enums seamlessly.

Using System.Text.Json:

class Company
{
    public string Name { get; set; }
    public List<Person> Employees { get; set; }
}

Company company = new Company
{
    Name = "Tech Corp",
    Employees = new List<Person>
    {
        new Person { Name = "John Doe", Age = 30 },
        new Person { Name = "Jane Smith", Age = 25 }
    }
};

string jsonString = JsonSerializer.Serialize(company);
Console.WriteLine(jsonString);

Using Newtonsoft.Json:

Company company = new Company
{
    Name = "Tech Corp",
    Employees = new List<Person>
    {
        new Person { Name = "John Doe", Age = 30 },
        new Person { Name = "Jane Smith", Age = 25 }
    }
};

string jsonString = JsonConvert.SerializeObject(company);
Console.WriteLine(jsonString);

Conclusion:

JSON serialization and deserialization are fundamental for building robust applications that can interact with web services, store data, and transmit information efficiently. The System.Text.Json namespace is modern and preferred for new projects in .NET, whereas Newtonsoft.Json remains a powerful alternative with more advanced features and broader compatibility.