How to create a JSON string in C# (2024)

What is JSON?

JSON (JavaScript Object Notation) is THE standard design for human-readable data interchange. It is a light-weight, human-readable format for storing and transporting data. Since JSON works with a tree structure, it looks like XMLExtensible Markup Language (XML)is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.. Due to its built-in features, it is very easy to comprehend and use.

JSON is mainly used when data is sent from a server to a web page.

How to create JSON string in C#

Create your new console project from Visual Studio.
Click File, New Project, Console Application.
Once the editor is opened, go to “Project”.
Click on “Manage NuGet Packages”.
Search “Newtonsoft.JSON” on Nuget Package Manager in the browse window and install it.

You can also install Newtonsoft.JSON from the terminal using this command:dotnet add package Newtonsoft.Json

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Add the relevant libraries as part of the code. The programming language used is C#:

using System;using System.Collections.Generic;using Newtonsoft.Json;

Create a class. For example, let’s create the class studentInfo that stores the name, Roll (as in roll number), and the list of courses each student is studying during the semester. We will output this information as a JSON string:

class studentInfo{ public int Roll {get; set;} public string name {get; set;} public List<string> courses {get; set;}}

Define a new instance of class studentInfo in the main function. In this example, I have named it student1. Add relevant values to store in this class attribute:

studentInfo student1 = new studentInfo() { Roll = 110, name = "Alex", courses = new List<string>() { "Math230", "Calculus1", "CS100", "ML" } };

Convert the object to a JSON string by serializing the object. Serialization will return a string. Finally, output the string.

string stringjson = JsonConvert.SerializeObject(student1);Console.WriteLine(stringjson);

Code

// necessary libraries to be used
using System;
using System.Collections.Generic;
using Newtonsoft.Json;
namespace JsonParser
{
// Define a class to store values to be converted to JSON 
class studentInfo
{
 // Make sure all class attributes have relevant getter setter.
 // Roll Number
 public int Roll {get; set;}
 // Name of the student
 public string name {get; set;}
 // The List of courses studying
 public List<string> courses {get; set;}
}
class HelloWorld
{
 // Main function
 static void Main()
 {
 // Creating a new instance of class studentInfo
 studentInfo student1 = new studentInfo() 
 {
 // Roll number
 Roll = 110,
 // Name
 name = "Alex",
 //list of courses
 courses = new List<string>()
 {
 "Math230",
 "Calculus1",
 "CS100",
 "ML"
 }
 };
 Console.WriteLine("JSON converted string: ");
 // convert to Json string by seralization of the instance of class.
 string stringjson = JsonConvert.SerializeObject(student1);
 Console.WriteLine(stringjson); 
 }
 }
}

Sample output

JSON converted string:{"Roll":110,"name":"Alex","courses":["Math230","Calculus1","CS100","ML"]}