How do I turn a C# object into a JSON string in .NET?

Since we all love one-liners

... this one depends on the Newtonsoft NuGet package, which is popular and better than the default serializer.

Newtonsoft.Json.JsonConvert.SerializeObject(new {foo = "bar"})

Documentation: Serializing and Deserializing JSON

You could use the JavaScriptSerializer class (add reference to System.Web.Extensions):

using System.Web.Script.Serialization;

var json = new JavaScriptSerializer().Serialize(obj);

A full example:

using System;using System.Web.Script.Serialization;public class MyDate{    public int year;    public int month;    public int day;}public class Lad{    public string firstName;    public string lastName;    public MyDate dateOfBirth;}class Program{    static void Main()    {        var obj = new Lad        {            firstName = "Markoff",            lastName = "Chaney",            dateOfBirth = new MyDate            {                year = 1901,                month = 4,                day = 30            }        };        var json = new JavaScriptSerializer().Serialize(obj);        Console.WriteLine(json);    }}

Use Json.Net library, you can download it from Nuget Packet Manager.

Serializing to Json String:

 var obj = new Lad        {            firstName = "Markoff",            lastName = "Chaney",            dateOfBirth = new MyDate            {                year = 1901,                month = 4,                day = 30            }        };var jsonString = Newtonsoft.Json.JsonConvert.SerializeObject(obj);

Deserializing to Object:

var obj = Newtonsoft.Json.JsonConvert.DeserializeObject<Lad>(jsonString );