JSON library for C#

Does Microsoft provide any library to work with JSON in C#? If not, what open source library do you recommend?

JSON.Net

You should also try my ServiceStack JsonSerializer - it's the fastest .NET JSON serializer at the moment based on the benchmarks of the leading JSON serializers and supports serializing any POCO Type, DataContracts, Lists/Dictionaries, Interfaces, Inheritance, Late-bound objects including anonymous types, etc.

Basic Example

var customer = new Customer { Name="Joe Bloggs", Age=31 };
var json = customer.ToJson();
var fromJson = json.FromJson<Customer>(); 

Note: Only use Microsofts JavaScriptSerializer if performance is not important to you as I've had to leave it out of my benchmarks since its up to 40x-100x slower than the other JSON serializers.

The .net framework supports JSON through JavaScriptSerializer. Here is a good example to get you started.

using System.Collections.Generic;
using System.Web.Script.Serialization;

namespace GoogleTranslator.GoogleJSON
{
    public class FooTest
    {
        public void Test()
        {
            const string json = @"{
              ""DisplayFieldName"" : ""ObjectName"", 
              ""FieldAliases"" : {
                ""ObjectName"" : ""ObjectName"", 
                ""ObjectType"" : ""ObjectType""
              }, 
              ""PositionType"" : ""Point"", 
              ""Reference"" : {
                ""Id"" : 1111
              }, 
              ""Objects"" : [
                {
                  ""Attributes"" : {
                    ""ObjectName"" : ""test name"", 
                    ""ObjectType"" : ""test type""
                  }, 
                  ""Position"" : 
                  {
                    ""X"" : 5, 
                    ""Y"" : 7
                  }
                }
              ]
            }";

            var ser = new JavaScriptSerializer();
            ser.Deserialize<Foo>(json);
        }
    }

    public class Foo
    {
        public Foo() { Objects = new List<SubObject>(); }
        public string DisplayFieldName { get; set; }
        public NameTypePair FieldAliases { get; set; }
        public PositionType PositionType { get; set; }
        public Ref Reference { get; set; }
        public List<SubObject> Objects { get; set; }
    }

    public class NameTypePair
    {
        public string ObjectName { get; set; }
        public string ObjectType { get; set; }
    }

    public enum PositionType { None, Point }
    public class Ref
    {
        public int Id { get; set; }
    }

    public class SubObject
    {
        public NameTypePair Attributes { get; set; }
        public Position Position { get; set; }
    }

    public class Position
    {
        public int X { get; set; }
        public int Y { get; set; }
    }
}

If you look here, you will see several different libraries for JSON on C#.

http://json.org/

You will find a version for LINQ as well as some others. There are about 7 libraries for C# and JSON.

Is this what you're looking for?

System.Web.Script.Serialization.JavaScriptSerializer

Have a look at the system.web.script.serialization namespace (i think you will need .Net 3.5)

To give a more up to date answer to this question: yes, .Net includes JSON seriliazer/deserliazer since version 3.5 through the System.Runtime.Serialization.Json Namespace: http://msdn.microsoft.com/en-us/library/system.runtime.serialization.json(v=vs.110).aspx

But according to the creator of JSON.Net, the .Net Framework compared to his open source implementation is very much slower.

To answer your first question, Microsoft does ship a DataContractJsonSerializer: see msdn How to: Serialize and Deserialize JSON Data

Try the Vici Project, Vici Parser. It includes a JSON parser / tokeniser. It works great, we use it together with the MVC framework.

More info at: http://viciproject.com/wiki/projects/parser/home

I forgot to say that it is open source so you can always take a look at the code if you like.