[c#] Creating JSON on the fly with JObject

For some of my unit tests I want the ability to build up particular JSON values (record albums in this case) that can be used as input for the system under test.

I have the following code:

var jsonObject = new JObject();
jsonObject.Add("Date", DateTime.Now);
jsonObject.Add("Album", "Me Against The World");
jsonObject.Add("Year", 1995);
jsonObject.Add("Artist", "2Pac");

This works fine, but I have never really like the "magic string" syntax and would prefer something closer to the expando-property syntax in JavaScript like this:

jsonObject.Date = DateTime.Now;
jsonObject.Album = "Me Against The World";
jsonObject.Year = 1995;
jsonObject.Artist = "2Pac";

There are some environment where you cannot use dynamic (e.g. Xamarin.iOS) or cases in where you just look for an alternative to the previous valid answers.

In these cases you can do:

using Newtonsoft.Json.Linq;

JObject jsonObject =
     new JObject(
             new JProperty("Date", DateTime.Now),
             new JProperty("Album", "Me Against The World"),
             new JProperty("Year", "James 2Pac-King's blog."),
             new JProperty("Artist", "2Pac")
         )

More documentation here: http://www.newtonsoft.com/json/help/html/CreatingLINQtoJSON.htm

You can use Newtonsoft library and use it as follows

using Newtonsoft.Json;



public class jb
{
     public DateTime Date { set; get; }
     public string Artist { set; get; }
     public int Year { set; get; }
     public string album { set; get; }

}
var jsonObject = new jb();

jsonObject.Date = DateTime.Now;
jsonObject.Album = "Me Against The World";
jsonObject.Year = 1995;
jsonObject.Artist = "2Pac";


System.Web.Script.Serialization.JavaScriptSerializer oSerializer =
         new System.Web.Script.Serialization.JavaScriptSerializer();

string sJSON = oSerializer.Serialize(jsonObject );

You can use the JObject.Parse operation and simply supply single quote delimited JSON text.

JObject  o = JObject.Parse(@"{
  'CPU': 'Intel',
  'Drives': [
    'DVD read/writer',
    '500 gigabyte hard drive'
  ]
}");

This has the nice benefit of actually being JSON and so it reads as JSON.

Or you have test data that is dynamic you can use JObject.FromObject operation and supply a inline object.

JObject o = JObject.FromObject(new
{
    channel = new
    {
        title = "James Newton-King",
        link = "http://james.newtonking.com",
        description = "James Newton-King's blog.",
        item =
            from p in posts
            orderby p.Title
            select new
            {
                title = p.Title,
                description = p.Description,
                link = p.Link,
                category = p.Categories
            }
    }
});

Json.net documentation for serialization

Sooner or later you will have property with special character. You can either use index or combination of index and property.

dynamic jsonObject = new JObject();
jsonObject["Create-Date"] = DateTime.Now; //<-Index use
jsonObject.Album = "Me Against the world"; //<- Property use
jsonObject["Create-Year"] = 1995; //<-Index use
jsonObject.Artist = "2Pac"; //<-Property use

Neither dynamic, nor JObject.FromObject solution works when you have JSON properties that are not valid C# variable names e.g. "@odata.etag". I prefer the indexer initializer syntax in my test cases:

JObject jsonObject = new JObject
{
    ["Date"] = DateTime.Now,
    ["Album"] = "Me Against The World",
    ["Year"] = 1995,
    ["Artist"] = "2Pac"
};

Having separate set of enclosing symbols for initializing JObject and for adding properties to it makes the index initializers more readable than classic object initializers, especially in case of compound JSON objects as below:

JObject jsonObject = new JObject
{
    ["Date"] = DateTime.Now,
    ["Album"] = "Me Against The World",
    ["Year"] = 1995,
    ["Artist"] = new JObject
    {
        ["Name"] = "2Pac",
        ["Age"] = 28
    }
};

With object initializer syntax, the above initialization would be:

JObject jsonObject = new JObject
{
    { "Date", DateTime.Now },
    { "Album", "Me Against The World" },
    { "Year", 1995 }, 
    { "Artist", new JObject
        {
            { "Name", "2Pac" },
            { "Age", 28 }
        }
    }
};

Simple way of creating newtonsoft JObject from Properties.

This is a Sample User Properties

public class User
{
    public string Name;
    public string MobileNo;
    public string Address;
}

and i want this property in newtonsoft JObject is:

JObject obj = JObject.FromObject(new User()
{
    Name = "Manjunath",
    MobileNo = "9876543210",
    Address = "Mumbai, Maharashtra, India",
});

Output will be like this:

{"Name":"Manjunath","MobileNo":"9876543210","Address":"Mumbai, Maharashtra, India"}