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Json.NET

TypeNameHandling setting

 

This sample uses the TypeNameHandling setting to include type information when serializing JSON and read type information so that the create types are created when deserializing JSON.

Sample
Types
public abstract class Business
{
    public string Name { get; set; }
}

public class Hotel : Business
{
    public int Stars { get; set; }
}

public class Stockholder
{
    public string FullName { get; set; }
    public IList<Business> Businesses { get; set; }
}
Usage
Stockholder stockholder = new Stockholder
{
    FullName = "Steve Stockholder",
    Businesses = new List<Business>
    {
        new Hotel
        {
            Name = "Hudson Hotel",
            Stars = 4
        }
    }
};

string jsonTypeNameAll = JsonConvert.SerializeObject(stockholder, Formatting.Indented, new JsonSerializerSettings
{
    TypeNameHandling = TypeNameHandling.All
});

Console.WriteLine(jsonTypeNameAll);
// {
//   "$type": "Newtonsoft.Json.Samples.Stockholder, Newtonsoft.Json.Tests",
//   "FullName": "Steve Stockholder",
//   "Businesses": {
//     "$type": "System.Collections.Generic.List`1[[Newtonsoft.Json.Samples.Business, Newtonsoft.Json.Tests]], mscorlib",
//     "$values": [
//       {
//         "$type": "Newtonsoft.Json.Samples.Hotel, Newtonsoft.Json.Tests",
//         "Stars": 4,
//         "Name": "Hudson Hotel"
//       }
//     ]
//   }
// }

string jsonTypeNameAuto = JsonConvert.SerializeObject(stockholder, Formatting.Indented, new JsonSerializerSettings
{
    TypeNameHandling = TypeNameHandling.Auto
});

Console.WriteLine(jsonTypeNameAuto);
// {
//   "FullName": "Steve Stockholder",
//   "Businesses": [
//     {
//       "$type": "Newtonsoft.Json.Samples.Hotel, Newtonsoft.Json.Tests",
//       "Stars": 4,
//       "Name": "Hudson Hotel"
//     }
//   ]
// }

// for security TypeNameHandling is required when deserializing
Stockholder newStockholder = JsonConvert.DeserializeObject<Stockholder>(jsonTypeNameAuto, new JsonSerializerSettings
{
    TypeNameHandling = TypeNameHandling.Auto
});

Console.WriteLine(newStockholder.Businesses[0].GetType().Name);
// Hotel