Json.net serialize/deserialize derived types?

Question

json.net (newtonsoft)
I am looking through the documentation but I can't find anything on this or the best way to do it.

public class Base {     public string Name; } public class Derived : Base {     public string Something; }  JsonConvert.Deserialize<List<Base>>(text); 

Now I have Derived objects in the serialized list. How do I deserialize the list and get back derived types?

Answer 1

You have to enable Type Name Handling and pass that to the (de)serializer as a settings parameter.

Base object1 = new Base() { Name = "Object1" }; Derived object2 = new Derived() { Something = "Some other thing" }; List<Base> inheritanceList = new List<Base>() { object1, object2 };  JsonSerializerSettings settings = new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.All }; string Serialized = JsonConvert.SerializeObject(inheritanceList, settings); List<Base> deserializedList = JsonConvert.DeserializeObject<List<Base>>(Serialized, settings); 

This will result in correct deserialization of derived classes. A drawback to it is that it will name all the objects you are using, as such it will name the list you are putting the objects in.

Answer 2

If you are storing the type in your text (as you should be in this scenario), you can use the JsonSerializerSettings.

See: how to deserialize JSON into IEnumerable<BaseType> with Newtonsoft JSON.NET

Be careful, though. Using anything other than TypeNameHandling = TypeNameHandling.None could open yourself up to a security vulnerability.