Can you Instantiate an Object Instance from JSON in .NET?

Question

Since Object Initializers are very similar to JSON, and now there are Anonymous Types in .NET. It would be cool to be able to take a string, such as JSON, and create an Anonymous Object that represents the JSON string.

Use Object Initializers to create an Anonymous Type:

var person = new {
    FirstName = "Chris",
    LastName = "Johnson"
};

It would be awesome if you could pass in a string representation of the Object Initializer code (preferably something like JSON) to create an instance of an Anonymous Type with that data.

I don't know if it's possible, since C# isn't dynamic, and the compiler actually converts the Object Initializer and Anonymous Type into strongly typed code that can run. This is explained in this article.

Maybe functionality to take JSON and create a key/value Dictionary with it would work best.

I know you can serialize/deserializer an object to JSON in .NET, but what I'm look for is a way to create an object that is essentially loosely typed, similarly to how JavaScript works.

Does anyone know the best solution for doing this in .NET?

UPDATE: Too clarify the context of why I'm asking this... I was thinking of how C# could better support JSON at the language level (possibly) and I was trying to think of ways that it could be done today, for conceptual reasons. So, I thought I'd post it here to start a discussion.

Answer 1

There are languages for .NET that have duck-typing but it's not possible with C# using Dot.Notation since C# requires that all member references are resolved at compile time. If you want to use the Dot.Notation, you still have to define a class somewhere with the required properties, and use whatever method you want to instantiate the class from the JSON data. Pre-defining a class does have benefits like strong typing, IDE support including intellisense, and not worrying about spelling mistakes. You can still use anonymous types:

 T deserialize<T>(string jsonStr, T obj) { /* ... */}

 var jsonString = "{FirstName='Chris', LastName='Johnson, Other='unused'}";
 var person     = deserialize(jsonString, new {FirstName="",LastName=""});
 var x          = person.FirstName; //strongly-typed

Answer 2

You should check out the JSON.net project:

http://james.newtonking.com/pages/json-net.aspx

You are basically talking about the ability to hydrate an object from JSON, which this will do. It won't do the anonymous types, but maybe it will get you close enough.