Determine type during json deserialize

I'm working on a protocol in which the receiver will receive json messages of certain specified custom types (currently 5, but could be 10-20). I'm struggling to come up with an optimal/fast solution which will automatically deserialize the json and return the correct type of object.

Example:

public class MessageA
{
    public string Message;
} 

public class MessageB
{
    public int value;
}

public class MessageC
{
    public string ValueA;
    public string ValueB;
}

Ideally, the method should be like

 Object Deserialize(string json);

and it will return one of the three message types OR null - in case there was a parsing error/the json didn't match any of the predefined type.

UPDATE: I have control over sender/receiver as well as the protocol design.

Solution

It would be helpful if the message could specify its type. Otherwise you have to infer it from some property or another.

You could use a message wrapper class when serializing, like this:

public class MessageWrapper<T>
{
    public string MessageType { get { return typeof(T).FullName; } }
    public T Message { get; set; }
}

So if you have a class Name with a First and Last property, you could serialize it like this:

var nameMessage = new MessageWrapper<Name>();
nameMessage.Message = new Name {First="Bob", Last = "Smith"};
var serialized = JsonConvert.SerializeObject(nameMessage);

The serialized JSON is

{"MessageType":"YourAssembly.Name","Message":{"First":"Bob","Last":"Smith"}}

When deserializing, first deserialize the JSON as this type:

public class MessageWrapper
{
    public string MessageType { get; set; }
    public object Message { get; set; }
}

var deserialized = JsonConvert.DeserializeObject<MessageWrapper>(serialized);

Extract the message type from the MessageType property.

var messageType = Type.GetType(deserialized.MessageType);

Now that you know the type, you can deserialize the Message property.

var message = JsonConvert.DeserializeObject(
    Convert.ToString(deserialized.Message), messageType);

message is an object, but you can cast it as Name or whatever class it actually is.