How to specify polymorphic type in ASP.NET mvc 6

我可以在MVC的早期版本中使用"TypeNameHandling=TypeNameHandling.Auto"。在MVC6中，我有以下类别的

public class BaseClass {
    public string Id {get;set;}
}
public class Foo : BaseClass {
    public string Name {get;set;}
    public string Address {get;set;}
}
public class Bar : BaseClass {
    public string Account {get;set;}
    public string Password {get;set;}
}

在我的webapi中，JSON结果将是以下

[
    {Id: "1", Name: "peter", Address: "address1"},
    {Id: "2", Account: "mary", Password: "1234"}
]

但我想要以下结果：

[
    {$type: "Foo", Id: "1", Name: "peter", Address: "address1"},
    {$type: "Bar", Id: "2", Account: "mary", Password: "1234"}
]

public class BaseClass {
    public string Id {get;set;}
    public readonly string type;
    public BaseClass()
    {
        type = this.GetType().Name;
    }
}