Question

In rails you can do the following to convert an object to Json but only with a subset of the fields included in the object.

@user.to_json :only => [ :name, :phone ]

Although i am using currently the ASP.NET MVC Json() function it doesn’t let me define which fields i want to include in the conversion. So my question is whether or not there is a function in JSON.NET or otherwise that will accept specific fields before doing the conversion to json.

Edit: Your answer should also cover the array scenario ie.

@users.to_json :only => [ :name, :phone ]

Answer 1

You could use anonymous types:

public ActionResult SomeActionThatReturnsJson()
{
    var someObjectThatContainsManyProperties = GetObjectFromSomeWhere();
    return Json(new {
        Name = someObjectThatContainsManyProperties.Name,
        Phone = someObjectThatContainsManyProperties.Phone,
    });
}

will return {"Name":"John","Phone":"123"}

---

UPDATE:

The same technique can be used for the array scenario:

public ActionResult SomeActionThatReturnsJson()
{
    var users = from element in GetObjectsFromSomeWhere()
                select new {
                    Name = element.Name,
                    Phone = element.Phone,
                };
    return Json(users.ToArray());
}