How to insert/create Header-Detail in ASP.Net MVC

See more:

C#

ASP.NET

MVC

I have a problem on how to do insert/create in ASP.Net MVC in Header-Detail.
My scenario.

Models:
-OrderHeader
-OrderDetail

In my controller

[HttpGet]
public JsonResult Create(int id){
   var order = context.OrderHeader.Include(d => d.OrderDetail).Where(i => i.id == id).ToList();
   return Json(order); //1.) Problem will have circular dependency
}

[HttpPost]
public ActionResult Create(OrderHeader order){
    //2.) how to insert or update OrderDetail here? How will i know if i trigger udpate/delete or create?
}

Please see my comments for my questions.