MVC Action直接在網頁上回傳Class to Json資料

       [HttpGet]
        public JsonResult SampleAction()
        {
            UserData udata = new UserData();
            using (ssEntities ssDBContext = new ssEntities())
            {
                var query = from t1 in ssDBContext.UserData
                            select t1;

                udata = query.FirstOrDefault();
            }

            /*
             
             回傳是一個字串, 內容都是文字
             "{\"PKID\":1,\"UserName\":\"彼得\",\"UserName_Eng\":\"Peter\",\"Sex\":\"Male\",\"Birthday\":\"1980-04-04T00:00:00\",\"MobilePhoneNo\":\"0968123123\",\"Interest\":\"Movie\",\"DeleteDate\":null,\"DeleteUserID\":null,\"DeleteUserName\":null,\"InterestText\":null,\"BirthdayString\":null}"
             
             */
            string json = JsonConvert.SerializeObject(udata);
            return Json(json, JsonRequestBehavior.AllowGet);

            /*
             回傳是Json格式, 沒有字串的雙引號包起來
             {
    "PKID": 1,
    "UserName": "彼得",
    "UserName_Eng": "Peter",
    "Sex": "Male",
    "Birthday": "/Date(323625600000)/",
    "MobilePhoneNo": "0968123123",
    "Interest": "Movie",
    "DeleteDate": null,
    "DeleteUserID": null,
    "DeleteUserName": null,
    "InterestText": null,
    "BirthdayString": null
}
             */
            //return Json(udata, JsonRequestBehavior.AllowGet);
        }

public class User
{
    public int PKID { get; set; }
    public string UserName { get; set; }
    public string UserName_Eng { get; set; }
    public string Sex { get; set; }
    public DateTime Birthday { get; set; }
    public string MobilePhoneNo { get; set; }
    public string Interest { get; set; }
    public DateTime? DeleteDate { get; set; }
    public int? DeleteUserID { get; set; }
    public string DeleteUserName { get; set; }
    public string InterestText { get; set; }
    public string BirthdayString { get; set; }
}