mvc 控制器返回json

  public ActionResult AutoCompleteFromHistory()           
 var m_JsonData = new
            {
                query = value,
                suggestions = list,
                data = new string[] { }
            };
            return Json(m_JsonData, JsonRequestBehavior.AllowGet);

　　

  public JsonResult ImgUpload(HttpPostedFileBase file)
        {
            if (file == null)
            {
                return Json(new { Success = false, Message = "请选择要上传的文件！" }, JsonRequestBehavior.AllowGet);
            }

  return Json(new { Success = false, Message = ex.Message }, JsonRequestBehavior.AllowGet);
return Json(new { code = 0, msg = "", data = "../wwwroot/image/QiXSP/"+ saveName });

 var  拼接不成 json