ASP.NET5-$.ajaxpostJSON.stringify(para)isnull

var para = {};para.id = $("#ad-text-id").val();para.title = $("#ad-text-title").val().trim();para.link = $("#ad-text-link").val().trim();$.Ajax({    url: '/ajax/AdText/SaveAdText',    data: JSON.stringify(para),    type: 'post',    dataType: 'json',    contentType: 'application/json; charset=utf-8',    cache: false,    success: function (data) {    },    error: function (xhr) {    }});

[HttpPost]public async Task<JsonResult> SaveAdText(int id, string title, string link){    //id, title, link para is null...}

public class Model{    public int Id { get; set; }    public string Title { get; set; }    public string Link { get; set; }}[HttpPost]public async Task<JsonResult> SaveAdText([FromBody]Model model){    //model.Id, model.Title, model.Link is not null...}