请注意是mvc2，不是mvc3哦
jquery ajax怎么给控制器中方法参数类型为List的传递参数

控制器代码：
[HttpPost]
        public ActionResult Set_ClassArray(List<Models.ClassA> ClassAlist)
        {
            List<Models.ClassA> li = new List<Models.ClassA>();

            foreach(Models.ClassA item in ClassAlist)
            {
                li.Add(new Models.ClassA()
                {
                    Name = item.Name + "名字变啦,并且长大10岁!",
                    Age = item.Age + 10,
                    IsMan = !item.IsMan
                });
            }

            //故意延时，以便演示效果
            System.Threading.Thread.Sleep(2000);

            return Json(li);
        }


public class ClassA
    {
        public string Name
        {
            get;
            set;
        }

        public int Age
        {
            get;
            set;
        }

        public bool IsMan
        {
            get;
            set;
        }
    }


页面代码：
 $("#Button_setclassarr").click(function ()
            {
                var str = '{"ClassAlist":[{"Name":"小高","Age":28,"IsMan":true },{"Name":"小皓","Age":16,"IsMan":false }]}';

                var options = {
                    url: "../De/Set_ClassArray",
                    type: "POST",
                    dataType: "json",
                    data: str,
                    success: function (response)
                    {
                        //返回的对象数组
                        var arr = response;
                        //循环
                        $.each(arr, function (index, va)
                        {
                            //得对象
                            var obj = va;
                            var str = "姓名:" + obj.Name + " 年纪:" + obj.Age + " 是男人:" + obj.IsMan + "  ";
                            $('#div_txt').append("第" + index + "项值=" + str + "   ");
                        })
                    }
                }

                $.ajax(options);
            });


用浏览器观察到Set_ClassArray方法接收到的值为null