今天总算弄明白了JsonResult怎么跟数据库数据进行交互

HomeController.cs

 public JsonResult Getjosn(int pid)
        {
            return Json(Area(pid));
        }
        public IEnumerable<HuiyuanInfo> Area(int pid)
        {
            return from c in db.HuiyuanInfo where c.ID == pid select c;
        }

Home/Index.aspx

 function GetArea(pid, obj) {
        $.getJSON("/Home/Getjosn", { pid: pid }, function(data) {
            $(obj).empty();
            $(obj).append("<option value='0'>请选择</option>");
            $(data).each(function(i, item) {
                $(obj).append("<option value='" + item.Huiyuan_ID + "'>" + item.Huiyuan_name + "</option>");
            });
        });
    }

<select id="Select1" onchange="GetArea(this.value,'select[name=\'City\']')">
         <option value="">请选择省份</option>
         <option value="1">fdfd</option>
          <option value="2">fdfd</option>
    </select>
    <select name="City" class="require" check="num">
                <option value="">请选择城市</option>
            </select>