MVC3中Json的应用

public ActionResult MaterialByClass(string l)
        {
            var materials = _db.Products.Where(m => m.CodeClass == l).ToList().Select(a => new SelectListItem() { Text = a.Material.Name != null ? a.Material.Name : "[NO Date}", Value = a.CodeMaterial });
            return Json(materials, JsonRequestBehavior.AllowGet);
        }

 $("#@orgFieldId").change(function () {
      var idProd = $(this).val();
      $.getJSON("/JsonService/GetAccounts", { orgId: idProd },
          function (myData) {
              var select = $("#@fieldId");
              select.empty(); 
              $.each(myData, function (index, itemData) {
                  select.append($('<option/>', {
                      value: itemData.Value,
                      text: itemData.Text
                  }));
              });
          });
  });

  $(document).ready(function () {
    $("#@orgFieldId").change();
  });

$(function () {
            $("#l").change(function () {
                var url = "/Home/MaterialByClass";
                var id_cz = $("#l").val();
                $.getJSON(url, { l: id_cz },
                 function (myData) {   
                     var items = "";
                     $.each(myData, function (i, cz) {
                         items += "<option value='" + cz.value + "'>" + cz.Text + "</option>";  
                     });
                      $("#c").html(items);   
                 });
            });
        });

        $(function () {
            $("#l").change();
        });

       [HttpPost]
        public ActionResult AddGroupAccount(string useraccount)
        {
        var result = new GroupViewModel
           {
               Id = addid,
               SubUserAccount = useraccount,
               Company=company,
               Statu="<span style='color:Red'>等待对方确认</span>",
               Message = message
           };   
            return Json(result);    
        }

 $(function () {
        $(".addbtn").click(function () {
            var put_sub_user = $("#put_sub_useraccount").val();
            if (put_sub_user != '') {
                $.post("/User/Index/AddGroupAccount", { "useraccount": put_sub_user },
              function (data) {
                  if (data.Message == "添加成功！") {
                      $("#userlist").prepend("<tr id=row-" + data.Id + "><td>" + data.SubUserAccount + "-" + data.Company + " [" + data.Statu + "]</td><td width='57'><a href='#'  class='RemoveLink'  data-id=" + data.Id + ">删除</a></td></tr>");
                      $("#message").text(data.Message);
                  }
                  else
                      $("#message").text(data.Message);
              });
            }
            else
                $("#message").text("出错！输入框不能为空！");
        });

var dataid = $("#curr_id").val();
                var datapcs = $("#PCS").val();
                $.post("/ShoppingCart/AddToCart", { id: dataid,pcs:datapcs}, function (data) {
                    if (data.Message = "ok")
                        alert(data.Message);
                    else
                        alert("Error");
                });