Jquery自动完成Ajax ASP.NET -什么也没发生

我不能让我的Jquery UI自动完成工作。编辑:我将列表解析为json，并在调试时获得json，但我的自动完成没有响应，文本框下没有任何内容，也没有errormessage

我有。net 4.5

    <script type="text/javascript">
        $( document ).ready(function() {
        $(function () {
            $(".tags").autocomplete({
                source: function (request, response) {
                    $.ajax({
                        type: "POST",
                        contentType: "application/json; charset=utf-8",
                        url: "../SearchService/Search.ashx?term=" + request.term,
                        data: {},
                        dataType: "json",
                        error: function (XMLHttpRequest, textStatus, errorThrown) {
                            console.log('error');
                        },
                        success: function (data) {
                            console.log('YES');
                            response($.map(data.d, function (item) {
                                return {
                                    value: item.dataFromServer
                                }
                            }))
                        }
                    });
                }
            });
        });
        });
 </script>

服务(编辑序列化json)

    public void ProcessRequest(HttpContext context)
    {
        string searchstring = context.Request.QueryString["term"]!= null ? context.Request.QueryString["term"] : string.Empty;
        //string searchstring = "Ögon";
        if (!String.IsNullOrEmpty(searchstring))
        {
            context.Response.ContentType = "text/json";
            context.Response.Write(GetJSON(ProductSearch(searchstring)));
        }

    }
    public List<String> ProductSearch(string searchstring)
    {
        LinqtoDBDataContext db = new LinqtoDBDataContext();
        var searchresult = db.SearchCatalog(searchstring);
        List<string> list = new List<string>();
        foreach (var item in searchresult)
        {
            list.Add(item.SearchOut);
        }

        return list;

    }
    public static string GetJSON(object obj)
    {
        var oSerializer = new JavaScriptSerializer();
        var sbJsonResults = new StringBuilder();
        oSerializer.Serialize(obj, sbJsonResults);
        return sbJsonResults.ToString();
    }

  success: function (data) {
                response($.map(data.d, function (item) {
                    return {
                        value: item.dataFromServer
                    }
                }))
            },