wcf - 通过传递数据从 wcf 绑定 Jquery 中的下拉列表

Question

我正在尝试通过将数据传递给 WCF 来绑定 JQuery 中的下拉列表。

jQuery代码是：

    function PopulateCity()
    {        
    var StateID = { 'stateId': $("[id$=ddlState]").val() };        
    var jsondata = JSON.stringify(StateID);        
    $('[id$=ddlCity]').empty().append('<option selected="selected" value="0">Loading...</option>');        
            $.ajax({
                type: "POST",
                url: 'http://localhost:49583/Service1.svc/PopulateCities',
                data: jsondata,
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function (data) {
                    BindCity(data,'ddlCity');
                },
                failure: function (response) {
                    alert(response);
                }
            });
    }

function BindCity(list, control) {    
         $.each(list, function (value, text) {            
            $("select[id$=" + control + "]").append($("<option></option>").val(this['Value']).html(this['Text']));
        });
 }

WCF 代码是：

    [OperationContract]
    [WebInvoke(Method = "POST", ResponseFormat = WebMessageFormat.Json)]
    List<CityDetails> PopulateCities(int stateId);

实现的接口是：

List<CityDetails> IService1.PopulateCities(int stateId) {

            List<CityDetails> arrCity = new List<CityDetails>();
            String strConnString = ConfigurationManager
                .ConnectionStrings["conString"].ConnectionString;
            //String strQuery = "select ID, CityName from Cities where CountryID=@CountryID";
            String strSP = "Car_GetSubMasterDetails";
            using (SqlConnection con = new SqlConnection(strConnString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    cmd.CommandType = CommandType.Text;
                    cmd.Parameters.AddWithValue("@MasterID", stateId);
                    cmd.Parameters.AddWithValue("@Key", "City");
                    cmd.Parameters.AddWithValue("@Culture", "en-US");
                    cmd.CommandText = strSP;
                    cmd.Connection = con;
                    con.Open();
                    SqlDataReader sdr = cmd.ExecuteReader();
                    while (sdr.Read())
                    {
                        arrCity.Add(new CityDetails() { Value = sdr["ID"].ToString(), Text = sdr["CityName_en_US"].ToString() });
                       // list.Add(new ListItem(
                       //sdr["CityName_en_US"].ToString(),
                       //sdr["ID"].ToString()
                       // ));
                    }
                    con.Close();
                    return arrCity;                    
                }
            }
        }

我不明白我错在哪里。它既没有绑定下拉列表也没有显示任何错误。请帮助..提前致谢。