如何使用Ajax和Asp.net返回对象列表?

我试图通过ajax从服务器端代码返回对象列表。它正在成功返回,但我无法提取。

Jquery代码

$.ajax({
            type: "POST",
            contentType: "application/json;charset=utf-8",
            url: "MyWebService.asmx/Execute_SequenceNo",

            data: JSON.stringify({
                "journalEntry": $('#ContentPlaceHolder1_txtJournalEntry').val().trim()
            }),
            dataType: "json",
            success: function (data) {
                alert("Success = " + data.d.length + ', Data 0 =' + data.d[0] + ' ' + data.d[1])
            },
            error: function (result) {


            }
        })

下面是从我的Sql Server获取记录的代码

[WebMethod]
    public SequenceNumber[] Execute_SequenceNo(string journalEntry)
    {
        DataTable dt = new DataTable();
        List<SequenceNumber> details = new List<SequenceNumber>();
        try
        {
            string cs = ConfigurationManager.ConnectionStrings["TestConnectionString"].ConnectionString;

            using (SqlConnection con = new SqlConnection(cs))
            {
                SqlCommand cmd = new SqlCommand("spTest", con);
                cmd.CommandType = CommandType.StoredProcedure;


                con.Open();
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                da.Fill(dt);
                foreach (DataRow drow in dt.Rows)
                {


                    sequence.errorMsg = "Valid";
                    details.Add(sequence);
                }
            }
            return details.ToArray();
        }
        catch (Exception ee)
        {
            //return "NotValid error = " + ee.ToString();
            SequenceNumber sequence = new SequenceNumber();
            sequence.errorMsg = "NotValid";
            return details.ToArray();
        }


    }

它成功返回,但我的警报如下所示

Success = 2, Data 0 =[object Object] [object Object]