Asp.Net Ajax Select Sql Query - asp.net

Question

Hello everyone I want to do ajax select query with parameters. I get select query but I want to do if writen on textbox doesnt have, get message "dont have this query".
Ajax Code..
<script type="text/javascript">
$(document).ready(function () {
$("#ekle").click(function () {
$('#ajaxloading').show();
$("#data").html("");
$.ajax({
type: "POST",
url: "Default.aspx/ekle",
data: "{'id':'" + txtemail.value + "'}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (msg) {
$('#ajaxloading').hide();
$("#data").html(msg.d);
},
error: function () {
if (txtemail.value == "") {
alert('Boş alan bırakmayın..');
$('#ajaxloading').hide();
}
else {
alert('Talep esnasında sorun oluştu. Yeniden deneyin');
$('#ajaxloading').hide();
}
}
});
});
});
</script>
Web Method Code
Web Method Kodlarım
[System.Web.Services.WebMethod]
public static string ekle(int id)
{
System.Threading.Thread.Sleep(1000);
DataTable dt = new DataTable();
dt.Columns.Add("ID");
dt.Columns.Add("GonderiNo");
dt.Columns.Add("Tarih");
dt.Columns.Add("GonderenAdSoyad");
dt.Columns.Add("AliciAdSoyad");
dt.Columns.Add("Adres");
dt.Columns.Add("Durum");
using (KargoTakipEntities kargo = new KargoTakipEntities())
{
var kargotakip = from v in kargo.KargoTakipSorgu where v.GonderiNo== id select v;
int i = 0;
foreach (var k in kargotakip)
{
dt.Rows.Add();
dt.Rows[i]["ID"] = k.ID;
dt.Rows[i]["GonderiNo"] = k.GonderiNo;
dt.Rows[i]["Tarih"] = k.Tarih;
dt.Rows[i]["GonderenAdSoyad"] = k.GonderenAdSoyad;
dt.Rows[i]["AliciAdSoyad"] = k.AliciAdSoyad;
dt.Rows[i]["Adres"] = k.Adres;
dt.Rows[i]["Durum"] = k.Durum;
i++;
}
GridView g = new GridView();
g.ShowHeader = false;
g.BorderWidth = 2;
g.CellPadding = 15;
g.CellSpacing = 15;
g.GridLines = GridLines.Both;
g.DataSource = dt;
g.DataBind();
StringWriter sw = new StringWriter();
HtmlTextWriter ht = new HtmlTextWriter(sw);
g.RenderControl(ht);
return sw.ToString();
}
}