Pls help to check why bind data to gridview no data reponse

Question

Pls help to check why bind data to gridview no data reponse as below:-

 

1) WebForm3.aspx

<script type="text/javascript" src="../js/jquery-1.3.2.min.js"></script>
<script type="text/javascript">
$(document).ready(function () {
$('#Data').change(function () {
$.ajax({
type: "POST",
contentType: "application/json; charset=utf-8",
url: "Fetch.aspx/GetData",
data: "{ JO_NO: '" + $('#Data').val() + "'}",
dataType: "json",
success: function (data) {
$("#DataDetails").html(data.d);
}
});
});
});
</script>
<form id="form1" runat="server">
<div id="SelectData">
<asp:DropDownList ID="Data" runat="server">
</asp:DropDownList>
</div>
<div id="DataDetails">
</div>
</form>

Code Behind

protected void Page_Load(object sender, EventArgs e)
{
string connect = "Data Source=(DESCRIPTION ="
+ "(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=xxx.xxx.xxx.xxx)(PORT=xxxx)))"
+ "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=xxxxxx)));"
+ "User Id=xxxxx;Password=xxxxxxxx;";
string query = "SELECT JO_NO,JO_PRD FROM table";
using (OracleConnection conn = new OracleConnection(connect))
{
using (OracleCommand cmd = new OracleCommand(query, conn))
{
conn.Open();
Data.DataSource = cmd.ExecuteReader();
Data.DataValueField = "JO_NO";
Data.DataTextField = "JO_PRD";
Data.DataBind();
}
}
}

2) Fetch.aspx Code Behind

[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json, UseHttpGet = true)]
public string GetData(string JO_NO)
{
string res = "<p>No customer selected</p>";
string st = "Data Source=(DESCRIPTION ="
+ "(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=xxx.xxx.xxx.xxx)(PORT=xxxx)))"
+ "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=xxxxxx)));"
+ "User Id=xxxxx;Password=xxxxxxxx;";
Customer com = new Customer();
if (JO_NO != null)
{
StringBuilder sb = new StringBuilder();
using (OracleConnection con = new OracleConnection(st))
{
using (OracleCommand cmd = new OracleCommand("SELECT JO_QTY,JO_PRD FROM TABLE WHERE JO_NO='" + JO_NO + "'", con))
{
con.Open();
OracleDataReader rdr = cmd.ExecuteReader();
if (rdr.HasRows)
{
while (rdr.Read())
{
com.CustomerID = rdr["JO_PRD"].ToString();
com.FirstName = rdr["JO_QTY"].ToString();
sb.Append("<p>");
sb.Append("<strong>" + rdr["JO_QTY"].ToString() + "</strong><br />");
sb.Append("<strong>" + rdr["JO_PRD"].ToString() + "</strong><br />");
sb.Append("</p>");
res = sb.ToString();
}
}
}
}
}
return res;
}
public class Customer
{
public string CustomerID { get; set; }
public string FirstName { get; set; }
}