Autocomplete on masterpage

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
 <asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server" />
    <asp:TextBox ID="txtAutoComplete" runat="server" />
    <asp:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server" DelimiterCharacters=""
        Enabled="True" ServicePath="SaveSelectedOption.asmx" ServiceMethod="GetCompletionList"
        TargetControlID="txtAutoComplete" MinimumPrefixLength="1" CompletionInterval="10"
        EnableCaching="true" CompletionSetCount="12">
    </asp:AutoCompleteExtender>

 [WebMethod]
        public string[] GetCompletionList(string prefixText, int count)
        {
            if (count == 0)
            {
                count = 10;
            }
            DataTable dt = GetRecords(prefixText);
            List<string> items = new List<string>(count);

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                string strName = dt.Rows[i][0].ToString();
                items.Add(strName);
            }
            return items.ToArray();
        }

        public DataTable GetRecords(string strName)
        {
            string strConn = ConfigurationManager.ConnectionStrings["jsupportconnectionstring"].ConnectionString;
            SqlConnection con = new SqlConnection(strConn);
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = con;
            cmd.CommandType = System.Data.CommandType.Text;
            cmd.Parameters.AddWithValue("@Name", strName);
            cmd.CommandText = "select CommentEmpId from LT_CommentReadHistory where CommentEmpId like '%'+@Name+'%'";
            DataSet objDs = new DataSet();
            SqlDataAdapter dAdapter = new SqlDataAdapter();
            dAdapter.SelectCommand = cmd;
            con.Open();
            dAdapter.Fill(objDs);
            con.Close();
            return objDs.Tables[0];
        }
using System.Configuration;
using System.Data.SqlClient;