Autocomplete asp.net Without Web Service

[System.Web.Script.Services.ScriptMethod()]
[System.Web.Services.WebMethod]
public static List SearchCustomers(string prefixText, int count)
{
    using (SqlConnection conn = new SqlConnection())
    {
        conn.ConnectionString = ConfigurationManager
                .ConnectionStrings["constr"].ConnectionString;
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "select ContactName from Customers where " +
            "ContactName like @SearchText + '%'";
            cmd.Parameters.AddWithValue("@SearchText", prefixText);
            cmd.Connection = conn;
            conn.Open();
            List customers = new List();
            using (SqlDataReader sdr = cmd.ExecuteReader())
            {
                while (sdr.Read())
                {
                    customers.Add(sdr["ContactName"].ToString());
                }
            }
            conn.Close();
            return customers;
        }
    }
}

source : http://www.aspsnippets.com/Articles/ASP.Net-AJAX-Control-Toolkit-AutoCompleteExtender-without-using-Web-Services.aspx