[WebMethod] public string FetchOrders(string key) { return LoadData(key);; } private string LoadData(string key) { DataSet ds = new DataSet(); ds.ReadXml(this.Context.Server.MapPath("App_Data\\northwind.xml")); ds.Tables["Orders"].DefaultView.RowFilter = "customerid = '" + key + "'"; return RenderResultTable((ds.Tables["Orders"].DefaultView)); }