public System.IO.Stream ExportHistory(string SenderID) { StringBuilder result = new StringBuilder(); try { IChatMessageRepository repo = new ChatMessageRepository(); var messages = repo.GetConversationHistory(SPContext.Current.Web.CurrentUser.ID, Int32.Parse(SenderID)); result.Append("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>"); result.Append("<ChatMessages>"); foreach (ChatMessage msg in messages) { result.Append(msg.GetXml()); } result.Append("</ChatMessages>"); } catch (Exception ex) { Config.WriteException(ex); WebOperationContext.Current.OutgoingResponse.StatusCode = System.Net.HttpStatusCode.InternalServerError; WebOperationContext.Current.OutgoingResponse.StatusDescription = Language.CreateChatMessageError; } WebOperationContext.Current.OutgoingResponse.ContentType = "text/xml"; return(new MemoryStream(Encoding.UTF8.GetBytes(result.ToString())));; }