/// <summary>
        /// 返回UI消息(xi)樹
        /// </summary>
        /// <returns></returns>
        public static string GetMongoLog(DateTime? fromDate, DateTime? toDate, int page = 1)
        {
            string from = DateTime.Now.Date.ToString("yyyy-MM-dd");
            string to = DateTime.Now.Date.AddDays(1).ToString("yyyy-MM-dd");
            if (fromDate.HasValue)
            {
                from = fromDate.Value.ToString("yyyy-MM-dd");

            }
            if (toDate.HasValue)
            {
                to = toDate.Value.ToString("yyyy-MM-dd");
            }
            var stages = new List<IPipelineStageDefinition>();
            stages.Add(new JsonPipelineStageDefinition<BsonDocument, BsonDocument>("{$match:{AddTime:{$gt:ISODate('" + from + "'),$lt:ISODate('" + to + "')}}}"));
            stages.Add(new JsonPipelineStageDefinition<BsonDocument, BsonDocument>("{$group:{_id: \"$RootId\", count: {$sum: 1}}}"));
            stages.Add(new JsonPipelineStageDefinition<BsonDocument, BsonDocument>("{$skip:" + page * 5 + "}"));
            stages.Add(new JsonPipelineStageDefinition<BsonDocument, BsonDocument>("{$limit:5}"));
            var pipeline = new PipelineStagePipelineDefinition<BsonDocument, BsonDocument>(stages);
            var result = NoSql.MongodbManager<LoggerContext>.Collection.Aggregate(pipeline);
            StringBuilder str = new StringBuilder();

            str.Append("<ol class='treeMsg'>");
            foreach (var item in result.ToList())
            {
                var timer = new List<DateTime>();
                var old = NoSql.MongodbManager<LoggerContext>.Instance.Find(i => i.RootId == item.Values.ToArray()[0].ToString() && i.ParentId == null).FirstOrDefault();
                timer.Add(old.AddTime);
                str.Append("<li style='margin:5px;border:1px dashed #aaa'>");
                str.AppendFormat("<span style='color:red;'>{0}</span&gt;<span style='color:green'>{1}</span><span>{2}</span>"
                   , old.Url
                   , old.MessageBody
                   , old.AddTime);
                MsgTree(str, old.ChildId, timer);
                str.AppendFormat("<p><b><em>本次請求用時{0}毫秒（{1}秒）<em></b></p&gt;"
                    , (timer.Max() - timer.Min()).TotalMilliseconds
                    , (timer.Max() - timer.Min()).TotalSeconds);
                str.Append("</li>");
            }
            str.Append("</ol>");
            return str.ToString();
        }