C # Common code for MONGDB fetching data

1, using aggregation to get the latest real-time data (each station has more than one data, take the date of the latest data. That is, each station takes the latest value)

varGroup =Newbsondocument {{"_id",Newbsondocument {{"StationID","$stationID"},                    {"StationName","$stationName" }                }        },                //{"StationID", new bsondocument{{"StationID", "$stationID"}}},{"StationID",NewBsondocument ("$last","$stationID")},                { "Timedata",NewBsondocument ("$max","$TimeData")},                {"Evalue",NewBsondocument ("$last","$eValue")}            };

var collection = modatabase.getcollection<bsondocument> (tablename);

 varList =collection. Aggregate (). Group (group). Tolistasync ().            Result; DoubleValue =0.0; foreach(Bsondocument Bsondocinchlist) {                DoubleEvalue =Double. TryParse (Bsondoc. GetElement ("Evalue"). Value.tostring (), outValue)? Value:0; stringStationid = Bsondoc. GetElement ("StationID"). Value.tostring ();

2, normal according to the order to take the latest data

If a station is a table name

/// <summary>        ///get the time for each data in the database and put it on the horizontal axis of the chart/// </summary>        /// <param name= "statioid" >Station ID</param>        /// <param name= "Pullutionid" >Indicator Type</param>        /// <returns></returns>         Public Staticlist<string> Getchartdata (stringStatioid,stringPullutionid,stringStartTime,stringEndTime) {List<string> XData =Newlist<string>(); if(ConnectionString = =NULL) Oncreatedb (); Modatabase= Moclient.getdatabase ("Ssmonitor"); Bsondocument Bsondoc=Newbsondocument (); Bsondoc.add ("Timedata",NewBsondocument () {{"$gte", Datetimetoint (StartTime)}, {"$lte", Datetimetoint (EndTime)}}); varCollection = Modatabase.getcollection<bsondocument> (string. Format ("{0}_{1}_day", Statioid, Pullutionid)); varsort = builders<bsondocument>. Sort.ascending ("Timedata"); varList =collection. Find (Bsondoc). Sort (sort).            ToList (); foreach(Bsondocument Bsondocinchlist) {                stringTime = Bsondoc. GetElement ("Monitortime").                Value.tostring ();            Xdata.add (time); }            returnXData; }

C # Common code for MONGDB fetching data