AppActs.API.DataMapper.EventMapper.GetDateOfDeviceLastVisit C# (CSharp) Méthode

        public Nullable<DateTime> GetDateOfDeviceLastVisit(Guid deviceId, Guid applicationId)
        {
            try
            {
                IMongoQuery queryBase = Query.And
                    (
                        Query<AppUsageSummary>.EQ<Guid>(mem => mem.ApplicationId, applicationId),
                        Query.EQ("DevicesVisits.DeviceId", BsonValue.Create(deviceId))
                    );

                MongoCursor<AppUsageSummary> appUsageSummaries =
                    this.GetCollection<AppUsageSummary>().Find(queryBase);

                appUsageSummaries.SetSortOrder(SortBy<AppUsageSummary>.Descending(x => x.Date));
                AppUsageSummary appUsageSummary = appUsageSummaries.FirstOrDefault();

                if (appUsageSummary != null)
                {
                    return appUsageSummary.Date;
                }

                return null;
            }
            catch (Exception ex)
            {
                throw new DataAccessLayerException(ex);
            }
        }