/// <summary> </summary>
        protected override void DoWork(CodeActivityContext context)
        {
            Success.Set(context, true);

            var obrId = ObrId.Get(context);
            var dataItemThresholds = DataItemThresholds.Get(context);

            if (dataItemThresholds == null)
            {
                return;
            }

            ObsDef obsDefEntity = ObsDef.GetEntityByObdGuid(dataItemThresholds.ObdGuid, PM);

            if (obsDefEntity.IsNullEntity)
            {
                return;
            }

            var query = new EntityQuery(typeof(ObsReq));

            query.AddClause(ObsReqDataRow.OBR_IDEntityColumn, EntityQueryOp.EQ, obrId);
            var obsReqEntity = PM.GetEntity <ObsReq>(query);

            if (obsReqEntity.IsNullEntity)
            {
                return;
            }

            query = new EntityQuery(typeof(Observe));
            query.AddClause(ObserveDataRow.OBD_IDEntityColumn, EntityQueryOp.EQ, obsDefEntity.OBD_ID);
            query.AddClause(ObserveDataRow.Pat_ID1EntityColumn, EntityQueryOp.EQ, obsReqEntity.Pat_ID1);
            query.AddClause(ObserveDataRow.OBR_SET_IDEntityColumn, EntityQueryOp.EQ, obsReqEntity.OBR_Set_ID);
            var observeEntity = PM.GetEntity <Observe>(query);

            if (observeEntity.IsNullEntity)
            {
                return;
            }

            var success = CommonCharting.CheckDataItemThresholds(observeEntity, dataItemThresholds);

            Success.Set(context, success);
        }
        /// <summary>
        /// Execute the activity and look up the flowsheet value.
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        protected override void DoWork(CodeActivityContext context)
        {
            //Get Variables
            Guid obdGuid = ObdGuid.Get(context);
            int? patId1  = PatId1.Expression != null?PatId1.Get(context) : (int?)null;

            int?obrId = ObrId.Expression != null?ObrId.Get(context) : (int?)null;

            FlowsheetLookupMethod lookupMethod = LookupMethod.Expression != null
                                               ? LookupMethod.Get(context)
                                               : FlowsheetLookupMethod.Earliest;

            //Lookup entities
            ObsDef obsDefEntity = ObsDef.GetEntityByObdGuid(obdGuid, PM);

            ObsDataValueFormat.Set(context, obsDefEntity.ObsDefDataFormat);

            string queryString;

            switch (lookupMethod)
            {
            case FlowsheetLookupMethod.Earliest:
                queryString = String.Format(EARLIEST_QUERY, patId1.GetValueOrDefault(0),
                                            obsDefEntity.OBD_ID);
                break;

            case FlowsheetLookupMethod.Latest:
                queryString = String.Format(LATEST_QUERY, patId1.GetValueOrDefault(0),
                                            obsDefEntity.OBD_ID);
                break;


            case FlowsheetLookupMethod.ByObrId:
                queryString = String.Format(OBR_ID_QUERY, patId1.GetValueOrDefault(0),
                                            obsDefEntity.OBD_ID, obrId.GetValueOrDefault(0));
                break;

            default:
                throw new InvalidOperationException("Invalid Lookup Operation");
            }

            var pQuery = new PassthruRdbQuery(typeof(Observe), queryString);
            var result = PM.GetEntity <Observe>(pQuery, QueryStrategy.DataSourceOnly);

            //If we didn't find any observations
            if (result == result.NullEntity)
            {
                ObsResultFound.Set(context, false);
                return;
            }

            //Assign output information.
            ObsResultFound.Set(context, true);
            ObsDtTm.Set(context, result.ObsReqTip.Obs_DtTm);
            ObrIdValue.Set(context, result.OBR_SET_ID);

            if (result.ObsReqTip.Obs_DtTm != null)
            {
                // Recalculating for hours since don't want to mess with day calculation
                TimeSpan span = DateTime.Now - result.ObsReqTip.Obs_DtTm.Value;
                AgeInDays.Set(context, span.TotalDays);
                AgeInHours.Set(context, span.TotalHours);
            }

            //Always populate ObsString.  Lab interface may populate this even if the ObsDef type is something
            //different.
            ObsStringValue.Set(context, result.Obs_String);
            if (result.ObsDefEntityOnObsChoice != null && !result.ObsDefEntityOnObsChoice.IsNullEntity)
            {
                ObsChoiceValue.Set(context, result.ObsDefEntityOnObsChoice.OBD_GUID);
            }
            else
            {
                ObsChoiceValue.Set(context, null);
            }

            //Set the appropriate output value.
            switch (result.ObsDefEntity.ObsDefDataFormat)
            {
            case ObsDefDataFormat.CheckBox:
                ObsCheckboxValue.Set(context, (result.Obs_Float == 0) ? false : true);
                break;

            case ObsDefDataFormat.Date:
                ObsDateTimeValue.Set(context, ClarionConversions.DateToDateTime(result.Obs_Float));
                break;

            case ObsDefDataFormat.Time:
                ObsDateTimeValue.Set(context, ClarionConversions.TimeToDateTime(result.Obs_Float));
                break;

            case ObsDefDataFormat.Numeric:
                ObsNumericValue.Set(context, result.Obs_Float);
                break;

            case ObsDefDataFormat.Choice:
            case ObsDefDataFormat.String:
            case ObsDefDataFormat.Memo:
                //Do nothing.  Already string and choice already set set above the switch statement
                break;

            default:
                throw new InvalidOperationException(
                          String.Format(Strings.Error_InvalidObsDefDataFormat,
                                        result.ObsDefEntity.ObsDefDataFormat));
            }
        }