StatisticType.Maximum on dates fields returns incorrectly in GeoDatabaseFeatureTable.QueryStatisticsAsync

[gmarbury]

StatisticRecord.Statistics.Value always looks like a value like this 1/1/1970 12:40:57 AM on 1/1/1970
Ironically, StatisticType.Sum seems to work. Below is an example function that illustrates the problem with StatisticType.Maximum. Just pass it a Geodatabase

        public async Task TestDateMax(Geodatabase gdb)
        {
       
            foreach (var t in gdb.GeodatabaseFeatureTables)
            {
                if (t.LoadStatus != LoadStatus.Loaded)
                {
                    await t.LoadAsync();
                }

                var dateFields = new List<Field>();
                //Get all the date fields
                foreach (var f in t.Fields)
                {
                    if (f.FieldType == FieldType.Date)
                    {
                        dateFields.Add(f);
                    }
                }

                //If no date fields or records skip this table
                if (dateFields.Count == 0 || t.NumberOfFeatures ==0 )
                {
                    continue;
                }

                System.Diagnostics.Debug.WriteLine($"Testing {t.TableName} with {t.NumberOfFeatures} features");
                var fieldToMax_Loop = new Dictionary<Field, DateTimeOffset?>();
              
                //Manually (slowly) get the max for each date field
                var qp = new QueryParameters();
                var features = await t.QueryFeaturesAsync(qp);

                foreach( ArcGISFeature feature in features)
                {
                    if (feature.LoadStatus != LoadStatus.Loaded)
                    {
                        await feature.LoadAsync();
                    }
                    foreach ( var f in dateFields)
                    {
                        var value = (DateTimeOffset?) feature.GetAttributeValue(f) ;

                        if( !fieldToMax_Loop.TryGetValue(f, out DateTimeOffset? currentValue))
                        {
                            fieldToMax_Loop[f] = value;
                        }
                        else
                        {
                            if( value > currentValue)
                            {
                                fieldToMax_Loop[f] = value;
                            }
                        }
                    }
                }


                //Now lets's try to use StatisticType.Maximum and log the differences.. HINT they all break
                var fieldToMax_StatisticTypeMaximum = new Dictionary<Field, DateTimeOffset?>();

                int fieldsWrongCount = 0;
                int fieldsOkCount = 0;
                foreach (var f in dateFields)
                {
                    var statList = new List<StatisticDefinition>();
                    string statFieldName = "MaxOf" + f.Name;
                    var sd = new StatisticDefinition(f.Name, StatisticType.Maximum, statFieldName);

                    statList.Add(sd);
                    var statParams = new StatisticsQueryParameters(statList);                  
                    var tableStats = await t.QueryStatisticsAsync(statParams).ConfigureAwait();

                    var statRecord = tableStats.First();
                    var statValue = (DateTimeOffset?)statRecord.Statistics[statFieldName];

                    fieldToMax_StatisticTypeMaximum[f] = statValue;
                    fieldToMax_Loop.TryGetValue(f, out DateTimeOffset? loopValue);

                    if (loopValue != null)
                    {
                        if (loopValue != statValue)
                        {  
                            //SHOULD NEVER GET TO THIS LINE OF CODE---BUT WE DO
                            System.Diagnostics.Debug.WriteLine($"{t.TableName}.{f.Name} LoopMax={loopValue},  statMax={statValue}");
                            fieldsWrongCount++;
                        }
                        else
                        {
                            fieldsOkCount++;
                        }
                    }
                               
                }

            }

        }