private async void OnExecuteStatisticsQueryClicked(object sender, EventArgs e)
{
// Create definitions for each statistic to calculate
StatisticDefinition statDefinitionAvgPop = new StatisticDefinition("POP", StatisticType.Average, "");
StatisticDefinition statDefinitionMinPop = new StatisticDefinition("POP", StatisticType.Minimum, "");
StatisticDefinition statDefinitionMaxPop = new StatisticDefinition("POP", StatisticType.Maximum, "");
StatisticDefinition statDefinitionSumPop = new StatisticDefinition("POP", StatisticType.Sum, "");
StatisticDefinition statDefinitionStdDevPop = new StatisticDefinition("POP", StatisticType.StandardDeviation, "");
StatisticDefinition statDefinitionVarPop = new StatisticDefinition("POP", StatisticType.Variance, "");
// Create a definition for count that includes an alias for the output
StatisticDefinition statDefinitionCount = new StatisticDefinition("POP", StatisticType.Count, "CityCount");
// Add the statistics definitions to a list
List <StatisticDefinition> statDefinitions = new List <StatisticDefinition>
{
statDefinitionAvgPop,
statDefinitionCount,
statDefinitionMinPop,
statDefinitionMaxPop,
statDefinitionSumPop,
statDefinitionStdDevPop,
statDefinitionVarPop
};
// Create the statistics query parameters, pass in the list of definitions
StatisticsQueryParameters statQueryParams = new StatisticsQueryParameters(statDefinitions);
// If only using features in the current extent, set up the spatial filter for the statistics query parameters
if (_onlyInExtentSwitch.Checked)
{
// Get the current extent (envelope) from the map view
Envelope currentExtent = _myMapView.GetCurrentViewpoint(ViewpointType.BoundingGeometry).TargetGeometry as Envelope;
// Set the statistics query parameters geometry with the envelope
statQueryParams.Geometry = currentExtent;
// Set the spatial relationship to Intersects (which is the default)
statQueryParams.SpatialRelationship = SpatialRelationship.Intersects;
}
// If only evaluating the largest cities (over 5 million in population), set up an attribute filter
if (_onlyBigCitiesSwitch.Checked)
{
// Set a where clause to get the largest cities (could also use "POP_CLASS = '5,000,000 and greater'")
statQueryParams.WhereClause = "POP_RANK = 1";
}
// Execute the statistical query with these parameters and await the results
StatisticsQueryResult statQueryResult = await _worldCitiesTable.QueryStatisticsAsync(statQueryParams);
// Display results in a list in a dialog
List <KeyValuePair <string, object> > statsList = statQueryResult.First().Statistics.ToList();
ShowStatsList(statsList);
}
private async void OnExecuteStatisticsQueryClicked(object sender, EventArgs e)
{
// Create definitions for each statistic to calculate
StatisticDefinition statDefinitionAvgPop = new StatisticDefinition("POP", StatisticType.Average, "");
StatisticDefinition statDefinitionMinPop = new StatisticDefinition("POP", StatisticType.Minimum, "");
StatisticDefinition statDefinitionMaxPop = new StatisticDefinition("POP", StatisticType.Maximum, "");
StatisticDefinition statDefinitionSumPop = new StatisticDefinition("POP", StatisticType.Sum, "");
StatisticDefinition statDefinitionStdDevPop = new StatisticDefinition("POP", StatisticType.StandardDeviation, "");
StatisticDefinition statDefinitionVarPop = new StatisticDefinition("POP", StatisticType.Variance, "");
// Create a definition for count that includes an alias for the output
StatisticDefinition statDefinitionCount = new StatisticDefinition("POP", StatisticType.Count, "CityCount");
// Add the statistics definitions to a list
List <StatisticDefinition> statDefinitions = new List <StatisticDefinition>
{
statDefinitionAvgPop,
statDefinitionCount,
statDefinitionMinPop,
statDefinitionMaxPop,
statDefinitionSumPop,
statDefinitionStdDevPop,
statDefinitionVarPop
};
// Create the statistics query parameters, pass in the list of definitions
StatisticsQueryParameters statQueryParams = new StatisticsQueryParameters(statDefinitions);
// If only using features in the current extent, set up the spatial filter for the statistics query parameters
if (OnlyInExtentSwitch.IsToggled)
{
// Get the current extent (envelope) from the map view
Envelope currentExtent = MyMapView.GetCurrentViewpoint(ViewpointType.BoundingGeometry).TargetGeometry as Envelope;
// Set the statistics query parameters geometry with the envelope
statQueryParams.Geometry = currentExtent;
// Set the spatial relationship to Intersects (which is the default)
statQueryParams.SpatialRelationship = SpatialRelationship.Intersects;
}
// If only evaluating the largest cities (over 5 million in population), set up an attribute filter
if (OnlyBigCitiesSwitch.IsToggled)
{
// Set a where clause to get the largest cities (could also use "POP_CLASS = '5,000,000 and greater'")
statQueryParams.WhereClause = "POP_RANK = 1";
}
try
{
// Execute the statistical query with these parameters and await the results
StatisticsQueryResult statQueryResult = await _worldCitiesTable.QueryStatisticsAsync(statQueryParams);
// Display results in the list box
StatResultsList.ItemsSource = statQueryResult.First().Statistics.Select(m => $"{m.Key}:{m.Value}").ToList();
ResultsGrid.IsVisible = true;
}
catch (Exception ex)
{
await Application.Current.MainPage.DisplayAlert("Error", ex.Message, "OK");
}
}