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RepoArcGIS Maps SDK for JavaScriptAggregation of Major US Cities

Query Related Features

This sample demonstrates querying related features on a layer that lives on a server. On the click action, the feature layer is queried to find which features were clicked, and then the results are used to update the population table.

US Cities

Click on a hexagon in the map to view the US cities located in that area.

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About this sample

This GeoBlazor sample, written in Blazor for .NET developers, demonstrates the queryRelatedFeatures method from the ArcGIS Maps SDK for JavaScript via GeoBlazor's FeatureLayer.QueryRelatedFeatures, RelationshipQuery, and FeatureLayerView.Highlight APIs. The page shows a 2D map of the contiguous United States at zoom level 3, rendered from an ArcGIS Online basemap. A FeatureLayer of hexagonal aggregation cells, each representing a region containing major US cities, is overlaid on top. An ExpandWidget anchored in the top-right corner of the map can be opened to reveal a LegendWidget. A custom overlay in the bottom-left corner contains a 'US Cities' panel with instructions and an initially empty results table. When the user clicks any hexagon on the map, the page first queries the layer for the matching ObjectIds, highlights the clicked hexagon via the FeatureLayerView, then issues a RelationshipQuery to retrieve the related city records (NAME and SUM_POPULATION) and renders them as rows in the table. A 'Clear Query' button below the table removes the highlight and empties the results. The sample is intended to demonstrate spatial click-to-query plus related-record retrieval in a Blazor application without writing JavaScript.