Popup Actions

This GeoBlazor sample, written in Blazor for .NET developers, demonstrates custom popup actions from the ArcGIS Maps SDK for JavaScript via GeoBlazor's PopupTemplate, ActionButton, and PopupWidget Razor components. The page shows a 2D map of the Inland Empire area near San Bernardino, California, rendered with the Modern Antique basemap loaded from an ArcGIS Online portal item, at zoom level 11. A FeatureLayer of trail-run lines is overlaid on top. There are no controls outside the map — the user clicks on any trail to open a popup titled 'Trail Run' that shows the trail name. The popup includes a custom action button labeled 'Measure Length', identified by a small ruler icon. Clicking the action invokes the .NET MeasureThis callback, which retrieves the selected feature's geometry, calls the injected GeometryEngine.GeodesicLength to compute the length in miles, and updates the popup content to display the rounded distance. The sample is intended to demonstrate adding custom buttons and .NET callbacks inside ArcGIS popups in a Blazor application without writing JavaScript.