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Map

BitMap is a generic, provider-pluggable interactive map component. It supports Leaflet, MapLibre GL, Mapbox GL, OpenLayers, ArcGIS, Azure Maps, and CesiumJS.

Notes

To use this component, install the
Bit.BlazorUI.Extras
 nuget package.
BitMap<TMapProvider> is generic - choose a provider class as the type argument and pass a configured instance via Provider. Providers: BitLeafletMapProvider, BitMapLibreMapProvider, BitMapboxMapProvider, BitOpenLayersMapProvider, BitArcGisMapProvider, BitAzureMapsMapProvider, BitCesiumMapProvider. Mapbox, Azure Maps, and ArcGIS (for non-OSM basemaps) require an API key on the provider instance.

Usage

Basic
The simplest usage: a Leaflet map centered on London using the bundled Leaflet 1.9.4 library (no CDN, no token).

Markers
Add markers with HTML popups, tooltips, and drag support via the imperative API. Always wait for OnReady before calling map methods. 



Seed markers are added on OnReady. Try the buttons.
Vectors
Draw polylines, polygons, circles, and rectangles. Each layer has a string id so you can remove or replace it individually. Clicking a shape raises OnVectorClick. 



Click Redraw to draw shapes, then click a shape.
GeoJSON
Load any GeoJSON string as a styled layer. Feature clicks forward the feature's properties as a JsonElement. 



Click 'Load GeoJSON', then click a feature.
Custom tiles
Switch the base tile layer at runtime by updating the Provider parameter. Any Leaflet-compatible XYZ template is accepted.

Events
OnClick returns the clicked coordinate. OnViewChanged fires after every pan or zoom. Use FlyTo for animated navigation and InvalidateSize after a container resize. 



Pan/zoom or click the map.
Advanced
Interaction toggles, scale bar, pan limits (MaxBounds), marker tooltips, z-order, and tile overlays. 



Toggle options or use the buttons.
MapLibre GL
MapLibre GL JS is loaded from unpkg on first render. No token required for the default demo style.

OpenLayers
OpenLayers 10 is loaded as ES modules from esm.sh. No token required; defaults to OpenStreetMap tiles.

Mapbox GL (token required)
Mapbox GL JS requires a public access token to load mapbox:// styles.

To get started:
  1. Create a free account at mapbox.com
  2. Copy your default public token from the Access Tokens page
  3. Pass it to BitMapboxMapProvider.AccessToken
Without a valid token the map canvas will remain blank.

Security: only ship a public token (pk.*) to the browser, never a secret token (sk.*). Public tokens are visible to anyone using your site, so restrict each token to your production domains via the URL allowlist on the Access Tokens page, set a billing cap, and use a separate token per environment so you can rotate or revoke without downtime. For stricter scenarios, mint a short-lived token from a server endpoint or proxy tile requests through your backend.
ArcGIS Maps SDK
ArcGIS Maps SDK 5.0 is loaded as an ES module from the Esri CDN. The osm basemap works without an API key.

Security: if you supply an API key for non-OSM basemaps, configure HTTP referrer restrictions on the key in the ArcGIS Developer dashboard so it can only be used from your own domains, and scope it to the minimum required services.

Azure Maps (subscription key required)
Azure Maps Web SDK v3 requires a subscription key for authentication.

To get started:
  1. Create an Azure Maps account in the Azure Portal
  2. Navigate to your Maps account → Authentication → Shared Key Authentication
  3. Copy the Primary Key and pass it to BitAzureMapsMapProvider.SubscriptionKey
Without a valid key the map will not render.

Security: shipping a shared subscription key to the browser is fine for demos but not recommended for production. For production, prefer Microsoft Entra ID or SAS token authentication: a backend mints a short-lived token and the client uses that instead of the primary key. If you must use a subscription key, restrict allowed origins on the Maps account and set usage alerts so a leaked key cannot quietly drain your quota.
CesiumJS 3D globe
CesiumJS renders a 3D globe. OSM imagery and smooth-ellipsoid terrain work without a token. A Cesium ion token unlocks Cesium World Terrain and Bing imagery.

Security: if you provide a Cesium ion token, create a dedicated token in the Cesium ion dashboard, grant only the asset access it needs, and add your production domains to the token's allowed URLs list so a copied token cannot be used from other origins.

API

BitMap parameters
Name
Type
Default value
Description
TMapProvider Type (generic) The map provider type. One of: BitLeafletMapProvider, BitMapLibreMapProvider, BitMapboxMapProvider, BitOpenLayersMapProvider, BitArcGisMapProvider, BitAzureMapsMapProvider, BitCesiumMapProvider.
Provider TMapProvider? null Provider configuration instance (center, zoom, tokens, etc.). When null a default instance is created.
ChildContent RenderFragment? null Optional content rendered above the map canvas.
ReplayStateOnProviderSwap bool false When true, imperatively-added markers, vector layers, and tile overlays are replayed after a destructive provider swap (different JsObjectName).
OnReady EventCallback Fires after the map is ready for imperative calls. Fires once on initial mount, and fires again after a destructive provider swap each time the new provider becomes ready.
OnClick EventCallback<BitMapLatLng> Fires when the user clicks the map canvas.
OnDoubleClick EventCallback<BitMapLatLng> Fires when the user double-clicks the map.
OnViewChanged EventCallback<BitMapViewState> Fires whenever the map view changes.
OnMarkerClick EventCallback<string> Fires when the user clicks a marker (argument is the marker id).
OnMarkerDragEnd EventCallback<BitMapMarkerDragEndArgs> Fires when a draggable marker is dropped.
OnVectorClick EventCallback<BitMapVectorClickArgs> Fires when the user clicks a vector layer.
OnGeoJsonFeatureClick EventCallback<BitMapGeoJsonFeatureClickArgs> Fires when the user clicks a GeoJSON feature.
OnInteropError EventCallback<BitMapInteropErrorArgs> Fires when an interop call into the underlying provider fails. Lets consumers surface errors that the component would otherwise swallow to prevent circuit-breaking exceptions.
BitMap public members
Name
Type
Default value
Description
IsReady bool false True after the map is ready for interop calls.
GetView Func<ValueTask<BitMapViewState>> Returns a snapshot of the current viewport.
SetView Func<BitMapLatLng, double?, bool, ValueTask> Pan and optionally zoom to the given center.
FlyTo Func<BitMapLatLng, double?, ValueTask> Animated pan/zoom to the given center.
FitBounds Func<BitMapLatLngBounds, int, ValueTask> Fit the view to the given bounding box.
FitBoundsToMarkers Func<int, ValueTask> Fit the view to include all current markers.
InvalidateSize Func<ValueTask> Recalculate map size after a container resize.
AddMarker Func<BitMapMarker, ValueTask> Add a marker to the map.
RemoveMarker Func<string, ValueTask> Remove a marker by id.
ClearMarkers Func<ValueTask> Remove all markers.
SetMarkerPosition Func<string, BitMapLatLng, ValueTask> Move a marker to a new position.
OpenMarkerPopup Func<string, ValueTask> Open a marker's popup.
SyncMarkers Func<IEnumerable<BitMapMarker>, ValueTask> Replace all markers in one batch.
AddPolyline Func<string, IReadOnlyList<BitMapLatLng>, BitMapVectorPathStyle?, ValueTask> Add a polyline.
AddPolygon Func<string, IReadOnlyList<BitMapLatLng>, BitMapVectorPathStyle?, ValueTask> Add a polygon.
AddCircle Func<string, BitMapLatLng, double, BitMapVectorPathStyle?, ValueTask> Add a circle (radius in meters).
AddRectangle Func<string, BitMapLatLngBounds, BitMapVectorPathStyle?, ValueTask> Add a rectangle.
AddGeoJson Func<string, string, BitMapVectorPathStyle?, ValueTask> Add a GeoJSON layer.
RemoveLayer Func<string, ValueTask> Remove a vector layer by id.
ClearVectorLayers Func<ValueTask> Remove all vector layers.
AddTileOverlay Func<BitMapTileOverlay, ValueTask> Add a tile overlay above the base map.
RemoveTileOverlay Func<string, ValueTask> Remove a tile overlay by id.
BitComponentBase parameters
Name
Type
Default value
Description
AriaLabel string? null Gets or sets the accessible label for the component, used by assistive technologies.
Class string? null Gets or sets the CSS class name(s) to apply to the rendered element.
Dir BitDir? null Gets or sets the text directionality for the component's content.
HtmlAttributes Dictionary<string, object> new Dictionary<string, object>() Captures additional HTML attributes to be applied to the rendered element, in addition to the component's parameters.
Id string? null Gets or sets the unique identifier for the component's root element.
IsEnabled bool true Gets or sets a value indicating whether the component is enabled and can respond to user interaction.
Style string? null Gets or sets the CSS style string to apply to the rendered element.
TabIndex string? null Gets or sets the tab order index for the component when navigating with the keyboard.
Visibility BitVisibility BitVisibility.Visible Gets or sets the visibility state (visible, hidden, or collapsed) of the component.
BitComponentBase public members
Name
Type
Default value
Description
UniqueId Guid Guid.NewGuid() Gets the readonly unique identifier for the component's root element, assigned when the component instance is constructed.
RootElement ElementReference Gets the reference to the root HTML element associated with this component.
BitVisibility enum
Name
Value
Description
Visible 0 The content of the component is visible.
Hidden 1 The content of the component is hidden, but the space it takes on the page remains (visibility:hidden).
Collapsed 2 The component is hidden (display:none).
BitDir enum
Name
Value
Description
Ltr 0 Ltr (left to right) is to be used for languages that are written from the left to the right (like English).
Rtl 1 Rtl (right to left) is to be used for languages that are written from the right to the left (like Arabic).
Auto 2 Auto lets the user agent decide. It uses a basic algorithm as it parses the characters inside the element until it finds a character with a strong directionality, then applies that directionality to the whole element.

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