GeofenceMonitor Class

Definition

public ref class GeofenceMonitor sealed

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
class GeofenceMonitor final

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
public sealed class GeofenceMonitor

Public NotInheritable Class GeofenceMonitor

Inheritance

Object Platform::Object IInspectable GeofenceMonitor

Attributes

ContractVersionAttribute MarshalingBehaviorAttribute

Windows requirements

Examples

Processing geofence state changes in a background task

public sealed class GeofenceBackgroundTask : IBackgroundTask
{
    public void Run(IBackgroundTaskInstance taskInstance)
    {
        var deferral = taskInstance.GetDeferral();

        try
        {
            ProcessGeofenceStateChangedReports();
        }
        catch (UnauthorizedAccessException)
        {
            // Location permissions disabled - handle gracefully
            // App-specific: log error and notify user when app resumes
        }
        finally
        {
            deferral.Complete();
        }
    }

    private void ProcessGeofenceStateChangedReports()
    {
        var monitor = GeofenceMonitor.Current;
        var reports = monitor.ReadReports();

        foreach (var report in reports)
        {
            var geofenceId = report.Geofence.Id;
            var timestamp = report.Geoposition.Coordinate.Timestamp;

            // Handle different state changes
            switch (report.NewState)
            {
                case GeofenceState.Entered:
                    // App-specific: log entry, trigger notifications, start tracking
                    HandleGeofenceEntered(geofenceId, timestamp);
                    break;

                case GeofenceState.Exited:
                    // App-specific: log exit, stop location tracking, update analytics
                    HandleGeofenceExited(geofenceId, timestamp);
                    break;

                case GeofenceState.Removed:
                    // Handle automatic removal (expired or single-use)
                    var reason = report.RemovalReason;
                    if (reason == GeofenceRemovalReason.Expired)
                    {
                        // App-specific: re-register if needed, update UI
                        HandleGeofenceExpired(geofenceId);
                    }
                    else if (reason == GeofenceRemovalReason.Used)
                    {
                        // App-specific: process single-use completion
                        HandleGeofenceUsed(geofenceId);
                    }
                    break;
            }
        }

        // App-specific: persist state changes, update tile notifications
        if (reports.Count > 0)
        {
            SaveReportSummary(reports);
        }
    }
}

Registering geofences and handling events in foreground

winrt::fire_and_forget SetupGeofenceMonitoring()
{
    using namespace winrt::Windows::Devices::Geolocation;
    using namespace winrt::Windows::Devices::Geolocation::Geofencing;

    auto monitor = GeofenceMonitor::Current();

    // Check permission before proceeding
    auto accessStatus = co_await Geolocator::RequestAccessAsync();
    if (accessStatus != GeolocationAccessStatus::Allowed)
    {
        // App-specific: show permission dialog or disable geofencing features
        co_return;
    }

    // Register for state change events with C++/WinRT event handling
    monitor.GeofenceStateChanged({ this, &MainPage::OnGeofenceStateChanged });
    monitor.StatusChanged({ this, &MainPage::OnGeofenceMonitorStatusChanged });

    // Create and register a geofence
    BasicGeoposition position{};
    position.Latitude = 47.6062;
    position.Longitude = -122.3321;

    auto geocircle = Geocircle(position, 100.0); // 100 meter radius
    auto geofence = Geofence(L"home-location", geocircle);

    monitor.Geofences().Append(geofence);
}

void OnGeofenceStateChanged(GeofenceMonitor const& sender,
                           winrt::Windows::Foundation::IInspectable const&)
{
    // Process real-time state changes (app is running)
    auto reports = sender.ReadReports();
    for (auto const& report : reports)
    {
        // App-specific: update UI, show notifications
        UpdateLocationStatus(report.Geofence().Id(), report.NewState());
    }
}

Remarks

Use the static Current property to get the GeofenceMonitor object which contains all of an app's geofence information.

Key properties and methods

• Geofences: Collection to register and manage geofences for monitoring
• ReadReports: Retrieves state change reports since the last read
• GeofenceStateChanged: Event fired when geofence states change
• Status: Current operational status of the monitor

Background task integration

The GeofenceMonitor class is commonly used in background tasks to handle geofence events when the app is not running. Background tasks should call ReadReports to process accumulated state changes and clear the report queue.

See also

• Geofence
• GeofenceState
• GeofenceStateChangeReport
• Windows.Devices.Geolocation
• Geolocation sample