OverviewMap.razor

@page "/Controls/OverviewMap"
@rendermode InteractiveServer

@using AzureMapsControl.Components.Controls
@using AzureMapsControl.Components.Map
<AzureMap Id="map"
          Controls="new AzureMapsControl.Components.Controls.Control[]
          {
              new AzureMapsControl.Components.Controls.OverviewMapControl(new AzureMapsControl.Components.Controls.OverviewMapControlOptions
              {
                  ShowToggle = true,
                  Style = new AzureMapsControl.Components.Atlas.Either<AzureMapsControl.Components.Controls.ControlStyle, string>(AzureMapsControl.Components.Controls.ControlStyle.Auto)
              },
              AzureMapsControl.Components.Controls.ControlPosition.TopLeft),
              new AzureMapsControl.Components.Controls.StyleControl(position: AzureMapsControl.Components.Controls.ControlPosition.TopRight)
          }"
          EventActivationFlags="MapEventActivationFlags.None().Enable(MapEventType.StyleData).Enable(MapEventType.Ready)"
          OnStyleData="OnStyleData"
          OnReady="OnMapReady"/>

@code {
    private bool _mapReady = false;
    private MapStyle? _style;
    private OverviewMapControl? _overviewControl;

    public async void OnMapReady(MapEventArgs eventArgs)
    {
        _mapReady = true;
        SetStyle();
    }
    
    public async void OnStyleData(MapStyleDataEventArgs eventArgs)
    {
        _overviewControl = eventArgs.Map.Controls?.OfType<AzureMapsControl.Components.Controls.OverviewMapControl>()?.FirstOrDefault();
        _style = eventArgs.Style;
        SetStyle();
    }

    private async void SetStyle()
    {
        if (_mapReady && _overviewControl != null && _style.HasValue)
        {
            await _overviewControl.SetOptionsAsync(options => options.MapStyle = _style.Value);
        }
    }
}