I watched yet another five minute chunk of the Blazor intro video I found.

Following up on this and this, this is offered for a debounce lookup feature:

@code {
   string searchQuery;
   bool isSearching;
   CancellationTokenSource currentSearchCts;
   Location[] locations = new Location[0];
   bool noResults;
   
   string SearchQuery
   {
      get => searchQuery;
      set
      {
         searchQuery = value;
         if (!string.IsNullOrEmpty(searchQuery))
         {
            _ = SearchDebounced(searchQuery);
         }
      }
   }
   
   bool IsSearching => isSearching || currentSearchCts != null;
   
   [Parameter]
   public EventCallback<Location> LocationChanged { get; set; }
   
   async Task GetLocalWeather()
   {
      isSearching = true;
      var geolocation = await GetlocationService.GetLocationAsync();
      var currentLocation = await
            WeatherForecastService.GetLocationByGeolocation(geolocation.Lati...
      isSearching = false;
      await LocationChanged.InvokeAsync(currentLocation);
   }
   
   async Task SearchDebounced(string query)
   {
      try
      {
         noResults = false;
         currentSearchCts?.Cancel();
         currentSearchCts = new CancellationTokenSource();
         var thisSearchToken = currentSearchCts.Token;
         
         await Task.Delay(500);
         if (!thisSearchToken.IsCancellationRequested)
         {
            var results = await WeatherForecastService.GetLocationByTest(query);
            if (!thisSearchToken.IsCancellationRequested)
            {
               locations = results;
               noResults = locations.Length == 0;
               currentSearchCts = null;
            }
         }
         
         StateHasChanged();
      }
      catch (Exception ex)
      {
         Console.Error.WriteLine(ex.StackTrace);
      }
   }
   
   void LocationSelected(ChangeEventArgs e)
   {
      var locationName = (string)e.Value;
      var selectedLocation = locations.FirstOrDefault(l => CityState(l) == locationName);
      if (selectedLocation != null)
      {
         searchQuery = null;
         noResults = false;
         locations = new Location[0];
         LocationChanged.InvokeAsync(selectedLocation);
      }
   }
   
   string CityState(Location location) => $"{location.LocalizedName},
         {location.AdministrativeArea....
   
   string GetSearchClass() => IsSearching ? "search-icon spinning" : "search-icon";

 
 

Some of the markup added:

<LocationSearch LocationChanged="LocationChanged" />

 
 

Later on there is talk of digging out the geolocation from the browser with JavaScript. Blazor has interop capabilities with JavaScript. AspNetMonsters.Blazor.Geolocation is a NuGet package that does the work already. An IJSRuntime is the type for a JavaScript interop like so:

var result = await jsRuntime.InvokeAsync<Location>
      ("AspNetMonsters.Blazor.Geolocation", requestId);

 
 

The parameters after the first one are generic parameters that will get past on to JavaScript and the generic parameter is the return type.