Program.cs

using Northwind.Blazor.Components;
using Northwind.Blazor.Services; // To use INorthwindService.

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorComponents()
  .AddInteractiveServerComponents()
  .AddInteractiveWebAssemblyComponents();

builder.Services.AddNorthwindContext();

builder.Services.AddTransient<INorthwindService,
  NorthwindServiceServerSide>();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
  app.UseExceptionHandler("/Error", createScopeForErrors: true);
  // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
  app.UseHsts();
}

app.UseHttpsRedirection();

app.UseStaticFiles();
app.UseAntiforgery();

app.MapRazorComponents<App>()
  .AddInteractiveServerRenderMode()
  .AddInteractiveWebAssemblyRenderMode()
  .AddAdditionalAssemblies(typeof(Northwind.Blazor.Wasm._Imports).Assembly);

app.Run();