what is the format of program.cs in a blazor application

August 27, 2022

I am just started to learn Blazor and created a sample blazor application in VS .

Looking at the generated code, I noted that file program.cs is not a class or method, as it contains the following code:

using BlazingPizza.Data;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddRazorPages();
builder.Services.AddServerSideBlazor();
// Register the pizzas service
builder.Services.AddSingleton<PizzaService>();

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
}

app.UseStaticFiles();
app.UseRouting();

app.MapRazorPages();
app.MapBlazorHub();
app.MapFallbackToPage("/_Host");

var scopeFactory = app.Services.GetRequiredService<IServiceScopeFactory>();
using (var scope = scopeFactory.CreateScope())
{
    var db = scope.ServiceProvider.GetRequiredService<PizzaStoreContext>();
    if (db.Database.EnsureCreated())
    {
        SeedData.Initialize(db);
    }
}

app.Run();

The code in this file seems more like a script than a class, method or similar construct in C#.

What is the format of this file? Where is the main function and how the main function related to this code/file?