ASP.NET Program
last modified April 3, 2025
In this article, we explore the Program class in ASP.NET 8. This class serves as the entry point for ASP.NET applications and configures the web host.
The Program class in .NET 8 follows the minimal API approach, providing a streamlined way to bootstrap applications. It replaces the traditional Startup class pattern from earlier versions.
Basic Definition
The Program class in ASP.NET is the entry point that configures and runs the web application. It creates a WebApplicationBuilder instance to set up services.
In .NET 8, the Program class typically uses top-level statements, eliminating explicit Main method declaration. This makes the code more concise while maintaining functionality.
The Program class handles dependency injection configuration, middleware pipeline setup, and application startup. It's the foundation of every ASP.NET Core application.
ASP.NET Program Example
The following example demonstrates a complete ASP.NET 8 Program class configuration with various features.
var builder = WebApplication.CreateBuilder(args);
// Add services to the container
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
var app = builder.Build();
// Configure the HTTP request pipeline
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.MapGet("/hello", () => "Hello World!");
app.MapGet("/products", () =>
{
var products = new[]
{
new { Id = 1, Name = "Laptop", Price = 999.99m },
new { Id = 2, Name = "Mouse", Price = 19.99m }
};
return Results.Ok(products);
});
app.Run();
public partial class Program { }
This Program.cs file demonstrates several key ASP.NET 8 features. The WebApplicationBuilder is created first to configure services and the app.
The example shows service registration for controllers, API explorer, and Swagger. The development environment check enables Swagger only during development.
The HTTP pipeline is configured with HTTPS redirection and authorization. MapControllers enables conventional routing for controller actions.
Two minimal API endpoints are defined directly in Program.cs. The first returns a simple string, while the second returns a product array as JSON.
The partial Program class declaration at the end enables integration testing. This is a common pattern in ASP.NET Core applications.
Source
Microsoft ASP.NET Core Fundamentals Documentation
In this article, we have explored the Program class in ASP.NET 8. This central component configures and launches ASP.NET applications with minimal boilerplate code.
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