Top-level statements, introduced in C# 9.0 (.NET 5.0), allow you to write executable code directly in a file without wrapping it in a class and Main method. One file in your project can contain top-level statements; the rest must use traditional class-based declarations. This feature is especially useful for scripts, utilities, and learning code.
Why it matters
- Reduces ceremony for simple console applications and scripts.
- Makes learning C# easier by removing the need to understand classes and entry points upfront.
- Improves readability of quick utilities and prototype code.
- Aligns C# with scripting languages for rapid exploration.
Cautions
Only one file in a project can use top-level statements; the others must use traditional Main methods or classes. Top-level statements do not work in libraries (class libraries)—only in executable projects. If your program grows beyond a simple script, consider migrating to classes and methods for better maintainability.
Simplified hello world program
Top-level statements eliminate boilerplate for simple console applications, making the code more direct.
Valid since C# 9.0
Without var
using System;
class Program
{
static void Main()
{
Console.WriteLine("Hello, World!");
}
}With var
Console.WriteLine("Hello, World!");Script-like argument parsing
Top-level statements can access command-line args directly, making simple CLI scripts feel more natural.
Valid since C# 9.0
var name = args.Length > 0 ? args[0] : "World";
Console.WriteLine($"Hello, {name}!");
Console.WriteLine($"You provided {args.Length} argument(s).");