Khalid Abuhakmeh explains how to add static properties to a top-level statements Program class in C# using partial classes. This post guides readers on creating more readable console applications and delves into the compiler-generated code structure.

Summary

In his article, Khalid Abuhakmeh addresses the stylistic changes introduced with top-level statements in modern C#, specifically focusing on ways to enhance utility console applications by adding properties to the implicit Program class.

Key Points

  • Top-level Statements: C#’s new style allows you to write the entry point of a console program without explicitly wrapping code in a Main method or class. The compiler generates a default Program class and static void Main entry during compilation.

  • Accessing Methods in Top-level Files: Functions declared after top-level code are translated by the compiler into static methods on the generated Program class. However, adding properties directly with the same syntax as methods is not valid.

  • Why Add Properties?: Using properties instead of methods can improve code readability, especially for values that represent state rather than behavior.

  • How to Add Properties: You cannot declare properties in the same file using top-level syntax, but you can extend the generated Program class with a partial class definition in the same file or another file. The property must be declared as static, since the compiler-generated entry method is static.

Console.WriteLine($"Hello, {Name}");

partial class Program
{
    static string Name => Environment.GetCommandLineArgs()[1];
}

  • Compiler Result: When compiled, the property is added to the Program class and can be accessed from top-level code, provided it is static.

  • Separation of Concerns: You may move the partial Program class implementation to a different file for organizational clarity, maintaining the minimalist appearance in your Program.cs entry point.

Additional Details

  • All properties added this way must be static due to their usage in the static context of the generated Main method.
  • This technique helps keep top-level files concise and maintainable, especially in simple utilities and scripts.

Takeaways

  • Leverage partial classes to supplement top-level statement files with state or derived properties.
  • Ensure properties are static to be compatible with the static compilation context.
  • This pattern supports both code clarity and separation, aligning with modern C# application style conventions.

This post appeared first on “Khalid Abuhakmeh’s Blog”. Read the entire article here