Explore C# 13 in .NET 9 (Preview)

C# 13 in .NET 9 Preview SDK

C# 13, powered by the .NET 9 Preview SDK, introduces a suite of features designed to boost developer productivity and code quality. Let's explore these key updates:

1. Params Collections Embracing Spans

The params keyword now extends its support to Span<T> and ReadOnlySpan<T>, bringing enhanced versatility when handling collections.

void PrintNumbers(params Span<int> numbers)
{
    foreach (var number in numbers)
    {
        Console.WriteLine(number);
    }
}

// Usage:
PrintNumbers(stackalloc[] { 1, 2, 3 });

2. Robust Locking with New Semantics

C# 13 introduces refined lock semantics, ensuring superior performance and reliability in multi-threaded environments.

lock (new object()) 
{
    // Critical section
}

3. Introducing the \e Escape Sequence

A new escape sequence, \e, makes its debut for representing the ASCII escape character.

string escapeChar = "\e";
Console.WriteLine(escapeChar); // Outputs ASCII escape character

4. Streamlined Method Group Conversions

Method group conversions receive a significant boost, simplifying their usage as delegates.

Action action = Console.WriteLine;
action(); // Direct use of method group as delegate

5. Implicit Indexers in Object Initializers

Object initializers now embrace implicit indexer access, leading to cleaner and more concise code.

var dict = new Dictionary<int, string>
{
    [1] = "One",
    [2] = "Two"
};

6. Power Up Iterators and Async Methods

C# 13 allows the use of ref locals and unsafe contexts within iterators and async methods, expanding their capabilities. This feature might remind developers of ANSI-C coding days, where low-level memory management and direct pointer manipulation were common. The introduction of these features in C# provides a similar level of control and precision, blending modern asynchronous programming with the kind of granular control typically seen in lower-level languages like C.

async Task UnsafeExample()
{
    unsafe
    {
        int* ptr = stackalloc int[1];
        *ptr = 42;
    }
}

7. ref struct Types Embrace Interfaces

ref struct types gain the ability to implement interfaces, amplifying their utility in various scenarios.

ref struct MyRefStruct : IDisposable
{
    public void Dispose() { /* Cleanup */ }
}

8. ref struct as Generic Type Parameters

You can now utilize ref struct types as generic type parameters, unlocking new possibilities in generic programming.

public class GenericClass<T> where T : struct
{
    // Implementation
}

9. Partial Properties and Indexers

C# 13 introduces support for partial properties and indexers within partial types, facilitating better code organization and modularity.

partial class MyClass
{
    public partial string Name { get; set; }
}

partial class MyClass
{
    public partial string Name { get; set; } = "Default";
}

Summary

I encourage you to explore these new features and discover how they can elevate your current and future projects. For a deeper dive, refer to the official C# 13 documentation and the Microsoft .NET Blog.