Key C# Features Every .NET Developer Should Know

#1 Asynchronous Programming

Asynchronous programming in C# allows developers to write non-blocking code, keeping applications responsive and efficient, especially when handling I/O-bound or CPU-bound tasks. The async and await keywords simplify this process, allowing for a synchronous-looking code structure while maintaining asynchronous execution.

This example showcases how to asynchronously retrieve data from a remote API using HttpClient, demonstrating the application’s responsiveness.

#2 LINQ (Language Integrated Query)

LINQ empowers developers to embed queries directly within C# code, offering an intuitive and expressive approach to accessing and manipulating data from various sources.

In this example, we use LINQ to filter a collection of integers, extracting only even numbers:

var evenNumbers = from num in numbers where num % 2 == 0 select num;

#3 Generics

Generics enable the creation of reusable code by defining classes, methods, and delegates that can operate with any data type.

public void Swap<T>(ref T a, ref T b) {

T temp = a;

a = b;

b = temp;

}

#4 Partial Class

Partial classes allow the definition of a class across multiple files, simplifying management of large classes and enabling collaboration among developers.

Here’s how you can define a partial class:

public partial class MyClass {

// Part 1

}

public partial class MyClass {

// Part 2

}

#5 Lambda Expressions

Lambda expressions offer a succinct way to represent anonymous methods or delegates, enhancing code readability and reducing verbosity.

For example:

Func<int, int> square = x => x * x;

#6 Extension Methods

Extension methods enable the addition of new functionalities to existing types without altering their source code.

public static class StringExtensions {

public static string CapitalizeFirstLetter(this string str) {

return char.ToUpper(str[0]) + str.Substring(1);

}

}

#7 Dynamic Type

The dynamic type in C# allows for flexible interaction with objects whose types are determined at runtime, facilitating interoperability with dynamic languages.

dynamic dynamicVar = 1;

dynamicVar = "Hello";

#8 String Interpolation

String interpolation simplifies string formatting by allowing the embedding of expressions directly within string literals.

var greeting = $"Hello, {name}. You are {age} years old.";

#9 Expression-Bodied Members

Expression-bodied members provide a compact syntax for defining members using lambda-like expressions, enhancing code clarity.

public string Name => $"{FirstName} {LastName}";

#10 Auto-Property Initializers

Auto-property initializers allow for immediate initialization of auto-implemented properties at their declaration, reducing boilerplate code.

public string Name { get; set; } = "John Doe";

#11 Tuples and Deconstruction

Tuples offer a convenient way to group multiple values, while deconstruction enables easy extraction of those values into variables.

var person = (Name: "Alice", Age: 30);

var (name, age) = person;

#12 Pattern Matching

Pattern matching simplifies conditional statements, allowing for clearer and more expressive code.

switch (item) {

case int i:

// Handle integer

break;

case string s:

// Handle string

break;

}

#13 Nullable Reference Types

Nullable Reference Types help to prevent null reference exceptions, promoting more robust code.

#nullable enable

string? nullableString = null;

#14 Default Interface Methods

Default Interface Methods allow method implementations within interfaces, aiding in the evolution of interfaces without breaking existing implementations.

#15 Record Types

Record Types provide a concise way to define immutable data types, enhancing code clarity and ensuring value-based equality.

public record Person(string FirstName, string LastName);

#16 Top-Level Statements

Top-level statements simplify the creation of small console applications by allowing direct execution of code without enclosing it in a class or method.

Console.WriteLine("Hello, World!");

#17 Global Using Directives

Global Using Directives reduce repetition by applying commonly referenced namespaces across the entire project.

global using System;

#18 List Patterns

List Patterns facilitate deconstruction of lists and arrays directly in pattern-matching scenarios.

if (numbers is [var first, .., var last]) {

// Use first and last

}

#19 Required Modifier

The required modifier ensures specific parameters must be provided when instantiating record types.

#20 Collection Expressions

Collection Expressions simplify collection initialization, making the code more readable.

var numbers = new List<int> { 1, 2, 3, 4, 5 };