Advanced C#

C# stands as a contemporary, object-oriented programming language crafted by Microsoft. It finds extensive application in the creation of a diverse array of software, spanning desktop, web, and mobile applications, along with games. Notably, it garners significant favor for crafting Windows applications.

In this guide, we will explore several sophisticated and recent functionalities of C# that programmers can leverage to develop code that is more effective, resilient, and easy to maintain. Our discussion will encompass subjects like Asynchronous Programming, LINQ, Delegates, Events, and additional concepts.

Asynchronous Programming:

Asynchronous Programming is a programming structure or model that enables developers to write code that doesn't impede the primary thread. This is particularly beneficial in applications that involve numerous input/output (I/O) tasks like retrieving files, accessing data from a database, or sending network requests.

C# offers a robust feature for Asynchronous Programming by utilizing the async/await keywords. The async keyword is employed to designate a method as asynchronous, and the await keyword is utilized to pause the execution until an asynchronous operation is finished.

For instance, contemplate the subsequent code that fetches a file in a synchronous manner:

C# Code:

using System.Net;

var client = new WebClient();
var data = client.DownloadData("https://example.com/image.jpg");

This code will halt the primary thread until the file is fetched, potentially leading to unresponsiveness in the application. To fetch the file asynchronously, we can employ the async/await keywords:

C# Code:

using System.Net;

var client = new WebClient();
var data = await client.DownloadDataTaskAsync("https://example.com/image.jpg");

This code ensures that the main thread is not blocked, enabling the application to stay interactive as the file downloads in the background.

LINQ:

LINQ, which stands for Language Integrated Query, is a robust capability in C# that empowers programmers to retrieve data from various sources like databases, XML files, or collections, by employing a uniform syntax.

LINQ offers a variety of operators that enable filtering, sorting, grouping, and projecting data. These operators can be merged to create intricate queries that are compatible with any data origin supporting the IEnumerable or IQueryable interface.

For instance, let's examine the code below, which sifts through a list of integers to exclusively retain even numbers:

C# Code:

var numbers = new List<int> { 1, 2, 3, 4, 5, 6 };
var evenNumbers = new List<int>();

foreach (var number in numbers)
{
    if (number % 2 == 0)
    {
        evenNumbers.Add(number);
    }
}

By employing LINQ, we have the capability to condense this code into a solitary line:

C# Code:

var numbers = new List<int> { 1, 2, 3, 4, 5, 6 };
var evenNumbers = numbers.Where(n => n % 2 == 0).ToList();

This code employs the Where operator to sift through the number list and retain solely the even numbers, then utilizes the ToList operator to transform the outcome into a list.

Lambda Expressions:

Lambda Expressions provide a more concise method of defining anonymous functions. They enable the creation of inline functions that can be passed as parameters to other functions. Lambda Expressions are commonly applied in conjunction with Delegates and LINQ operations.

For instance, the code snippet below defines a Delegate and employs a Lambda Expression to create an instance of it:

C# Code:

delegate int MyDelegate(int a, int b);

MyDelegate myDelegate = (a, b) => a + b;

int result = myDelegate(1, 2); // result = 3

Delegates:

Delegates serve as a secure and object-oriented reference to functions. They are employed to symbolize a function that can be executed at a different point in time. Delegates are commonly utilized in event-based programming to manage event handling. To declare a delegate, the delegate keyword is used along with specifying the return type and method signature that it will point to.

For instance, the code snippet below defines a Delegate that points to a function accepting two integers as parameters and producing an integer as output:

C# Code:

delegate int MyDelegate(int a, int b);

Delegates can be created by instantiating them with a method that matches the delegate's signature. For instance, the code below demonstrates the instantiation of a Delegate with a method that performs addition on two integer values:

C# Code:

MyDelegate myDelegate = (a, b) => a + b;

The Delegate can then be invoked like a method:

C# Code:

int result = myDelegate(1, 2); // result = 3

Extension Methods:

Extension Methods enable the addition of methods to current types without altering their original source code. These methods are declared as static within a static class, with the initial parameter marked with the " this " keyword to specify the extended type.

For instance, the code below illustrates the creation of an extension method for the string data type:

C# Code:

public static class StringExtensions
{
    public static bool IsPalindrome(this string str)
    {
        int left = 0;
        int right = str.Length - 1;
        while (left < right)
        {
            if (str[left++] != str[right--])
            {
                return false;
            }
        }
        return true;
    }
}

The IsPalindrome extension method can now be invoked on any string instance:

C# Code:

string str = "racecar";
bool isPalindrome = str.IsPalindrome(); // isPalindrome = true