C# Advanced Features: Unlocking the Full Power of the Language 💪

Welcome to the final stage of your C# journey! 🎉 You’ve learned the basics, tackled intermediate concepts, and now it’s time to master advanced features. In this article, we’ll:

1. Explore delegates, events, and generics.
2. Harness the power of APIs.
3. Build two exciting projects to put your skills into action.

Let’s dive into the deep end! 🏊‍♂️

Delegates and Events: The Backbone of Flexibility 🎛️

Delegates and events are like the magic wands of C#. They let you pass behavior (methods) as arguments and respond to actions dynamically.

Delegates: Passing Methods Around

A delegate is a reference to a method, allowing you to store and pass methods like variables.

Example: Custom Calculator

using System;

class Program
{
    delegate int MathOperation(int a, int b);

    static void Main()
    {
        MathOperation add = (x, y) => x + y; // Lambda for addition
        MathOperation multiply = (x, y) => x * y; // Lambda for multiplication

        Console.WriteLine($"Sum: {add(5, 3)}");
        Console.WriteLine($"Product: {multiply(5, 3)}");
    }
}

Events: Notifying When Something Happens

Events allow objects to notify others when something of interest occurs.

Example: Alarm Clock

using System;

class Alarm
{
    public event Action AlarmRang;

    public void Ring()
    {
        Console.WriteLine("⏰ Alarm is ringing!");
        AlarmRang?.Invoke(); // Notify subscribers
    }
}

class Program
{
    static void Main()
    {
        Alarm myAlarm = new Alarm();

        myAlarm.AlarmRang += () => Console.WriteLine("Wake up! 🌞");
        myAlarm.AlarmRang += () => Console.WriteLine("Time to start coding! 🖥️");

        myAlarm.Ring();
    }
}

Generics: Type-Safe Flexibility 📦

Generics allow you to write reusable code that works with any type, ensuring type safety.

Example: Custom Stack Implementation

using System;

class CustomStack<T>
{
    private T[] items = new T[10];
    private int index = 0;

    public void Push(T item) => items[index++] = item;
    public T Pop() => items[--index];
}

class Program
{
    static void Main()
    {
        CustomStack<int> numberStack = new CustomStack<int>();
        numberStack.Push(10);
        numberStack.Push(20);

        Console.WriteLine(numberStack.Pop()); // Outputs 20
        Console.WriteLine(numberStack.Pop()); // Outputs 10
    }
}

Working with APIs: Connecting to the World 🌐

APIs let your application interact with the world, from fetching weather data to posting tweets.

Example: Fetching Data from a REST API

Using HttpClient to fetch data from a public API:

using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        string url = "https://api.agify.io?name=michael";

        using HttpClient client = new HttpClient();
        string response = await client.GetStringAsync(url);

        Console.WriteLine($"API Response: {response}");
    }
}

🧙‍♂️ Pro Tip: Use libraries like Newtonsoft.Json or System.Text.Json to parse JSON responses.

Advanced C# Projects 🛠️

Now, let’s combine these advanced features into two exciting projects. 🚀

Project 1: Event-Driven Stock Tracker 📈

Build a stock tracker that alerts users when the price of a stock goes above a certain threshold.

Code Example:

using System;
using System.Collections.Generic;

class Stock
{
    public string Name { get; set; }
    public decimal Price { get; set; }

    public event Action<Stock> PriceThresholdReached;

    public void UpdatePrice(decimal newPrice)
    {
        Price = newPrice;
        Console.WriteLine($"{Name} new price: ${Price}");
        
        if (Price > 100) // Threshold
        {
            PriceThresholdReached?.Invoke(this);
        }
    }
}

class Program
{
    static void Main()
    {
        Stock stock = new Stock { Name = "TechCorp", Price = 90 };

        stock.PriceThresholdReached += (s) =>
        {
            Console.WriteLine($"Alert! {s.Name} price exceeded $100! 🚨");
        };

        stock.UpdatePrice(105); // Triggers the event
    }
}

Project 2: API-Based Weather App 🌤️

Let’s create a console app that fetches weather data using a weather API.

Code Example:

using System;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        string city = "London";
        string apiKey = "your_api_key_here"; // Replace with a real API key
        string url = $"https://api.openweathermap.org/data/2.5/weather?q={city}&appid={apiKey}&units=metric";

        using HttpClient client = new HttpClient();
        string response = await client.GetStringAsync(url);

        var weatherData = JsonSerializer.Deserialize<WeatherResponse>(response);

        Console.WriteLine($"The weather in {city} is {weatherData.Main.Temp}°C with {weatherData.Weather[0].Description}.");
    }
}

class WeatherResponse
{
    public WeatherMain Main { get; set; }
    public Weather[] Weather { get; set; }
}

class WeatherMain
{
    public float Temp { get; set; }
}

class Weather
{
    public string Description { get; set; }
}

👩‍💻 Next Steps:

• Get a free API key from OpenWeather.
• Replace your_api_key_here in the code with the real key.

Tips for Mastering Advanced C# 🏋️‍♂️

1. Read the Documentation: The official C# docs are a treasure trove.
2. Contribute to Open Source: Gain experience by contributing to projects on GitHub.
3. Experiment Boldly: Build fun projects like chatbots, games, or automation tools.

Wrapping Up: You’re a C# Master Now! 🏆

Congratulations on completing this series! 🎉 You’ve traveled from C# basics to advanced features, building real-world projects along the way. The possibilities are endless from here:

• Dive into .NET Core for web development.
• Build mobile apps with Xamarin or .NET MAUI.
• Try game development with Unity.

👩‍💻 Your next challenge: Create your own advanced project and share it with the world!