✅ Markdown with colorful code snippets

Real-World C# Delegate Example: Event Handling in Action

Delegates are one of the most powerful features in C#. They allow methods to be passed around like variables, and are the foundation for events and callbacks.

Let’s look at a real-world example — handling a button click in a Windows Forms application.

What is a Delegate?

A delegate is a type that represents references to methods with a specific parameter list and return type.

public delegate void ClickHandler(string message);

Real-World Example: Button Click Event

Here’s a scenario: you’re building a simple desktop app with a button. When the button is clicked, you want to log a message.

Step 1: Define the Delegate

public delegate void ButtonClickHandler(string message);

Step 2: Create a Class That Uses It

public class Button
{
    public ButtonClickHandler OnClick;

    public void Click()
    {
        OnClick?.Invoke("Button was clicked!");
    }
}

Step 3: Use It in Your App

class Program
{
    static void Main()
    {
        var button = new Button();
        button.OnClick = LogMessage;

        button.Click();
    }

    static void LogMessage(string msg)
    {
        Console.WriteLine(msg);
    }
}

Why Is This Useful?

• Allows loose coupling — your Button class doesn't need to know what LogMessage does.
• Encourages reusability and testability.
• Forms the basis of event-driven programming in .NET.

Bonus: Use with event Keyword

To follow proper event conventions, use event:

public event ButtonClickHandler OnClick;

This prevents external classes from invoking the delegate directly.

Final Thoughts

Delegates are a core part of C#. Whether you're handling button clicks or building custom event systems, understanding how they work can level up your .NET skills.

Stay tuned for more C# tips and patterns. Happy coding!