C#- Delegates vs Events

Delegates and events are closely related concepts in C# and .NET, and they are often used together to implement the Observer design pattern. Here are the key differences between delegates and events, along with their common usage:

They allow you to select and transform data from the source collection or query into a new form. Here are some common projection operators



Delegates:

A delegate is a type that represents references to methods with a specific signature. It acts as a function pointer, allowing you to encapsulate a method and pass it around in your code.

Usage:

Delegates are used to define and work with method signatures. They are commonly used in scenarios where a callback mechanism is needed, such as in event handling or asynchronous programming.

   
  
  public delegate void MyDelegate(string message);

public class MyClass
{
    public void MyMethod(string message)
    {
        Console.WriteLine(message);
    }
}

// Usage
MyDelegate myDelegate = new MyDelegate(new MyClass().MyMethod);
myDelegate("Hello, Delegate!");

  
  
Events:
   
  

public class MyEventPublisher
{
    public event MyDelegate MyEvent;

    public void RaiseEvent(string message)
    {
        MyEvent?.Invoke(message);
    }
}

// Usage
var publisher = new MyEventPublisher();
publisher.MyEvent += (msg) => Console.WriteLine($"Event Handler: {msg}");
publisher.RaiseEvent("Hello, Event!");
  

Key Points
  • 🔾Delegate is a pointer to a fucntion and its is used for callback.A Delegate is a variable that holds the reference to a method or pointer to a method.
  • 🔾Event is a notification mechanism that depends on delegates. 🔾Event is like a wrapper over delegates to improves its security.
  • Events are encapsulation over delegates and its helps in publisher/subscriber model. functions=> Delegates => Events

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