What is delegate and event in C#?

04/03/2019 Off By admin

What is delegate and event in C#?

A delegate is an object which refers to a method or you can say it is a reference type variable that can hold a reference to the methods. Delegates in C# are similar to the function pointer in C/C++. It provides a way which tells which method is to be called when an event is triggered.

How Use delegates and events in C#?

First, you need to define a delegate type that will hold the list of methods to be called when the event is fired. Next, you declare an event using the event keyword. To illustrate the event, we are creating a console application.

What is difference between delegate and events in C#?

Delegate is a function pointer. An event is dependent on a delegate and cannot be created without delegates. Event is a wrapper around delegate instance to prevent users of the delegate from resetting the delegate and its invocation list and only allows adding or removing targets from the invocation list.

What is delegate in EventHandler?

The delegate is a type that defines a signature, that is, the return value type and parameter list types for a method. The EventHandler delegate is a predefined delegate that specifically represents an event handler method for an event that does not generate data.

Why we go for delegates in C#?

Delegates in C# are similar to function pointers in C++, but C# delegates are type safe. Delegates are used to define callback methods and implement event handling, and they are declared using the “delegate” keyword. You can declare a delegate that can appear on its own or even nested inside a class.

Why delegates are type-safe?

A delegate is a type-safe function pointer that can reference a method that has the same signature as that of the delegate. You can take advantage of delegates in C# to implement events and call-back methods. A multicast delegate is one that can point to one or more methods that have identical signatures.

Why delegate is used in C#?

Understanding delegates in C# Delegates are used to define callback methods and implement event handling, and they are declared using the “delegate” keyword. You can declare a delegate that can appear on its own or even nested inside a class.

What are delegates in C sharp?

A delegate is a type that represents references to methods with a particular parameter list and return type. When you instantiate a delegate, you can associate its instance with any method with a compatible signature and return type. You can invoke (or call) the method through the delegate instance.

How are events and delegates related in C #?

An event is a reference to a delegate i.e. when an event is raised, a delegate is called. In C# terms, events are a special form of delegates. Events play an important part in user interfaces and programming notifications. Events and delegates work hand-in-hand to provide a communication between code from one class to other class.

Why do we use a delegate in C?

Using a delegate allows the programmer to encapsulate a reference to a method inside a delegate object. The delegate object can then be passed to code which can call the referenced method, without having to know at compile time which method will be invoked. Unlike function pointers in C or C++, delegates are object-oriented, type-safe, and secure.

Can a delegate be invoked through an event handler?

You can invoke (or call) the method through the delegate instance. Delegates are used to pass methods as arguments to other methods. Event handlers are nothing more than methods that are invoked through delegates.

How is an event declared in C #?

Events are members of a class and are declared using the event keyword. The syntax to declare an event is shown here: Here, the EventName is the name of delegate used to support an event, and EN is the name of the event object. Note: Events are based on the EventHandler delegate and the EventArgs base class.