Delegate C#

Can Be Used

The preceding delegate can be used to reference any method that has a single string parameter and returns an int type variable

Following example demonstrates declaration instantiation and use of a delegate that can be used to reference methods that take an integer parameter and returns an integer value

The delegate printString can be used to reference method that takes a string as input and returns nothing

The Print delegate shown above can be used to point to any method that has same return type & parameters declared with Print

Be Invoked

An instantiated delegate can be invoked as if it were the wrapped method itself

You don't want to evaluate the code now but only when needed so you register a delegate that can be invoked when the event occurs

The delegate can be invoked like a method because it is a reference to a method

The delegate can be invoked by two ways

Be Used

The Event

The source calls the delegate when the event occurs

The delegate then calls the event handling method on the recipient delivering the event data

Whichever is appropriate you assign the delegate to the event which effectively registers the method that will be called when the event fires

String Message

public delegate void TestDelegate string message

public delegate void Del string message

} } public delegate void NotifyDelegateWithMessage string message

That Can

The following example declares a delegate named that can encapsulate a method that takes a string as an argument and returns void

To The

All the OnEventX delegate to the methods the user defines

The Method

" people IsChild is what passing and finally within if the delegate will call the method

Here delegate object encapsulates the method functionalities and returns the result as we specified in the method

Method That

The following method from Listing 14 1 shows a delegate handler method that conforms to the signature of theComparer delegate

All you really need to do is define your callback method delegate handler method that is invoked when someone presses the clickMe button

And The

For use with anonymous methods the delegate and the code to be associated with it are declared together

The "+" operator adds a function to the delegate object and the " " operator removes an existing function from a delegate object

Is A Reference

A delegate is a reference type variable that holds the reference to a method

A delegate is a reference to a method

Reference Type

Today I’m going to introduce a new reference type called adelegate

As A Parameter

This allows a method to accept a delegate as a parameter and call the delegate at some later time

@PersyJack When you pass a delegate as a parameter then your method trusts that a suitable delegate is passed and your method has no understanding of the delegate's value/logic it is decoupled

Type And

A method can have a parameter of a delegate type and can invoke the delegate parameter

It is declared with the eventkeyword a delegate type and an event name

You Can

The OnClickMeClicked method shown below conforms to the signature of the EventHandler delegate which you can look up in the

The Same

The delegate and method have the same signature and parameter type

To A Method

A delegate can refer to a method which has the same signature as that of the delegate

Static Void

private static void NotifyIfComplete { Console

Create

To use a delegate you must create an instance of it

The Code

Passed To The

When creating a delegate the argument passed to the new expression is written similar to a method call but without the arguments to the method

When The

Derived From

Because delegate types are derived from the methods and properties defined by that class can be called on the delegate

The Answer

Will you please elaborate the answer of "Why"

The Methods

The Reference

It is a delegate which holds the reference of more than one method

An Object

Because the instantiated delegate is an object it can be passed as a parameter or assigned to a property

To Call

We use this delegate to call two methods the first prints the string to the console and the second one prints it to a file

Methods The

With The

Identify the class as a delegate with the "delegate" keyword

Reference To A Method