MULTICAST DELEGATE IN C#

multicast delegate

MULTICAST DELEGATE

            “A delegate holds more than one method reference and can be call by that delegate name”.

            If we have more than one method with same signature, here signature take as the same return type and same parameter accepts. Than for those methods we use multicast delegate to call all that method with one delegate name.

            In this topic we will discuss about three step to perform multicast delegate.

    1.    Defining the delegate

It is same like as delegate that’s the delegate signature should match with method

     signature except name. The multi task will perform in creating instance part.

      SYNTAX

                        [< Modifier >] delegate <return type> Name (parameter list)

    2.    Instantiating the instance of multicast delegate

The main difference between delegate and multicast delegate is going to declare here. We will create multiple method reference by using one delegate name like this.

            <Delegate name> d.name = new <delegate name> (reference method)

This syntax can be return like this

            <Delegate name> d.name = <1^st reference method>

            d.name += <2^nd reference method >

Here we use d.name for both methods and when we give one time values theses method will execute by same value see the example to clarify.

    3.    Calling the multicast delegate

It is also same like delegate calling. Calling will do in two different ways.

1^st way:   <d.name> (value1, value2… value n)         //as above mention d.name

2^nd way:  <d.name>.invoke (value1, value2… value n)

When we call one time all the linked method will execute using same values.

Points to be noted while going to perform multicast delegate

            There some points that should keep in mind when decide to make multicast delegate that’s

1.    We use multicast delegate in such a time where multi method has to execute by same values.

2.    Before using of this delegate make sure that all your methods are non-value returning type otherwise only the last method result will be shown and rest all are overwrites by the last one. If your methods are value returning type it better to use delegate instead of multicast delegate.

EXAMPLE OF MULTICAST DELEGATE IN C#

example of multicast delegate c#

            Suppose we have methods about square problem, area of square ( ) and perimeter of square ( ) are two diff. method let see how this two method execute using multicast delegate.

Delegate class namespace MulticastDeg {     public delegate void SquareForm(double Lenght); //defining delegate stage 1     class Square     {         public void AreaOfSquare(double length)         {             Console.WriteLine("area of square = " + Math.Pow(length,2));         }         public void PremOfSquare(double length)         {             Console.WriteLine("perimeter of square = " + 4*length);         }     } }

Main class namespace MulticastDeg {     class Program     {         static void Main(string[] args)         {             Square sq = new Square();             SquareForm sqf = sq.AreaOfSquare;     //creating instance stage 2             sqf += sq.PremOfSquare;              // multicasting             Console.WriteLine("enter the lenght of sqaure");             double length = double.Parse(Console.ReadLine());             sqf(length);                         //calling the delegate stage 3             Console.ReadKey();         }     } }