Use of delegate in c#
C-Sharp Delegates References To Methods Delegates are like C++ function pointers, but delegates are fully object-oriented.
Delegate is used to pass methods as arguments to another methods of an class.
you might also visit: C-Sharp Func Delegate
A delegate is a type, which represents references to methods with a particular parameter list and return type.
Lets take an example to understand delegate, First of all we declare delegate, then assign a variable to delegate and pass this variable as an argument to a method. Delegates are object-oriented and type-safe.
Use of delegate in c#
1). Most important use of delegate is you can pass methods as an parameters to an event or method.
2). you can use delegate for defining callback methods.
3). you can make a chin of delegates like passing different methods to an single event.
4). you can encapsulate both an object instance and a method by using delegates.
Declaring delegate
delegate int Calculate(int a, int b);
Delegate definitions
public class Calc
{
public int Add(int x, int y) => (x + y);
public int Subs(int x, int y) => (x - y);
public int Multiply(int x, int y) => (x * y);
public int Divide(int x, int y) => (x / y);
}
Create Class Object to pass class methods as an argument
Calc c = new Calc();
Delegate variable and passing class method as an argument
Calculate cc = new Calculate(c.Add);
Invoke delegate methods
Console.WriteLine(cc(102, 34));
Complete Program:
using System;
namespace SWClass
{
// delegate Declaration
delegate int Calculate(int a, int b);
// delegate definition
public class Calc
{
public int Add(int x, int y) => (x + y);
public int Subs(int x, int y) => (x - y);
public int Multiply(int x, int y) => (x * y);
public int Divide(int x, int y) => (x / y);
}
class Program
{
static void Main(string[] args)
{
Calc c = new Calc();
// Delegate variable
Calculate cc = new Calculate(c.Add);
// Invoke delegate methods
Console.WriteLine(cc(102, 34));
cc = new Calculate(c.Subs);
Console.WriteLine(cc(102, 34));
cc = new Calculate(c.Multiply);
Console.WriteLine(cc(102, 34));
cc = new Calculate(c.Divide);
Console.WriteLine(cc(102, 34));
Console.ReadKey();
//Returns 136 68 3468 3
}
}
}
Why use delegate in c#?
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