C# | DELEGATES

We all learned how to implement REFERENCE TYPEs using languages constructs like
 

• ·         CLASSES
• ·         REFERENCES

These references types allow programmers to create instances of objects and use them in special ways to accomplish development procedure aims.

Classes allows us to create object that contained members with attribute or the functionality. While on other hand interface allows us to declare a set of attributes and behavior that all objects implementing them can expose them publicly or privately.

Now am introducing a new reference type DELEGATE.

A delegate is a C# language element that allows programmers to reference a method for their development work. Generally C or C++ programmers are much more familiar with the concept of delegate in comparison to other.

C# DELEGATE | Features

•      Maximum Flexibility
•      Several built in functionalities at runtime
•    Manipulation of variables

C# DELEGATE | Description

Delegates provide flexibility and scalability, so that is can be used according to the requirement or goal of your development procedure. There is less boundation limits of delegates. Interfaces also can be used in place of delegates but due to some extra functionality programmers do prefer delegate in place of other reference methods.

C# DELEGATE | Declaration

Declaration of delegates is somewhat similar like methods. Except that delegate have an extra feature of delegate modifier. Delegate modifier are terminated through semi colon(;) and requires no implementation

Ex:
public delegate int Comparer(object obj1, object obj2)

C# DELEGATE | Delegate Handler

Delegate handler methods works as follows:

Public static int CompareFirstNames(object name1, object name2);

{

……

}

Reference Example:

using System;

public delegate int Comparer(object obj1, object obj2);

public class Name

{

    public string FirstName = null;

    public string LastName = null;

    public Name(string first, string last)

    {

        FirstName = first;

        LastName = last;

    }

    public static int CompareFirstNames(object name1, object name2)

    {

        string n1 = ((Name)name1).FirstName;

        string n2 = ((Name)name2).FirstName;

        if (String.Compare(n1, n2) > 0)

        {

            return 1;

        }

        else if (String.Compare(n1, n2) < 0)

        {

            return -1;

        }

        else

        {

            return 0;

        }

    }

    public override string ToString()

    {

        return FirstName + " " + LastName;

    }

}

class SimpleDelegate

{

    Name[] names = new Name[6];

    public SimpleDelegate()

    {

        names[0] = new Name("abhishek", "jaiswal");

        names[1] = new Name("ashish", "verma");

        names[2] = new Name("gopi", "chand");

        names[3] = new Name("hari", "prakash");

        names[4] = new Name("prashant", "kumar");

        names[5] = new Name("pratiyush", "anand");

    }

    static void Main(string[] args)

    {

        SimpleDelegate sd = new SimpleDelegate();

        Comparer cmp = new Comparer(Name.CompareFirstNames);

        Console.WriteLine("\nBefore Sorting: \n");

        sd.PrintNames();

        sd.Sort(cmp);

        Console.WriteLine("\nAfter Sorting: \n");

     sd.PrintNames();

    }

 

    public void Sort(Comparer compare)

    {

        object temp;

     for (int i=0; i < names.Length; i++)

        {

            for (int j=i; j < names.Length; j++)

            {

             

                if ( compare(names[i], names[j]) > 0 )

                {

                    temp = names[i];

                    names[i] = names[j];

                    names[j] = (Name)temp;

                }

            }

        }

    }

    public void PrintNames()

    {

      Console.WriteLine("Names: \n");

        foreach (Name name in names)

        {

            Console.WriteLine(name.ToString());

        }

    }

}