using System;
class Publisher {
    public event EventHandler MyEvent;
}

public class Subscriber {

    public static void Handler(object obj, EventArgs args) {
    }

    public static void Main() {
        Publisher pub = new Publisher();
        pub.MyEvent += Handler;
        // other processing
    }
}

    

   
 

using System;

public delegate void DelegateClass();

public class Starter {
    public static void Main() {
        DelegateClass del = (DelegateClass)
        DelegateClass.Combine(new DelegateClass[] { MethodA, MethodB, MethodA, MethodB });
        del();
        foreach (DelegateClass item in
            del.GetInvocationList()) {
            Console.WriteLine(item.Method.Name + " in invocation list.");
        }
    }
    public static void MethodA() {
        Console.WriteLine("MethodA...");
    }

    public static void MethodB() {
        Console.WriteLine("MethodB...");
    }
}

    

   
 

using System;

public delegate void DelegateClass();

public class Starter {
    public static void Main(){
         DelegateClass del=MethodA;
         del+=MethodB;
         del+=MethodC;
         del=del-MethodB;
         del();
     }
    public static void MethodA() {
        Console.WriteLine("MethodA...");
    }

    public static void MethodB() {
        Console.WriteLine("MethodB...");
    }

    public static void MethodC() {
        Console.WriteLine("MethodC...");
    }
}

    

   
 

using System;

public delegate void Task();

public class Starter {
    public static void Main() {
        Task[] tasks = { MethodA, MethodB, MethodC };
        string resp;
        tasks[0]();
        tasks[1]();
        tasks[2]();
    }

    public static void MethodA() {
        Console.WriteLine("Doing TaskA");
    }

    public static void MethodB() {
        Console.WriteLine("Doing TaskB");
    }

    public static void MethodC() {
        Console.WriteLine("Doing TaskC");
    }
}

    

   


using System;

public class DelegatesMulticasting
{
    delegate void ProcessHandler(string message);
    
    static public void Process(string message)
    {
        Console.WriteLine("Test.Process("{0}")", message);
    }
    public static void Main()
    {
        User user = new User("George");
        
        ProcessHandler ph = new ProcessHandler(user.Process);
        ph = (ProcessHandler) Delegate.Combine(ph, new ProcessHandler(Process));
        
        ph("Wake Up!");        
    }
}
public class User
{
    string name;
    public User(string name)
    {
        this.name = name;
    }    
    public void Process(string message)
    {
        Console.WriteLine("{0}: {1}", name, message);
    }
}



           
          

   


using System;

public class DelegatestoInstanceMembers
{
    delegate void ProcessHandler(string message);
    
    public static void Main()
    {
        User aUser = new User("George");
        ProcessHandler ph = new ProcessHandler(aUser.Process);
        
        ph("Wake Up!");        
    }
}

public class User
{
    string name;
    public User(string name)
    {
        this.name = name;
    }    
    public void Process(string message)
    {
        Console.WriteLine("{0}: {1}", name, message);
    }
}

           
          

/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress L.P.
ISBN: 1-893115-62-3
*/
// 22 – DelegatesUsing Delegates
// copyright 2000 Eric Gunnerson
using System;

public class DelegatesUsingDelegates
{
public static void Main()
{
Container employees = new Container();
// create and add some employees here

// create delegate to sort on names, and do the sort
Container.CompareItemsCallback sortByName =
new Container.CompareItemsCallback(Employee.CompareName);
employees.Sort(sortByName);
// employees is now sorted by name
}
}

public class Container
{
public delegate int CompareItemsCallback(object obj1, object obj2);
public void Sort(CompareItemsCallback compare)
{
// not a real sort, just shows what the
// inner loop code might do
int x = 0;
int y = 1;
object item1 = arr[x];
object item2 = arr[y];
int order = compare(item1, item2);
}
object[] arr = new object[1]; // items in the collection
}
public class Employee
{
Employee(string name, int id)
{
this.name = name;
this.id = id;
}
public static int CompareName(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;
return(String.Compare(emp1.name, emp2.name));
}
public static int CompareId(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;

if (emp1.id > emp2.id)
return(1);
if (emp1.id < emp2.id) return(-1); else return(0); } string name; int id; } [/csharp]