static void Main(string[] args)
{
MyDelegate del = new MyDelegate(display);
del("Hello C#");
MyDelegate del2 = display;
del2("Chichi");
del2.Invoke("Chima");
/*Multicast Delegate*/
MyDelegate dele = Display;
dele += Show;
dele += Screen;
dele("C# Developer");
dele -= Show;
dele("dot NET");
/*Using the GetInvocationList method to loop through the methods in a delegate*/
IntClass intClass = new IntClass();
IntDelegate intDel = intClass.Get15;
intDel += intClass.Get20;
intDel += intClass.Get30;
foreach (IntDelegate method in intDel.GetInvocationList())
{
Console.WriteLine(method());
}
/*Built in delegates: Action*/
Action action = EmptyClass.EmptyMethod;
action += EmptyClass.VoidMethod;
action();
/*Built in deledates: Action<>*/
MyClass myclass = new MyClass();
Action <string, string> devLang = myclass.Dev;
devLang("Tochukwu ", "C#");
Action <string, int> devSal = myclass.DevSal;
devSal("Tochukwu ", 33000);
/*Built in delegates: Func<> */
Func <string, string> myname = myclass.DevName;
Console.WriteLine(myname("Tochukwu Nwachukwu"));
Func <int, int, int> arithmetic = myclass.Add;
arithmetic += myclass.Subtract;
foreach (Func <int, int, int> method in arithmetic.GetInvocationList())
{
Console.WriteLine(method(10, 5));
}
/*Built in delegates: Predicate<T>*/
Predicate <int> isEven = myclass.Even;
Console.WriteLine(isEven(7));
/*Covariance*/
PersonDelegate personDel = new Student().StudentName;
Console.WriteLine(personDel("Jimi"));
/*Contravarience */
Student student = new Student {
Name = "Gomo Briam"
};
ChildDelegate childDel = student.PersonName;
childDel(student);
/*Problems with using delegates*/
Room room = new Room();
room.roomTemp = room.Alarm;
room.Temperature = 68;
//Does not display as expected but contrary to the book's expectation. I don't see the probelm here.
room.Temperature = 55;
room.Temperature = 63;
/*Anonymous methods*/
Action act = delegate()
{
Console.WriteLine("An anonymouse method of type Action");
};
Func <int, int> func = delegate(int num)
{
Console.Write("An anonymouse method of type Func<int, int> returns: ");
return(num);
};
act();
Console.WriteLine(func(33000));
/*Passing anonymous method as argument to a method.*/
room.AcceptAction(delegate()
{
Console.WriteLine("Passing anonymouse method of type Action");
});
room.AcceptFunc(delegate(int num)
{
return(num);
}, 28000);
/*Anonymouse methods using Lambda Expression*/
Action actLamb = () =>
{
Console.WriteLine("Anonymouse method of type Action using the Lambda expression");
};
Func <int, int> funcLamb = (int salary) =>
{
Console.Write("Anonymouse method of type Func<int int> using Lambda expresssion returns: int ");
return(salary);
};
actLamb();
Console.WriteLine(funcLamb(28000));;
/*Single line Lambda Expression*/
Action singleAct = () => Console.WriteLine("Single line Lambda expresion with no return value");
Func <int, int> singleFunc = (int x) => x + 1000;
singleAct();
Console.WriteLine(singleFunc(18000));
/*Anonymous methods without specifying parameter type.*/
Action <string> user = (name) => Console.WriteLine("User name is {0}", name);
Action <string> username = name => Console.WriteLine("User is {0}", name); //You may omit the parenthesis for single parameter
Func <int, int> userID = (id) => id;
user("truetochukz");
username("tochukz");
Console.WriteLine(userID(1054375));
/*Pass Lambda expression as method argument*/
room.AcceptAction(() => Console.WriteLine("Labda expression as Method argument"));
room.AcceptFunc((salary) => salary, 21000);
/*Events*/
Employee tochukwu = new Employee {
Name = "Tochukwu", Position = "senior", Salary = 32000
};
Employee tochi = new Employee {
Name = "Tochi", Position = "junior", Salary = 18900
};
Employee chuks = new Employee {
Name = "Chuks", Position = "senior", Salary = 28000
};
Company company = new Company();
company.AddSenoir += company.OnSenior;
company.AddSenoir += company.OnShowSalary;
company.AddWoker(tochukwu);
company.AddWoker(tochi);
company.AddWoker(chuks);
/*Using the built in EventHandler delegate*/
HotelRoom bigRoom = new HotelRoom {
Price = 450, Size = "big"
};
HotelRoom smallRoom = new HotelRoom {
Price = 350, Size = "small"
};
HotelRoom pricyBigRoom = new HotelRoom {
Price = 950, Size = "big"
};
HotelRoom pricyRoom = new HotelRoom {
Price = 850, Size = "medium"
};
List <HotelRoom> hotelRooms = new List <HotelRoom> {
bigRoom, smallRoom, pricyBigRoom, pricyRoom
};
Hotel hotel = new Hotel("Honey Moon Hotel");
hotel.BigRoom += hotel.OnBigSize;
hotel.ExpensiveRoom += hotel.OnExpensive;
foreach (HotelRoom hiredRoom in hotelRooms)
{
hotel.HireRoom(hiredRoom);
}
Console.ReadLine();
}
public void OnBigSize(object obj, EventArgs empty)
{
Hotel hotel = obj as Hotel;
Console.WriteLine("Hotel Name: {0}.", hotel.Name);
}