static void Main(string[] args)
{
// Test Casting
// Person(base) casting to Employee(sub Class) is not ok
int a = 100;
WriteLine("INT type:{0}", a.GetType().Name);
Person edwardInPerson = new Person {
Name = "Edward"
};
if (edwardInPerson is Employee)
{
Employee edwardInEmployee = (Employee)edwardInPerson;
}
else
{
WriteLine("EdwardInPerson is Not Employee, is {0}", edwardInPerson.GetType());
}
Employee YvonneInEmployee = new Employee {
Name = "Alice", EmployeeCode = "AA123"
};
if (YvonneInEmployee is Employee)
{
Person YvonneInPerson = YvonneInEmployee; // Employee casting to Person is ok
WriteLine("YvonneInPerson is {0}", YvonneInPerson.GetType());
WriteLine("YvonneInEmployee is {0}", YvonneInEmployee.GetType());
if (YvonneInPerson is Employee)
{
WriteLine("YvonneInPerson is actually Employee!");
Employee explicitYvonneInPersonToEmployee = (Employee)YvonneInPerson;
}
}
else
{
WriteLine("YvonneInEmployee is Not Employee, is {0}", edwardInPerson.ToString());
}
var harry = new Person {
Name = "Harry"
};
var mary = new Person {
Name = "Mary"
};
var jill = new Person {
Name = "Jill"
};
var may = new Person {
Name = "May"
};
// call instance method
var baby1 = mary.ProcreateWith(harry);
baby1.Name = "Gary";
// call static method
var baby2 = Person.Procreate(harry, jill);
WriteLine($"{harry.Name} has {harry.Children.Count} children.");
WriteLine($"{mary.Name} has {mary.Children.Count} children.");
WriteLine($"{jill.Name} has {jill.Children.Count} children.");
for (int i = 0; i < harry.Children.Count; i++)
{
WriteLine(
format: "{0}'s {1} child is named \"{2}\".",
harry.Name, i, harry.Children[i].Name);
}
var baby3 = may * jill;
WriteLine($"{may.Name} has {may.Children.Count} children.");
for (int i = 0; i < jill.Children.Count; i++)
{
WriteLine(
format: "{0}'s {1} child is named \"{2}\".",
jill.Name, i, jill.Children[i].Name);
}
WriteLine($"Person Factorial 5: {may.Factorial(5)}");
// event handler: assign Event Listener
// When assigning a method to a delegate field, you should not use the simple assignment operator as we did in the preceding example, and as shown in the following code:
// harry.Shout = Harry_Shout;
// If the Shout delegate field was already referencing one or more methods, by assigning a method, it would replace all the others. With delegates that are used for events
// we usuallywant to make sure that a programmer only ever uses either the += operator or the -= operator to assign and remove methods:
harry.Shout += Harry_Shout;
harry.Shout += Harry_Shout;
harry.Shout += Harry_Shout;
harry.Shout -= Harry_Shout;
harry.Poke();
harry.Poke();
harry.Poke();
harry.Poke();
// -----------------------------------
// test coommon interface[Icomparable/Icompare] by Array.Sort
// -----------------------------------
Person[] people =
{
new Person {
Name = "Simon"
},
new Person {
Name = "Jenny"
},
new Person {
Name = "Adam"
},
new Person {
Name = "Richard"
}
};
WriteLine("Initial list of people:");
foreach (var person in people)
{
WriteLine($" {person.Name}");
}
WriteLine("Use Person's IComparable implementation to sort:");
Array.Sort(people);
foreach (var person in people)
{
WriteLine($" {person.Name}");
}
for (int idx = 0; idx < people.Length; idx++)
{
WriteLine($" {people[idx].Name}");
}
WriteLine("Use PersonComparer's IComparer implementation to sort:");
Array.Sort(people, new PersonComparer());
foreach (var person in people)
{
WriteLine($" {person.Name}");
}
// Defining interfaces with default implementations
var dvdplayer = new DvdPlayer();
dvdplayer.Play();
dvdplayer.Pause();
dvdplayer.Stop();
dvdplayer.Error();
dvdplayer.Error2();
var odvdplayer = new DvdPlayerOld();
odvdplayer.Play();
odvdplayer.Pause();
odvdplayer.Stop();
odvdplayer.Error();
// ----------------------------
// test generics Type:
// ----------------------------
// Note the following:
// • When instantiating an instance of a generic type, the developer must pass a
// type parameter. In this example, we pass int as the type parameter for gt1 and
// string as the type parameter for gt2, so wherever T appears in the GenericThing
// class, it is replaced with int and string.
// • When setting the Data field and passing the input parameter, the compiler
// enforces the use of an int value, such as 42, for
// ----------------------------
var gt1 = new GenericThing <int> {
Data = 42
};
WriteLine($"GenericThing with an integer: {gt1.Process(42)}");
var gt2 = new GenericThing <string>();
gt2.Data = "apple";
WriteLine($"GenericThing with a string: {gt2.Process("apple")}");
string number1 = "4.5";
WriteLine("{0} squared is {1}",
arg0: number1,
arg1: Squarer.Square <string>(number1));
byte number2 = 3;
WriteLine("{0} squared is {1}",
arg0: number2,
arg1: Squarer.Square(number2));
// ----------------------------------
// test struct
// ----------------------------------
var dv1 = new DisplacementVector(3, 5);
var dv2 = new DisplacementVector(-2, 7);
var dv3 = dv1 + dv2;
WriteLine($"({dv1.X}, {dv1.Y}) + ({dv2.X}, {dv2.Y}) = ({dv3.X},{dv3.Y})");
// ----------------------------------
// test Inheriting from classes
// ----------------------------------
Employee john = new Employee {
Name = "John Jones",
DateOfBirth = new DateTime(1990, 7, 28)
};
WriteLine(format: "employee {0}'s birthdate is {1:dddd,dd/MM/yy}", john.Name, john.DateOfBirth);
john.EmployeeCode = "JJ001";
john.HireDate = new DateTime(2014, 11, 23);
WriteLine($"{john.Name} was hired on {john.HireDate:dd/MM/yy}");
john.WriteToConsole();
WriteLine("==============================");
WriteLine("Testing polymorphic");
WriteLine("==============================");
Person pMike = new Person();
Employee aliceInEmployee = new Employee {
Name = "Alice", EmployeeCode = "AA123"
};
// implicit casting
Person aliceInPerson = aliceInEmployee;
// When a method is hidden with new, the compiler is not smart enough to know that the object is an Employee, so it calls the WriteToConsole method in Person.
aliceInEmployee.WriteToConsole();
aliceInPerson.WriteToConsole();
// When a method is overridden with virtual and override, the compiler is smart enough to know that although the variable is declared as a Person class, the object itself is an Employee class and, therefore, the Employee implementation of ToString is called.
WriteLine($"Person ToString():{pMike.ToString()}");
WriteLine($"aliceInEmployee ToString():{aliceInEmployee.ToString()}");
WriteLine($"aliceInPerson ToString():{aliceInPerson.ToString()}");
WriteLine("==============================");
WriteLine("Testing casting");
WriteLine("==============================");
// checking type before casting using "is"
if (aliceInPerson is Employee)
{
WriteLine($"{nameof(aliceInPerson)} IS an Employee");
Employee explicitAlice = (Employee)aliceInPerson;
explicitAlice.WriteToConsole();
}
else
{
WriteLine($"{nameof(pMike)} is NOT an Employee");
}
// checking type before casting using "is"
if (pMike is Employee)
{
WriteLine($"{nameof(pMike)} IS an Employee");
Employee explicitMike = (Employee)pMike;
explicitMike.WriteToConsole();
}
else
{
WriteLine($"{nameof(pMike)} is NOT an Employee");
}
// checking type before casting using "as"
WriteLine("*** checking type before casting using 'is'");
Employee aliceAsEmployee = aliceInPerson as Employee;
if (aliceAsEmployee != null)
{
WriteLine($"{nameof(aliceInPerson)} AS an Employee");
}
else
{
WriteLine($"{nameof(aliceInPerson)} NOT as an Employee");
}
// checking type before casting using "as"
WriteLine("*** checking type before casting using 'as'");
Employee mikeAsEmployee = pMike as Employee;
if (mikeAsEmployee != null)
{
WriteLine($"{nameof(pMike)} AS an Employee");
}
else
{
WriteLine($"{nameof(pMike)} NOT as an Employee");
}
try
{
john.TimeTravel(new DateTime(1999, 12, 31));
john.TimeTravel(new DateTime(1950, 12, 25));
}
catch (PersonException ex)
{
WriteLine(ex.Message);
}
try
{
john.TimeTravel2(new DateTime(1999, 12, 31));
john.TimeTravel2(new DateTime(1950, 12, 25));
}
catch (Exception ex)
{
WriteLine(ex.Message);
}
WriteLine("===================================");
WriteLine("Testing Extending types when you can't inherit");
WriteLine("===================================");
string email1 = "*****@*****.**";
string email2 = "ian&test.com";
WriteLine("*** Using static methods to reuse functionality");
WriteLine(format: "{0} is a valid e-mail address: {1}",
arg0: email1,
arg1: StringExtensions.IsValidEmail(email1));
WriteLine(format: "{0} is a valid e-mail address: {1}",
arg0: email2,
arg1: StringExtensions.IsValidEmail(email2));
WriteLine("*** Using extension methods to reuse functionality");
WriteLine(format: "{0} is a valid e-mail address: {1}",
arg0: email1,
arg1: email1.IsValidEmail());
WriteLine(format: "{0} is a valid e-mail address: {1}",
arg0: email2,
arg1: email2.IsValidEmail());
}