How to implementation OOP concept with C#

1. Object-Oriented
Programming
Pakorn Weecharungsan

2. Contents
 Introduction to Object-Oriented
Programming
 Defining Classes
 Defining Class Members

3. Object-Oriented Concept
 Class
 Instance
 Method
 Inheritance
 Abstraction
 Encapsulation
 Polymorphism

4. Programs and Classes

5. Declaring a class
 The class name
 Bank
 The members of the class
 Fields
 BankName
 Methods
 GetAccounts
 The characteristics of the class
 Public or Private

6. Declaring a class

7. Class Members
 Fields – A field is variable that belongs to
a class
It can be any type, either predefined or user-
defined
Like all variables, fields store data, and have
the following characteristics
 They can be written to
 They can be read from

8. Class Members
 Syntax
 Example

9. Class Members
 Methods - A method is a named block of
executable code that can be executed fro
m many different parts of the program, an
d even from other programs
Return type
Name
Parameter list
Method body

10. Class Members

11. Creating Variables and Instances of
a Class

12. Access Modifiers
 private
 public
 protected
 internal
 protected internal

13. Access Modifiers

14. Access Modifiers
 Private Access - Private members are only accessible
from within the class in which they are declared-other
classes cannot see or access them
 Private access is the default access level-so if a
member is declared without an access modifier, it is a
private member

15. Access Modifiers
 Public Access - Public members are accessible to all
other objects in the program. You must use the public ac
cess modifier to specify public access

16. Access Modifiers

17. Accessing Members from Inside
the Class

18. Accessing Members from Outside
the Class

19. Putting It All Together

20. Methods
 The method header
 The method body

21. Method Invocations

22. Return Value

23. The Return Statement and Void
Methods

24. Parameters

25. Value Parameters

26. Reference Parameters

27. Parameter Arrays

28. Method Overloading
 The name of the method
 The number of parameters
 The data types and order of the
parameters

29. Method Overloading

30. Properties

31. Instance Constructors

32. Destructors

33. Classes and Inheritance
 Class Inheritance
 Accessing the Inherited Members
 Member Access Modifiers

34. Class Inheritance

35. Accessing the Inherited Members

36. Member Access Modifiers
 public
 All classes both inside and outside the assembly have
free access to the member
 private
 A private class member can be accessed only by
members of its own class. It cannot be accessed by
other classes, including classes that are derived from
it
 A private member can, however, be accessed by
members of classes nested in its class

37. Member Access Modifiers
 protected
The protected access level is like the private
access level, except that it allows classes
derived from the class to access the member
 internal
Members marked internal are visible to all the
classes in the assembly, but not to classes
outside the assembly

38. Member Access Modifiers
 protected internal
Members marked protected internal are
visible to all the classes that inherit from the cl
ass, and also to all classes inside the assembl
y

39. Summary of Member Access
Modifiers

40. Summary of Member Access
Modifiers