Definition:
Object-oriented programming (OOP) is a programming paradigm that uses "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction, encapsulation, modularity, polymorphism, and inheritance.
Example:
Assume that we want to keep track of all our contacts. In order to do that, we'll have to describe a contact object as a class that has certain properties (qualities) and methods (behaviors). For example, if we want to track each contact's name, phone number and birthday information, we should create a property for each of those attributes in our contact class (see below) and initialize them prior to instantiating the contact object:
Public Class contact
Private pFirstName As String
Private pLastName As String
Private pPhone As String
Private pDateOfBirth As DateTime
Public Property FirstName() As String
Get
Return pFirstName
End Get
Set(ByVal value As String)
pFirstName = value
End Set
End Property
Public Property LastName() As String
Get
Return pLastName
End Get
Set(ByVal value As String)
pLastName = value
End Set
End Property
Public Property PhoneNumber() As String
Get
Return pPhone
End Get
Set(ByVal value As String)
pPhone = value
End Set
End Property
Public Property DateOfBirth() As DateTime
Get
Return pDateOfBirth
End Get
Set(ByVal value As DateTime)
pDateOfBirth = value
End Set
End Property
Public Sub New()
LastName = String.Empty
FirstName = String.Empty
PhoneNumber = String.Empty
DateOfBirth = DateTime.MinValue
End Sub
End Class
Now that we have defined the different properties of our contact object, we can begin describing the different methods/functions that we will use with our contact object. One thing that we'll want to be able to do is to look up information of a specific contact. In order to do that, we'll have to add an additional property to our contact object that will uniquely identify that specific contact. We'll name that property ContactId and make it an Integer and initialize it to 0 in the constructor:
Private pContactId As Integer
Public Property ContactId() As Integer
Get
Return pContactId
End Get
Set(ByVal value As Integer)
pContactId = value
End Set
End Property
Public Sub New()
LastName = String.Empty
FirstName = String.Empty
PhoneNumber = String.Empty
DateOfBirth = DateTime.MinValue
ContactId = 0
End Sub
Public Function GetContactInfo(ByVal ContactId As Integer) As contact
'Code that retrieves the information and then returns the contact object goes here
End Function
Happy Coding!