Explanation of the creation of classes and objects in the two main languages of the .Net platform.
To explain the creation of classes we will use a simple example based on a main class “bicycle”.
To create a class we must define its properties and its methods, in this example the following terms are used as properties of the bicycle class: Model, Price, NumberOfSpeeds and Speed; as methods of the class are used: Accelerate(km) , Brake() and CheckSpeed().
vb.net
Public Class Bicycle
Public Model as String
Public Price as Double
Public NumberOfSpeeds as Integer
Private Velocity as Integer
Public Sub Speed(ByVal km As Integer)
Speed = Speed + km
End Sub
Public Sub Brake()
If Velocity > 0 Then
speed = speed -1
End If
End Sub
Public Function QuerySpeed() As Integer
Return Speed
End Function
end class
C#
Class Bicycle
{
public string Model;
public double Price;
public int NumberOfSpeeds
private int Speed
public void Speed(int km)
{
Speed = Speed + km;
}
public void Brake()
{
if (Speed > 0)
{
speed = speed – 1;
}
}
public int QuerySpeed()
{
return speed;
}
}
Our bike class consists of several properties and methods, the keywords Private and Public define the accessibility of the properties, functions or subroutines. The definition of a private type property or method indicates that it can only be used within the code of the same class, if we created a bicycle type object, the class specifications would not allow us to access the speed property to consult or modify it, since it is defined as private. On the other hand, you can use the Accelerate() and Brake() subroutines since they are of the Public type, and from within them you interact with the private properties, with this we are able to encapsulate the code and make accessible only what we want.
Once the class is built, objects of it can be instantiated.
vb.net
Dim objBike as Bike = New Bike
Dim CurrentSpeed as Integer
objBicicleta.Model = “Mountain”
objBike.Price = 200
objBike.NumberOfSpeeds = 21
objBike.Accelerate(5)
objBike.Brake()
CurrentSpeed = objBicycle.QuerySpeed
C#
Bike objBike = new Bike();
int CurrentSpeed;
objBike.Model = “Mountain”;
objBike.Price = 200;
objBike.NumberOfSpeeds = 21;
objBike.Accelerate(5);
objBike.Brake();
CurrentSpeed = objBike.QuerySpeed();
After creating the object objBicicleta from the class, you can modify the values of the properties of type Public, and call the methods of type Public.
In the example, the methods Accelerate(5) are called, passing the number of km that we want to accelerate through the “km” parameter that is defined in the subroutine.
Then the Brake() method is called, which decreases the value of the Speed property by one unit.
Finally, the function CheckVelocity() is used, which returns the value of the Velocity property to introduce it in the variable VelocidadActual.
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