·
What
is Class?
In object-oriented programming,
Class is a category of objects or we can say group name. For example, there might be
a class called shape that contains objects which are circles, rectangles, and triangles. The
class defines all the common properties of the different objects that belong to
it.
Simply, A set or
category of things having some property or attribute in common and
differentiated from others by kind, type, or quality.
One other
example, a class named Animal
Contains Cat, Dog, Donkey etc.
In the real
world, you'll often find many individual objects all of the same kind. There
may be thousands of other bicycles in existence, all of the same make and
model. Each bicycle was built from the same set of blueprints and therefore
contains the same components. In object-oriented terms, we say that your
bicycle is an instance of the class of objects known as bicycles. A class is
the blueprint from which individual objects are created.
In .NET languages,
Classes are
templates used for defining new types.
Classes describe both the properties and
behaviors of objects.
Properties
contain the data that are exposed by the class.
Behaviors are the
functionality of the object, and are defined by the public methods (also called
member functions) and events of the class.
Collectively, the
public properties and methods of a class are known as the object interface.
Classes themselves are not objects, but instead they are used to instantiate
(i.e., create) objects in memory.
·
What
is Object?
An object
doesn't exist until an instance of the class has been created; the class is
just a definition. When the object is physically created, space for that object
is allocated in RAM. It is possible to have multiple objects created from one
class.
Let’s take one
basic example for full guide of class and object.
The basic
building blocks of object-oriented programming are the class and the object. A
class defines the available characteristics and behaviour of a set of similar
objects and is defined by a programmer in code.
A class is an abstract definition that is
made concrete at run-time when objects
based upon the class are instantiated and take on the class's behaviour.
As an analogy,
let's consider the concept of a 'vehicle'
class. The class developed by a programmer would include methods such as Steer(),
Accelerate() and Brake(). The class would also include properties such as Colour, NumberOfDoors, TopSpeed and NumberOfWheels.
The class is an abstract design that becomes real when objects such as Car, RacingCar, Tank and Tricycle are created, each
with its own version of the class's methods and properties.
Now we going to view how class
created and work in asp.net application.
First open any website. Let in my
case it is ClassAndObject
Right click on WebApplication1 from
solution explorer and Click on Add->and Class. And provide class name Here I
provided ‘Vehicle’.
Here you can see I already
created class Vehicle and it is in new
Vehicle.cs file.
frmVehicle.axpx code file
<%@ Page
Language="C#"
AutoEventWireup="true"
CodeBehind="frmVehicle.aspx.cs"
Inherits="WebApplication1.frmVehicle"
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD
XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td>
Property of
</td>
<td>
<asp:DropDownList ID="DropDownList1"
runat="server"
AutoPostBack="True"
onselectedindexchanged="DropDownList1_SelectedIndexChanged">
<asp:ListItem>Car</asp:ListItem>
<asp:ListItem>RacingCar</asp:ListItem>
<asp:ListItem>Tank</asp:ListItem>
<asp:ListItem>Tricycle</asp:ListItem>
</asp:DropDownList>
</td>
<td>
</td>
</tr>
<tr>
<td>Value of
Obj.Colore=</td>
<td>
<asp:Label ID="Label1" runat="server"
Text="Label"></asp:Label>
</td>
</tr>
<tr>
<td>Value of
Obj.NumberOfDoors=</td>
<td>
<asp:Label ID="Label2" runat="server"
Text="Label"></asp:Label>
</td>
</tr>
<tr>
<td>Value of
Obj.NumberOfWheels=</td>
<td>
<asp:Label ID="Label3" runat="server"
Text="Label"></asp:Label>
</td>
</tr>
<tr>
<td>Value of
Obj.TopSpeed=</td>
<td>
<asp:Label ID="Label4" runat="server"
Text="Label"></asp:Label>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
frmVehicle.aspx.cs file
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class frmVehicle :
System.Web.UI.Page //This is the
frmVehicle class inherited from System.Web.UI.Page class
{
//By defult created at the time of new page
create in Asp.Net
Vehicle Obj=new Vehicle(); //Here I created one new Object named Obj of Vehicle class
protected void
Page_Load(object sender, EventArgs e)
{
Obj.MethodVehicleClass(this); //Calling method of
Vehicle class using Object 'Obj.MethodName()'
DropDownList1_SelectedIndexChanged(sender, e);
}
protected void
DropDownList1_SelectedIndexChanged(object
sender, EventArgs e)
{
Vehicle Car = new Vehicle(); //Here I
created one new Object named Car of Vehicle class
Car.Colore = "Red";
Car.NumberOfDoors = 2;
Car.NumberOfWheels = 4;
Car.TopSpeed = "60Mph";
Vehicle
RacingCar = new Vehicle();//Here I created one new Object named RacingCar of Vehicle
class
RacingCar.Colore = "Yellow";
RacingCar.NumberOfDoors = 0;
RacingCar.NumberOfWheels = 4;
RacingCar.TopSpeed = "200Mph";
Vehicle Tank = new
Vehicle(); //Here
I created one new Object named Tank of Vehicle class
Tank.Colore = "Green";
Tank.NumberOfDoors = 1;
Tank.NumberOfWheels = 12;
Tank.TopSpeed = "40Mph";
Vehicle Tricycle = new
Vehicle();//Here I
created one new Object named Tricycle of Vehicle class
Tricycle.Colore = "Orange";
Tricycle.NumberOfDoors = 0;
Tricycle.NumberOfWheels = 2;
Tricycle.TopSpeed = "50Mph";
switch (DropDownList1.SelectedValue.ToString())
{
case "Car":
Obj = Car;
break;
case "RacingCar":
Obj = RacingCar;
break;
case "Tank":
Obj = Tank;
break;
case "Tricycle":
Obj = Tricycle;
break;
}
Label1.Text = Obj.Colore;
Label2.Text = Obj.NumberOfDoors.ToString();
Label3.Text = Obj.NumberOfWheels.ToString();
Label4.Text = Obj.TopSpeed;
}
}
}
Vehicle.cs file
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
namespace WebApplication1
{
public class Vehicle //Class created by me with name Vehicle which will access
by other class frmVehicle class.
{
public string
Colore; //public
beacuse to access from out side of class
public int
NumberOfDoors;
public int
NumberOfWheels;
public string
TopSpeed;
public void
MethodVehicleClass(System.Web.UI.Page
VehPage)
{
VehPage.Response.Write("Hi I am Vishal
Hirpara and this Message is printed by method of Vehicle class from frmVehicle
class's PageLoad method");
VehPage.Response.Write("<br>
------------------------");
}
}
}
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