This document provides guidance on using inheritance in C# and ASP.NET. It includes an example to demonstrate inheritance by creating Parent and Child classes, with the Child class inheriting from the Parent class. The example shows calling a method from the Parent class using an object of the Child class. The document also includes exercises for learners to practice inheritance by creating Polygon and Square classes, with Square inheriting from Polygon. Learners are asked to display a string showing the number of sides for different polygon types.

1. A Programme Under the compumitra Series
Programming Primer - INHERITANCE
LAB WORK GUIDE
1

2. OUTLINE
Inheritance Using C# in asp.net
A Parent-Child Class Example.
Example Explanation.
Home Exercise.
Summary
2

3. Inheritance
Using C# in asp.net
3

4. InheritanceCS -Web Site Creation-1
From Start Page Click New Website and reach this screen
2. Select 'ASP.NET Empty Web Site'
3. Select Location=File System
4. Click 'Browse..' tab to
select the location where
you want to save your Web
Site
5. click 'OK'
1. Select Language=Visual C#
 By default Your Web Site shall be saved in the Location- "C:Documents and
SettingsMy DocumentsVisual Studio 2008WebSites." Change it to
 "C:Learner<student-id>ProgrammingPrimerInheritanceCS" folder4

5. InheritanceCS -Web Site Creation-2
In the Solution Explorer Window
Select the path -> Right click ->
Add New Item…
5

6. InheritanceCS -Web Site Creation-3 'Add New Item' dialog box will open
1. Select 'Web Form'
2. Simply Click on
'Add' button
6

7. InheritanceCS – Creating a Button to create an event handler
2. Set the 'Text' Property
equal to 'Inheritance'
1. Select and Drag and Drop
'Button' in div
7

8. InheritanceCS – Creating Output Display Placeholders Using Label
4. Set the 'Text' Property
equal to 'Blank'
1. Press 'Enter' key to bring the
cursor one line below.
2. Select and Drag and Drop
Two 'Labels' in div
Like 'Label1', Set the 'Text Property' of 'Label2'.
3. Select the 'label1'
8

9. InheritanceCS – Copy Code-1
Child c = new Child();
string n;
n = c.C1();
Label1.Text = n;
string m;
m = c.P1();
Label2.Text = m;
Copy this Code
9

10. InheritanceCS -Paste Code-1
Go to 'Default.aspx.cs' by double clicking on
'Button' ('Inheritance' Button)
of 'Default.aspx' and
'Paste' the Code in 'Button1_Click' handler.
Child c = new Child();
string n;
n = c.C1();
Label1.Text = n;
string m;
m = c.P1();
Label2.Text = m;
10

11. InheritanceCS – Copy Code -2
public class Parent
{
string s;
public string P1()
{
s = "Parent P1";
return s;
}
}
public class Child : Parent
{
string r;
public string C1()
{
r = "Child C1";
return r;
}
}
Copy this Code
11

12. InheritanceCS - Paste Code-2
Run Code By
pressing 'F5'
'Paste' code after the End
of '_Default' class
public class Parent
{
string s;
public string P1()
{
s = "Parent P1";
return s;
}
}
public class Child : Parent
{
string r;
public string C1()
{
r = "Child C1";
return r;
}
}
Child c = new Child();
string n;
n = c.C1();
Label1.Text = n;
string m;
m = c.P1();
Label2.Text = m;
12

13. InheritanceCS -Output
Click on
'Inheritance'
button.
Output on browser
Output after clicking 'Inheritance' button.
Output from 'P1 Function' of
'Parent' class, although called
using a child class object.
Output from 'C1
Function' of 'Child' class
13

14. public partial class _Default : System.Web.UI.Page
{
protected void Button1_Click(object sender, EventArgs e)
{
Child c = new Child();
string n;
n = c.C1();
Label1.Text = n;
string m;
m = c.P1();
Label2.Text = m;
}
}
public class Parent
{ string m;
public string P1()
{ m = "Parent P1" ;
return m;
}
}
public class Child : Parent
{ string r;
public string C1()
{ r = "Child C1";
return r;
}
}
InheritanceCS - Example Explanation -1
This is 'Child' class, which 'Inherits'
'Parent' class and has 'C1' function
This is 'Parent' class, which has
'P1' function.
This statement creates the
object 'c' of 'Child' class.
This statement uses the object 'c' of 'Child'
class but using a method in 'parent' class.
This is possible due to INHERITANCE.
This statement uses the object 'c' of 'Child'
class using a method in 'Child' class itself.
This is normal usage.
14

15. public partial class _Default : System.Web.UI.Page
{
protected void Button1_Click(object sender, EventArgs e)
{
Child c = new Child();
string n;
n = c.C1();
Label1.Text = n;
string m;
m = c.P1();
Label2.Text = m;
}
}
public class Parent
{ string m;
public string P1()
{ m = "Parent P1" ;
return m;
}
}
public class Child : Parent
{ string r;
public string C1()
{ r = "Child C1";
return r;
}
}
InheritanceCS- Example Explanation - 2
This is 'C1' function of 'Child' class.
This statement 'returns' the value
of 'r'.
This statement calls the function 'C1' of
'Child' class and stores returned value in 'n'
which is output in next line as "Child C1"
This statement calls the function 'P1' of 'Child'
class and stores returned value in 'm' which is
output in next line as "Parent P1"
This is 'P1' function of 'Parent' class.
15

16. InheritanceCS- Example Explanation - 3
'n=c.C1( )' statement calls the function 'C1' of
'Child' class.
'm=c.P1( )' statement calls the function 'P1' of
'Parent' class. This is actually done using a child
class object.
16

17. InheritanceCS: Home Exercise
 Write a program similar to the example given which can demonstrate
two classes "polygon" and a child class "square". From the main routine,
Use class "polygon" to return the string "sides" and use class "square" to
return the string "4".
Finally display the string, "I am a polygon called square, I have 4 sides".
Remember that the program should be based on INHERITANCE.
 You can further extend this program where a user inputs the name of a
polygon and based on user's provided name the program returns number
of sides. For example input triangle to return "3 sides" and square to
return "4 sides".
 Modify any of these programs to test whether a parent class object can use
methods or properties from child class.
17

18. InheritanceCS : Learning Summary Review
Concept of Inheritance
Child class inherits properties of parent class.
Objects created from child class can always use
methods and properties from parent class. (The
reverse is not true).
Programming techniques to create classes,
and subclasses.
Programming techniques to return values.
Programming techniques to concatenate
strings.
18

19. Ask and guide me at
sunmitraeducation@gmail.com
Share this information with as
many people as possible.
Keep visiting www.sunmitra.com
for programme updates.
19