OOP Class9
Contents
Encapulation
I forgot to show this earlier
http://iam.colum.edu/oop/browser/browser.aspx?f=/classsource/class4/DogBark
PolyMorphism
Using the least specific class to increase reuse.
Review Coins
?'s
Review MotorVehicle
?'s
Motorvehicle Diagram
http://iam.colum.edu/oop/browser/browser.aspx?f=/classsource/class7/MotorvehicleRace
Private instance data members - accessors
Microsoft has stared calling private variables with accessors Properties
Private class memebers the use get and set keyword to set and retrieve data. Get and set are known as accessor methods private members are helpful when you want to also do other things when a data member is changed or change the rutern value under certain conditions. C# Programmer's Reference - Accessors http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vclrfaccessorspg.asp. Lastly accessor also make read only and write only variables possible
<csharp>//private string color read/write private string color;
public string Color {
get { return color; } set { color = value; }
}
//private string color read only private string color;
public string Color {
get { return color; }
}</csharp>
Another property that is a good candidate for a private instance data member is the dogs age
<csharp> private string age;
public int Age {
//age can only be accessed with get there is no set accessor //age must be set with HappyBirthday() get { return age; }
}
public int HappyBirthday() {
age++; return age;
}
</csharp>
Windows forms
Events
- events from a windows form or web page are handled by event handlers. Events are raised when a user interacts with interface elements and handled by the event handlers.
http://www.csharphelp.com/archives/archive253.html
Examaple of event handlers and classes
http://iam.colum.edu/oop/MotorvehicleRace.zip
<csharp> private void button1_Click(object sender, EventArgs e)
{ Console.WriteLine("button1 Clicked"); MessageBox.Show("button1 Clicked"); }
</csharp>
Create a windows form with a button the uses your class.
<csharp> using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms;
namespace WindowsDog {
public partial class Form1 : Form { Dog fido; public Form1() { InitializeComponent(); fido = new Dog(); }
private void btnBark_Click(object sender, EventArgs e) { lblBark.Text = fido.Bark(); }
public class Dog { public string Name; // the dog's name public int Age; // the dog's age public int Weight; // the dog's weight public string BarkSound; // the sound of the dog's bark
public Dog() { BarkSound = "Woof!!!"; }
public string Bark() { return this.BarkSound; } public void Eat() { //put eat code here } } }
} </csharp>
Home Work
- Create a UML diagram of Your classes that use association, containment, and inheritance. POst an imgage of the UML on your website.
700 px wide large image 175 px thumbnail Make sure there is you name and email.
- Practice #2 alone or use Pair Programming to make tests and classes from the following UML
If you need to add any supporting methods or properties that are not on the diagram feel free.
Test Student() Jeff Meyers says hello. StudentDiagram.Student Jeff Meyers StudentID = 0000 0 Courses Test Student("Matina" , "Navratilova" ) Matina Navratilova says hello. StudentDiagram.Student Matina Navratilova StudentID = 0000 0 Courses Test Student("Dan", "Rockwood") Dan Rockwood says hello. StudentDiagram.Student Dan Rockwood StudentID = 0000 0 Courses Make Some Course CourseName: Object Oriented Programming CourseName: 36-1300 Add Course StudentDiagram.Student Dan Rockwood StudentID = 0000 5 Courses CourseName: Object Oriented Programming CourseName: 36-1300 CourseName: Media Theory and Design 1 CourseName: 36-1000 CourseName: Media Theory and Design 2 CourseName: 36-2000 CourseName: English 101 CourseName: 52-1000 CourseName: Gym 101 CourseName: 11-1111 StudentDiagram.Student Dan Rockwood StudentID = 0000 4 Courses CourseName: Object Oriented Programming CourseName: 36-1300 CourseName: Media Theory and Design 1 CourseName: 36-1000 CourseName: English 101 CourseName: 52-1000 CourseName: Gym 101 CourseName: 11-1111 StudentDiagram.Student Dan Rockwood StudentID = 0000 5 Courses CourseName: Object Oriented Programming CourseName: 36-1300 CourseName: Media Theory and Design 1 CourseName: 36-1000 CourseName: test 101 CourseName: 00-0000 CourseName: English 101 CourseName: 52-1000 CourseName: Gym 101 CourseName: 11-1111 Test Instructor StudentDiagram.Instructor Edna Krabappel FacultyID = 0000 1 Course CourseName: English 101 CourseName: 52-1000 Test Pencil StudentDiagram.Pencil.isSharp = True Dan has no pencil StudentDiagram.Pencil.isSharp = True All work and no play makes Dan a dull student. StudentDiagram.Pencil.isSharp = False All work and no play makes Dan a dull student. StudentDiagram.Pencil.isSharp = False