Chapter 5

Completed the Practice Test
Got 2 wrong

UML & VB/Net Open File Dialog

UML Class Diagram & VB.NET OpenFileDialog
A class diagram in the Unified Modeling Language (UML), is a type of static structure dagram that describes the structure of a system by showing the system's classes, their attributes, and the relationships between the classes.OpenFileDialog: This class lets you do the following tasks:Enable users to select one or more files on the local computer or on a networked computer.Filter the file types shown in the dialog box.Specify which filter is used when the dialog box is first displayed.

Classes & Objects - in class

Tuesday 24th March 2009

Things to remember:

Properties: things Button has
Methods: things Button does

New Class = Constructor of the Class (every Method has)

Today we started construction for "Dog and Cat"

C4 Programming 23/3/09

Blog Task

Classes are types and Objects are instances of the Class.
Classes and Objects are very much related to each other.
Without objects you can't use a class.

In Visual Basic we create a class with the Class statement and end it with End Class.
The Syntax for a Class looks as follows:

Public Class Test
-----Variables
-----Methods
-----Properties
-----EventsEnd Class

The above syntax created a class named Test.
To create a object for this class we use the new keyword and that looks like this:
Dim obj as new Test().

The following code shows how to create a Class and access the class with an Object.

Sub Main()
Dim obj As New Test()
'creating a object obj for Test class
obj.disp()
'calling the disp method using obj
Read()

End Sub

End Module

Public Class Test
'creating a class named Test
Sub disp()
'a method named disp in the class
Write("Welcome to OOP")
End Sub
End Class

Fields, Properties, Methods, and Events are members of the class.
They can be declared as Public, Private, Protected, Friend or Protected Friend.
Fields and Properties represent information that an object contains.
Fields of a class are like variables and they can be read or set directly.
For example, if you have an object named House, you can store the numbers of rooms in it in a field named Rooms. It looks like this:

Public Class House
Public Rooms as Integer
End Class

Properties are retrieved and set like fields but are implemented using Property Get and Property Set procedures which provide more control on how values are set or returned.

Methods represent the object’s built-in procedures.
For example, a Class named Country may have methods named Area and Population.
You define methods by adding procedures, Sub routines or functions to your class.

For example, implementation of the Area and Population methods discussed above might look like this:

Public Class Country
Public Sub Area()
Write("--------")
End Sub
Public Sub population()
Write("---------")
End Sub
End Class

Events allow objects to perform actions whenever a specific occurrence takes place.
For example when we click a button a click event occurs and we can handle that event in an event handler.

Horoscope

We learned how to use a Combo Box today and did the Horoscope

I worked out how to have the "Please Select..." text to initially show on the Combo Box without having to scroll to it.

Almost finished the Parking Fines

Visual Studio 23/3/09

Finished the Wood Cabinet Estimate
and started on the Parking Ticket Fines
still finding it difficult to remember the coding
understanding the designs easier

If Statements

Learning If Statements today - understand the theory - got to get the practical right